Search

Cotton, one of the main commercial crops in the world, mostly distributes in several major growing regions, including Xinjiang of western China. An important renewable biomass resource, the cotton stalk has received most attention to serving as the poultry feed, paper making, environmental protection materials, and biomass briquette fuel. Particularly, the highly efficient recycling of cotton stalk can be widely expected to bring enormous economic and ecological benefits. However, most previous treatments are focused on pulverizing cotton stalks and returning to the field. A great challenge is still posed on the current pulling machines for cotton stalks, with emphasis on operational requirements, leakage, and breaking rate. In this study, a novel horizontal-roller cotton stalk pulling machine was proposed to efficiently implement the pulling of the whole cotton stalk after harvesting. The machine was mainly composed of traction, gearbox, stalk conveying, transmission system, machine body, road wheel, spacing regulating mechanism, stalk pulling, dam-board, and support frame. Specifically, the power input shaft of the gearbox was connected to the power output shaft of a tractor. In working, the power was transferred to the chain drive by the power output shaft of a gearbox, and then to realize the stalk conveying and pulling operation under the rotation of the toothed belt and the opposite rotation of the stalk pulling roller. A systematic kinematic analysis was conducted to determine the influencing factors in the working process. A field test was also carried out in a farmland in Korla City, Xinjiang Uygur Autonomous Region of China in October 2019. The soil firmness was 467 kPa, and the moisture content of the soil was 15%-20%, due to the perennial drought and little rain in the study area. The average height of cotton stalk was 700 mm, while, the plant spacing was 50 mm in a wide and narrow close planting mode. The power was from a CFD604A wheeled tractor with a calibrated power of 44.2 kW. The test was performed on the national standard of a harvester combine test(GB/T 8097-2008). A three-level quadratic regression orthogonal test was designed, where the forward velocity of the machine, the rod velocity of the deflector, and the speed of the stalk pulling roller were selected as the influencing factors, whereas, the leakage rate and plucking rate were the response factors. A response surface method was utilized to establish the regression equations for the relationship between the factors and assessment indexes. An optimal combination of parameters was obtained, while an experiment was also conducted to verify the mathematical model. The test results demonstrated that there were great effects of factors on the performance of horizontal-roller cotton stalk pulling. The significant effects on the leakage rate were ranked in a decreasing order: the forward velocity of the machine, the rod velocity of the deflector, and the speed of the stalk pulling roller. Correspondingly, the significant effects on the plucking rate were ranked in a decreasing order: the speed of the stalk pulling roller, the rod velocity of the deflector, and the forward velocity of the machine. The verification test indicated that the leakage rate of the cotton stalk was 5.24%, and the plucking rate was 3.75%,when the forward velocity of the machine was 0.68 m/s, the rod velocity of the deflector was 1.75 m/s, and the speed of the stalk pulling roller was 221 r/min. The optimal combination was better consistent with the predicted one in model optimization, indicating a reasonable structural design. The findings can provide a sound reference for the structural design and optimization of operation parameters in the horizontal-roller cotton stalk pulling machine. [ABSTRACT FROM AUTHOR]

Non-till farming has attracted increasing attention in developing sustainable agriculture, but the straws and the stubbles left over after harvest could block dispatch of fertilizer and seeds in seed drilling, which could detach the seeds and soil and result in nonuniform seed drilling both vertically and horizontally. Therefore, developing devices able to clean and crush the corn straw on seedbed before fertilization and seed drilling/spraying are demanded. However, the existing blade in such devices for laterally cutting the stubbles cannot completely clean and transport the stubble. The leftovers in soil make seed drilling problematic as they could block seed dispatch, increase energy consumption and, under certain circumstances, even make the sowing device unbale to operate. In order to resolve these problems, we designed a device to laterally cut and remove the stubbles from corn field. In this paper, we analyzed its efficacy in stubble clearance, soil disturbance, energy consumption, as well as conveying and throwing the cut/cleaned stubbles. The optimal structure of the stubble-cleaning blade and the working parameters of the device were calculated by taking the bending angle of the blade α, the transverse cutting edge B, and the angular velocity of the blade ω as determinants, and the stubble clearance ratio, soil disturbance ratio and equivalent energy consumption of the blade as quantitative indexes of its performance, using the three-factor and three-level orthogonal test and the fuzzy comprehensive evaluation method. The results showed that the stubble clearance ratio was significantly impacted by the bending angle, while the performance indexes were significantly impacted by the width and angular velocity of the blade. The factors that affected the performance of the device were ranked in the order of bending angle > transverse cutting edge > angular velocity. It was also found that soil disturbance ratio was mostly impacted by the transverse cutting edge, followed by the bending angle and the angular velocity, while the equivalent energy consumption was mostly affected the transverse cutting edge, followed by the bending angle and the velocity of the cutter tooth angle. The optimized results for the device operation were that when the operation speed was 7.2 km/h, the bending angle was 0.86 rad, the transverse cutting edge was 50 mm, and the angular velocity was 52 rad/s, the associated stubble clearance ratio was 94.3%, soil disturbance ratio was 54.3%, and the equivalent energy consumption was 3.4 kW. Under these conditions, clogging and straw entanglement did not occur. The results in this paper are helpful for designing devices to clear straw and stubbles left over after harvest in no-till farming. [ABSTRACT FROM AUTHOR]

Thinning is one of the three labor-consuming sections (pruning, thinning and harvesting) in orchard management process. Chemical thinning, not only unstable but also reduces fruit safety, has been banned gradually in recent years. Pure artificial thinning, especially artificial fruit thinning, needs larger workload and higher labor cost, unsuitable seriously for the requirements of modern orchard planting. Two kinds of pear mechanical flower thinners were designed in the paper. They were three arms tractor-mounted flower thinner (TMFT) and hand-held flower thinner (HHFT), to alleviate the heavy labor pressure in the process of thinning and improve the efficiency of orchard operation. The width of TMFT was controlled by hydraulic cylinder that range from 1.2 to 1.7 m. TMFT rotation speed of thinning shaft that range from 0 to 300 r/min was controlled by electronic governor. The length of HHFT can change through adjusting the extension rod that range from 0.95 to 1.6 m. HHFT rotation speed of thinning shaft that range from 0 to 900 r/min was controlled by electronic governor too. ‘Y’ trellis ‘Cuiguan’ pear was taken as the research object in the paper. TMFT impact forces of thinning rope with different rotation speed of thinning shaft and thinning distance were measured in bench test, to find the working range of rotation speed. Field test setting 50% flower bud preserved rate (it is easier to thin flower buds than flowers) and 0.44 m/s tractor work speed, and the best rotation speed of thinning shaft was ensured: 254 r/min. Flower bud reserve rate, fruit set rate, work efficiency, fruit yield and quality of four kinds of operation methods were tested, which were TMFT combined with artificial fruit thinning, HHFT combined with artificial fruit thinning, artificial flower fruit thinning and artificial fruit thinning only. Twenty-four ‘Y’ trellis pear trees (6 a) with almost same size were selected for four operation methods. The canopies of each tree were divided into the upper middle lower three layers and five branches were selected as samples in each layer. In order to reduce the operation error, except the TMFT, the operation of each group was completed by two workers with experienced job skill. Field test show that three flower thinning methods can meet the requirement of 50% flower bud preserved rate, the coefficient of variation all less than 15%. There is no obvious difference between TMFT and artificial method in thinning quality and the stability of TMFT is the highest among test groups. Mechanical and artificial flower thinning can significantly reduce about 50% absolute fruit set rate. TMFT will damage the young fruits in a certain degree, but does not affect the yield and quality in the last. Work efficiency of TMFT was highest among flower thinning methods and 66.17% artificial fruit thinning time can be saved. TMFT has a higher requirement for pear orchard mechanization degree, suitable for large-scale mechanized pear orchard. Work efficiency of HHFT is second only to TMFT, 37.26% artificial fruit thinning time can be saved. HHFT is suitable for small and medium sized pear orchard. For fruit yield and quality, total and high quality fruit yield per tree of pure artificial fruit thinning group is higher 11.37% and 8.59% respectively than average values of three kinds of flower thinning group, but the average weight of high quality fruit and brix of sugar solids of is lower 6.58% and 1.55% respectively. The research is helpful to improve the working quality of flower thinner and provide reference for the mechanization management of pear orchard. [ABSTRACT FROM AUTHOR]

In the rice area of the Northeast China, the large amount of rice straw with low moisture content is tough to chop. However, the existing method of chopping combined auxiliary slitting could not meet the requirements of chopping under such condition, which could cause some problems such as incomplete straw crushing and unqualified rate of straw crushing. It would affect the subsequent land preparation and transplanting operations and caused problems such as machine blocking, straw floating before transplanting and seedling floating during transplanting. In order to solve these problems, this paper designed a straw chopper based on the principle of differential sawing, which could realize the same direction with different speed between the saw disc blade and the crushing knife to achieve supporting sawing. The friction force and relative linear velocity of crushing straw were increased to improve the crushing effect. Structural parameters of saw disc blade, crushing knife and other key components were designed through theoretical analysis, and the structure and operating parameters of the machine were preliminarily obtained. In order to improve the wind velocity and straw feeding performance of the crushing chamber, three kinds of fan blade forms, namely facade fan blade, reverse fan blade and diverse fan blade, were designed to compare with no fan blade through simulation analysis. Simulation results by Fluent showed that the facade fan blade could improve the wind velocity in the crushing chamber and contributed to improving straw fluidity, and the verification test was in accordance with the simulation results. According to the movement track of crushing knife and saw disc blade, the rotation speeds of them were designed. The rotation speed of crushing knife ranged from 1815 to 2475 r/min, accordingly, and the saw disc blade rotation speed ranged from 605 to 825 r/min, to be specific, the ratio of rotation speed between saw disc blade and crushing knife was 1/3 constantly. The dynamics analysis of straw crushing process showed that rotation speed of crushing knife and the tilt angle between the saw disc blade could affect crushing performance. Therefore, a field experiment of two factors with three levels was designed by using the average length of straw crushing and the crushing qualification rate as an evaluation index. The test results showed that the crushing knife rotation speed and angle of slope had a significant impact on average length of straw crushing and straw crushing qualification rate. Considering straw crushing performance and energy consumption, the optimal combination was determined as follows: The crushing knife rotation speed was 1800 r/min and the angle of slope was 65°, the corresponding saw disc blade rotation speed was 600 r/min. The field test results under the optimized combination conditions were as follows: the average length of straw crushing was 9.58 cm, the proportion of straw under 10 cm was 93.23%, and the scatter unevenness was 20.89%, which met the quality requirements of straw crushing and scattering in the northeast rice region. In the paper, a comparison test between the differential sawing rice straw chopper and the ordinary straw chopper was carried out. The filed test showed that the average length of straw crushing of the ordinary straw chopper was 13.42 cm, and the proportion of straw under 10 cm was 71.5%, which was not as good as the differential sawing rice straw chopper, and there was no obvious difference in the scatter unevenness between them. After the chopping operation, the same plow was used for the plowing operation, and the straw burying rate was 98.92% of the differential sawing rice straw chopper while the ordinary straw chopper was 90.21 %. Its successful implementation could greatly improve the operation effect for chopping rice straw and stubble on one hand, and on the other hand provided better growing surface conditions for rice. The design of the machine provided a basis for the popularization and application of straw mulching technology in northeast China. [ABSTRACT FROM AUTHOR]

In order to develop a more efficient and universal flower auto-transplantation technique, an auto-transplantation mechanism with the integrated function of seedling pick-up and transplanting has been designed. This mechanism involves gear driving and two transplanting arms of the same structure. The gear driving system is made up of one semi-circle gear, four oval planet gears and concave-convex lock-up arc. It aims to move with the non uniform speed through the operation of planet gears and pulling and imbedding of concave-convex lock-up arc. The auto-transplantation arm includes the transplanting claw, convex gear and removing gear-gap parts. It transfers the whirling operation of planet gear into straight-line operation of pick-up seedling. The manual finger scratching and planting were simulated by two pins at the end of the seedling arm. The auto-transplantation mechanism combines the pick-up and planting. The transplanting trajectory and the location of pick-up and planting were special. Thus, it is essential to design new mechanism accordance with the movement of pick-up clip and achieve “Double beak sharp” trajectory. In this paper, we designed a device of bouncing clip to lengthen the trajectory to realize the function of pick-up and planting, and it could facilitate the integration of the planting. At the same time, when the claw moves nearly to the pot seedling, the seedling needle was inserted into the soil with a certain angle of inclination, which could effectively avoid the injury of the seedlings and the interference with the seedling box. Based on the kinematics characteristics of the mechanism, a corresponding mathematic model was established, and the Visual Basic 6.0 software was used to optimize the mechanism parameters. The program was used to analyze the influence of the parameters of mechanism on the trajectory and attitude of the “Double beak sharp". Finally, the best group of mechanism parameters was selected, and then the 3D design and components assembly were carried out based on SolidWorks 2015 software. Importing the 3D model to Adams, the trajectories of seedling needle could be obtained by the kinematics simulation. Finally, the prototype test was carried out and the test trajectory of the prototype was obtained by the test platform. Through the platform, the operation process was recorded by high-speed camera. Therefore, the trajectories of seedling needle could be tracked through the Bestcam picture analysis software. The results were basically the same among the simulation trajectory, the test trajectory of the prototype and the theoretical trajectory, which verified the correctness and feasibility of the design in this paper. Experimental research was carried out using the prototype, “Marigold chrysanthemum” seedlings were selected in the experiment, the basic composition of the pot seedling combines the pearl cave and peat mud, with the water component of 46%, the seedling tray were eight lines and 16 rows, both the length and width of seedling were 31 mm, and depth was 43 mm, and the test seedlings of marigold were 35 days, with the average height of 10 cm. The rotation speed of the mechanism was set as 35 r/min, its mean efficiency was 70 stems per minute. The obtained seedling success rate was 97.27%, while the transplanting success rate was 77.62%. It reflected the practicality of the integrated transplanting mechanism; the research could provide a reference for the key technology of automatic transplanting. [ABSTRACT FROM AUTHOR]

Cotton stalk is an important renewable resource. China is rich in cotton stalk, if such a large amount of resources are recycled, it will produce huge economic benefits. But most of them are not recycled at present. In order to improve the mechanized recovery level of cotton stalk, study the influence of different parameters on the mechanized recovery of cotton stalk, and solve the outstanding problems such as high cotton stalk plucking rate and high cotton stalk leakage rate, this paper studied and designed a toothed disc cotton stalk harvester. The machine was consisted of suspension device, limit wheel, pull-out tooth plate, stalk discharge device, hydraulic motor, hydraulic pipeline and hydraulic control box. The key component of the machine was a toothed disc type stalk pulling device. During operation, the cotton stalk was lifted out through the toothed disc, and then the cotton stalk was discharged to the surface through the stalk discharge device. Leakage rate and plucking rate of cotton stalk were the main parameters to evaluate the performance of toothed disc cotton stalk harvester. In this paper, Box-benhnken central combination test method was used to study the working parameters of toothed disc cotton stalk harvester. Three-factor and three-level quadratic regression orthogonal test was designed. The three-dimensional model of response surface was established with the diameter of the toothed disc, the toothed disc speed ratio and the lifting height as the influencing factors. The influence of each factor on the quality of work was analyzed, and the influencing factors were optimized synthetically. The results showed that the lifting height and the toothed disc speed ratio had significant effects on the cotton stalk plucking rate (P< 0.01), while the lifting height, the diameter of the toothed disc and the toothed disc speed ratio had significant effects on the rate of cotton stalk leakage rate (P<0.01). The working parameters of the machine were deduced from the regression model optimization as follows: the lifting height was 66.2 mm, the diameter of the toothed disc was 627.59 mm, and the toothed disc speed ratio was 0.57. In November 2018, field test was carried out in the Yellow River Delta (Binzhou) National Agricultural Science and Technology Park. Test area was divided into 17 test plots, leakage rate and plucking rate of cotton stalk at each test plot were calculated. The results of the Daejeon experiment showed that when the lifting height was 70 mm, diameter of the toothed disc was 630 mm and the toothed disc speed ratio was 0.57, the cotton stalk plucking rate could reach 1.5% and the cotton stalk leakage rate was low to 3.0%. The test results showed that the theoretical results were coincident with the measuring results, and the error between them was less than 4%. The research results can provide references for the structure improvement design and operation parameters optimization of toothed disc cotton stalk harvester. [ABSTRACT FROM AUTHOR]

Cotton stalk is an important renewable resource. China is rich in cotton stalk, if such a large amount of resources are recycled, it will produce huge economic benefits. But most of them are not recycled at present. In order to improve the mechanized recovery level of cotton stalk, study the influence of different parameters on the mechanized recovery of cotton stalk, and solve the outstanding problems such as high cotton stalk plucking rate and high cotton stalk leakage rate, this paper studied and designed a toothed disc cotton stalk harvester. The machine was consisted of suspension device, limit wheel, pull-out tooth plate, stalk discharge device, hydraulic motor, hydraulic pipeline and hydraulic control box. The key component of the machine was a toothed disc type stalk pulling device. During operation, the cotton stalk was lifted out through the toothed disc, and then the cotton stalk was discharged to the surface through the stalk discharge device. Leakage rate and plucking rate of cotton stalk were the main parameters to evaluate the performance of toothed disc cotton stalk harvester. In this paper, Box-benhnken central combination test method was used to study the working parameters of toothed disc cotton stalk harvester. Three-factor and three-level quadratic regression orthogonal test was designed. The three-dimensional model of response surface was established with the diameter of the toothed disc, the toothed disc speed ratio and the lifting height as the influencing factors. The influence of each factor on the quality of work was analyzed, and the influencing factors were optimized synthetically. The results showed that the lifting height and the toothed disc speed ratio had significant effects on the cotton stalk plucking rate (P< 0.01), while the lifting height, the diameter of the toothed disc and the toothed disc speed ratio had significant effects on the rate of cotton stalk leakage rate (P<0.01). The working parameters of the machine were deduced from the regression model optimization as follows: the lifting height was 66.2 mm, the diameter of the toothed disc was 627.59 mm, and the toothed disc speed ratio was 0.57. In November 2018, field test was carried out in the Yellow River Delta (Binzhou) National Agricultural Science and Technology Park. Test area was divided into 17 test plots (each plots is 30 m×0.76 m), leakage rate and plucking rate of cotton stalk at each test plot were calculated. The results of the Daejeon experiment showed that when the lifting height was 70 mm, diameter of the toothed disc was 630 mm and the toothed disc speed ratio was 0.57, the cotton stalk plucking rate could reach 1.5% and the cotton stalk leakage rate was low to 3.0%. The test results showed that the theoretical results were coincident with the measuring results, and the error between them was less than 4%. The research results can provide references for the structure improvement design and operation parameters optimization of toothed disc cotton stalk harvester. [ABSTRACT FROM AUTHOR]

Deep rotary tillage is a hot and difficult problem in the research field of tillage machinery. Scholars at home and abroad have made a lot of explorations on deep rotary tillage technology and theory. At present, deep rotary tillage is mainly realized through the following three methods: 1) plowing depth was increased by directly increasing the diameter of the knife roller; 2)Two-axis stratified rotary tillage. Two rows of knife rollers are set in front and back for the first rotary tillage of the former one, and then the latter one for further rotary tillage; 3) subsoil reverse rotary tillage, that is, deep tillage is achieved by sinking the knife shaft below the surface. These three methods can achieve the goal of deep rotation tillage, but they all have their own disadvantages. Considering the characteristics of oblique rotary tilling and reverse tilling, the principle of oblique submerged reverse rotary tillage is put forward in this paper, which can not only destroy the soil by “pull” but also reduce the heaping soil as well as make the central transmission box easy to sink subsoil, and realize low energy consumption deep tilling with short knife. The back-up amount of tilting rotary tilter directly depends on the performance of tilting rotary tilter. Oblique submerged reverse rotary tillage is put forward in this paper. It is important to study the mechanism of throwing soil to optimize the design of this machine. Oblique submerged reverse rotary tillage is a new type of rotary tillage. It is important to study the mechanism of throwing soil to optimize the design of inclined subterranean reversal rotary tiller. In this paper, a simulation model of SPH (Smoothed Particle Hydrodynamics) is established on the LS-DYNA platform. The model is used to reverse the rotary tillage in different working conditions. The simulation results show that the post-soil rate of different layers in the reverse rotation of different parameters under different parameters is obtained. The post-soil rate of different layers obtained under the same conditions and the post-casting of different layers obtained by the indoor soil trough test are obtained. The soil rate was compared and analyzed. The verification results show that the maximum simulation error is 12.50%, the minimum simulation error is 0.20%, and the average error is 3.09%. Applying the corrected simulation model, the oblique angle, the forward speed, the depth of the submerged soil and the speed of the cutter roll were taken as the four factors of the test, and three levels were taken for each factor. Afterwards, the throwing rate was measured and the tilt was set. The virtual orthogonal experiment of reversing the rotary tillage and throwing soil was conducted. The test results were analyzed by the range analysis method, the variance analysis method and the regression analysis method. The data analysis results show that the primary and secondary order of the impact rate after the impact is the subsoil depth and the oblique angle, the forward speed and the knife roll speed. The influence on the post-lost rate is not significant, and the mathematical relationship model of the subsoil depth, the oblique angle and the post-lost rate is obtained. According to the results of virtual experiment, the physical prototype of the inclined submersible soil reverse rotation tillage machine was optimized and the field experiment was carried out. The field test results showed that the reverse rotation of the inclined subterranean soil successfully solved the problem of the rotary tiller bracket and the central transmission box. And with the R175 standard rotary cultivator, the tilling depth of 20 cm was achieved, and deep tilling using short knife was realized in this paper. [ABSTRACT FROM AUTHOR]

Castor is one of the top ten oil crops in the world, which has a extremely high economic value. For a long time, the harvesting of castor bean has relied on manual operations, so the development of the castor industry have been greatly restricted by the high labor intensity and low efficiency. At present, there are few studies on harvesting machinery of castor, and the mechanization of castor harvesting is still in the initial stage. The existing castor harvesting equipments are not suitable for the growth features of castor, which has the problems of high loss rate and high damage rate. In order to solve these problems, a brush-roller harvesting method was proposed in this paper. The harvesting principle of brush-roller castor harvester is that the castor capsules are separated from the plant by the brushing force caused from the brush wire. According to the physical characteristics and planting mode of castor, the picking mechanism of brush-roller castor harvester was designed. Firstly, the structure of the picking mechanism was introduced, the picking mechanism is mainly composed of crop divider, brush roller, screw conveyor, transfer case, et. Then, the kinematic and mechanical analysis of the working process of the mechanism was carried out, so as to determine the structural parameters and working parameters of each part of the picking mechanism. In order to improve the harvesting quality of castor, we conducted a field experiment in October 2020 in Hohhot, Inner Mongolia. In the field experiment, Box-benhnken response surface design theory was used on the basis of single fator experiment to optimize the working parameters of the picking mechanism. The picking rate, the breakage rate and the impurity rate were used as the evaluation indexes of working quality. And the moving speed, the brush roller speed and the length of brush wire were taken as three factors influencing the working quality. The quadratic polynomial response surface regression model was established, and the influence of various factors on the response value was analyzed. From the regression model and variance analysis of regression equation, it could be seen that: lower moving speed, moderate brush roller speed, and shorter brush wire led to higher picking rate; Lower moving speed, lower brush roller speed, and longer brush wire led to lower breakage rate; Higher moving speed, lower brush roller speed, and longer brush wire led to lower impurity rate. The experiment results also showed that the significant effects of moving speed, length of brush wire and brush roller speed on increasing the picking rate were in a decreasing order. The significant effects of brush roller speed, length of brush wire and moving speed on reducing the breakage rate and the impurity rate were in a decreasing order. At the same time, the factors were multi-objective optimized comprehensively, and the optimization results were verified by experiments. The results showed that the optimum parameters were: 0.72 m/s for the moving speed, 372 r/min for the brush roller speed and 57 mm for the length of brush wire. Under these conditions, the picking rate was 91.36%, the breakage rate was 0.18%, and the impurity rate was 11.67%. The measured values of each index were in good agreement with the theoretical optimization values, which meant that the model established was reliable and could be used for optimization. The results can provide a reference for further improving the structure design and working parameters optimization of the brush-roller castor harvester. [ABSTRACT FROM AUTHOR]

Grain cleaning is the core technology of peanut harvest. Therefore, in the process of peanut harvesting, how to enhance operation fluency and efficiency, and to ensure technical indicators such as low loss rate of cleaning, low impurity rate of peanut pods, has been a difficult technical problem of whole-feed peanut combine harvester. In order to settle the above difficulties, a cleaning device of tangential flow and whole-feed peanut combine harvester was designed, realizing the grain winnowed combined with screened, one-time large and small sundries clearance, sieve surface unencumbered. The cleaning device of tangential flow and whole-feed peanut combine harvester consisted of pole sieve, multi-stage elastic sieve, behind sieve, straw-shaking wheel, eccentric sleeve, main fan, auxiliary fan. The vibrating sieve consisted of pole sieve, multi-stage elastic sieve, behind sieve. Pole sieve was above the vibrating sieve. Multi-stage elastic sieve and behind sieve were below the vibrating sieve. Combined with existed mechanism advantages, a crank-rocker mechanism which consisted of the vibrating sieve and swinging arm was brought forward. In the application of cleaning device of tangential flow and whole-feed peanut combine harvester, there are many problems such as high impurity rate of peanut pods, high loss rate of cleaning, agricultural film tangles, and debris blockage. Utilizing kineto-statics method, in this paper, we researched relative motion of grain on the sieve surface, analyzed limiting conditions of grain upglide, downglide, jump from sieve surface, and determined the key motion parameter in theory. Vibration acceleration of vibrating sieve was 17.5-24.5 m/s2. Amplitude of vibrating sieve was 7.5-17.5 mm. Vibration frequency of vibrating sieve was 5-9 Hz. Utilizing D'Alembert's principle, in this paper, we also researched sieve force under alternating loads, determined the important structure parameter of sieve. Cleaning device was matched onto the whole-feed combine and a lot of tests were carried out in the field. Loss rate of cleaning and impurity rate of peanut pods were taken as the evaluation indicator of cleaning quality. The key factors affecting cleaning quality were researched by field experiment in this paper. A scheme of orthogonal test, which included 3 factors and 3 levels, was designed. That key factor included amplitude, vibration frequency and revolving speed of main fan. The value range of amplitude and vibration frequency was based on the preceding theoretical analysis. The value range of revolving speed of main fan was based on single factor experiment. The experimental results showed that significant order for multi-factors affected on cleaning quality was: revolving speed of main fan, amplitude, vibration frequency. Within the scope of the 95% confidence coefficient, revolving speed of main fan was extremely significant for cleaning quality, amplitude and vibration frequency were significant for cleaning quality. The optimal parameter combination was that revolving speed of main fan was 2 100 r/min, amplitude was 12.5 mm, vibration frequency was 9 Hz. Under the above optimal parameters, field experiments were carried out, loss rate of cleaning was 5.03% and impurity rate of peanut pods was 5.39%. The operation of cleaning device is fluent, almost no agricultural film tangles and debris blockage. The research results provide theoretical basis for design and parameter optimization of whole-feed peanut combine harvester and cleaning device [ABSTRACT FROM AUTHOR]

Grain loss rate is one of the most important performance index of corn head in mechanized harvesting. Seed harvesting is the main development direction of mechanized corn harvesting. The characters of seed harvesting corn variaty increased the urgency to reduce grain loss on corn head. The paper was proposed to solve the problem of grain loss on corn head. Theoretical analysis was conducted to the snapping process. Corn ear was subjected to pull force by the snapping rolls and the pull force transferred by corn stalk. Corn kernels were divided into 2 types due to their force condition. A kernel at the bottom end of corn ear was subjected to reaction forces by stripper plates, corn cob and the adjacent kernels and shear force by the pedicel. Kernels out of contact with the stripper plates were subjected to reaction forces by the adjacent kernels, pull force and shear force by corn cob. As the impact force was related to the impact time according to the theorem of impulse, the paper analyzed collision model between corn ear and stripper plates in the snapping process. A mathematical model was obtained about the impact time and intrinsic parameters of the system. The impact time was dependent on system mass, stiffness coefficient and damping coefficient, which lays on the mechanical structure and materials of collision objects. So, the impact force would decrease as the impact time could be prolonged by reducing the stiffness coefficient and raising the damping coefficient. The quantity of shed kernels could be reduced consequently. The paper proposed a corn head with wheel type rigid-flexible coupling snapping device to reduce loss. The corn head consisted of the frame, gear-box, snapping rolls, gathering chain, wheel type rigid-flexible coupling snapping device, and chain wheels. The wheel type rigid-flexible coupling snapping device consisted of snapping wheel axle, spring seat axle, supporting axle, buffer spring, and snapping wheel frame. Force analysis was conducted on the snapping wheel. According to the force conditions and dimension boundary condition, the structure diameters of snapping wheel, snapping wheel frame, and buffer spring were confirmed. In order to obtain the optimal parameters with the minimum loss rate of wheel type rigid-flexible coupling snapping device, the optimization experiments were conducted of the factors at 3 different levels. In the optimization experiments, the snapping wheel radius was designed at 10, 15 and 20 mm respectively, the flexible body thickness was at 2, 4 and 6 mm respectively, the snapping rolls rotating speed at 700, 800 and 900 r/min respectively. The Response Surface Analysis method was used to design the experiments. The software Design-Expert 8.0.6.1 was used to analyze the data. Regression equation was induced according to the experiment and analysis above. The optimal combination of wheel type coupling snapping device was as follows: The snapping rolls rotating speed was 700 r/min, the snapping wheel radius was 15 mm, the flexible body thickness was 4 mm. Verification contrast test was conducted between corn head with wheel type rigid-flexible coupling snapping device and the one with snapping rolls and stripper plates on corns at different moisture contents. As the kernels moisture contents were 21.8%, 16.7% and 13.4%, the grain loss rate decreased 53.4%, 48.6% and 47.0% respectively. This study provides not only theoretical basis but also design reference for the improvement of corn harvester design. [ABSTRACT FROM AUTHOR]

In order to develop a more efficient and universal flower auto-transplantation technique, an auto-transplantation mechanism with the integrated function of seedling pick-up and transplanting has been designed. This mechanism involves gear driving and two transplanting arms of the same structure. The gear driving system is made up of one semi-circle gear, four oval planet gears and concave-convex lock-up arc. It aims to move with the non uniform speed through the operation of planet gears and pulling and imbedding of concave-convex lock-up arc. The auto-transplantation arm includes the transplanting claw, convex gear and removing gear-gap parts. It transfers the whirling operation of planet gear into straight-line operation of pick-up seedling. The manual finger scratching and planting were simulated by two pins at the end of the seedling arm. The auto-transplantation mechanism combines the pick-up and planting. The transplanting trajectory and the location of pick-up and planting were special. Thus, it is essential to design new mechanism accordance with the movement of pick-up clip and achieve “Double beak sharp” trajectory. In this paper, we designed a device of bouncing clip to lengthen the trajectory to realize the function of pick-up and planting, and it could facilitate the integration of the planting. At the same time, when the claw moves nearly to the pot seedling, the seedling needle was inserted into the soil with a certain angle of inclination, which could effectively avoid the injury of the seedlings and the interference with the seedling box. Based on the kinematics characteristics of the mechanism, a corresponding mathematic model was established, and the Visual Basic 6.0 software was used to optimize the mechanism parameters. The program was used to analyze the influence of the parameters of mechanism on the trajectory and attitude of the “Double beak sharp". Finally, the best group of mechanism parameters was selected, and then the 3D design and components assembly were carried out based on SolidWorks 2015 software. Importing the 3D model to Adams, the trajectories of seedling needle could be obtained by the kinematics simulation. Finally, the prototype test was carried out and the test trajectory of the prototype was obtained by the test platform. Through the platform, the operation process was recorded by high-speed camera. Therefore, the trajectories of seedling needle could be tracked through the Bestcam picture analysis software. The results were basically the same among the simulation trajectory, the test trajectory of the prototype and the theoretical trajectory, which verified the correctness and feasibility of the design in this paper. Experimental research was carried out using the prototype, “Marigold chrysanthemum” seedlings were selected in the experiment, the basic composition of the pot seedling combines the pearl cave and peat mud, with the water component of 46%, the seedling tray were eight lines and 16 rows, both the length and width of seedling were 31 mm, and depth was 43 mm, and the test seedlings of marigold were 35 days, with the average height of 10 cm. The rotation speed of the mechanism was set as 35 r/min, its mean efficiency was 70 stems per minute. The obtained seedling success rate was 97.27%, while the transplanting success rate was 77.62%. It reflected the practicality of the integrated transplanting mechanism; the research could provide a reference for the key technology of automatic transplanting. [ABSTRACT FROM AUTHOR]

In order to develop a more efficient and universal flower auto-transplantation technique, an auto-transplantation mechanism with the integrated function of seedling pick-up and transplanting has been designed. This mechanism involves gear driving and two transplanting arms of the same structure. The gear driving system is made up of one semi-circle gear, four oval planet gears and concave-convex lock-up arc. It aims to move with the non uniform speed through the operation of planet gears and pulling and imbedding of concave-convex lock-up arc. The auto-transplantation arm includes the transplanting claw, convex gear and removing gear-gap parts. It transfers the whirling operation of planet gear into straight-line operation of pick-up seedling. The manual finger scratching and planting were simulated by two pins at the end of the seedling arm. The auto-transplantation mechanism combines the pick-up and planting. The transplanting trajectory and the location of pick-up and planting were special. Thus, it is essential to design new mechanism accordance with the movement of pick-up clip and achieve “Double beak sharp” trajectory. In this paper, we designed a device of bouncing clip to lengthen the trajectory to realize the function of pick-up and planting, and it could facilitate the integration of the planting. At the same time, when the claw moves nearly to the pot seedling, the seedling needle was inserted into the soil with a certain angle of inclination, which could effectively avoid the injury of the seedlings and the interference with the seedling box. Based on the kinematics characteristics of the mechanism, a corresponding mathematic model was established, and the Visual Basic 6.0 software was used to optimize the mechanism parameters. The program was used to analyze the influence of the parameters of mechanism on the trajectory and attitude of the “Double beak sharp". Finally, the best group of mechanism parameters was selected, and then the 3D design and components assembly were carried out based on SolidWorks 2015 software. Importing the 3D model to Adams, the trajectories of seedling needle could be obtained by the kinematics simulation. Finally, the prototype test was carried out and the test trajectory of the prototype was obtained by the test platform. Through the platform, the operation process was recorded by high-speed camera. Therefore, the trajectories of seedling needle could be tracked through the Bestcam picture analysis software. The results were basically the same among the simulation trajectory, the test trajectory of the prototype and the theoretical trajectory, which verified the correctness and feasibility of the design in this paper. Experimental research was carried out using the prototype, “Marigold chrysanthemum” seedlings were selected in the experiment, the basic composition of the pot seedling combines the pearl cave and peat mud, with the water component of 46%, the seedling tray were eight lines and 16 rows, both the length and width of seedling were 31 mm, and depth was 43 mm, and the test seedlings of marigold were 35 days, with the average height of 10 cm. The rotation speed of the mechanism was set as 35 r/min, its mean efficiency was 70 stems per minute. The obtained seedling success rate was 97.27%, while the transplanting success rate was 77.62%. It reflected the practicality of the integrated transplanting mechanism; the research could provide a reference for the key technology of automatic transplanting. [ABSTRACT FROM AUTHOR]

In order to develop a more efficient and universal flower auto-transplantation technique, an auto-transplantation mechanism with the integrated function of seedling pick-up and transplanting has been designed. This mechanism involves gear driving and two transplanting arms of the same structure. The gear driving system is made up of one semi-circle gear, four oval planet gears and concave-convex lock-up arc. It aims to move with the non uniform speed through the operation of planet gears and pulling and imbedding of concave-convex lock-up arc. The auto-transplantation arm includes the transplanting claw, convex gear and removing gear-gap parts. It transfers the whirling operation of planet gear into straight-line operation of pick-up seedling. The manual finger scratching and planting were simulated by two pins at the end of the seedling arm. The auto-transplantation mechanism combines the pick-up and planting. The transplanting trajectory and the location of pick-up and planting were special. Thus, it is essential to design new mechanism accordance with the movement of pick-up clip and achieve “Double beak sharp” trajectory. In this paper, we designed a device of bouncing clip to lengthen the trajectory to realize the function of pick-up and planting, and it could facilitate the integration of the planting. At the same time, when the claw moves nearly to the pot seedling, the seedling needle was inserted into the soil with a certain angle of inclination, which could effectively avoid the injury of the seedlings and the interference with the seedling box. Based on the kinematics characteristics of the mechanism, a corresponding mathematic model was established, and the Visual Basic 6.0 software was used to optimize the mechanism parameters. The program was used to analyze the influence of the parameters of mechanism on the trajectory and attitude of the “Double beak sharp". Finally, the best group of mechanism parameters was selected, and then the 3D design and components assembly were carried out based on SolidWorks 2015 software. Importing the 3D model to Adams, the trajectories of seedling needle could be obtained by the kinematics simulation. Finally, the prototype test was carried out and the test trajectory of the prototype was obtained by the test platform. Through the platform, the operation process was recorded by high-speed camera. Therefore, the trajectories of seedling needle could be tracked through the Bestcam picture analysis software. The results were basically the same among the simulation trajectory, the test trajectory of the prototype and the theoretical trajectory, which verified the correctness and feasibility of the design in this paper. Experimental research was carried out using the prototype, “Marigold chrysanthemum” seedlings were selected in the experiment, the basic composition of the pot seedling combines the pearl cave and peat mud, with the water component of 46%, the seedling tray were eight lines and 16 rows, both the length and width of seedling were 31 mm, and depth was 43 mm, and the test seedlings of marigold were 35 days, with the average height of 10 cm. The rotation speed of the mechanism was set as 35 r/min, its mean efficiency was 70 stems per minute. The obtained seedling success rate was 97.27%, while the transplanting success rate was 77.62%. It reflected the practicality of the integrated transplanting mechanism; the research could provide a reference for the key technology of automatic transplanting. [ABSTRACT FROM AUTHOR]

In order to develop a more efficient and universal flower auto-transplantation technique, an auto-transplantation mechanism with the integrated function of seedling pick-up and transplanting has been designed. This mechanism involves gear driving and two transplanting arms of the same structure. The gear driving system is made up of one semi-circle gear, four oval planet gears and concave-convex lock-up arc. It aims to move with the non uniform speed through the operation of planet gears and pulling and imbedding of concave-convex lock-up arc. The auto-transplantation arm includes the transplanting claw, convex gear and removing gear-gap parts. It transfers the whirling operation of planet gear into straight-line operation of pick-up seedling. The manual finger scratching and planting were simulated by two pins at the end of the seedling arm. The auto-transplantation mechanism combines the pick-up and planting. The transplanting trajectory and the location of pick-up and planting were special. Thus, it is essential to design new mechanism accordance with the movement of pick-up clip and achieve “Double beak sharp” trajectory. In this paper, we designed a device of bouncing clip to lengthen the trajectory to realize the function of pick-up and planting, and it could facilitate the integration of the planting. At the same time, when the claw moves nearly to the pot seedling, the seedling needle was inserted into the soil with a certain angle of inclination, which could effectively avoid the injury of the seedlings and the interference with the seedling box. Based on the kinematics characteristics of the mechanism, a corresponding mathematic model was established, and the Visual Basic 6.0 software was used to optimize the mechanism parameters. The program was used to analyze the influence of the parameters of mechanism on the trajectory and attitude of the “Double beak sharp". Finally, the best group of mechanism parameters was selected, and then the 3D design and components assembly were carried out based on SolidWorks 2015 software. Importing the 3D model to Adams, the trajectories of seedling needle could be obtained by the kinematics simulation. Finally, the prototype test was carried out and the test trajectory of the prototype was obtained by the test platform. Through the platform, the operation process was recorded by high-speed camera. Therefore, the trajectories of seedling needle could be tracked through the Bestcam picture analysis software. The results were basically the same among the simulation trajectory, the test trajectory of the prototype and the theoretical trajectory, which verified the correctness and feasibility of the design in this paper. Experimental research was carried out using the prototype, “Marigold chrysanthemum” seedlings were selected in the experiment, the basic composition of the pot seedling combines the pearl cave and peat mud, with the water component of 46%, the seedling tray were eight lines and 16 rows, both the length and width of seedling were 31 mm, and depth was 43 mm, and the test seedlings of marigold were 35 days, with the average height of 10 cm. The rotation speed of the mechanism was set as 35 r/min, its mean efficiency was 70 stems per minute. The obtained seedling success rate was 97.27%, while the transplanting success rate was 77.62%. It reflected the practicality of the integrated transplanting mechanism; the research could provide a reference for the key technology of automatic transplanting. [ABSTRACT FROM AUTHOR]

The degree of automation of domestic combine harvester is low, and the operation is complex, it is difficult for workers to understand the actual adjustment of working parts. Crop height, crop length, height of the ground and the lack of consistency in course of project led to the continuous adjustment of harvester's joystick. The traditional operation method, in which experiences are excessively relied on, cannot meet the requirements of automatic operation of domestic-made combine harvester. The current operation method is an obstacle to the development of the automatic control of the combine harvester. In this paper, a device of adjusting combine harvester header parameters was designed. The header parameters include height of header, height of reel, position of reel and speed of reel. The control function of header parameters adjusting device is to adjust height of header, height of reel, position and speed of reel. The header parameter adjusting device was composed of sensor modules, PLC control units, display modules, key module, header drive parts module and so on. The sensor modules were used to detect the parameter of header which include height of header, height of reel, position of reel, speed of reel and forward speed. Sensor modules detect the signal inputed into PLC control unit. PLC control unit is the core component of the adjusting device. PLC performs data operation and processing. Using touch display screen as human-computer interaction tools, which communicates with PLC. The display interface includes parameters displaying and setting, and displayed parameters include header parameter, operating speed, crop height and so on. The key module adopts self-reset and self-locking switch to realize manual and automatic function signal input. At the same time, PLC receives the key information and make judgments, and then sends the control signal to drive header hydraulic system to carry out the movement of the mechanism. Header drive parts modules include lectromagnetic directional valve and proportional solenoid valve, which adopts the hydraulic control principle. High reel speed has a large impact on crop yield and increase grain losses. It is difficult to push crops to header and proceed to the next step of threshing, clearing and collection at low reel speed, and it is difficult to match the change of operation speed with the reel speed. In this paper, an automatic control method of reel speed was presented. By analyzing the working process of reel, a mathematical model of reel speed was established, and fuzzy PID algorithm is used to realize the automatic control of reel speed. The header parameter adjusting device was installed on the test prototype, and the regulatory tests, data records and data analysis were carried out. The test results showed that header height, reel height, reel position and reel speed could be electrically controlled by the header parameter adjusting device. Relative adjustment errors of header height, reel height, reel position and reel speed were 7.4%, 3.4%, 2.0% and 7.8% respectively. The operation speed of maximum relative error was 3.4%. The response time is less than 0.8 s, and the adjustment time is less than 1.7 s. The system was proved to meet the design requirements of header parameter controller of combine harvester. The research results can be applied in intelligent operation of combine harvester. [ABSTRACT FROM AUTHOR]

As a main grain production equipment, the combine wheat harvester plays an important role in grain production, and its technological development level is an important indicator of the degree of agricultural modernization. However, during the harvesting process, the working parts of the harvester interact with the crop to be harvested, so that the dust originally attached to the surface of the crop is disturbed and separated from the surface of the organism, forming floating and flying dust, some of which are scattered around the harvester, seriously affecting The driver’s body is healthy; some infected plants carry diseased dust, which is more harmful to the human body; more dust is dispersed in the air with the wind, causing a wider range of air pollution and increasing the amount of inhalable particles in the air. This has become one of the sources of air pollution during the crop harvest season. In order to understand the dust generation status and the characteristics of the dust composition, this paper first conducts the dust concentration and distribution test on the operation site of the combine wheat harvester .The result is as the header and tail of harvester are the main areas where dust is generated, Excessive dust mass concentration will harm the health of workers .The characteristics of the dust sample was tested results as follows: the proportions of dust with a particle size of 10μm and 100μm or less are 45% and 92%, the dust is mostly composed of minerals, grease and carbohydrates. The dust measurement test revealed for the first time the dust generation and dust composition characteristics of combine wheat harvester operations in the rice-wheat (oil) rotation area in southern my country. On this basis, a dust suppression system installed on the combine wheat harvester was designed. The system adopts the working principle of negative pressure dust suction and filter cartridge dust collection. The system utilizes the power of the existing combine wheat harvester and can change the working parameters of the fan at any time to meet a variety of field working conditions. Conduct field tests on the dust suppression system. Through theoretical analysis to determine the main factors that affect the efficiency of the dust suppression system. Taking the harvester header dust suppression efficiency and harvester tail dust suppression efficiency as the test indicators, and the harvester speed, fan speed and environment humidity as the test factors. Using Box-Behnken central combination test method, the three-factor and three-level test are carried out. A mathematical regression model of various factors and test indicators was established. Through variance analysis and response surface analysis, the influence of harvester speed, fan speed and environment humidity on the test indicators is obtained. Use Design-Export8.0.6.1 data analysis software to fitting and optimization analysis of the test results, the optimal parameter combination is obtained as follows: harvester speed 3.73 km/h, fan speed 3 507 r/min, and ambient humidity 56%. On this condition, the efficiency of the header dust suppression is 76.8%,the efficiency of the tail dust suppression is 79.6%. The optimal working parameters are tested and verified to verify the feasibility of optimizing the optimal parameter combination, the minimum fan speed of the dust suppression system to meet the dust suppression requirements under difficult working conditions is 3 332 r/min. This research can provide a basis for the design of the harvester dust suppression system. [ABSTRACT FROM AUTHOR]

The banana stalks are rich in fiber, and the existing returning machines for banana straw and stubble crushed in China have generated a few problems such as overly severe cutting resistance, the fiber of banana straw winding crushing blade roller on the returning machine, working on the unstable condition and serious fuel consumption. In order to deal with the above problems which the existing choppers met with in the working process, with the help of theoretical study and the analysis on the planting model for banana in Hainan Province, this paper put forward a returning method that the moving knives on the front knife roller were used to crush banana straws and the flail knives on the back knife roller were used to break stubble under the earth. The rotational direction of stubble crushing roller in the returning machine was same to the forward direction of the machine providing power, while the rotational direction of straw crushing roller was contrary to that of stubble crushing roller. On the basis of establishing theoretical model and the analysis on the planting model for banana in southern China, the key shaped parameters of the sliding-cutting blade and the structural parameters of crushing blade rollers were determined respectively. Besides, the sliding-cutting and anti-twining returning device for banana straw was put forward. The overall structure and working principle of sliding-cutting and anti-twining returning device were described. The performance of crushing banana straw and the power consumption were evaluated by simulating the breaking operation of banana straw in farmland through a bench test driven by double electric motors. The machine was composed of electrical motors, a tractor powered by electricity, the frame of machines, the straw crushing device and the stubble crushing device. Through Design-Expert software, a quadratic orthogonal rotating experiment was performed. Based on the variance analysis and regression fitting, a multiple regression equation was gained, presenting the effects of the working speed of the returning device, the rotating speed of rotating roller of moving knives and the rotating speed of rotating shaft of stubble breaking on the qualified rate of straw crushing and power consumption. It could be seen that the rotating speed of rotating roller of moving knives had the most influential effect, followed by the rotating speed of rotating shaft of stubble breaking, and the working speed of the returning device had the least influence on the qualified rate of straw chopping. The operation condition was optimized by applying the response surface method. The optimum factors for straw and stubble crushing process were as follows: The rotating speed of rotating roller of moving knives was 1 600 r/min, the rotating speed of rotating shaft of stubble breaking was 500 r/min, and the working speed of the returning device was 1.39 m/s. Based on the theoretical analysis, the higher qualified rate of straw crushing was achieved under the faster rotating speed of rotating roller of moving knives. The smaller power consummation was obtained under the lower rotating speed of rotating roller of moving knives and the lower rotating speed of rotating shaft of stubble breaking. Under the optimal condition, the corresponding qualified rate of straw crushing and power consumption were 95.2%, and 4.96 kW, respectively. The differences between the experimental and the analytical values of the qualified rate of straw chopping and power consumption were 0.31 percentage points and 0.27%, respectively, which indicated that the software analytical value was in great agreement with the experimental value. And by field test, qualified rate of straw crushing of machine proposed in this paper was higher by 1.94 percentage points and power consumption was lower by 11.3%, compared with vertical flail banana stalk crushing machine. Its successful implementation can greatly improve the production efficiency for crushing banana straw and stubble on one hand, and on the other hand prevent the pollution brought by deserted banana straw putridity. [ABSTRACT FROM AUTHOR]

Large-scale grain drying technology has a nearly 50 years of development history in China. There are concurrent flow dryer, countercurrent dryer, cross flow dryer and mixed flow dryer, which meet the actual needs in various fields. But compared with the similar foreign products, there are many defects on our grain dryer, such as low manufacturing technology, low level of automation and high energy consumption. The co-current flow dryer has the characteristics of dry uniformity, low unit heat consumption and high productivity. But there are some defects, such as poor control of drying quality, high cost of drying and environmental pollution. These shortcomings are not conducive to the sustainable development of agricultural production and ecological environment. Therefore, from the perspectives of the structure and the process of the high temperature grain dryer, combining energy saving with conservation of grain quality is the key to the development of modern grain drying technology. Generally, the form of air supply in large-scale grain dryer is positive pressure, with easy maintenance and adjustment. The negative pressure air supply technology is only used for small cycle dryers. In this paper, the negative pressure technology in the large-scale grain drying system was applied for the first time. Negative pressure drying can effectively solve the internal control problems of the drying process based on the theory of micro pressure. Negative pressure is beneficial to collect the grain dust, create excellent production environment and realize safe production. The losses of static pressure and dynamic pressure are relatively small in the process of negative pressure drying, and this technology can reduce power consumption, and is easier to realize intelligent control of air volume and air medium parameters. In order to reduce primary energy consumption and improve corn drying process capacity, combined with grain drying characteristics in cold region, 5HFS-10 type negative pressure grain dryer was designed based on the principle of negative pressure drying. This drying technology combined the multi-stage concurrent flow and countercurrent flow, and a set of advanced structure and control system were applied in this drier. The parallel dilated fan was combined with variable diameter cornute duct, the cold air quota regulation agencies were coordinated, online work parameters were real-time collected with multi sensors, the adaptive control system was adopted, and all of these completed the intelligent quality-guaranteeing drying production of the staple food crop. In this paper the calculation of drying parameters and structure parameters was carried out providing the theory basis for the comprehensive evaluation and the design of negative pressure dryer. Production test shows that the machine’s work performance is good, its energy saving is significant, and it has good drying quality, unit mass of low cost, high degree of automation, and so on. The deviation of the moisture of discharged grain is less than ±0.5% w.b. Compared with the traditional positive pressure air supply dryer, this dryer saves the power by more than 20%, and reduces the production cost by more than 12%. The operating performance can perfectly meet the requirements of farm drying and large-scale drying technique. It provides the theoretical basis for the development of energy-saving intelligent grain dryer. [ABSTRACT FROM AUTHOR]

Sweet potato is an important food crop and energy crop. In order to solve the problems of larger loss rate and high damage rate of 4UZL-1 sweet potato combine harvester during the operation process, a potato connection and conveying mechanism was designed based on the analysis of the structure of 4UZL-1 sweet potato combine harvester and characteristics of domestic sweet potato planting models in this paper. The potato connection and conveying mechanism was mainly composed of a depth limiting mechanism, a digging conveying mechanism, an arc grid conveying mechanism and a scraper chain conveying mechanism. The working parameters were obtained through the kinematic and mechanical analysis of the working process of the mechanism. Aiming at the main evaluation indexes of potato damage rate and loss rate during the transfer and transportation, the Box-Benhnken test was presented on the basis of single-factor test. The angle of the digging conveyor, the conveyor angle of the scraper chain, the conveyor speed of the digging and the conveyor speed of the scraper chain were selected as testing factors. The multiple regression model of evaluation index to each factor was established, and the influence of each factor on operation quality was analyzed, and the optimal structure and operation parameters were obtained. The results showed that the order of the significance influence of factors on potato loss rate from large to small was that the conveyor angle of the scraper chain, the conveyor speed of the digging conveyor, the conveyor speed of the scraper chain and the angle of the digging conveyor. The order of the factors influencing on potato damage rate from large to small was the conveyor speed of the digging, the angle of the digging conveyor, the conveyor speed of the scraper chain and the conveyor angle of the scraper chain. When the forward speed of the machine was 1 m/s, the angle of the digging conveyor was 20°, the conveyor angle of the scraper chain was 68°, the conveyor speed of the digging was 1.2 m/s, and the conveyor speed of the scraper chain was 0.67 m/s, respectively, the potato loss rate was 1.12%, and the potato damage rate was 0.94%. Compared with the predicted values, the relative errors were 3.4% and 1.1%, respectively, the results satisfied the performance requirements of the 4UZL-1 sweet potato combine harvester. The study is benefit for the structure improvement and operation parameters optimization of the sweet potato combine harvester. [ABSTRACT FROM AUTHOR]

To solve the problems of low removal rate and incomplete separation for the current longitudinal-axial-flow combined harvester in the case of harvesting rice and wheat, a segmented longitudinal-axial-flow threshing device was designed in this paper. The threshing device mainly comprised a tapered threshing roller, a concave sieve with adjustable threshing strength, a 360° separation device and an electric control system for operating parameters. Through the single factor tests, the optimal switching states of the concave sieve with adjustable threshing strength for rice and wheat threshing was obtained respectively. In order to find out the influence rule of the working parameters of the device on the threshing effects and the optimal parameter combination, the multi-objective optimization tests were carried out. The rotational speed of roller, the angle of deflector, the threshing gap of concave sieve, the separation gap of concave sieve and the feeding rate were selected as the influence factors and the crushing rate, impurity rate and loss rate were selected as the test indexes. The test results showed that the significant sequence of influence of threshing parameters on the crushing rate was the rotational speed of roller, the threshing gap of concave sieve, the angle of deflector, the feeding rate, the separation gap of concave sieve. The significant sequence of influence of threshing parameters on impurity rate was the rotational speed of roller, the angle of deflector, the threshing gap of concave sieve, the feeding rate, the separation gap of concave sieve. The significant sequence of influence of threshing parameters on loss rate was the rotational speed of roller, the angle of deflector, the threshing gap of concave sieve, the feeding rate, the separation gap of concave sieve. Through multi-objective parameter optimization analysis, the optimal working parameters combination for wheat threshing were determined that the rotational speed of roller was 905 r/min, the angle of deflector was 69°, the threshing gap of concave sieve was 18 mm, the separation gap of concave sieve was 19 mm and the feeding rate was 4 kg/s. The field verification tests were carried out using the optimal working parameters combination. The results indicated that the crushing rate was reduced from 1.46% to 1.00%, the impurity rate was reduced from 1.85% to 1.43% and the loss rate was reduced from 1.72% to 1.20% compared with the conventional longitudinal-axial-flow threshing device. All the relative errors between the measured values and the optimized values were less than 5%, the working indicators met the requirements of relevant national standards. The device effectively solved the problems of high crushing rate, unclean threshing and incomplete separation, the research results can provide reference for the structural improvement and operation parameters optimization of the threshing device of longitudinal-axial-flow combined harvester. [ABSTRACT FROM AUTHOR]

Cotton is an important cash crop in China, the cotton straw produced after cotton harvest is an important biomass energy. In view of the environmental problems existing in the traditional utilization of cotton straw, it is of great significance to transform cotton straw from agricultural waste to biochar. Based on the research of biochar processing equipment for cotton straw at home and abroad, it can be found that biomass carbonization equipment is mainly divided into microwave cracking carbonization and traditional electric heating carbonization. The traditional carbonization technology has the disadvantages of uneven carbonization and low carbonization efficiency. The traditional carbonization technology has the disadvantages of uneven carbonization and low carbonization efficiency, microwave cracking carbonization can not only improve carbonization homogeneity, but also shorten carbonization time. In order to improve the carbon yield of cotton straw and analyze the effect of different operation parameters on the carbon yield of cotton straw by microwave pyrolysis, a microwave cracking equipment was developed in this paper. The microwave cracking equipment was mainly composed of gas-liquid treatment system, cracking chamber, inert gas supplying system, constant temperature control system and so on. The key component of the equipment was the magnetron device in the cracking chamber, the magnetron device provided energy for the pyrolysis and carbonization of the cotton straw. Taking the moisture content of cotton straw, carbonization time and microwave power as the experimental factors and the carbon yield of cotton straw as the index, the response surface tests of three factors and three levels were carried out for the microwave cracking process of cotton straw. The quadratic polynomial response model of cotton yield of cotton straw to experimental factors was established. The significant order of the influence of each experimental factor on the carbon yield of cotton stalk was determined as water content of cotton straw, microwave power and carbonization time. Optimization of operation parameters was carried out by box benhnken combined test method, the result was that the moisture content of the cotton straw was 11%, carbonization time was 6 min and microwave power was 1.8 kW, at this time, the carbon yield reached 31.61%. The verification test results showed that under the optimal parameter conditions, the carbon yield of cotton straw was 30.9%, and the relative error with the theoretical value was 0.71%, the designed microwave cracking equipment basically meet the design requirements. The results can provide reference for the design and operation parameters optimization of microwave cracking equipment for cotton straw. [ABSTRACT FROM AUTHOR]

Aiming at the problems of grapevine cold-proof cleaning in sandy loam soil areas of northern China in spring, such as, the degree of mechanization is low, the soil is not clean thoroughly, and the grape trees are easy to be damaged, this paper proposed a cold-proof soil cleaning parts with flexible brushes and rubber, and designed an automatic obstacle-avoiding grapevine cold-proof soil cleaner based on the coupled simulation method of multi-body dynamics software RecurDyn and discrete element software EDEM. The machine was mainly composed of frame, obstacle-avoiding swing mechanism, obstacle-avoiding signal acquisition mechanism, controller, soil cleaning parts, soil retaining plate, transmission mechanism and depth wheel. The structural parameters of the key components were determined based on the analysis of the working principle of the machine. The stroke of the obstacle-avoiding cylinder was 200 mm, the obstacle-avoiding cylinder bore was 40 mm, and the turning diameter of the soil cleaning parts was 550 mm. In order to reduce the amount of simulation calculations and improve simulation efficiency, the model was simplified and imported into the multi-body dynamics software RecurDyn. Using the discrete element software EDEM to model the soil particles and a ridge with an isosceles trapezoidal cross section was obtained. Based on coupling simulation tests of RecurDyn and EDEM, the automatic obstacle-avoiding process and the soil cleaning effects of the machine were simulated. The operating parameters of the machine were set in RecurDyn software, and the process and effect of soil cleaning were simulated in EDEM software. Taking the forward speed of the machine, the velocity of the obstacle-avoiding cylinder, the rotation speed of the soil cleaning parts and the threshold value of rotation angle of the touch rod as the test factors, the soil cleaning rate was the test index, the four-factor quadratic regression orthogonal rotation center combination simulation test were carried out. Design-Expert software was used to analyze the regression significance of the test data. The results showed that the four test factors all had a significant effect on the test index. Among the interaction factors, only the rotation speed of the soil cleaning parts and the threshold value of the rotation angle of the touch rod had a significant impact on the soil cleaning rate, while the other interaction factors had no significant impact. Among the quadratic factors, the square of velocity of obstacle-avoiding cylinder had a significant effect on soil cleaning rate, while the rest factors had no significant effect. Taking the maximum soil cleaning rate as the optimization goal, the optimal operating parameters of the machine was obtained: the forward speed of the machine was 0.43 m/s, the velocity of the obstacle-avoiding cylinder was 60 mm/s, the rotation speed of the soil cleaning parts was 550 r/min, and the threshold value of the rotation angle of the touch rod was 10 °, at this time, the theoretical soil cleaning rate was 54.65%. Based on the optimization result, the physical prototype was processed. Using the iron tubes inserted into the soil to simulate the concrete column, cold-proof soil ridges similar to that in the vineyard were generated by grapevine soil burying machine, the soil cleaning tests were carried out. The test results showed that the average value of the soil cleaning rate was 59.73%, the relative error between the test result and the simulation optimization result was 8.50%, the operation effects meet the requirements of automatic obstacle-avoiding grapevine cold-proof soil cleaning. The research results can provide theoretical basis and technical support for the overall design and optimization of obstacle-avoiding mechanism of earth-touching machines and tools. [ABSTRACT FROM AUTHOR]

At present, the vegetable planted by seedling cultivation and transplantation accounts for more than 60% of the total vegetable planting. It has the advantages of high and stable yield, climate compensation and land use efficiency improvement. However, vegetable production belongs to labor-intensive industry, the increasingly serious problem of difficult employment leads to the fact that the labor cost of vegetable production accounts for more than 50% of the total cost of vegetable production, which has become the main factor restricting its development. Therefore, it is an inevitable trend for the sustainable development of vegetable industry to study the mechanization and automation of vegetable transplantation. Taking and dropping seedlings is a very important link in vegetable transplanting. In view of the problems of automatic transplanting of vegetable seedlings in China, such as the complex and easy to fail of seedling picking and throwing device, a kind of oblique inserting plug seedling taking and throwing device is designed in this paper. The principle of picking and seeding device was analyzed, and then the location of taking point, throwing point and any point in the process of picking seedlings were selected. The projection method was used to design the device, and the structure and working parameters were determined. The length of the frame, driven rod, connecting rod, driving rod and seedling clip were 122, 196, 80, 186 and 227 mm respectively. In order to ensure that the device has a good effect of taking and throwing seedlings, the tilt angle of the seedling tray and the parameters of the seedling clamping into the hole are designed, and the movement process is analyzed. The feasibility of the scheme is verified by comparing the simulation trace curve with the actual test trace curve. According to the mathematical model of the working process of seedling taking and throwing device, kinematics analysis and simulation are carried out, and the position of seeding taking and throwing, speed and acceleration curve of the seedling clamp endpoint are obtained, the design meets the requirements of automatic transplanting. Considering the factors affecting the effect of taking and throwing seedlings, the spring stiffness coefficient, rotational speed of the active rod and the inclination angle of the seedling tray are selected as the experimental factors, and the orthogonal experiment was carried out. The results show that the best effect is obtained when the spring stiffness coefficient is 500 N/m, the speed of the active rod is 12 r/min, and the inclination angle of the seedling tray is 45°. Repeated experiments were conducted with the optimum parameters, the results show that the broken rate of substrates is 3.13%, the expulsion rate of seedlings is 2.43%, the success rate of seedling taking and throwing is 94.44%, the reliability of the device is high. The design provides a reference for the study of full automatic transplanting. [ABSTRACT FROM AUTHOR]

Residual plastic films degrade soil structure and have a detrimental impact on seed germination and the subsequent seedling development and establishment, thereby leading to reductions in crop yield. Removing the films from soil prior to sowing is hence critical to safeguarding crop growth. This paper presents a roller-type device incorporated into ploughing machine to simultaneously strip, collect the films from the soil and then unload them in a row prior to sowing. The device was nail-teeth designed to pick up and strip the residual films. The optimal combination of the structure and working parameters of the device was theoretically analyze using a quadratic regression orthogonal rotation test by taking forward speed of the machine, rotating speed of film pick up roller and rotating speed of film stripping shaft as determinants, and the efficiency of both film pick up rate and film stripping rate to represent the performance of the device. The significance of each determinant in affecting the rate of film pick up and stripping was analyzed using the Design-Expert software. The results show that in terms of impact on film pick up rate, the three determinants were ranked in the order of machine forward speed > rotating speed of film pick up roller > rotating speed of film stripping shaft, while in terms of impact on film stripping rate, the determinants were ranked in the order of rotating speed of film stripping shaft > rotating speed of film pick up roller > machine forward speed. Optimization calculated using MATLAB showed that the optimal working parameters were: device forward speed 1.62 m/s, rotating speed of film pick up roller 90 r/min, and rotating speed of film stripping shaft 1 055 r/min. We verified these optimal results against field experiments and found that the film pick up and film stripping rate was 70.56% and 82.96%, respectively. The differences between the experimental results and the calculated results was small, indicating that the optimized working parameters were reliable and robust. [ABSTRACT FROM AUTHOR]

The problem of environmental pollution caused by excessive use of chemical fertilizers has seriously restricted the sustainable development of green-oriented agriculture in China. Quantitative and uniform mechanized fertilization as an important measure to improve the utilization rate of chemical fertilizers and reduce the amount of chemical fertilizers has become an important way to solve agricultural environmental pollution. In this paper, a spiral disturbance cone centrifugal chemical fertilizer apparatus was designed to solve the problem of precision fertilization due to the insufficient fluency and stability of the fertilizer apparatus fertilizing processes and insufficient uniformity of fertilizer discharge. First of all, the design principles and working principles of the fertilizer apparatus is illustrated. Then the structural parameters of the spirally disturbance cup and curved cone disk are designed, based on the physical and mechanical properties of the granular fertilizer and the requirement of fertilization for rapeseed sowing. Moreover, fluency, uniformity and stability of the fertilizing performance are verified by bench test and field test. The SINO-AGRI fertilizer, STANLEY fertilizer and EZHONG fertilizer are respectively used as experimental materials to carry out the bench test of the fertilizer apparatus. The rotational speed of cone disc measured by SW6234C laser speedometer, there are total 6 levels, are 80, 90, 100, 110, 120, 130 r/min. Coefficient of variation of fertilizing amount consistency in every row, the coefficient of variation of fertilizing amount stability and coefficient of fertilizing amount consistency in same row are used as the evaluation index in the bench test for evaluating fluency, uniformity and stability of the fertilizing performance. The test results of bench show that the variation coefficient of fertilizing amount in every row of three compound fertilizers is below 11.5%. The coefficient of variation of fertilizing stability under chemical fertilizer conditions with different rotational speeds and physical and mechanical properties is below 6.3%, and the variation coefficient of fertilizing amount in same row is above 93%. Therefore, the fertilizer apparatus meets the quality requirements of fertilizer discharge. Meanwhile, variation coefficient of fertilizing amount in every row is 9.82% when the rotational speed of cone is low and the fertilizer apparatus is tilted, that means that the fertilizer apparatus still has better fertilizing performance in the inclined state. The adaptability applied to a narrow-width fertilizing machine of less than 8 rows is weak. The cone disc is successively rotated through the 1 to 8 row of fertilizer tube. When the rotational speed of cone disc is low, the next discharge tube of the blocked fertilizer pipe has a larger amount of fertilizer, the amount of chemical fertilizer in the other fertilizer pipes is basically the same, and the difference in the amount of fertilizer discharged from each row of fertilizer pipes is small. While the rotational speed of cone disc is high, the previous discharge tube of blocked has a larger amount of fertilizer, the difference between the fertilizing amount of this discharge tube and other discharge tube is larger, the amount of fertilizer in the other fertilizer tube is basically same. Furthermore, the field test was carried out to verify the fertilizing performance of the spiral disturbance cone centrifugal fertilizer apparatus. The results of field experiment show that the variation coefficient of fertilizing amount in every row is below 7.9%, the coefficient of variation of fertilizing stability is below 5.3%, the variation coefficient of fertilizing amount in same row is above 93.5%. This research provides effective technical support for chemical fertilizer reduction and precision fertilization. [ABSTRACT FROM AUTHOR]

The stem tip of vegetable sweet potato is an excellent nutritious and healthy food, which is widely used in many countries. It’s estimated that the total value of Chinese vegetable sweet potato’s market is about tens of billions of yuan, which means it has a promising future. Due to the difficulties of the long harvest period, high harvest requirement, and low mechanized level, the high cost and low efficiency in harvest is prominent. As such, it decreases the motivation of the farmers deeply. Also, the market still has a strong need for the stem tip harvester urgently. In order to fill the blanket in the mechanized harvest on stem tips of vegetable sweet potatoes in China, and to solve the current problems, in this research, we designed a stem tip harvester for vegetable sweet potatoes in combination with agronomy, which was composed of the reeling, cutting, conveying and collecting devices. It could finish cutting, conveying and collecting the stem tips for vegetable sweet potatoes every single row in one operation. In this paper, we introduced the harvester’s working theory based on analyzing the whole machine’s mechanical structure. To improve the integrity rate of stem tip, to lower the missing rate in cutting, to lower the stubble height and to improve the harvester’s working quality, we did a test on the harvester’s working parameters, using Box-Benhnken's central combination test method based on the single factor test. Three-level quadratic regression orthogonal experimental design was done through the forward speed, the reel speed and the reciprocating cutter line speed. The model of response surface was established to research and analysis the machine’s working quality due to different factors. Finally, the optimization of machine operation parameters was realized. The results showed that the prominent order in the stem tips’integrity rates was the reel speed > the reciprocating cutter line speed > the forward speed. The prominent order in the stem tips’missing rate was the forward speed > the reciprocating cutter line speed > the reel speed. The prominent order in the stem tip’s stubble height was the reel speed > the forward speed > the reciprocating cutter line speed. In 2019, the test was done in three times to verify the model’s correction in Baiba test base, Nanjing Research Institute for Agricultural Mechanization. The field test results showed the optimal working parameters were the forward speed 0.38 m/s, the reel speed 26 r/min, and the reciprocating cutter line speed 0.60 m/s. The integrity rate of stem tips was 97.10%, the missing rate was 12.11%, and the stubble height was 62.09 mm. The error was in the range of 5% compared to the theoretical optimization. Compared with the single manual picking efficiency of 0.001 hm²/h, the operating efficiency of this machine can reach 0.1 hm²/h, The operation effect of the machine was obviously improved compared with that of manual operation, better to meet the requirements of the vegetable sweet potatoes’stem tips machinery harvesting. The test research supplies a strong support and theoretical basis to the mechanical development of the harvester for vegetable sweet potatoes’stem tips. [ABSTRACT FROM AUTHOR]

The soil-covering and press wheel are the main parts of the corn planter, and their performances are directly related to the growth and the output of the corn. The device with the functions of soil covering and soil compaction can improve the soil moisture content after planting and simplify the structure of machine. The squeeze-type coverer is a typical device with the functions of soil covering and soil compaction. But due to that the contact area is too small to bring the poor stability of soil-covering and soil-compacting during work process, the squeeze-type coverer is often used on no-till planter. A new type of soil-covering and soil-compacting device for corn planter was designed in this paper. The device was composed of 2 soil-covering-pressing wheels with cone-shaped structure, and realized the functions of soil-covering and soil-compacting depending on the extrusion force of soil produced by soil-covering-pressing wheel during planting. The main structure parameters of the soil-covering and soil-compacting device were determined through theoretical analysis and experiment of double-disk opener, which were mean diameter of 350 mm, width of the horizontal part of single soil-covering-pressing wheel of 20 mm, width of the inclined surface of single cover-press wheel of 70 mm, and the value range of horizontal interval of left and right soil-covering-pressing wheel of less than 29 mm. The leaning angle of soil-covering-pressing wheel was determined through theoretical analysis of soil-covering process based on the shape of soil furrows, which meant the leaning angle was about less than 20°. Based on the agronomic requirement of soil-compacting, the range of external load was about 609-790 N. Through analyzing, it was found that the external load, the horizontal interval between left and right soil-covering-pressing wheel and the leaning angle were the main influencing factors on the functions of soil-covering and soil-compacting of the device. Taking the 3 indices as the experimental factors using Design-Expert software, the Box-Benhnken experiments of 3 factors and 3 levels were conducted, and the results showed that the order of the influence of the factors on the soil compactness in the top 5 cm soil layer of the seed furrow from high to low was the external load, the horizontal interval between left and right soil-covering-pressing wheel and the leaning angle. The order of the influence of the factors on thickness of covering soil was the leaning angle, the load and the horizontal interval between left and right soil-covering-pressing wheel. The optimal parameter combination of the device was the external load of 900 N, the horizontal interval between left and right soil-covering-pressing wheel of 13 mm and the leaning angle of 16°. Verification testing indicated that the soil compactness in the top 5 cm soil layer of the seed furrow was (43.8±1.9) kPa, the coefficient of variation was 4.3%, and the thickness of covering soil was (32.9±2.3) mm with the coefficient of variation of 6.9%. The soil-covering and soil-compacting device designed in this paper has good performance of soil-covering, soil-compacting and working stability. This study can provide a reference for the design of planters. [ABSTRACT FROM AUTHOR]

As a large agricultural country, there are still more than 40% of people in China engaging in agricultural production activities. In recent years, the soil erosion and desertification have been in serious state, and the arable land has decreased year by year, which means that it is very necessary to develop agricultural technology to improve crop yield per unit area. Therefore, in recent years, China has vigorously developed agricultural greenhouse cultivation which has characteristics of high input, high technology and high yield. Agricultural greenhouse cultivation is an important part of China’s agricultural production. In 2014, the area of greenhouse in China was up to 4.109 million hm2. With the promotion of precision agriculture, the technology of modern agricultural greenhouse cultivation is developing towards precision. Precision fertilization is one of the important parts of precision agriculture operation system. Due to that the structure of modern agricultural greenhouse is closed, and the planting area is limited in China, the large agricultural machinery cannot be applied to greenhouse operations, leading to that the mechanization level in greenhouse production is lower than other developed countries in the world. At present, the fertilization in greenhouse in China is still mainly relying on manpower. Because of the increasing labor cost and decreasing yield in greenhouse production, the profits of greenhouse is reduced. In the pursuit of more profit, people’s requirements of precision fertilization in greenhouse are increasingly urgent. This paper mainly introduced a small, precise and practical fertilizing machine. This machine was mainly used in greenhouse and it was intelligent and automatic. The fertilization machine used ARM9 S3C2440 microprocessor as the core of circuit control module. It was equipped with a fertilizer level monitoring alarm device, and would alarm automatically when the fertilizer level was less than 15 cm, so that the staff could add fertilizer in time. The machine used the Geneva mechanism as fertilizer metering mechanism. By controlling the pulse frequency of the stepping motor, the amount of fertilization could be controlled so as to achieve quantitative precision fertilization. The three-dimensional model of the fertilization machine was built by the SolidWorks. The intensity check was performed for its main parts of the force with simulation. All those verified that the structure could meet the requirements of hardness and intensity. The fertilization effect was simulated by the EDEM (enhanced discrete element method), a general CAE (computer-aided engineering) software applied to the discrete element method. In the simulation, the speed of the sheave was set to 10 r/min, the output time step was 0.05 s, and the total simulation time was 5 s. It was found that there weren't flying particles during the process of simulation, which showed that the selected rotational speed of the sheave and the parameter of the simulation time step were reasonable. The sheave grooves in the process of simulation were almost filled with the fertilizer particles, which proved that the device could get a good effect of fertilization and the parameter of the sheave was reasonable. The brush structure in the fertilization device could effectively get rid of the extra fertilizer particles and supplement fertilizer particles for other incompletely filled groove in order to make sure every groove could discharge a certain amount of fertilizer. The simulation results showed that the fertilization device could discharge the fertilizer particles evenly, stably and continuously. By properly controlling the rotation speed of the drive shaft, the fertilization machine could achieve the goal of precise fertilization. The results show that maximum error of fertilizer test actual value and the theoretical value is 2.42%, less than 3% under four kinds rotational speed (5, 10, 15, 20 r/min). Therefore, the machine designed in this paper could greatly improve the automation level for greenhouse production and reduce the labor intensity of fertilization in greenhouse. It has broad applicability and popularity in our facility greenhouse production. [ABSTRACT FROM AUTHOR]

To enhance the mechanization level of potato cultivation and promote the development of potato industry, we research and design a cup-belt type seed-metering device of potato seeder. This potato seed-metering device is mainly aimed to solve many problems, including the high multiple index and missing index, heavy manual labor intensity, poor universality and other problems commonly occurring in the widely used potato seed-metering device at present. This paper introduces the main structure, the working principle and the related structural parameters of the device in detail. In this paper, we design the structure of many key components. The arrangement form of scoops on the belt, the working principle and the structure of the vibrating cleaning device, and the structure of the active belt pulley and the arch breaker are analyzed through the theoretical analysis. The parameters obtained from the theoretical analysis are used to design the cup-belt type seed-metering device. The actual utilization indicates that the seed-clearing system driven by electric motor has a simpler structure and more stable operating condition. The arch breaker increases the liquidity of the seeds and improves the filling rate. We also make a list of experiments to understand how the factors affect the performance of the potato seed-metering device and analyze the experiment results. These experiments include the overall experiment, the bench test and the field experiment. We also design an overall experiment to investigate the filling performance and the height caused by entrainment. We determine the revolving speed of the driving pulley and the number of the seeds in the seed case as the experimental factors of this experiment. The experimental results show that: when the revolving speed of the driving pulley is 33.4 r/min and the seed case is full of seeds, the average empty scoop rate is 0.33%; when the revolving speed of the driving pulley is 33.4 r/min and the seed volume is 12.5% of the seed case volume, the average height caused by entrainment is 25 cm. But even the seed case is full of potato seeds, the maximum height caused by entrainment is below the driving pulley axle. In other words, the phenomenon will not happen that the seeds are entrained into the guide pipe which causes reseeding. So when the revolving speed of the driving pulley is 33.4 r/min and the seed case is full of seeds, the working performance of the seed-metering device also meets the requirements. An orthogonal experiment is carried out in order to understand how the experimental factors affect the performance of the seed-metering device. These factors include the revolving speed of the driving pulley, the inclination of the seed-metering device and the vibration strength of the seed-clearing device. Each factor has different influence on the performance. The optimal working parameters can be concluded through these experiments and a validation experiment is carried out to verify the optimal working parameters. The experimental results show that: when the revolving speed of the driving pulley is 42 r/min, the inclination of the seed-metering device is 0° and the vibration strength of the seed-clearing device is 0.75, leading to the best performance. The qualified index is 92.6%, the multiple index is 4.5%, and the missing index is 2.9%. The field validation experiment shows that the performance of metering device under the condition can meet the potato seeder’s working performance requirements. This research provides a theoretical and technical reference for the research and design of seed-metering device of potato seeder. [ABSTRACT FROM AUTHOR]

Potato is one of the fourth staple food crops in China. Medium tillage operations such as loosening soil, crushing soil, soil cultivation and weeding during the early seedling and middle growth stages of potatoes have a great influence on potato yield. The main functions of mid-tillage include loosening soil, enhancing soil permeability, preserving soil moisture and drought resistance, improving soil physical properties, improving soil fertility and eliminating weeds, and mid-tillage can resist lodging and increase crop yield. Potato mid-tillage production has a large amount of work and its operation process is limited by growing crops. Therefore, it is of great significance to develop a potato mid-tillage machine with high working efficiency and good operation effect. Aiming at the problems of low soil breaking rate, weeding rate and poor soil cultivation effect of traditional hoe-shovel type cultivator under the condition of soil cohesion and compaction, a driving potato cultivator which integrates the functions of deep loosening and crushing soil, weed eradication, side deep fertilization, soil cultivation and ridging is designed in this paper, the key parts of the machine and the structure of the deep loosening shovel, soil crusher and soil cultivator are designed and analysed. On the basis of design and analysis, field experiments are carried out. The machine is mainly composed of deep loose soil device, soil conservation device, fertilization device and transmission system. Eight blade dishes are installed symmetrically on the left and right sides of the blade shaft. Each blade dish is fixed with two soil breaking blades. The length of the soil breaking blade is 242 mm, the width of the soil breaking blade is 40 mm and the thickness of the soil breaking blade is 10 mm. In order to adapt to different kind of soil conditions, the adjustment range of the subsolier is 150-250 mm, the height of the subsolier is 560 mm. The test results show that the soil breaking rate of driving-type cultivator is 95.1%, weeding rate is 96.3% and the injury rate is 1.2%, the soil bulkiness is 49.3%, and the fuel consumption is 13.2 kg/hm2, which met the relevant performance evaluation indicators. Compared with the traditional hoe-shovel type cultivator, the soil breaking rate of, weeding rate and soil bulkiness of the driving-type cultivator increase by 3.3%, 3.1% and 7.8%, injury rate and fuel consumption decrease by 1.6% and 28%. The operation effect of the driving-type cultivator has been improved significantly, exceeding the national standards and meeting the requirements of potato cultivation and agronomy. This research results can provide a reference for the development of potato cultivators. [ABSTRACT FROM AUTHOR]

Vegetable pot seedling transplantation has many advantages, such as high survival rate, promoting crop early maturity and improving land use rate. Mechanized transplanting of vegetable can be divided into semi-automatic transplanting and fully-automatic transplanting. Semi-automatic transplanting is mainly carried out by feeding the seedlings into the seedling transplanter manually, which has low efficiency and high labor intensity, and it is not conducive to field operations. At present, the automatic transplanting machine mainly adopts multiple mechanisms to complete a series of actions such as picking up seedling, conveying and planting, but it has the disadvantages of complex structure, high cost and low efficiency. In order to simplify the structure, the way to complete the transplanting operation with a single mechanism is proposed. However, due to the complicated working trajectory of transplanting vegetable seedling and much posture requirements, the transmission ratio of the mechanism is required to be changed greatly, which resulting in the irregular shape of the non-circular gear section of the single planetary gear is not conducive to processing and affects the transmission performance of the gear. A double-planetary non-circular gears linkage of vegetable pot seedling transplanting mechanism is proposed to solve the problem mentioned above in this paper. The transmission part of transplanting mechanism is composed of planetary gear train mechanism and crank rocker mechanism, The main planetary frame rotates at a uniform speed, through the transmission of internal gears and connecting rods, the unequal transmission of non-circular gear system and the periodic variable-speed swing of crank-rocker mechanism are superimposed, which makes the sub-planetary frame swing with respect to the main planetary frame and the transplanting arm rotate with respect to the sub-planetary frame, thus the transmission ratio needed to realize the complex transplanting trajectory and posture is obtained. Non-uniform B-spline curve is applied to fit the pitch curve of non-circular gear to obtain closed, smooth and continuous pitch curves, and the mathematical model of gear train is established based on coordinate transformation theory. Based on the development platform of Matlab, an optimization program is compiled to analyze the effect of transmission case noncircular gear pitch curve and crank rocker mechanism on the shape of trajectory. Further, the effects of the structure and position parameters of the gears and transplanting arm on the target parameters of the transplanting trajectory are analyzed. According to the requirements of 220 mm planting spacing, 120 mm seedling height and 40 mm deep pot for celery transplantation, a set of sharp beak trajectory that satisfies the requirements of the operation posture of picking up seedling and planting is optimized. The optimizing values are that the length of the picking up seedling trajectory is 33 mm, the distance from the lowest point of the trajectory to the lowest point of the planet carrier is 55 mm, the angle of picking up seedlings is 23°, the angle of change in the process of picking up seedlings is 16°, the angle of planting seedlings is 65°, the whole height of the trajectory is 355 mm, and the height of the buckle of the moving trajectory is 125 mm. A three-dimensional model of the mechanism is built and a virtual simulation is performed based on the optimization result. The results show that the simulated trajectory and velocity of the transplanting mechanism are basically consistent with the theoretical results. The trajectory and postures of the transplanting arm are analyzed by a test bench, industrial camera and image processing software. The results show that the trajectory of seedling-taking and seedling-pushing sections coincides with the simulation trajectory basically and the theoretical data, and the error is within 2 mm, which can meet the requirements of transplanting operation, the transplanting mechanism designed is reasonable and feasible. [ABSTRACT FROM AUTHOR]

The rice-wheat cropping system is the main grain production model in many areas of China, especially in Jiangsu with the area of about 1.8×106 hm2. In other provinces of China along the Yangtze River valley, such as Sichuan, Anhui and Hubei, there are large areas of such cropping system. However, the rice straw processing before wheat planting has caused some problems in these places. As straw burning is forbidden by the government, straw incorporated to field is an available alternative method to process the rice straw. Traditionally, rice straw should be smashed and buried before wheat planting, which requires time and energy. Also, burying rice straw in soil will influence the growing of wheat if the seed stay on the straw. Furthermore, the soil nutrient will be consumed during straw decomposing. The clean area planting technology under full straw cropland, invented by Nanjing Research Institute for Agricultural Mechanization, Ministry of Agriculture and Rural Affairs, China, can complete seeding and straw mulching in the same time, which is a good method to deal with the straw processing problem. However, as the quantity of rice straw is relatively larger than any other straw, the excess rice straw mulching will impact the emergence of wheat, which is likely to cause low yield. To solve the problem, in this paper, we provided the rice straw processing model of part burying and part mulching based on the clean area planting technology under full straw cropland. Then, different straw distributed retention devices with different structures, including flat board with horizontal upward opening, oblique board with horizontal downward opening, flat board with several longitudinal openings and curved board with several longitudinal openings, were designed and introduced respectively. After the tests of these distributed retention devices under different parameters, the structure of curved board with several longitudinal openings was selected as the best one. On the basis of structural development, the central composite test method was used to optimize the key parameters of straw distributed retention device. The gross width of longitudinal opening, quantity of longitudinal opening and revolving speed of picking and smashing device were taken as the influencing factors. The variable coefficient of uniformity and deviation rate of distribution were taken as response values in the experimental study. Orthogonal rotational quadratic combination test with three factors and three levels was made to evaluate the combined influence of the factors on the test index value. Furthermore, regression equations to describe the relationships between the factors and each assessment index were established by using the regression analysis and response surface analysis with the software Design-Expert 8.0.6. The optimum combination of the selected parameters was obtained and verified, and the experimental verification of the mathematical model was also conducted. The results showed that trial factors had great effects on the performance of straw distributed retention device. The significant effects of quantity of longitudinal opening, gross width of longitudinal opening and revolving speed of picking and smashing device on reducing the variable coefficient of uniformity were in a decreasing order. The significant effects of gross width of longitudinal opening, quantity of longitudinal opening and revolving speed of picking and smashing device on reducing the deviation rate of distribution were in a decreasing order. The best parameters of the integrated straw distributed retention were as follows: when the gross width of longitudinal opening was 600mm, the quantity of longitudinal opening was 7 and the revolving speed of picking and smashing device was 1900r/min, the variable coefficient of uniformity and deviation rate of distribution were 18.75% and 0 respectively. The model validation tests were repeated for 3 times on the simulation field by using the optimization results, the values of practical variable coefficient of uniformity and deviation rate of distribution were 19.68% and 0 respectively. The percentage points of absolute error between the experimental and predicted values of variable coefficient of uniformity and deviation rate of distribution were 0.93 percentage point and 0.33 percentage point respectively, which indicated a reasonable choice of optimization conditions. The research results can provide references of technology and equipment for wheat planting after the harvest of rice in rice-wheat cropping system area in China. [ABSTRACT FROM AUTHOR]

In order to reduce tillage resistance, ameliorate the soil layer structure and improve soil breaking rate of soil crushing roller, a combined tillage machine which has function of subsoiling, rotary tillage and soil breaking was designed in this paper. The machine mainly consists of a fixed mount to connect the subsoiler, rotary and soil crushing roller with the machine frame, the self-excited vibration subsoiler breaks the bottom of the plow pan, the rotary tiller flattens the soil and further shreds the soil, the soil crushing roller further breaks the soil thus creating a seedbed suitable for plant growth. 2 major components of machine are optimized to solve the problem of large tillage resistance and poor soil breaking effect. Firstly, the self-excited vibration subsoiler with controllable penetration angle was designed, which can avoid the problem of poor drag reduction effect and stability of tillage depth when the penetration angle of subsoiler is too large. The subsoiler produces a vibration to loosen the soil to achieve the purpose of drag reduction because of resistance changes in soil operation. In addition, the penetration angle of subsoiler is controlled to a range to maintain the stability of subsoiling depth. To ensure the compression spring can not be tilted during the subsoiling operation, and considering the problem of large load and limited installation space, the combination spring is selected as the self-excited vibration spring. Through the kinematics and mechanical model of self-excited vibration subsoiler, the deflection is 15 mm and the minimum and maximum loads are 7 500 and 15 000 N respectively, then the parameters of the combined spring was determined. Secondly, in order to realize the secondary soil-broken function, a caged soil crushing roller was designed by staggered welding of rhombic soil-broken teeth on a cylindrical drum with clearance. The soil is first broken by the outside teeth of soil-broken tooth, and the large soil will enter the cylindrical drum inside through the gap and will broken under the action of inside teeth, which can’t adhere to the cylindrical drum. The caged soil crushing roller diameter and thickness of soil-broken teeth is calculated according to the design formula of the disc harrow. To study the drag reduction effect and tillage quality of self-excited vibration subsoiler, the experiment in the soil bin is carried out, and the field experiment of operation performance of the machine is carried out. The soil bin experiment results showed that the self-excited vibration subsoiler has obvious effect on drag reduction, and the average drag reduction is 9.22%, and the soil fluffy degree and disturbance coefficient is 26.16% and 77.21% respectively. The field experiment results showed that the stability coefficient of subsoiling depth, stability coefficient of depth of soil preparation, surface flatness, vegetation coverage and soil breaking rate is 94.92%, 92.50%, 1.17cm, 93.36% and 84.18% respectively. The soil breaking rate of ordinary soil crushing roller is 71.41%, which indicates that the caged soil crushing roller can effectively improve the soil breaking effect. Moreover, the caged soil crushing roller did not appear soil adhesion and congestion during the test. All parameters meet the requirements of the work quality standards. Therefore, the machine has obvious effect of reducing resistance and quality of the soil preparation. This study can provide a theoretical reference for further research of combined tillage machine of subsoiling and rotary. [ABSTRACT FROM AUTHOR]

Astragalus smicus, also known as Chinese milk vetch, Zi yunying and so on, is one of the main winter green manure crops in paddy fields of central and southern China, it has the advantages of reducing fertilizer input, improving soil fertility, increasing crop yield and quality, and protecting ecological environment, and has strong nitrogen fixation ability and high utilization efficiency. In recent years, the production machinery of Astragalus smicus has been developed and applied rapidly in terms of capacity and utilization efficiency, but its development still lags behind. Ditching and sowing are important links in the production of Astragalus smicus. The yield of Astragalus smicus is largely determined by the quality of sowing, and ditching operation can make Astragalus smicus grow well in low-humid field with poor drainage or sandy soil with poor fertilizer and water retention. Astragalus smicus is often used as green manure in paddy field, but high stubble retention, large amount of straw, insufficient in sowing height of existing other sowing equipments, working parts easily clogged, etc., bring difficulties for mechanized production of Astragalus smicus. In order to solve the influence of machine-harvested rice stubble on mechanized production of Astragalus smicus, aiming at the problems of low quality and low production efficiency in independent ditching and sowing links at present, a Astragalus smicus ditching and sowing machine which suitable for machine-harvested rice stubble field was developed. A height adjustable sowing device was designed, by which the sowing components could be lifted to a proper position according to the residual straw situation in the field. The special seed-metering wheel and quantitative evenly-sowed device for Astragalus smicus were developed to achieve precision sowing and improve the sowing uniformity. The structure and working parameters of the double-disk ditching components were determined. The variation coefficients of ditching width and depth determined by field experiments were less than 6%, which met the drainage requirements of Astragalus smicus growth process. The multiple factor experiments and regression analysis of the test data were carried out by Design-expert software, the results showed that forward speed of machine, rotation speed of seed-metering wheel, seed-uniforming cylinder diameter significantly affected the sowing performance, the results of variance analysis showed that the rotation speed of seed-metering wheel had the greatest influence on the emergence rate and coefficient of variation of sowing uniformity, while the forward speed of machine had the least influence on the emergence rate and coefficient of variation of seed-metering quantity consistency, regarding the coefficient of variation of sowing uniformity, the most influential factor was seed-uniforming cylinder diameter, and the minimum impact factor was the rotation speed of seed-metering wheel, the optimal factor parameters combination which affected the sowing quality of Astragalus smicus ditching and sowing machine was as follows: forward speed of machine was 4.6 km/h, rotation speed of seed-metering wheel was 44 r/min, seed-uniforming cylinder diameter was 6 mm. Verified by field experiments, the Astragalus smicus emergence rate was 95.87%, quantity consistency was 12.7%, coefficient of variation of sowing uniformity was 8.07% in the condition of optimal parameter combination, the relative error was below 3% compared with optimal values predicted by the model. Compared with the existing sowing methods of Astragalus smicus, working efficiency of the designed ditching and sowing machine was 1 hm2/h, which was superior to the artificial sowding working efficiency of 0.1 to 0.125 hm2/h, the hand-shaking working efficiency of 0.2 to 0.3 hm2/h and the motorized sowing working efficiency of 0.5 to 0. 8 hm2/h, and was lower than the UAV sowing working efficiency of 3 to 4 hm2/h. In addition, the coefficient of variation of sowing uniformity and the combination type of ditching and sowing machine were also significantly superior to that of other methods. The Astragalus smicus ditching and sowing machine developed in the paper integrated ditching and sowing links in one operation, the working efficiency was greatly improved, the research provided a new method for Astragalus smicus ditching and sowing machine for machine-harvested rice stubble field. [ABSTRACT FROM AUTHOR]

The main ways of crushed corn straw conveying are pneumatic conveying, screw conveying, belt conveying, scraper conveying, bucket lifting and chain conveying. Screw conveyor is widely used in the processing of rubbing and breaking corn straw due to its advantages of compact structure, flexible arrangement, good sealing and controllable feeding amount. However, due to the small density, viscosity and poor fluidity of crushed corn straw, the conveying performance is difficult to be guaranteed. There are some problems such as low productivity, high power consumption, easy jammed and serious abrasion in the process of conveying the agricultural fiber materials. In order to solve these problems, the theoretical analysis of conveying process about screw-pneumatic conveying device was carried out in this paper. The force of crushed corn straw during the conveying was analyzed. On this basis, the productivity model, power consumption model and specific power consumption were built. The screw flow transmission principle was considered, and the screw-pneumatic coupling conveying device was designed. The experimental platform was mainly composed of screw conveying device and pneumatic auxiliary conveying system. The parameters of the experimental platform were as follows: the conveying gap length was 2 500 mm, the diameter of the screw blade was 250 mm, the diameter of the center shaft was 60 mm, the screw pitch was 335 mm respectively, and the space between the screw blade and the shell was 5 to 8 mm. The pneumatic auxiliary conveying system was mainly composed of Y-shape nozzle holder with adjustable injection angle, nozzle, air compressor with maximum outlet pressure of 1.6 MPa, polypropylene random straight pipe with 10 mm diameter, 15° bending pipe and pressure gauge. The experiment materials were the corn straw after crushing through 9R-60 rubber and with less than 100 mm long, 2 to 8 mm wide, and 38% moisture content. Based on the performance index of specific power consumption, axial thrust, pressure on the screw blade and shell, the impacts of airflow velocity on transportation performance were analysed. The results showed that: When the screw pitch was 335 mm, the rotation speed was 100 r/min, and the feeding amount was 70 kg/min, within the range of airflow velocity 10～50 m/s, the greater the pressure on the outer edge, the greater the pressure on the screw blade. the pressure was different at different points of screw blade, the closer to the outlet, the greater the pressure was on all parts of the blade. On the same area of the shell, the pressure on the arc segment was greater than that of the vertical section. For different area of the shell, the pressure on the arc segment and vertical section of areaⅠwas greater than that of the areaⅡ. The pressure was different at different points of shell, the closer to the outlet, the greater the pressure was on all parts of the shell. The specific power consumption of the screw-pneumatic coupling conveying device first decreased and then increased with the increase of airflow velocity, when the airflow velocity was 20 m/s, the specific power consumption was the minimum, which was 10.78 W/kg, which was 8.3% lower than that of without airflow. The axial thrust, pressure on blade and shell decreased with the increase of airflow velocity, and was all less than that of without airflow. [ABSTRACT FROM AUTHOR]

Considering the problems of low efficiency and large area without weeding around the vine after operation, a bilateral operation intra-row auto obstacle avoidance weeder for trellis cultivated grape was designed. The weeder consisted of frame, hydraulic system, transmission system, land wheel and weeding device. Frame was installation carrier for all of machine components. Hydraulic system was used to provide power for weeder, driving two hydraulic motors and four hydraulic cylinders. Transmission system was the medium which transmitted power from tractor to hydraulic system. Land wheel made it possible to adjust the weeding depth. Weeding device was the key component for the weeder, and it was composed of row width adjustment mechanism, signal acquisition mechanism, auto obstacle avoidance mechanism and weeding cutter head. The extending distance of row width adjustment mechanism could be adjusted from 0 to 400 mm to adapt different row spacings in different fileds. The specific location of the grape vine could be identified correctly with signal acquisition mechanism. And the obstacle avoidance mechanism could avoid weeding cutter head from contacting the grape vine, which probably caused injuries. The weed was destroyed under high-speed rotation of weeding cutter head driven by hydraulic motor. The parameters of these key components of weeding monomer were determined by theoretical analysis and experiment. In order to research the effects of structural and operation parameters of automatic obstacle avoidance weeder, a brief virtual prototype model was built in ADAMS software, and key components were parameterized simultaneously. To simplify calculation, using link mechanism to replace the complex machine and constraints were set between different links. Kinematics simulations was carried out using virtual prototype model, and the simulation results of operating trajectory of weeding cutter head agreed with theoretical analysis. Then single factor simulation experiments were carried out in ADAMS with the coverage rate of weeding selected as the evaluation index. The simulation results confirmed that speed of obstacle avoidance hydraulic cylinder, operating speed of the weeder and angle threshold (defined as the rotation angle of feeler lever when control system triggered the automatic obstacle avoidance mechanism) were the main influence factors. Operating speed and angle threshold had positive impact on it, while speed of obstacle avoidance hydraulic cylinder had negative impact on it. In addition, quadratic regression general combination experiments were conducted by taking speed of obstacle avoidance hydraulic cylinder, operating speed and angle threshold as the experiment factors and coverage rate of weeding as the evaluation index. Analysis of variance (ANOVA) was performed to find the statistically significant parameters in field experiments and quadratic regression model was set up by response surface methodology with Design-Expert 8.0.6. It was showed that speed of obstacle avoidance hydraulic cylinder, operating speed and angle threshold were extremely significantly (P<0.01) effective parameters, and the interaction of speed of obstacle avoidance hydraulic cylinder speed, operating speed and angle threshold were significantly (P<0.05) effective on coverage rate of weeding. Furthermore, the optimizing function of Design-Expert 8.0.6 was used for the optimization in this paper and the results showed that when speed of obstacle avoidance hydraulic cylinder was 160 mm/s, operating speed was 380 mm/s and angle threshold was 15.12°, the optimal average coverage rate of weeding was 90.15%. Field experiment with the optimal combination of key parameters were carried out to testify the validity of optimization. The coverage rate of weeding was 90.02%, which is 0.67 percentage points higher than the results of quadratic regression general combination tests. This study could provide a reference for further research of intra-row weeder for trellis cultivated grape and other plants. [ABSTRACT FROM AUTHOR]

Small deep-cultivators with light weight and simple structure are urgently needed to satisfy the requirements of deep cultivating in hilly regions. Development of a low power-consumption rotavator is a prerequisite for the lightweight of a small deep-cultivator. In this paper, in order to reduce the power consumption of the rotavator for a small vertical-shaft deep-cultivator, a multi-helical rotavator was proposed. The multi-helical rotavator consisted of a vertical-shaft rotavator head and 3 discontinuous multi-helical cutters that are unevenly distributed along the circumference of the head. The discontinuous multi-helical cutter consisted of a cutter-shaft and 3 discontinuous helical cutter edges that are evenly distributed along the axis of the cutter-shaft. The rotavator head had a diameter of 250 mm and the rotavator had a design tillage depth of 30 cm. The cutter-shaft length was 0.35 m and the helical angle of the helical cutter edge was 53º. Based on the motion analysis of the multi-helical rotavator, the motion path and its parameters model were established. The structure and operating parameters of the discontinuous multi-helical cutter and the rotavator were designed and analysed. Then the three-dimensional models of the discontinuous multi-helical cutter and the rotavator were established for simulation analysis. Based on the SPH (smoothed particle hydrodynamics) algorithm, the motion of soil particles, cutting resistance and power consumption were simulated and analysed during the operation of the discontinuous helical cutter and the traditional vertical-shaft orthogonal cutter in ANSYS LS-DYNA. In addition, an actual multi-helical rotavator was manufactured and its tillage effect and power consumption were tested. The simulation results showed that, comparing with the traditional vertical-shaft orthogonal cutter, the performance of the discontinuous helical cutter was significantly improved. 1) The discontinuous multi-helical cutter could greatly stir the upper soil particles, and the displacement of the upper soil particles was obviously increased during the cultivation process. At the same time, the lower soil particles were only slightly disturbed, and the displacement of the lower soil particles was significantly reduced. 2) The cutting resistance of the designed discontinuous helical cutter decreased by an average of 37.5%. Besides, the fluctuation range of cutting resistance decreased by an average of 60.6%, which could reduce the rotavator vibration and make the small deep-cultivator to work more stably and more reliable. 3) The total energy consumption of the designed discontinuous helical cutter was reduced by 58.7% and the average power consumption was reduced by 47.6%, which could reduce the weight of the small deep-cultivator under the same power consumption conditions. The test results showed that the actual power consumption of the designed multi-helical rotavator was 2.86 kW, which was 11.28% higher than the simulation value of 2.57 kW. The simulated power consumption value was close to the test value, which verifies the validity of the simulation results. At the same time, the average tillage depth of the designed multi-helical rotavator was 28.7 cm with a stability coefficient of 94.64% and the average soil pulverizing rate is 76.02%. Therefore, the designed multi-helical rotavator had better crushing and throwing ability than the traditional vertical-shaft orthogonal cutter, and could improve the soil subsoiling effect while meeting the requirement of the tillage depth. The reduction in cutting resistance and the decrease in cutting resistance fluctuation could also reduce the power consumption and vibration of small deep-cultivators. [ABSTRACT FROM AUTHOR]

Aiming at the present situation of high labor intensity and low precision of plant spacing control in fruit tree planting, the agricultural machinery agronomic integration technology based on standardized cultivation mode was studied in this paper, and an apple planting machine for high density dwarfing orchard was designed, the key technical problems in mechanized planting of fruit seedlings, such as continuous wide and deep furrow opening, vertical planting of fruit seedlings and precise control of plant spacing, were solved. The apple planting machine for high density dwarfing orchard was powered by a tractor above 58 kW and used a rear three-point suspension operation mode. The structure mainly composed of continuous ditching device, clamping and conveying device, fixed-distance planting device, overburden pressing device and other auxiliary devices. The ditching device was powered by power-output shaft to drive opener ditching continuously. V-type double-disc opener was used, ditching blade was installed on ditch cutter supported by inclined bearings. Soil retaining plate was installed at the rear of the opener, front and side plates were used with the opener to ensure the grooving structure was stable. Bottom plate was used together with grid bar to assist positioning. By manually placing the seedlings and placing the rotes on the bottom plate, the tree trunk was placed obliquely on the grid bar lying on the conveying channel for initial positioning. After the sensor of the fixed-distance planting device installed at the rear of the frame detected the position information of the planted seedlings, the cylinder action of the clamping conveyor was started by controlling the switch. the positioning bar was opened, and the seedlings entered the clamping state, and then the seedlings were transmitted backward by the carrying belt. The carrying belt was powered by the ground wheel with the same rate, therefore, the speed of the carrying belt was the same as the machine working speed, and the seedlings were placed in the planting ditch statically with a zero speed relative to the ground, then the scraper-type cover pushed back the soil and the compaction wheel pressed the soil compactly, at the same time it pushed forward the seedlings to complete the upright planting. The fixed-distance sensor detected the seedlings just planted, the process was repeated, ensuring the distance between the adjacent 2 seedlings was equal, continuous ditching, vertical planting, backfilling and repressing were realized in one-time. By adjusting the height of the bottom plate (from 0 to 20 cm), the angle and depth for initial inclined positioning could be changed, so that the machine could work in different soils and for different varieties. The ditching depth of the machine was adjustable from 0 to 40 cm, the ditching width was 30~37 cm, and the working speed was 0.8-1.5 km/h. The results of field experiment showed that the average qualification rate for planting depth was 91.43%, the average planting qualification rate was 93.79%, and the variation coefficient of plant spacing was about 5.03%, average planting efficiency was about 720 plants per hour, which was 36 times more efficient than manual planting, the machine worked stably and the planting effect met the mechanized production requirements of modern standard orchard. [ABSTRACT FROM AUTHOR]

Rapeseed is an important oil crop in China. High-speed precision direct-seeding technology, which has the advantages of cost saving and efficiency increasing, low lodging risk and suitable for mechanized harvest, is one of the important ways to promote the sustainable development of rapeseed industry. Aiming at the problems that the seeds of the existing pneumatic rape seed metering device are difficult to be separated quickly and sucked accurately from the seed-group during the high-speed working process, which result in leakage suction, and reducing the performance of seed metering, a sucking-seed plate combined with groove-tooth to improve the filling performance of rape high-speed direct seeding was designed in this paper, and the key structures of sucking-seed plate combined with groove-tooth were analysed and determined, the mechanical model of the seed suction for groove-tooth interference was constructed, EDEM numerical simulation was used to analyze the effects of 3 kinds of sucking-seed plates: smooth plate, groove plate and groove-tooth plate on the intensity of directional disturbance for seed-group. Combined with bench test, the optimum selection of seed sucking plate structure was carried out. The test results showed that adding of grooves and disturbing teeth on the traditional smooth plate could significantly increase the disturbance intensity of the seed-group and reduce the seed leakage suction rate. Taking the sum of average kinetic energy as the quantitative index of the seed-group disturbance intensity, the order of the sum of average kinetic energy at the same speed from large to small was: grooved tooth plate, grooved plate and smooth plate. Taking Deyouaizao as the experimental variety, suction performance tests of groove-tooth plate, groove plate and smooth plate were carried out under the work condition that negative pressure of 1.5-2.5 kPa, rotation speed in 10-150 r/min. The test results showed that leakage suction rate and the suction qualification rate of groove-tooth plate were obviously better than those of groove plate and smooth plate. There was no obvious change in the multiple suction rate of groove-tooth plate, groove plate and smooth plate. When rotation speed was greater than 90 r/min, the maximum leakage suction rate of groove-tooth plate was 7.4%, and the minimum leakage suction rate of groove plate was 14.02%, the minimum leakage suction rate of smooth plate was 30.4%, leakage suction rate was reduced by 47.2% compared with groove plate, and leakage suction rate was reduced by 75.7% compared with smooth plate. The performance test of directional disturbance suction showed that with the variety of rapeseed named Deyouaizao and Zhong Shuang 11, under the same work negative pressure, leakage suction rate was increasing, suction qualified rate was decreasing, and multiple suction rate had no obvious change with plate speed increasing. Under the same plate speed, suction qualified rate increased, and leakage suction rate decreased with the increase of negative pressure. Under the plate speed in 10-110 r/min and negative pressure in 1.5-2.5 kPa, suction qualified rate was not less than 92.0%, and the sum of leakage and re-suction rate was not more than 8.0%. Despite the variety of commonly used rapeseed seeds, the difference in sphericity and average grain size is not large, there was no suction hole blockage in the test of the high-speed precision seed metering rack of the rapeseed with groove plate, groove-tooth plate and smooth plate. Through the reasonable design of the diameter of the suction cell, the multiple suction rate and the blocking rate could be well controlled, increasing the average kinetic energy of the seed-group (the disturbance intensity) could significantly improve the filling performance, thereby improving the suction performance of the rapeseed pneumatic high-speed seed metering device and reduce the leakage suction rate. The research results showed that groove and tooth composition plate had a high suction precision and could be provide reference for structural improvement and optimization of pneumatic rapeseed high speed precision seed metering device. [ABSTRACT FROM AUTHOR]

Currently, there is a large amount of maize straw mulching on farmland in Northeast China. Under conditions of conservation tillage, there are large amount of straws mulching on soil surface that it required the opener of no-tillage seeder should have excellent functions for straw cutting, anti-blocking and seedbed cleaning, as well as stable ditching performance that can keep the ditch depth and the ditch width fluctuating uniformly. During the mechanized sowing period, maize no-tillage seeder with sharp angle opener is facing the problem of seriously clogged up and high-power consumption, while planter with disc opener shows little disturbance to soil under straw mulching condition and a good trafficability. However, large positive pressure and counterweight that auxiliary ditching operation will be needed for general double disc opener, with poor soil entry ability and straw blockage problem, especially in the conditions of large amount of straw mulching on the surface of farmland, the disc opener will press the straw into furrow instead of cutting them off when ditching in farmland with quantities of straw mulching. Based on the above issues, an asymmetric large-small double disc ditching device for corn seeding was put forward in this paper, which is mainly composed of large disc, small disc, direct-axis, oblique-axis and rack. The large disc and the small disc are arranged asymmetrically, which forming rotating connection with the rack by direct-axis and oblique-axis respectively. The rotating plane of the large disc is perpendicular to the horizontal plane and the small disc is inclined setting. The angle between the rotating plane of the small disc and the vertical plane is 8° (the working inclination of small disc), besides, the angle between the rotating plane of the small disc and the direction of the ditching operation is 12° (the working deflection of small disc). When working, large disc mounted on front of small disc cuts maize straw and stubble in advance, and then small disc that staggered set in the rear-lower part removes straws and ditches seed furrows, in order to prepare clean seedbeds for maize sowing. Based on mechanical analysis and kinematics analysis, diameter of large disc and small disc was obtained, which was 460 mm and 360 mm respectively. The gathering point located on the front edge of the small disc that gathering point angle of small disc is 56°, meanwhile the gathering point located in the interior of large disc with radius of 190 mm, gathering point angle of 56°. The performance of asymmetric large-small double disc ditching device was tested by EDEM simulations and field experiments without straw mulching on soil in advance beforehand, and the difference of ditching depth and ditching width were 2.15 mm and 1.62 mm respectively. Results of field experiments under wheat straw mulching showed that asymmetric large-small double disc ditching device could realize relatively stable and reliable ditching effect. Under straw mulching conditions, the ditching device could meet the requirements of no-tillage maize sowing, the average ditching depth was 71.41 mm and the average ditching width was 38.27 mm. Besides, anti-blocking performance of asymmetric large-small double disc ditching device was tested in field experiments with 4 straw mulching amount(full-straw coverage, small amount of coverage (0.66 kg/m2), middle amount of coverage (1.64 kg/m2), large amount of coverage (2.18 kg/m2)), at 2 different working speeds (4 km/h, 6 km/h). Anti-blocking tests indicated that the ditching device was operating smoothly, and there was no obvious blockage and continuous breaking in the ditch overall, which revealed better straw-cutting capability and enhanced penetrability. The device meets the requirements of agronomic production and standards of maize sowing, and this research can provide theoretical support and technical basis for the development of maize no-tillage planter. [ABSTRACT FROM AUTHOR]

At present, the methods of seeding detection are photoelectric-based method, image-based method and capacitance-based method. For the photoelectric-based method, the detection accuracy of photoelectric sensor is affected by the vibration, light, temperature and other factors on the farmland. When multiple seeds fall simultaneously, the refraction phenomenon of photoelectric sensor also affects the accurate detection. For the image-based method, its high precision detection provides a new way to improve the performance of wheat-planter seeding. However, image processing technology requires special equipment with high cost, and cameras are easy to be interfered by external light. Consequently, it is difficult to be widely applied in the complex environment on the farmland. Compared with photoelectric-based and image-based methods, the capacitance-based method is less affected by light and dust and thus has a strong environmental adaptability. However, when multiple seeds fall simultaneously, the detection accuracy of the capacitance-based method still needs to be improved. In this paper, a precise detection system for wheat-planter seeding quantity was designed using the capacitance-based method. The detection resolution and the constraint relation between the seeding speed and the sampling frequency determine the structure size of the capacitance sensor. To guarantee the detection accuracy, every seed should be detected only once as far as possible when it passes through the parallel plate of capacitance sensor. Then the initial sampling period can be determined according to the above sampling method. Meanwhile, high detection accuracy is difficult to be achieved due to the small capacitance change in detection system and the influence of parasitic capacitance and environment in conditioning circuit. Therefore, the capacitance analog-to-digital conversion chip of AD7746 is utilized to effectively reduce the error caused by the above factors. The signal acquisition and processing circuit for precise detection of wheat-planter was designed based on the AD7746 and the single chip microprocessor of STM8. Ideally, the seed passing through the capacitor plate will be sampled only once by the capacitive sensor. However, the times of the seed passing through the parallel plate will be changed with different wheat-planter seeding speeds, which will affect the distribution of sampling times when the seed passes through the capacitor plate. The least squares regression model of the real-time wheat-planter seeding quantity detection was built under the condition with the sampling period of 15 ms and the wheat-planter speed of 20 r/min. The results showed that when the sampling period is 15 ms, the relative error between the number of seeds calculated by the least squares regression model and the actual number of seeds increases with the speed of the wheat planter. Consequently, to make the detection system suitable for the different seeding speeds, a detecting method was proposed by changing the sampling period, in which the sampling period was reduced by 0.4 ms when the wheat-planter speed was increased by 5 r/min. The least square regression model established above is still applicable for this case. The results showed that high detection accuracy can be obtained for different seeding speeds, and the relative error was between -2.26% ~ 2.17%. [ABSTRACT FROM AUTHOR]

In order to improve the status quo that mechanical direct seeding level for cotton is insufficient in the Yellow River basin, a kind of inside-filling precision seed-metering device with stepped filling holes which can reduce the shearing damage on seeds and blocking of nest inside hole was designed. To realize stepless adjustment of the seeding rate, a composite seeding plate which consists of inner seeding plate, lug and outer seeding plate assembled by bolts and nuts was adopted. This paper set forth the working principle of inside-filling seed-metering device and determined the general structure along with necessary parameters of key components. The cotton seed variety E`kangmian-10 with moisture content 11.01% (wet basis) was selected as experimental object. Before testing, all of the cotton seeds had been delinted and coated, and there were no damaged cotton seeds after manual selection. In bench test, the single factor experiment was performed on the seed-metering device. The factor was the shape of filling hole which was changed by replacing lugs, so as to study the effect of shape of filling hole on seeding performance and the optimal one was used for cotton direct seeding. Based on pre-experiments, the nest inside hole depth, seed entrance height and seeding plate rotational speed were taken as main impact factors and the qualified rate, reseeding rate, miss seeding rate and damage rate of seeding were taken as the test indexes. Then quadratic regression rotation-orthogonal combination experiment with concave filling hole was executed. The regression model was established and the influence law of various factors on test indexes was analyzed. Through the tests above, the optimal combination of each factor was obtained. The results indicated that the structural design of anti-injury was reasonable due to the low damage rate, and the concave filling holes are more suitable for cotton direct seeding than straight and convex filling holes. Due to its small volume and the incapability of cotton seeds filling into the hole smoothly under the application of gravity, centrifugal force and interaction force of cotton seeds, the convex filling hole adopted in the inside-filling seed-metering device was seriously blocked which resulted in a high miss seeding rate, the miss seeding rate decreased and qualified rate increased with the increasing of filling hole volume for straight filling hole and the phenomenon of blockage still existed, and seeding performance reached the optimal state without blockage for concave filling hole. The order influencing qualified rate of seed-metering device was seeding plate rotational speed>nest inside hole depth>seed entrance height, and the order influencing miss-seeding rate of seed-metering device was nest inside hole depth>seed entrance height>seeding plate rotational speed. The optimal combination was nest inside hole depth with 7.7 mm, seed entrance height with 62.9 mm, seeding plate rotational speed with 23.52 r/min. On the condition above, the qualified rate (1-3 seeds per hole), reseeding rate (more than 3 seeds per hole), miss seeding rate (0 seed per hole) and damage rate of seeding were 96.23%, 1.92%, 1.85% and 0.17%, respectively. In order to test the seeding performance of seed-metering device in the field, the field experiment was carried out and the results showed that the qualified rate was 95.44%, reseeding rate was 2.28%, miss eeding rate was 2.28%, damage rate was 0.06%, the qualified rate of hole distance was 97.63% and the variation coefficient of hole distance was 23.11%, which meet agronomy requirement for cotton direct seeding. The study provide a reference for the structural design and optimization of inside-filling precision seed-metering device for cotton. [ABSTRACT FROM AUTHOR]

In order to solve the problem of equipment adjusting in the operation of plough rotary tiller, an automatic leveling system of plough-rotary tiller is designed, which includes executive mechanism, automatic leveling control module, hydraulic system and tilt sensing module. The plough-rotary tiller is a kind of well-behaved machine on tillage and straw returning, which combines the function of plough turning and rotary tillage. It can be used to carry out multiple work processes such as plough turning, rotary tillage and burying ground straw into soil. The soil is finely ground after ploughing, and the crop stalks and stubble are directly buried in the fields to achieve the soil preparation effect. It can also reduce the number of operations of going into soil for the machine, reduce the compaction of the soil, and improve the efficiency of farming. In the process of work, one side of tractor wheel drives on the balk, the other side drives on the cultivated furrows, causing tractor to incline to walk, and then leading to a certain inclination in horizontal direction of the plough-rotary tiller connected with the tractor through the three-point suspension mechanism. However, the tilting of plough-rotary tiller will affect the flatness and depth of the plow, so it is necessary to continuously adjust the equipment to ensure the work effect. Due to the complexity of field work condition, it needs to adjust frequently on the first 2 work routes and every route caused by the unstable work of the hydraulic system in each field. It not only is time-consuming but also has not high precision, which results in poor performance and low efficiency of work. In order to solve the problem of frequent adjustment of the plough-rotary tiller during work of plough, combining the characteristics of the plough-rotary tiller, a method to determine the angle range of leveling is put forward. The plough-rotary tiller as a compound tillage machine has great quality. It will cause great burden to the hydraulic system of the tractor by automatic leveling. At the same time, the downward motion will appear more severe during the downgrading process of the plough rotary mechanism. Therefore, a set of independent hydraulic system is designed in this paper. According to the actual field work situation, the soil model is established by using EDEM (enhanced discrete element method) simulation software, and the virtual simulation of field operation is carried out. The simulation results show that the surface roughness is less than 2 cm and meets the agronomic requirements. On the basis of design and simulation, field experiments were carried out to compare the operation of manual leveling plough-rotary tiller and the operation of automatic leveling plough-rotary tiller. The content of the test includes the system performance and mechanical performance of automatic leveling. The system performance is obtained by analyzing the change of the inclination angle of the tractor. The mechanical performance is obtained by analyzing ploughing depth, its stability and surface roughness after the operation. The results show that the automatic leveling plough-rotary tiller has a marked improvement in the stability of ploughing and surface evenness after tillage compared with the manual leveling plough rotary machine. The stability coefficient of the former tillage depth is 87.31% and the latter is 84.76%. The surface roughness of the former is 1.97 cm and the latter is 2.56 cm. It can provide reference for the design of automatic leveling system for compound agricultural machinery. [ABSTRACT FROM AUTHOR]

Sowing is a very important link in the process of agricultural production, and it is essential to make it timely, appropriate and meet agronomic environmental conditions according to the requirements of agricultural technology, so that crops can get a good foundation for growth. Precision planter for rapeseed can complete the ditching, stubble cleaning, rotary tillage, precision sowing, fertilization, soil covering and other operations, and it is widely used because of its high operating speed and high working efficiency. When the rapeseeds are sown, the flow process of rapeseeds is in a closed room, the color of rapeseed is similar with the color of soil, and the precision sowing index of rapeseed is mainly indirectly obtained through the change of the seed quantity in the seed box or through the speed of the seed metering device and the number of the type holes of the disks. Therefore, a set of sowing monitoring system for precision planter for rapeseed is designed to achieve sowing performance and sowing statistics in the process of rapeseed sowing. It is one of the trends to achieve transparency, informatization and intelligentization in sowing link. In recent years, many sowing monitoring systems for precision combined direct planter studied by experts at home and abroad were mainly used for the seed of large and medium size, such as corn and soybean. In this paper, the sowing monitoring system for precision combined direct planter is designed for rapeseed. The monitoring system is composed of multirow rapeseed flows sensing device and monitoring display terminal. Six rapeseed flow sensing devices are installed at the appropriate positions that are under 6 precision seeders on precision planter for rapeseed respectively to detect rapeseed flows. The weak voltage signals produced by rapeseed impacting on the piezoelectric film are processed by signal conditioning circuit, and then the seed pulse sequence corresponding to the seed flow is formed. Time capture interrupt program and timing counting program of MSP430F149 singlechip system in seed flow sensing device for rapeseed are used to record the metering time interval sequence of rapeseed flow, the metering frequency and the amount of metering, and the average time interval of seeding was calculated and used as the standard time interval of seeding. Through the national standard GB/T 6973-2005 (Testing methods of single seed drill (precision drill)), we got the leakage index and the qualified index of sowing. Then the data were sent to the sowing monitoring display terminal device wirelessly in “many to one” way, and the monitoring and display terminal single chip microcomputer system analyzed and processed the data and then displayed them through liquid crystal display screen in real time, including the multirow sowing monitoring and performance detection information and the sowing frequency curve for each row, so as to realize the real-time monitoring and the calculation of sowing quantity for precision planter for rapeseed. A polling data transfer protocol of response mode was designed to achieve reliability, fault tolerance and accuracy in data transmission, and the sowing monitoring system was tested. The results of bench test and field test of sowing monitoring system showed that the seeding monitoring system is stable and reliable, the monitoring accuracy of sowing quality is above 96%, and the data transmission is accurate, the transmission distance is about 60 m, which can meet the need of sowing monitoring, and provide effective technical support for the formation of sowing state diagram of rapeseed. [ABSTRACT FROM AUTHOR]

At present, both domestic and foreign grafting robots have the problem of low cost performance ratio. In order to increase in per capita productivity to improve cost performance ratio, this paper selected 2JT-1600 assembly line solanaceous fruit grafting robot(2Jt-1600B) researched and developed by South China Agricultural University, and split a working position that completed both seedling feeding and seedling cutting into 2 working positions that separately completed seedling feeding and seedling cutting based on the improved feeding seedling device by adding seedling seat and transmitting manipulator. The process that feeding device feeds stock to grafting robot can be divided into 2 phases: transportation phase and transmitting phase. In transportation phase, one operator places stock on seedling seat repeatedly, and seedling seat is circulated step by step together with conveying chain to transport stock to the position; slot is designed on seedling seat to provide convenience for positioning and placement of stock. As nursery substrate is attached on stock, the center of stock is deviated to the side of nursery substrate, thus leading to the trend of overturning from seedling seat. In order to prevent stock falling out from seedling seat when transporting, highly elastic rubber is selected to be fixed on slot to give friction force for stock to overcome falling by squeeze of rubber with stem of stock. In transmitting phase, transmitting manipulator picks up stock, and transfers it into holding device of grafting robot after rotating by 90°. In order to prevent transmitting manipulator harming the stock, by analyzing the stress of stock in the rotation of transmitting manipulator, the structural sizes of transmitting manipulator were affirmed. The seedling holder was also developed to pick seedlings up in crossed closing form. After the test, seedling holder was found to have a tolerance of 5 mm. In order to dock transmit manipulator with seedling seat and holding device, two-piece design was adopted for seedling holder and seedling seat. In this paper, the design and experiments are both mainly focused on the structure parameter of seedling seat. In transportation phase, when stock is excessively bending to place inside the slot, it is easy to cause alignment difficulty or crush stock owing to two-piece structure of slot. So, it is required to straighten seedling. The operation will influence feeding efficiency. When the depth of slot is bigger to hold stock, and the suspension rubber above seedling seat is longer, thus the ability of rubber deformation is favorable, it is easy to place stock into the slot, but the stroke of stock at the slot bottom is increased. When the depth of slot is shallow and the rigidness of slot is bigger, it is easy to crush seedling. When the thickness of rubber used for slot is changed, it will influence the deformation ability of slot and lead to the changes of friction between stock and slot wall, which will cause the changes of holding performance. The test of holding parameters of seedling seat, which were the curvature of stock, depth of slot and thickness of rubber, was conducted under grafting productivity of 2000 seedlings per hour. When stock is not damaged or falling out while being placed into the slot of seedling seat and transferred to picking position of transmitting manipulator via seedling seat, the position is considered to be suitable to pick by transmitting manipulator and the experiment is regarded to be successful. Test results showed that when the stock bending was chosen within the 95% percentile(6.55 mm), the depth of upper slot of seedling seat reaches 8 mm and its rubber was 3 mm thick, the holding function of seedling seat could achieve 100%, and the feeding success rate of transmitting manipulator could reach 92%. Due to the working position station split, the operation cycle is shortened, the grafting productivity reaches 2000 seedlings per hour, the feeding device implements feeding stock and scion on single, and per capita productivity increases to 1000 seedlings per hour. [ABSTRACT FROM AUTHOR]

In China, Camellia oleifera fruit is deeply loved by consumers as specific woody oil resource. Because of the composition of fatty acid for camellia seed oil is highly similar to olive oil, it is also known as “Oriental olive oil”. However, the shelling operation of Camellia oleifera fruit largely relies on natural drying, which is of low efficiency, high labor intensity, high processing cost, and great dependence on weather. In order to improve the performance of shelling machine for Camellia oleifera fruit, increase the shelling rate and reduce the seed breaking rate, choosing the shelling rate and seed breaking rate as the indices, 3 aspects were studied based on the existing shelling equipment and practical engineering experience in this paper. Firstly, the physical parameters of Camellia oleifera fruit were studied. The parameters such as density, bulk density, grain size, water content and proportion of each component of Camellia oleifera fruit from Changning City were measured, which provided the data for the design of shelling machine parts. Secondly, the mechanism and main structure of the shelling machine were studied. In the beginning, the merits and defects of commonly-used methods for shelling were summed based on their working principle and mechanism. According to practical engineering experience and the measured data above, the final squeeze-rub shelling method for Camellia oleifera fruit was determined. Then the structure of main parts was designed, which included the shelling device consisting of the roller, annular plate and the regulating mechanism, and the separation device consisting of stirring shaft and circular groove structure screen. Finally, the three-dimensional (3D) prototype model was established and the drawing design was completed. Thirdly, the operating parameters of shelling machine for Camellia oleifera fruit were studied. The shelling machine for Camellia oleifera fruit was manufactured based on the structure design, and then the operating parameters’ optimization test was made. In the experiment, Camellia oleifera fruit’s shelling gap, speed of shelling motor, speed of separation motor were taken as single factors, respectively, and the shelling rate and seed breaking rate were taken as indices. The influence trend of these factors on the indices was drew out. Based on the result, the orthogonal experiment was designed, which aimed at studying the effects of the speed of shelling motor, the speed of separation motor and the gap of shelling on shelling rate and seed breaking rate. The results indicated that the water contents of the fresh Camellia oleifera fruit, shell and seed were 60.08%, 74.55% and 45.60%, respectively. The particle size distribution was 20-50 mm, and the bulk density was 0.52 kg/L. The optimal combination parameters were that the speed of shelling motor was 125 r/min, the speed of separation motor was 343 r/min and the shelling gap was 12 mm. And under the condition, the shelling rate was 96.91%, the seed breaking rate was 3.38% and the production capacity was up to 2 t/h. The optimal parameters achieved in this paper can provide reference and technical support for the actual application of shelling machine for Camellia oleifera fruit. And it will benefit the processing industry of Camellia oleifera fruit. [ABSTRACT FROM AUTHOR]

Maize is one of the main crops in the Northeast China. The agronomic requirement of maize planting in this region is stubble cleaning and ridging before sowing. Stubble cleaning can crush crop straw, which could promote the growth speed of maize and increase the organic matter content in soil. Ridging can increase the surface area of the land, which is beneficial for improving the soil temperature. Transverse ridge can hold water from flowing away. High ridge can avoid the submergence of corn. Side deep fertilizing can supply abundant nutrient for maize seedlings, increase root length, and improve seedling growth. Most maize-growing regions in the Northeast China use small four-wheel tractors to clean stubble and ridge, and sow on the ridge with small seeders. As for the above model, the multiple field operations are needed, which always break the physical structure of soil, disturb soil layer and even lead to water consumption with low mechanical efficiency. The existing combined machines can not ridge and sow together, resulting in ridge damage and difficulties in row-follow. In terms of this problem, there is hardly combined equipment to fulfill the above tasks. In order to solve problems mentioned above, this paper designed 2BYMQF-4 maize stubble cleaning fertilization ridging seeder, which was suitable for the agronomic requirement (cleaning stubble, ridging, fertilizing and sowing in one time) in the Northeast China. By researching multiple ridging method, theoretical analysis of ridging and sowing was made by this paper. The multiple ridging method of this machine was divided into 5 steps: stubble cleaning and small ridging after rotary tillage; ditching, fertilizing and seed dropping; covering soil by double disks; hilling with ploughshare and compacting with broad width flexible compacting roll. This paper described the overall design of the machine, and determined the structure parameters and the working parameters of the main parts, such as the connecting mechanism, stubble cleaning device, sower unit and ridging device. The paper also described the working principles of the parallel quadrilateral adaptive connecting mechanism and the compensated suspension mechanism, as well as the mechanical structure and working principles of the precision planter unit, analyzed the stress under ideal condition by theoretical calculation, and made the finite element static force analysis of the ploughshare according to the calculation results. The paper calculated the power consumption of the track equipment and the power take-off shaft to analyze the power disposition, and analyzed longitudinal stability of the tractor mounted implement based on virtual prototype technology. According to this operation method, researchers made the test program and test method of maize stubble cleaning, ridging, fertilizing and seeding machine, and also carried out the field experiment on this machine based on the program and test method. Field experiment indicated that stubble crushing ratio reached 88.2% at the conventional working speed. The qualified rates of the ridging height, the width of ridging top and the distance between ridging rows were respectively 95%, 90% and 90%. The pass rate of average grain distance was over 92%, with the standard deviation of 43.65 and the coefficient of variation of 5.24. The average depths of seeds and fertilizer were respectively 56.22 and 114.36 mm, with the coefficients of variation of 10.07 and 10.28. The machine has the advantages of combined operation in maize stubble cleaning, ridging, fertilizing and seeding, such as simple operation, reasonable structure, safe and reliable work as well as high operation efficiency, which meets the design requirements. [ABSTRACT FROM AUTHOR]

Today, ridge tillage method is an effective farming method that can resist the drought and flood in the northeast area of China. Because of the climate and natural conditions, most of the northeast area of China will continue to adopt ridge tillage method. In the case of ridge planting, no-till can improve the ground temperature, and can control the summer flood and drainage. In recent years the strip rotary tillage type no tillage planter has been extended. Because of the rotary tillage, the root stubble is broken and the anti-blocking performance is good. However, the soil tillage intensity is between 6.5 and 7.8, and the tillage destroys the original ridge, and forms the new ditch. At present, the number of no tillage finger clip type precision seeding and fertilizing machine applied in the production, is about 3000 in the northeast area of China, and the soil tillage intensity index is 1, which reduces the soil tillage intensity and produces no new ditch; but the two-row machine has the complete machine weight of 1000 kg, which brings too large compaction on soil, and makes ridge stand almost flat, therefore, wheel rut compaction seriously affects maize root growth. This machine not only loses the advantage of ridge planting, increases soil hardness, but also enhances manufacturing cost, and makes the price per machine high. The cost of the field operation is greatly improved, which does not accord with the requirements of energy saving and emission reduction in agricultural production. For no tillage planter, the current problem is the existence of the problem remains a ridge shape. Aiming at the requirement of researching and developing new no tillage planter for the conservation tillage corn ridge agricultural technology in the northeast area in China, based on the Archimedes spiral theory, this paper analyzes the notched disc knife break crop performance and the technical requirements to stubble breaking cutter for ideal seed bed, optimizes the spiral notched disk break stubble cutter structure and carries out the optimal selection of parameter; and develops the stubble breaking ditching device and stubble breaking anti-blocking device. Through test verification of stubble breaking ditching device, it opens a "V"-shape groove, and 2 pieces of spiral-notch disc cutters have a diameter of 350 mm, when sowing depth is 40 mm, sowing and ditching width is 28 mm. Increasing the weight makes the stubble breaking ditching device achieve a weight of 100 kg, and in the area implementing high stubble conservation tillage mode and with a field coverage rate of 30%, stubble breaking ditching device can be adopted instead of the conventional planter seeding furrow opener, and ordinary seeder can realize no tillage planting. When stubble breaking anti-blocking device’s breaking stubble depth is between 70 and 100 mm, ditching width is 40-50 mm, and ridge cleaning width of ridge cleaning parts is 210 mm, which are up to the requirement of agricultural technology. Increasing the weight makes the monolithic disc broken stubble device achieve a weight of 113 kg in the area implementing conservation tillage of high stubble breaking rod cover mode and with covering rate of 1 kg/m2, stubble breaking anti-blocking device can be adopted, and ordinary seeder can realize no tillage planting. In this paper, the development of the rolling disc coulter and its edge is Archimedes spiral gap, after test for many times, stubble cutting resistance is small, the weight of machines can be reduced, because it is a passive anti-blocking device, keeping the shape of ridge. [ABSTRACT FROM AUTHOR]

In order to solve the problems such as the lower operation speed, lower precision at the present stage of China’s potato planting machine, the potato air-powered precision planter was developed in this paper. This planting machine contains fertilizer shovel, seed-metering device, wind blowing fan, potato seed box, wind suction fan, soil coverer, transmission device and land wheel. The whole machine is tracked by tractor with the power of more than 88.6 kW, and the power of fan rotary dynamic device is provided by tractor. The air-powered precision seed-metering device for potato is different from the traditional air suction device, and it has the distributed multi suction arms and at the end of each arm is installed with suction nozzles. With the rotation of seed-metering device and the working of suction fan and blowing fan, the potato can be sucked on the suction nozzles and cast into furrow in special position. As the most important structure of the seed-metering device, the sealing property of the device is very significant, and the air distribution valve of this seed-metering device is made of alumina alloy covered with porcelain. The static value cooperates with rotary value. The areas of positive pressure and negative pressure zone in static value are independent, and the negative pressure zone and the positive pressure area account for 300° and 13°, respectively. The suction nozzle contains miniature potato nozzle and conventional potato nozzle. The soil particles are cut and crashed by the edge of the shovel at the front side of the sliding-knife opener, and move along the side of opener. Some of the soil particles fall into the furrow first to create a soft furrow, and the rest of soil particles move backwards along the opener, and then cover the potato when it falls into furrow. The lower soil particles can firstly provide a better furrow situation for potato to grow. Besides, the seed-supplying device is designed to meet the needs of the transfer of potato. This potato level switch is the key part of this device. The electrical signal can be transferred from switch to motor to transfer potato seed. Fan blade is designed to meet the requirements of suction pressure. The centrifugal fan is used due to the higher efficiency. The test was implemented in Heilongjiang Academy of Agricultural Sciences and Keshan Farm in 2016 and 2017. Potato in this test was prepared by Northeast Agricultural University. Field experiments showed that the potato air-suction planter’s operating speed reached 10.2 km/h, emergence of seedling was 2-3 days earlier than potato planted by traditional planter, and the seedling rate reached 96%, indicating that the production practice of the seedlings of this device is strong. The field production test area was 200 hm2, the replay rate of the 2CMP2 potato air-powered planter was below 1%, the missing rate was below 1%, and the coefficient of variation for row spacing was less than 10%, exceeding the national standard and meeting the requirements of potato planting agronomy; the mean absolute deviation of sowing width was less than the traditional potato planter due to the use of sliding-knife opener. This air-powered planter can provide a new technology for high speed precision potato sowing and promote the potato production mechanization process in China. [ABSTRACT FROM AUTHOR]