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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]

The Diameter at Breast Height (DBH) (at a height of 1.3 m on the bole of a tree) has been one of the most important indicators during tree measurements in forestry resource inventory. However, the current DBH measurement cannot fully meet the requirement in recent years, due to the low portability, precision, efficiency, applicability, and stability, together with the complex operation, rudimentary software, high costs, and short range. In this study, an innovative device was developed to accurately, efficiently, and conveniently measure the tree DBH suitable for the complex tree shapes and the different diameter classes, while cost-saving in the office-field work survey. The specification of the device was as follows (size: 8.35 cm×5.80 cm×5.55 cm; weight: 230 g; resolution: 0.01 cm; linear range: 0-150 cm; battery capacity: 4 000 mAh input vatage: 3.7 V, output votuge: 5 V; micro-processor chip: STC15W4K48, 8 bits; encoder type: PD-1503-SDI, 12 bits). A Tunnel Magneto-Resistance (TMR) rotary encoder was also combined with the low-cost, small size, and light weight electro-mechanical structure, and high-resolution processing. As such, the measurement device was achieved in the electronization, digitization, portability, and integration of office and filed work for the tree DBH. A supporting system software was also developed, including the embedded software, mobile terminal application, and Web terminal application. In the process of an individual tree survey, the electro-mechanical structure of the device firstly converted the mechanical parameter of tree DBH to the magnetic signal, and then the magnetic signal was converted to an electrical signal. Secondly, the electrical signal was converted into the DBH measurement data using the processing integrated into the embedded software. Thirdly, the operation flow was better applied to measure the trees with special shapes and large diameters using multi-function key combinations. After all individual tree surveys, the DBH measurement data was transmitted by Bluetooth in the device to the Android application, and then uploaded to the database managed by the Web application. The measurement accuracy and operation efficiency of the device were verified to select the 196 standing trees with many tree species and a small sample plot of 42 standing trees in the Botanic Garden of Beijing Forestry University, China. The test results showed that the device presented a higher accuracy to measure the standing trees of different diameter classes than before. The total tree DBH measurement data from different diameter classes (weight: 1 092 g; resolution: 0.001 cm; linear range: 0-500 cm) indicated the mean absolute error (MAE) of 0.08 cm, Mean Absolute Percentage Error (MAPE) of 0.37%, Root Mean Square Error (RMSE) of 0.12 cm, and Relative Root Mean Square Error (RRMSE) of 0.54%, compared with an electronic draw-wire displacement sensor. In addition, a high measurement efficiency was achieved, where the average measurement time per person of each tree was 9.3 s from the efficiency test. The devices demonstrated nearly two times faster than the traditional diameter tape (weight: 42 g; resolution: 0.01 cm; linear range: 0-200 cm), while one time faster than the electronic draw-wire displacement sensor. Additionally, the price of the device was only 260 RMB, due to a 12 bits encoder (price: 135 RMB). In conclusion, this device behaved at a low cost and less labor consumption, fully meeting the technical requirement of accuracy for the Continuous Forest Inventory (CFI) in China. Therefore, the finding can provide broad application prospects in forestry resource inventory. [ABSTRACT FROM AUTHOR]

There were some design and building drawbacks of traditional solar greenhouses in high latitudes areas, such as smaller front-roof angle and poor heat storage and insulation, which decreased the indoor temperature of greenhouse and restricted vegetable growing in winter. Local planters had to supplement heat to increase vegetable yield and quality in winter, which added production cost. In addtion, because of the unreasonable spatial layout of traditional solar greenhouses and plantation planning and design, vegetable cultivation and processing links separated, and freezing damage occurred frequently in the course of transportation, which also restricted production of greenhouse. Based on the advantages and existing problems of traditional solar greenhouse, and combined with the climatic characteristics of high latitudes, this paper put forward a new design scheme of solar greenhouse from two aspects of greenhouse structure optimization and function innovation. Using the classical greenhouse design theory, combined with the vegetable production practice, the paper optimized the designs of greenhouse from lighting angle, front-roof radian, heat insulation, and calculated the snow load, wind load, moving and construction load and crop hanging load of the new-type solar greenhouse. Furtherly, the paper analyzed the load combined factor and determined key load combinations. Finally, the paper calculated the structural stability of each parameter of the greenhouse using structural analysis software Midas. According to the stability calculation results and relevant standards and norms in this industry, the rationality of design parameters were analyzed. The main design parameters were that the total span is 16 m, the span of the first floor planting part is 9 m, the span of production and processing part is 7 m, the total height is 6.5 m, the main lighting angle of the front-roof is 37°, and land utilization radio attains 1.7. The new-type solar greenhouse not only makes further use of solar energy, but also has good heat insulation performance. The design realizes that the greenhouse in high latitudes can grow fruits and vegetables without heating in winter. Based on the innovative use of traditional greenhouse shade part of the back wall, the new-type solar greenhouse has three-layer space from above ground to underground, i.e. storage space, production and processing space and potting space. The design improved significantly the land utilization and realized multiple functions, such as planting, processing, storage. The new-type solar greenhouse is an innovative exploration in high latitudes, which can serve as an important role in greenhouse vegetables plantation. [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]

In most areas of Xinjiang, edible sunflower is harvested in stages by means of transplanting plates for drying and taking plates for threshing. In some areas, edible sunflower harvesters are used for field operations, and problems such as edible sunflower plate leakage and grain loss exist in the process of harvest, which seriously hinder the development of edible sunflower scale and industrialization. In order to solve these problems and improve the harvesting efficiency of edible sunflower machine, this paper conducted a field survey on planting mode and biological characteristics of the edible sunflower in Xinjiang, and summarized the harvesting mechanism of edible sunflower. Starting from the operation path of manual harvesting sunflower tray, and combining with the requirements of field harvesting, a kind of collecting station for edible sunflower was designed. Field experiment was carried out to verify the field performance of the collecting station for edible sunflower. The specific research contents and conclusions were as follows. First of all, experimental study on the physical characteristics of edible sunflower was made during harvest in Xinjiang. It mainly included the determination test of the basic physical quantity, the friction characteristic test and the impact seed falling test. The average moisture content of edible sunflower plate was 38.97% and that of culm was 65.49%. By the bevel method, we got the friction angle between the dish and the steel plate was about 29.2°, the static friction coefficient was 0.56. The experiments were carried out to obtain the operating parameters with less loss of sunflower plate, which provided the theoretical basis for the field operation of edible sunflower harvesting platform. Secondly, in this paper, the whole plan of the collecting station for edible sunflower was determined, and the structural design and parameter analysis of the key devices were carried out. This paper designed a kind of station for collecting edible sunflower by imitating the manual way of picking dish. The whole machine structure was mainly composed of the pick-up device, conveying device, collecting dish box, walking device, power transmission system and frame. By analyzing the segmented path map of manual picking-up and parabolic dish, and combining the working posture of the pick-up device in each harvesting stage, the bionic pick-up device was designed and the basic structural parameters were determined to achieve the goal of bionic dish taking action and the shortest parabolic dish path. The 3D model of the pick-up device was established and the kinematics analysis were carried out to obtain the displacement, speed and acceleration change rules of the pickup device's disk-bar and determined the best structure and working parameters combination of the pickup device. The conveying device was designed and the speed of it was calculated to be 92 r/min, the theoretical productivity was 2.19 t/h. By analyzing the power transmission system, we got the transmission law of chain. The field harvest test finally was carried out with the total harvest loss rate as the test index, the height of the plug plate, the rotational speed of the take-up rod and the forward speed of the unit as the test factors. The results showed that the collecting station for edible sunflower could complete the functions of picking up, transporting and collecting. The optimal combination of the collecting station for edible sunflower was that the height of the disc was 650 mm, the forward speed of the unit was 0.88 m/s, the rotational speed of the take-up rod was 23 r/min, and the total loss rate of harvest was less than 5%, which could meet the operation requirements of Xinjiang edible sunflower harvesting. [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]

There are many uncertain factors in the amount of artificial feeding, which cause the waste of bait easily, moreover, a huge labor cost. The author briefly introduces the research status of automatic feeding machine at home and abroad, and points out that the existing quantitative feeding machine cannot take both the structural simplicity and functional perfection into account. Aiming at the complex structure and expensive price of the volume quantitative baiting machine, the author studies and designs a simple baiting machine for marine crabs. In the modern factory circulating aquaculture system, each crab is placed in separate baskets. Its amount of feeding and feeding time are strict, which needs to be adjusted according to the weight and food intake of the crabs. As a result, the designed feeding machine must have a stepless adjustment according to the real-time status of the breeding objects with the ability that can vary the amount of bait, simple structure, stable performance and easy maintenance. Therefore, based on the principle of variable volume method, this paper designs an automatic feeding system for single-cage culture sea crabs with a strong anti-interference ability, which overcomes the shortcoming that the accuracy of quantitative weighing method is susceptible to vibration. The author introduces the basic structure and basic working principles of this system. The whole feeding system consists of hopper, rack, lower barrel, lower barrel, motors, Scissor mechanism and control system. When the MCU sends the start command, the upper and lower valves remain closed, and the material level photoelectric sensor detects whether the storage hopper has material. If there is material, the upper motor moves to open the valve plate between the storage hopper and the lower barrel, and the baits fall into the lower barrel. After the barrel is filled with bait, the upper valve plate is closed and the lower valve plate is opened for feeding, when the single chip transmits a signal for adjusting the amount of the feed, the middle motor operates to change the total volume of the lower cylinder by varying the height of the lower barrel, thereby realizing variable quantitative feeding. The programming controller (microcontroller) performs automatic control, and the touch screen realizes human-computer interaction operation. Then with combination of theoretical calculation, the paper determines the relationship between different quantitative volumes and motor control time. The second chapter optimizes the scissor lift mechanism to obtain the most efficient initial angle. The article also designs the control system, introduces the composition of the control system and the selection of the execution motor, details the operation of the control system during the work process, and briefly introduces the hardware of the human-computer interaction interface. Combined with automatic feeding system control circuit of the mater controller, it realizes the intelligent control of the entire automatic feeding system, leads to the system to be more convenient and intelligent. As for software, an interactive software is designed to implement functions such as parameter setting, working status, historical data query, and help interface, which helps new users quickly master the use of the feeding machine. Based on the automatic feeding systems for single basket of crabs breeding, the author experimented in Xinyi fresh aquatic Ltd. (Xiangshan, Ningbo) to test the function of casting bait at accurate time and quantity. After experiment, the performance test of the precision error of the feeding system shows that the design scheme is effective and feasible. On the premise of precise time point, the system can control the average error of feeding accuracy to less than 8%, which meets the needs of Marine crabs farming in factory. The test results show that the overall design scheme of the system is effective and feasible within the allowable error range of the factory aquaculture industry, especially in the case of a large feeding amount. To achieve automation and intelligent farming of factory-based aquatic products, reduce farming costs and improve the quality of marine crabs. [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]

Oats have been paid more and more attention because of their high nutritional value and economic benefits. In view of the inconsistency of grain maturation in the same plant caused low maturity of grains is difficult to desquamate, so the content of grains with skin (shell) is high, which affects the harvest quality and subsequent processing. The oat-grains are strong and tough, are not easy to break, this paper according to the special characteristics of oat-grains, combined with the advantages of rubbing resistance, put forward a scheme to purify oat-grains. The scheme used the advantages of strong toughness and rubbing resistance to rub and remove the shell (peel) of the oat-grains first, then cleaned the grains with negative pressure clearance. It could avoid the disadvantages of miscellaneous surplus and separate the grain easier. This paper used the principle of rubbing grain peel (shell) and negative pressure clearance, designed a high degree of clarity and low loss oat grain purification device to solve the problem of high clutter content of oat grain caused by the large grains with shell. The device used a vertical conical rubbing roller to rub and treat the miscellaneous residues of oat leather grain and so on, and used the negative pressure cleaning room to clear and remove the clutter in the oat grain. The device could achieve the high cleanliness and low loss result, improve the quality of oat grains harvesting, and avoid the loss of grains, finally achieved the goal of increasing harvest yield and improving grain quality. In this study, the factors affecting including the speed of rubbing roller, the air speed of miscellany expert and the bezel length were analyzed and screened, and the clean ratio and loss ratio were used as the evaluation indicators. A single factor test was carried out to determine the range of optimal values for each influencing factor, and multivariate regression test was carried out on the basis of the single factor test. The multivariate regression model of test factors and evaluation indicators were established and solved, and the response surface analysis of the influence of 2 factors on the evaluation index was processed. The parameter values after optimization were validated. The test results showed that the single factor affecting the performance index of the device was 700-900 r/min of the roller speed, the air speed of miscellany expert was 12-16 m/s, the bezel length was 15-25 cm. The multivariate regression test results in a better combination of parameters: the roller speed was 816 r/min, the air speed of miscellany expert was 13.8 m/s, the bezel length was 20.5 cm, then the clean ratio of the index was 99.23% and the loss ratio was 1.53%. When the optimization parameter combination condition was pressed, the verification test results were trusted within the allowed test error within 3%. This study provides a reference and experimental basis for improving the technical level of oat harvesting machinery in China and the development of subsequent oat food processing machinery. [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]

Tires are very important on the performance of automobiles. The tread structure guarantees that the vehicle and the road surface have a good grasp, so as to play the traction performance and braking effect of the vehicle. The paper based on Reverse Engineering technology, the characteristic structure of reindeer feet was applied to the design of tread element structure, which could effectively improve the passing performance of tires on ice. In order to improve the anti-skid performance of tire, based on the mathematical model of reindeer’s plantar morphology, the bionic ribbed tread element and bionic non-ribbed tread element were designed by engineering bionics technology. Based on reverse engineering, the inner and outer edge curve of reindeer sole was simplified as a mathematical function of characteristic curve, and the reconstructed model of convex crown was transformed into a 3-dimensional model. 2 bionic anti-skid tread elements and herringbone tread elements were established in Solidworks software, combining with the microstructure of convex crown. The adhesion test of tread element and ice was carried out on UTM (QT-1090) linear friction tester. The thermo-mechanical coupling between tread element and ice was established by finite element analysis software ABAQUS. Moreover, the ice surface temperature of 3 tread elements under low pressure of 0.02 MPa and temperature of -11°C was analyzed. The anti-skid performance of bionic trad elements were analyzed by ice adhesion test and Finite Element Method (FEM), compared with the same size conventional herringbone tread element. Under the condition of low pressure (pressure≤0.02 MPa), the 3 kinds of tread elements with self-made ice block was tasted through the ice adhesion test. The result showed that the Dynamic Coefficient of Friction (DCOF) of bionic non-ribbed tread element was the highest at the same velocity, temperature and pressure. It was 1.04-1.26 times herringbone tread element. Through the finite element analysis, it was found that under the low pressure (pressure=0.02 MPa), the ice surface temperature of bionic ribbed tread element, bionic non-ribbed tread element and herringbone tread element increased by 0.21, 0.66 and 0.54 °C relative to the initial temperature, respectively. The ice temperature of bionic non-ribbed tread element increased the highest. The results showed that the anti-slip performance of bionic non-ribbed tread element was the best under low pressure. At high pressure (pressure = 2 MPa), finite element analysis showed that the ice surface temperature under bionic ribbed tread element, bionic non-ribbed tread element and herringbone tread element increased by 7.76, 4.07 and 3.39 °C relative to the initial temperature, respectively. The ice temperature of bionic ribbed tread element increased the highest. The results showed that the anti-slip performance of bionic ribbed tread element was the best under high pressure. Therefore, the bionic non-ribbed tread element and the bionic ribbed tread element had good anti-skid performance under low pressure and high pressure, respectively. The tire slippage caused by ice effect was solved effectively. This paper will provide research direction and theoretical basis for anti-slip design of tread element on ice ground. [ABSTRACT FROM AUTHOR]

The existing phase change material (PCM) devices of PCM refrigerated truck are mostly arranged on the top of the carriage, which has the problems of high gravity center and uncontrollable temperature and so on. In view of the above problems, a new type refrigerated truck was designed in this paper, which integrated phase change thermal storage unit, refrigeration system, heat-insulated carriage, air supply system and so on. The cold storage device was set independently in the front of the truck and was insulated. The phase change thermal storage unit used was 360 kg PCM (the phase transition temperature is -30 ºC and the latent heat of phase change is 175.3 kJ/kg), which used cheap electricity at night to store energy, when working, the temperature in carriage could be adjusted between -25-10 ºC. The simulation and tests of 2 working modes were carried out with the setting temperature of 0 and -18 ºC in a refrigerated sample. A computational fluid dynamics (CFD) simulation model of PCM refrigerated truck was built and the temperature field in carriage was simulated, the root mean square error and maximum absolute error between simulations and measurements of 2 working modes were 0.7 and 0.8 ºC, 1.1 and 1.2 ºC respectively, the simulated temperature calculated by the simulation model agreed well with the measured temperature, and the measured temperature near the air outlet in the carriage was slightly lower than the simulation temperature, while the measured temperature near the rear section was slightly higher than the simulation temperature, this was due to the fact that the simulation data were generally in an ideal state, but the cold leak was unavoidable at the return air outlet of the actual refrigerated truck and the heat leak (air leak) at the door. The test results showed that the new type of PCM refrigerated truck proposed in this paper could effectively control the temperature more than 10 h on the basis of sufficient cold storage. The average temperature fluctuated between 1.1-2.9 ºC and -14.8--16.9 ºC and the fluctuation ranges were 1.8 and 2.1 ºC under the 2 working modes. The lowest temperature in the carriage was located at the front of the carriage and close to both sides of the air outlet, the high temperature area was located at the top of the middle of the carriage and near the air inlet. The coefficient of temperature non-uniformity was less than 1.0 when the setting temperature in carriage was 0 ºC and was less than 0.4 when the setting temperature in carriage was -18 ºC. In terms of cooling time, it took 60 minutes when the carriage was set to 0 ºC and 90 minutes when the carriage was set to -18 ºC. The tested results showed that the average temperature fluctuation of the new type temperature controlled PCM refrigerated truck was 48.7% lower than that of the traditional PCM refrigeration truck, the coefficient of temperature non-uniformity was 50% lower, and the center of gravity was 25.9% lower than that of the overhead traditional PCM refrigeration truck. In addition, the temperature stability of the new type PCM refrigerated truck was better than that of the similar mechanical refrigerated truck because it didn’t need to defrost the evaporator during long-term operation. The new type PCM refrigerated truck can effectively reduce the transportation energy consumption and cost while guaranteeing the quality and safety of goods, and the research provided the basis for the optimization and application of the PCM refrigerated truck. [ABSTRACT FROM AUTHOR]

Automatic directional packaging of corn seeds is the precondition for realizing mechanical directional sowing of corn. The key technology is tip orientation and embryo side facing recognition. Combined with the actual demand of directional packaging, tip orientation for dent corn seeds needs that the tip orientation success rate reaches 100% (i.e. the tip is completely directed), and the embryo side facing recognition accuracy rate is required to achieve a high level at the same time. In addition, combining the actual demand of agricultural production and popularization, the method and its dependent device used to realize the tip orientation and embryo side recognition method for corn seeds should have low requirements for the working environment and the operation cost should be reduced as far as possible. The existing methods of tip orientation and embryo recognition are difficult to fulfil practical requirement. On the basis of the available research results of the research team, taking dent corn seeds with horizontal posture and tip orientation incomplete exported by existing tip orientation device as research object, a tip orientation and embryo side recognition method for dent corn seeds based on laser switch and range theory was proposed and the tip orientation and embryo side recognition device was designed in this paper. According to the shape characteristics of the corn seeds, the corn seeds large head facing forward was removed by using the laser sensors and other components first to get the seeds tip orientation done, and then the embryo side facing direction of each corn seed was identified one by one and outputed. There were 2 main characteristics of the corn seed shape: shape characteristic and surface characteristic. The shape characteristic was that the outline of corn seed was similar to "V" shape with narrow tip and wide large head, the surface characteristic was that there was a germinal groove extending from tip to large head on the embryo side, and the germinal groove shape was approximately elliptical, and its long axis coincided with the symmetric axis of the embryo side, the reverse side was smooth. The tip orientation method was proposed based on the shape characteristics of corn seed and laser switch sensor. Referring to the shape characteristics of the corn seed, a "V" shape slot was designed, the corn seeds with tip facing forward could enter into the slot, while the corn seeds with large head facing forward could not enter the slot as the large head of seed would block the entrance, based on this difference, by means of a normally open laser switch sensor, a specific straight track and a push rod, the tip orientation of each corn seed could be identified and the corn seeds with large head facing forward were removed. When the seed’s tip was oriented, it would be stayed in the slot with tip facing forward, and then the direction of embryo side would be recognized based on the surface characteristic and laser range sensor. With the combined of designed device and existing tip orientation device, a practical test bench was built and the orientation test for dent corn seeds was carried out to verify the actual effect of tip orientation and embryo side recognition method. The result showed that: the tip orientation success rate of existing tip orientation device was 89.6%, the embryo side recognition accuracy rate of designed device was 96.4% and the tip orientation success rate of designed device was 99.1%, which increased by 9.5 percentage points comparing with the existing tip oriented devices. The orientation method proposed in this study could basically realize the tip orientation of the corn seeds, and at the same time, the embryo side recognition accuracy rate could be reached to a high level. Generally, the tip orientation and embryo side recognition method and the device proposed in this paper have low requirements for working environment and low operation cost, which could provide a reference for automatic directional packaging and mechanically directional sowing of corn. [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 performance of the supercharger volute directly affects the overall efficiency and capability of the turbocharger. It is important to improve the efficiency and performance of the turbocharger by reducing the flow resistance and decreasing the energy loss of the volute. Many measures are taken to improve the efficiency of the volute. Ocean spiral shells have evolved to reduce fluid resistance and cut down fluid energy loss during motion. In this paper, the spiral shell was taken as the biomimetic prototype, and the cavity data of the spiral shells were obtained by reverse engineering technology. The internal cavity cross-section data of shells were extracted in the range of 270 degrees. After the cross-section curves were optimized, they were taken as the section curves to construct the bionic volute. And then the volute bionic surface design was realized. The computational models of the prototype and bionic supercharger were finished. Taking the turbocharger volute of the gasoline engine with 1.5-liter displacement as the research object, the numerical analysis method was used to realize the performance difference between the bionic volute and the prototype volute. First, the prototype numerical model’s reliability was verified. Then the bionic volute was matched with the prototype turbine system. The numerical simulation of the bionic volute and the prototype volute was carried out in the range of common working conditions, and the difference between the two was explored from the microscopic flow field. During the modeling process, the A/R values of the two turbine volutes were the same, and the outlet width of the volute was consistent with the outlet diameter. The verification test was carried out on a QYZ-2 turbocharger test bench. The inlet flow of the compressor was measured by a double-line flowmeter, and the maximum measurement error was less than 2% FS. Both the inlet and the outlet of the compressor were provided with a pressure sensor and a temperature sensor. The turbine inlet was provided with a turbine inlet pressure sensor and an intake temperature sensor, and the turbine outlet had a turbine exhaust pressure sensor and an exhaust temperature sensor in the extension duct. The maximum error of the pressure sensor was less than 2.5% FS, and the maximum error of the temperature sensor was less than 3% FS. The maximum error of the simulation calculation was within the allowable range. The simulation results showed that the simulation model was in good agreement with the test bench, and has good reliability. Therefore, the numerical model can meet the requirements of subsequent research. In the simulation, 12×104 r/min, 16×104 r/min and 20×104 r/min were selected to represent the low, medium and high operation speed of turbine respectively. The evaluation parameters included turbine efficiency, flow characteristics and total volute loss coefficient. The results showed that the turbine flow capacity increases with the increase of the expansion ratio increase. And the turbine flow characteristics of the two volutes were basically the same. The results showed that the turbine efficiency can be increased by 3% and by up to 5% under the condition of keeping the same turbine flow capacity matching two volutes. The flow field analysis results showed that the bionic optimization volute reduces the flow loss near the inner surface of the volute and the airflow friction in the flow channel. And the flow resistance was small, the whole flow in the bionic volute was smooth and uniform, and there was no swirling flow. Therefore, the turbine efficiency can be significantly improved. The bionic design method used in this paper had a significant improvement on turbocharger turbine performance, and can provide reference and method innovation for the design and optimization of automotive and agricultural machinery turbocharging systems. [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]

A hybrid refrigeration system of refrigerator car was designed in this paper. Photovoltaic energy storage system was the auxiliary power source of the refrigeration system and it drove the refrigerator during refrigerator car parking for a long time midway or at night. Engine drove refrigerator when refrigerator car was driving. The experimental analysis of hybrid refrigeration system of refrigerator car found that power generation of solar panels could only keep electric compressor working for 4.13 hours in one day. The power generation was not enough to support refrigeration system working for all night and this would affect the quality of cargo in the refrigerated carriage. In order to solve this problem, on the one hand, the energy consumption of refrigeration system needed to be reduced. On the other hand, the power generation capacity should be increased. Firstly, mathematical model of the hybrid refrigeration system of refrigerator car was established. Then, experiments about photovoltaic energy storage system and refrigeration system have been down. Correctness of the model was verified by comparing experimental data and simulation data. On this basis, the refrigeration efficiency and economic coefficient of photovoltaic power generation were put forward as the system evaluation indexes in this paper. The refrigeration efficiency was the ratio of energy consumption to cooling capacity and represented the energy consumption of the refrigeration system. If the refrigeration efficiency is lower, the energy saving of the refrigeration system is more. The economic coefficient of photovoltaic power generation is the ratio of power generation of solar panels to the power capacity of batteries and it represents the power generation capacity of per-unit cost of photovoltaic energy storage system. If the economic coefficient of photovoltaic power generation is greater, the power generation capacity per unit cost of photovoltaic power generation system is more. The two evaluation indexes were unified as the objective function. Nine constraints were enumerated. Based on chaotic ant colony algorithm, the hybrid refrigeration system of refrigerator car was optimized. The results after optimization showed that the energy consumption of the refrigeration system was reduced by 238.63 W, the cooling capacity was increased by 103.11 W and the refrigeration efficiency was reduced from 0.542 to 0.402. The optimized refrigeration system was more energy-saving. The volume of optimized refrigeration system was smaller, which made refrigeration system easier to install on the refrigerator car. Also, the power capacity of batteries was decreased by 2.67 kW·h, the whole day power generation capacity of solar panels was increased from 4.45 to 5.82 kW·h and the economic coefficient of photovoltaic power generation was increased from 0.464 to 0.840. In summary, the optimized hybrid refrigeration system of refrigerator car was more energy-efficient and economical. The optimization method and encouraging results in this paper will provide a fundamental reference for optimization design of the research on solar refrigeration system. [ABSTRACT FROM AUTHOR]

With the increase of water demand in winter in northern China, more and more open-channel water diversion projects transport water under the ice cover in winter such as the Middle Route of South-to-North Water Diversion Project. The method of transporting water using open channel under the ice cover has become increasingly common to delivery water from reservoirs, rivers and lakes to cities. The normal water depth is an important parameter in channel design, operation, flood control, and flow measurement and maintenance of the open channel or sewage systems. The explicit calculation algorithms of the normal water depth for the open channel are mainly for free-ice channels. This paper proposed algorithm of normal water depth of open channel under ice cover. The expression of the synthesis roughness for the flow of the channel under the ice cover was determined based on the studies of Sabaneev. The relationship between the normal water depth and the flow rate of the trapezoid section under the ice cover was derived. The Newton iterative formula for the normal water depth under the ice cover was obtained. However, the expression of the Newton iterative formula was too complex for engineering practice. A simple explicit iterative algorithm to compute the normal water depth was then proposed. It proved that the new iterative algorithm was convergent using the convergence theory of iteration. The formula to getting the initial value was proposed using the best hydraulic section. The application examples were given to compute the normal depth under the ice cover by using the new iterative algorithm. The results showed that the explicit iterative algorithm proposed had a fast convergence speed. In general, the error would be less than 0.01 m with only 3-5 times iterations. The number of the iteration decreased when using the initial value from the best hydraulic section. When the number of iterations was increased, the iterative value would be closer to the theoretical value of the normal depth. By using the same method, the relationship between the normal water depth and the flow rate under the ice cover was derived for the parabolic section, and a simple explicit iterative algorithm for calculating the normal depth of water was proposed too. The examples showed that the explicit iterative formula of the parabolic section proposed was simple and had a fast convergence speed too. In general, the error would be less than 0.01 m with only 3-5 times iterations as well as trapezoid section. The study of this paper provides a convenient method for the calculation of the normal water depth of the water conveyance channel under the ice cover. The research has theoretical and practical significance for the design, operation and management of the water conveyance channels under the ice cover because the normal depth is most widely used in the water conservancy project. [ABSTRACT FROM AUTHOR]

Super hybrid rice is a kind of rice variety that provides excellent quality and high yield. Super hybrid rice is very popular as a large-scale rice crop in China. The precision seeding of tray nursing seedling requires (2±1) seeds per hole. At present, the performance of seed metering devices can reach 1-4 seeds per hole, but the rate of single seed is high (more than 20%), and there are cavities. Due to the factors such as the germination rate, survival rate, characteristics of blanket and injured seedling rate, the seeding results cannot reach 1-2 plants per hole. Therefore, seeding target should be raised to 2-3 seeds per hole, which will reduce single-grain rate and eliminate the presence of cavities. When the seedlings for planting rice, vegetables, flowers, and so on, especially the super hybrid rice were used to mechanized seeding, the situation of cavity and single seed commonly exists. In order to achieve the goal of digital and intellectual precision seeding, which is difficult to achieve by the traditional seeding device or seed metering device, focusing on imitating the manual sowing principle with the monocular camera as eyes, the vision inspection systems as the brain, and the hill-drop device performing hand movements, this paper presents a new method of intelligent reseeding based on machine vision technology, and develops an intelligent reseeding devices, which is mainly used for quality detection and compensating seeds of the super hybrid rice. Firstly, the image of seedling tray was collected by CCD (charge coupled device) camera, the positions of cavities and the holes of single seed were obtained by image processing and analysis, and then the positioning mechanism and reseeding mechanism were used to realize the function of picking up the seed from seed groove and dynamically reseeding on the designated location. Applying LabVIEW graphical programming software, on-line testing and motion control system of seedling planting quality was developed to realize the task of intelligent reseeding. According to the statistics of the test results, the hill-drop machine can meet the production requirements of 450 trays per hour and the average reseeding time per hole was about 2.48 s when the reseeding rate was less than 2%. The average processing time of an image was about 0.518 s, and the accuracy was more than 95%. The paper achieves the intelligent reseeding according to the required number of seeds per hole. As a new precision seeding technology, the method will raise the level of planting accuracy, and have important scientific significance and application prospects. However, in the practical application of intelligent reseeding, considering the single dibbler’s working efficiency is still relatively low, the integrated design method can be used with 2-3 seeding devices according to reseeding rate and productivity, or the lightweight, fast reseeding mechanism, such as SCARA, parallel or serial manipulator, which can play a better advantage of intelligent reseeding. In addition, with the rapid development of robot technology, the cost of intelligent dibbler will become lower and lower, and the efficiency will be higher and higher. [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]

Sowing opener is one of the key parts of seeders, and its working performance affects the seeding quality. Domestic and foreign scholars have done a great deal of research on sowing openers in terms of traction resistance, soil disturbance, soil return performance and blocking performance. But there are few reports on the research of sowing opener for the integrative structure of ditching, earthing and suppressing. In this paper, an integrated sowing opener, which can be used to ditch, earth and suppress, was designed. It can solve the problems such as large disturbance of soil, insufficient compactness of seed bed soil, and poor uniformity of sowing depth. The combination of its sliding knife, retaining plate and repressing wheel can realize the seeding ditch, the seed falling to the bottom of the ditch, the wet soil returning to ditch, the suppressing wheel suppressing the seeding ditch, and the seed being in close contact with the soil. In this paper, the cutting edge curve is analyzed according to the slip cutting principle. It sets the cutting edge curve equation as parabola equation to deduce the conditions which can satisfy the needs of the slide cutting. That is, the slip angle is larger than the friction angle. The final result shows the range of the slider slip angle is 25°-65°. Based on the analysis of the principle of soil reflux after the operation of the trench opener, it can be seen that the change of the obliquity angle of the retaining plate affects the soil disturbance and the soil reflux, and the range of the inclination of retaining soil plate is 0-12.4°. According to the agronomic requirements, the range of soil compactness required for seed growth is 30-50 kPa, and the spring deformation amount is calculated to be 9-15 mm. Finally, the influencing factors can be determined. They are the slip angle, the slope of the retaining plate and the deformation of the spring. The slider slip angle, inclination of retaining soil plate and deformation variables of spring were selected as test factors. Soil compaction and soil disturbance were selected as experimental indices. The optimal parameter combination of the integrated seeding opener obtained from the soil bin text of optimizing the structural parameters was as follows: The slider slip angle was 44.6°, the inclination of retaining soil plate was 3.2° and the deformation variable of spring was 11.8 mm. In order to verify the operation performance of the integrated seeding opener better, field contrast tests were carried out with a double-disc opener and a sharp angle opener under the optimal parameters. The variation coefficient of sowing depth, soil compactness, soil disturbance and backing soil quantity were selected as test indices. The experimental results showed that variation coefficient of sowing depth of the integrated opener was 6.03%, which was 32.4% lower than that of the double-disc opener and 25.2% lower than the sharp angle opener. When the integrated opener was operated, the seeds fell into the ditch prior to the soil, which improved the seeds depth uniformity. The soil compactness was 38.6% higher than that of the double-disc opener and 62.9% higher than that of the sharp angle opener after the working of integrated opener. The suppression part of the integrated opener suppressed the ditches, after the soil-covering ditches were suppressed again by suppressing wheels of the seeder, which increased the soil compaction of the seed bed. The amount of soil disturbance generated by the integrated opener was 16.3% lower than that of the double-disc opener and 36.5% lower than that of the sharp angle opener. But its backing soil quantity was 29.9% higher than that of double-disc opener and 61.5% higher than that of sharp angle opener. Therefore, the integrated opener has little disturbance to the soil. In general, the integrated opener can improve the seedbed environment, enhance soil compaction and improve the uniformity of seeding depth. Besides, this type opener provides an integrated reference for the design of sowing openers. [ABSTRACT FROM AUTHOR]

Unmanned aerial vehicles are widely used in agriculture because of the advantages of flexible landing, no contact with plots, and wide adaptability of terrain. Currently, the unmanned aerial vehicle sowing operation is mainly based on the centrifugal sowing device, which mainly relies on the disc to sowing, forming the circular-shape falling area, causing the unstable uniformity of sowing, and it is difficult to control in the direction of the sowing width. In order to meet the needs of unmanned aerial vehicle low-altitude and high-speed sowing operations, and to ensure the uniformity of the sowing, a pneumatic unmanned aerial vehicle sowing device was designed in this paper, making use of the air-flow to blow the seeds out in different directions. The basic working principle was that the seed particles discharged from the metering device were mixed with the high-speed air flow in the flow-spitting box, forming a gas-solid two-phase flow, and then separated into a few streams of seed particles along the diversion channels. The high-spread streams of seed particles, released from the outlet of the diversion channels, cause the formation of a larger width, achieving satisfying sowing presentation. Meanwhile, the key components of the sowing device were simulated and tested. In this paper, the rotor wind field of the multi-rotor unmanned aerial vehicle was simulated and analyzed. The wind field distribution was summarized from two aspects of the vertical plane and the horizontal plane of different heights, and the movement and reasons of the particles in the rotor wind field were analyzed. Three main aspects (the relationship between the outlet size and the wind speed of the air-flow outlets, and the influence of the cone angles of the diversion channel on the airflow, and air pressure distribution in the diversion channel) were studied. The reasons for doing these tests were that the wind speed at the air-flow outlets was the key factor to determine whether the seed can be blown out or not. The design of the diversion channel affected the trajectory of the internal seed particles flow, and the most important thing was the effect on the velocity of the seed when leaving the diversion channel in the size and direction. The effect of the cone angle of the diversion channel on the sowing width and the sowing uniformity was tested. The test results showed that there was a strong negative correlation between the outlet size of the flow-spitting box and the outlet wind speed, and thus, the air outlet size can be determined according to the required wind speed. There was a strong linear correlation between the cone angle and the sowing width of the diversion channel. The correlation coefficient (R2 = 0.999) can be used to determine the appropriate cone angle according to the requirement of sowing width. Considering the distribution of pressure and flow velocity in the diversion channel and the influence on the width and uniformity, 130° was preferred as the cone angle of the diversion channel. Finally, the effects of sowing height on sowing width and sowing uniformity were studied. The correlation analysis method was used to analyze whether the working height in a certain range had an effect on the sowing width. By analyzing the uniformity variation coefficient in the sample areas the effect of working height on sowing uniformity was determined. The results showed that, in the range of 1-2.8 m, the correlation coefficient of height and width was 0.359, greater than 0.05, and the variation coefficient of sowing uniformity was above 15%, and the significance of height and coefficient of variation was 0.197, greater than 0.05, both of which mean that the height of unmanned helicopter had no significant effect on sowing width and sowing uniformity in the range of 1-2.8 m. Therefore, in this range, it is not necessary to consider the effect of the working height fluctuation on the sowing width and uniformity when sowing by this device. In the actual operation, taking into account the sowing width and uniformity coefficient of variation and energy consumption and other factors, the optimal height of 2 m was preferred on the unmanned aerial vehicle. This study provides the basic reference for further optimization of the prototy [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]

Swine effluent poses not only serious threats to the environment and soil but also affect the sustainable development of livestock industry. So the treatment and supervision of swine sewage is imperative. In this paper, we divided the swine treatment methods into ecological treatment, industrial treatment and centralized treatment. To realize the remote monitoring and illegal discharge warning of swine effluent disposed by the three treatment methods, a smart supervisory system and real time data supervisory strategy was designed and proposed. Based on Internet, the newly developed system collected and monitored the effluent information such as rainfall, level, flow, location, chemical oxygen demand and biochemical oxygen demand in water, ammonia concentration and so on through data acquisition system. The system was mainly comprised of sensors, microprocessors, and GPRS wireless transmission module. The collected data were transmitted to the cloud server as real-time data for the entire supervisory system. According to the change rules of data and the practical demand of supervision, real-time data was obtained every 10 minutes. In addition, to determine the credit rating of the industries and push the alarm information in different conditions, the system would select the principle identity as the primary index of warning decision, while for the real-time warning, industry credit rating, alarm grade, and alarm processing time as the secondary indexes were used. Furthermore, the index system of warning-push was proposed in this paper. Combing the real time data and index system of warning-push, the system could realize functions of real time data monitoring, video monitoring, site management, equipment management, data statistic and early warning management. A lower inter-module coupling and a higher cohesion between the functions were designed to improve its scalability and flexibility, and to ensure that the modules could be interrelated in the logical structure and independent in the physical structure. In the centralized treatment, the system used the GPS data and basic information of sewage disposal plant to judge whether the tank car took the sewage to the designated place to discharge it or not. Based on fuzzy reasoning theory, the supervisory system of industrial treatment with five monitoring subsystems, which had two inputs and one output variables, was established. In this fuzzy supervisory system, suspended solid difference, ammonia-nitrogen difference, biochemical oxygen demand difference, chemical oxygen demand difference, total phosphorus difference and its variation rate were selected as input variables, and corresponding warning rank as an output variables. Also, symmetry triangle was selected as the membership function of input and output variables to ensure the sensitivity and robustness of the system. According to the effluent discharge standards of the livestock and poultry industry, fuzzy reasoning rules of the subsystem can be generated. To monitor the ecological treatment of swine effluent, in this paper, we constructed the corresponding supervision strategy and ecological mathematical model. Based on the principle of the supervisory strategy, the model predicted and analyzed the real-time data by qualitative and quantitative method to calculate the discharging interval during rainy days and to judge whether there existed the phenomenon of night discharge, stealing and leaking, overflowing and so on. Through the simulation test, the results showed that the system's average warning accuracy reached 96.17%, the average error time was 33.22 s, the illegal discharge capacity caused by error time was 15.77 L. Therefore, this supervisory system could meet the requirements of swine effluent discharge regulation and improve the supervision efficiency significantly. [ABSTRACT FROM AUTHOR]

Agricultural implements tilt angle measurement is one of the key technologies to achieve agricultural implements and equipment precision operations. For example, the precision navigation control and the leveling control of agricultural implements are all dependent on the accurate measurement of tilt angle. What’s more, agricultural implements of tilt angle are one of the key parameters of agricultural mechanics modeling and agricultural implements safety warning learning. In order to further improve the quality of agricultural implements operation, we developed a new agricultural implement tilt angle measurement system in this paper and verified by tests on triaxial turntable platform and field. Modern micro-electromechanical systems (MEMS) technologies provide the moderate-cost and miniaturized solutions for the development of attitude reference system. Using highly-integrated inertial measurement units (IMUs) ADIS16445 provided by ADI company and micro ARM processor STM32F446 provided by ST company, we built the hardware platform. ADIS16445 ISensor® includes tri-axial gyroscopes and tri-axial accelerometers, the raw sensors data was sampled by STM32F446RC processor through SPI interface. The attitude calculation was carried out based on the Euler angle algorithm. The Kalman filter model with four state vectors and two observations was established to fuse the accelerometer and gyroscope information to achieve the accurate measurement of the tilt angle of agricultural implements. Considering the zero bias and drift characteristics of the gyroscope and the motion characteristics of the MEMS micro sensor, adaptive error covariance matrix Q and R rules were established to achieve precise tilt angle measurement of agricultural implements under different working conditions. Tests were conducted on SGT320E triaxial turntable platform and ZP9500 high level sprayer provided by LOVOL company dual in the field with the assistance of antenna positioning and attitude module BD982 provided by Trimble company. The SGT320E triaxial turntable platform was the standard equipment for testing the angular motion parameters and inertial systems. By setting the triaxial motion parameters to simulate a variety of motion states, it had speed, position and sine swing modes on all triaxial with a rate resolution of 0.0001°/s. In this paper, we used six position accelerometer calibration method and gyroscope error model to verify the performance of accelerometers and gyroscopes. Three-axis multi-function turntable test results showed that ADIS16445 built-in gyroscopes’ and accelerometers’ zero bias were under 0.15°/s and 0.075 mg, qualified to meet the system design hardware requirements. Kalman fusion algorithm were more accuracy and effective compare to simple integral by gyroscope and can solve the problem of zero bias and drift characteristics of the gyroscope with tilt static measurement error accuracy was 0.15°, typical dynamic measurement accuracy was 0.3°, maximum measurement error was less than 0.5°. The BD982 supports high precision positioning, attitude and heading output with high stability and fast dynamic response, which is widely used in construction implements, automobiles, agricultural implements and other fields, making it to be the leader of the industry. In this paper, the baseline length was 1.4 m with the measurement accuracy of 0.1°. Test results from high level sprayer showed that the average error of the attitude inclination was less than 0.55°, maximum measurement error was less than 0.91°, which satisfied the precise operation requirement of the agricultural equipment. Test results also verified that self-adaptive Kalman filter algorithm was more accuracy and stable than normal Kalman filter algorithm, which made the system development by this paper have more applicability. The agricultural implements tilt angle measurement system developed in this paper not only can reducing costs but also can improving the quality of agricultural implements operations. [ABSTRACT FROM AUTHOR]

Hydropower is one of the most reliable source of green energy and is widely used to meet real-time electricity demand. The ever escalating energy demand and iterative development in hydropower have pushed the generation of hydropower towards a low lost-cost and more flexible state which can work in a wider hydrodynamic region without compromising its performance. So the research on multidisciplinary optimization of hydro turbine needs to be carried out. Francis-type turbine is attractive because the efficiency of the unit at its design point exceeds the other types. As mentioned above, with the needs of robust operation in wide region without compromising its performance, the Francis turbine runner has to be optimized under multidisciplinary constraints. Multidisciplinary optimization technology of Francis runners has always been a key point in the field of turbine research. The coupling strength of each variable is the basis for establishing a concise and efficient multidisciplinary optimization strategy. So in the multidisciplinary optimization of Francis runner, it is necessary to analyze the coupling strength of design variables. In this paper, based on the global relative sensitivity of design variables, a coupling strength analysis method of runner design variables has been presented. First, combing three-dimensional (3D) inverse design theory with curve parametric method, a parametric 3D inverse-design method has been developed to control the Francis runner geometry. According to this parametric 3D inverse-design method, the meridional flow passage and geometry of runner blade can be controlled by a set of discrete parameters. These parameters are treated as runner design variables. The hydraulic efficiency of turbine, the minimal pressure coefficient on runner blade and the maximum static stress of blade are selected as objective functions. Then the global relative sensitivity of each objective function to design variables is calculated by an improved Morris OAT method. Compared with the traditional Morris OAT method, an optimal Latin hypercube design technique is adopted in the improved method. The optimal Latin hypercube design technique has a better space filling property than the traditional one. So the sampling only needs to be done once, which reduces the time of global relative sensitivity analysis without compromising its precision. On the basis of the improved Morris OAT method, the speed of global relative sensitivity calculation is improved obviously. Secondly, the set which contains global relative sensitivity of design variables is treated as universe, and the semi-trapezoidal function in fuzzy mathematics is imported to quantify the membership of each variable to objective functions. After obtaining the membership of each variable, a judgment principle of variable's coupling strength is presented in this paper. According to this judgment principle, the coupling strength property of each design variable can be defined as strong coupling, middle coupling and weak coupling. Finally, based on the coupling strength of each design variable, the multidisciplinary optimization strategy of Francis runner is established. And then the multidisciplinary optimization of Francis runner can be carried out. In order to validate the coupling strength analysis method, an application case is presented in the paper. In that case, the design variables of a Francis turbine runner with the head of 200 m are chosen as the analysis object. From the analysis result, it can be found that only the coupling strength property of maximum thickness is weak coupling, and the others are middle coupling. According to the result, a multidisciplinary optimization strategy is established and used in the optimization of Francis turbine runner. After optimization, both the hydraulic performance and strength property of the optimized runner are improved, demonstrating the effectiveness of the coupling strength analysis method. In conclusion, the method proposed in this paper can be adopted to analyze the coupling strength of design variables of Francis runner. [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]

In recent years, the pneumatic centralized fertilizing and seeding methods were developing rapidly. The pneumatic centralized fertilizing system was mainly used for layered fertilizing operation. The fertilizing pipes of the fertilizer discharging system were connected with the fertilizer outlet of the layered fertilizing shovel. Under the actions of air flow, the fertilizer was transported to the outlet of the fertilizing shovel quickly and remotely, so as to realize the layered application of the fertilizer in the soil. In this paper, in view of the problems such as the fertilizer falling into the inlet was not smooth and the airflow velocity at the outlet was too high, which leading to fertilizer bounce and dust when the fertilizer discharging system and layered deep fertilizing shovel were combined, the relationship between the structure of each part of the fertilizer discharging system and the working parameters was studied through the test-bench of the pneumatic centralized fertilizer discharging system, and the structure of the fertilizing system was optimized. An air-fertilizer separation device was designed, which was installed between the distributor outlet and the fertilizer discharging pipe of the layered deep fertilization shovel, part of the airflow from the fertilizing system was discharged by the air-fertilizer separation device in advance to reduce the airflow velocity at the fertilizer outlet of fertilizing system. The structure and basic working parameters of each component of fertilizing system were determined through theoretical analysis and parameter calculation. In specific, the airflow velocity of the fertilizing system inlet should be greater than 25 m/s, the diameter of the air-fertilizer conveying pipe, fertilizer inlet and fertilizer outlet was 76, 55 and 20 mm, respectively. The main factors affecting the airflow velocity at fertilizer outlet and inlet of fertilizing system were also determined through analysis. Taking the exhaust outlet area of the air-fertilizer separation device (A), the airflow velocity of the fertilizing system inlet (B) and the fertilizing rate (C) as the test factors, the quadratic regression rotary orthogonal platform experiment was conducted. According to the test results, the mathematical regression model between the test indexes and the influencing factors was established. The results showed that the exhaust outlet area of air-fertilizer separation device, airflow velocity of the fertilizing system inlet and fertilizing rate had a significant effect on airflow velocity at fertilizer outlet of fertilizing system, and exhaust outlet area of air-fertilizer separation device had a significant effect on the airflow velocity at inlet of fertilizing system. The optimized parameters were conducted by fitting and optimizing the test results. It was obtained that airflow velocity at fertilizer outlet, fertilizer inlet of fertilizing system was 5.91 and 3.94 m/s, respectively, the exhaust outlet area of the air-fertilizer separation device, airflow velocity of the fertilizing system inlet and fertilizing rate were 798.0 mm², 28.10 m/s and 0.28 kg/s, respectively. The verification test results showed that the airflow velocity at fertilizer outlet and fertilizer inlet of the system was 6.02 and 4.11 m/s, the fertilizer at the inlet of the fertilizer discharging system falled smoothly and stably. [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]

China is the largest producer and exporter of Lentinus edodes in the world. To improve its market value, twin-screw extrusion and expansion machine has been developed to further process the Lentinus edodes. To resolve the problems of blockage, low prematurity and missing operation parameters of this machine in producing Lentinus edodes pufferent, we presented an improved twin-screw extrusion and expansion machine in this paper to lower puffer ability, improve water absorption and reduce its hardness. The equipment consists of a frame, a mixing device, a feeding device, a tempering device, a heating device, an extruding and bulking device and a rotary cutting device. It is equipped with a cooling system, a lubricating system, a transmission system, a control system and a pressure detection system. Design and determination of the anti-blocking device for the feed mixing device, the pre-maturing and tempering device, and the structural parameters of the twin screw were conducted. In order to investigate the influence of operation parameters on swelling performance of the product, the Box-benhnken combined test method was used to study the working parameters of the double screw extruder. The effects of screw speed, extrusion temperature and water content on the swelling rate, hardness, brittleness and water absorption of the expanded product were analyzed, and the determinants were optimized. The results showed that, based on the level of the significance, 1) factors affecting the expansion rate were ranked in material water content > expansion temperature > screw speed, 2) factors affecting hardness were ranked in material moisture content > screw speed > swelling temperature, 3) factors affecting brittleness were ranked in material moisture content > screw speed, 4) factors affecting water absorption were ranked in material moisture content > swelling temperature > screw speed. The optimal operating parameters were: screw speed 167.23 r/min, swelling temperature 151.68℃, material moisture content 16.83%. Under these conditions, the swelling rate, hardness, brittleness and water absorption of the product were increased by 4.04%, 18.61 N, -8.46 mm/cm2 and 313.86% respectively, compared to the traditional machine. Practical application of the optimized parameters revealed that the error between the optimized productivity and real productivity was less than 4%, with the maximum productivity being 165 kg/h. Compared with the existing equipment in the laboratory at School of Mechanical Engineering in Yangzhou University, the designed machine increased the swelling rate, brittleness, water adsorption and brittleness by 25.00%, 40.55% and 62.35% respectively, while reducing the hardness by 48.21%. Therefore, the design of this machine can provide relatively mature technical equipment for the development of mushroom swelling products. [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]

Fertilizer is essential to safeguard food security, and rationalizing fertilization and improving fertilizer use efficiency can reduce its detrimental impact on environment and sustain agriculture production. Current corn fertilization in China is largely growth stage-based with a base fertilization coupled with a number of topdressings. This is inefficient in fertilizer use and labor-intensive, difficult to meet the requirements for sustainable agriculture. Delivering the fertilizer to the location in soil where the crop mostly demands for is a technology to effectively improve fertilizer use efficiency and increase crop yield. In this paper we present a pneumatic centralized device to stratifying fertilizer in soil based on the demand of crop roots. The structure and working parameters of the key components in the device were calculated theoretically; the diameter of the conveying pipe in the device was 76 mm, the inlet airflow velocity should be higher than 25 m/s, and the distribution ratio of the fertilizer can be adjusted arbitrarily from 1:1 to 1:2. The performance of the device was analyzed using the discrete element method coupled with the computational fluid dynamics by taking the rotational speed of the rotary cone (A), the inlet airflow velocity (B) and the fertilization velocity (C) as determinants, and the coefficient of variation (CV) of the fertilizer amount at each fertilizer outlet as an performance index. A quadratic-regression rotation orthogonal simulation test was used to link the performance index to the determinants. The results showed that both rotational speed of the rotating cone and the inlet airflow velocity had a significant effect on the CV. When rotational speed of the rotary cone was 735-1 196 r/min, the inlet airflow velocity was 36-41 m/s, the fertilization velocity was 0.14-0.42 kg/s and the distribution ratio was 1:2, the associated CV at different fertilizer outlets varied from 3.7% to 4.9%. The influence of all determinants on the CV was ranked in the order of A>B>C. Bench test of the device was conducted in the Conservation Tillage Research Center of the Ministry of Agriculture and Rural Areas, with rotational speed of the rotary cone being 735 r/min, the inlet airflow velocity being 36 m/s, the fertilization rate being 0.42 kg/s and the distribution ratio being 1:2. The results showed that the CV was less than 5.18% and the deviation of the distribution ratio was less than 2.68%, consistent with the results obtained from simulation and meeting the requirements for fertilization operation. This work provides a new technology with theoretical support to optimize pneumatic centralized device for stratifying fertilizers into soil. [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]

Bearingless flywheel battery has many advantages, such as high specific power, high specific energy, high current receiving capacity (recharge and regenerative braking), long service life, fast charge and discharge, and it is considered to be the most competitive auxiliary batteries for electric vehicle. However, there are some problems in bearingless flywheel motors and some magnetic bearings in bearingless flywheel battery systems, such as low integration, large energy loss and low reliability. Aiming at above problems, an axially suspended hybrid magnetic bearing with asymmetric excitation and unloading which consists a lower stator, a upper stator with permanent magnet ring and a rotor is proposed in this paper. First of all, the mechanical structure of the axially suspended hybrid magnetic bearing with asymmetric excitation and unloading is introduced, and the different operating mechanisms under the conditions of unloading, demagnetization, down disturbance and upward disturbance are discussed. The design criteria is set according to the operating mechanisms under different working conditions. According to the design criteria and the working curve of rare earth permanent magnet materials, the numerical model of unloading force and the axial compensation under demagnetization/maximum eccentricity are deduced. Then, the structural parameters of upper stator and permanent magnet are designed, and the windings of the upper stator and lower stator are calculated considering the constraint conditions of demagnetization and eccentricity. Based on this, three-dimensional finite element model is established. Simulation results show that the flux density is about 0.605 T between upper stator and air gap under unloading mode which verifies the validity of the design method for permanent magnet and upper stator parameters. The suspension force of finite analysis is about 100 N and the relative error with theoretical suspension force value (104 N) is 4%. When working under the demagnetization mode, the flux density is about 0.53 T between upper stator and air gap which approximately equals to the theoretical value(0.54 T). The suspension force of finite analysis is about 78 N and the relative error with the theoretical suspension force value(81N) is 3.7%. When the maximum downward eccentricity is 0.2 mm, the flux density is 0.515 T which approximately equals to the 0.5 T of theoretical value, the suspension force of finite analysis is about 65 N and the relative error with the theoretical suspension force value(69 N) is 5.8%. When the maximum upward eccentricity is 0.2 mm, the flux density is 0.65 T and the suspension force of finite analysis is about 110 N. Finally, in order to further verify the correctness of theoretical analysis, a prototype is manufactured according to the design results. The results of prototype test show that the maximum error between theoretical calculation value and measured value of unloading force is about 4%, and the average error is 2%, the rotor radial displacement is about 25 μm when the axial load is 80 N, the rotor radial displacement is about 35 μm when the axial load is 120 N. The results indicate the proposed magnetic bearing has a good unloading and suspension performance of the magnetic bearing, which provides a new idea and method for the design of high integration, low loss and high reliability flywheel battery system. [ABSTRACT FROM AUTHOR]

Bearingless flywheel battery has many advantages, such as high specific power, high specific energy, high current receiving capacity (recharge and regenerative braking), long service life, fast charge and discharge, and it is considered to be the most competitive auxiliary batteries for electric vehicle. However, there are some problems in bearingless flywheel motors and some magnetic bearings in bearingless flywheel battery systems, such as low integration, large energy loss and low reliability. Aiming at above problems, an axially suspended hybrid magnetic bearing with asymmetric excitation and unloading which consists a lower stator, a upper stator with permanent magnet ring and a rotor is proposed in this paper. First of all, the mechanical structure of the axially suspended hybrid magnetic bearing with asymmetric excitation and unloading is introduced, and the different operating mechanisms under the conditions of unloading, demagnetization, down disturbance and upward disturbance are discussed. The design criteria is set according to the operating mechanisms under different working conditions. According to the design criteria and the working curve of rare earth permanent magnet materials, the numerical model of unloading force and the axial compensation under demagnetization/maximum eccentricity are deduced. Then, the structural parameters of upper stator and permanent magnet are designed, and the windings of the upper stator and lower stator are calculated considering the constraint conditions of demagnetization and eccentricity. Based on this, three-dimensional finite element model is established. Simulation results show that the flux density is about 0.605 T between upper stator and air gap under unloading mode which verifies the validity of the design method for permanent magnet and upper stator parameters. The suspension force of finite analysis is about 100 N and the relative error with theoretical suspension force value (104 N) is 4%. When working under the demagnetization mode, the flux density is about 0.53 T between upper stator and air gap which approximately equals to the theoretical value(0.54 T). The suspension force of finite analysis is about 78 N and the relative error with the theoretical suspension force value(81N) is 3.7%. When the maximum downward eccentricity is 0.2 mm, the flux density is 0.515 T which approximately equals to the 0.5 T of theoretical value, the suspension force of finite analysis is about 65 N and the relative error with the theoretical suspension force value(69 N) is 5.8%. When the maximum upward eccentricity is 0.2 mm, the flux density is 0.65 T and the suspension force of finite analysis is about 110 N. Finally, in order to further verify the correctness of theoretical analysis, a prototype is manufactured according to the design results. The results of prototype test show that the maximum error between theoretical calculation value and measured value of unloading force is about 4%, and the average error is 2%, the rotor radial displacement is about 25 μm when the axial load is 80 N, the rotor radial displacement is about 35 μm when the axial load is 120 N. The results indicate the proposed magnetic bearing has a good unloading and suspension performance of the magnetic bearing, which provides a new idea and method for the design of high integration, low loss and high reliability flywheel battery system. [ABSTRACT FROM AUTHOR]

With the modernization of agriculture and social informatization, the internet of things (IoT) and the wireless sensor network (WSN) are widely used in the agricultural application. The sensor nodes play important roles in IoT and WSN system, which have strict requirements on the battery. In the traditional scheme, WSN is powered by the lithium battery or solar panel. It is very hard to recharge the lithium battery in the wild, while the solar panel is greatly limited by the environment. It brings great challenge to the power supply of sensor nodes. The microbial full cell (MFC) is one of the most promising renewable energy, which can be used for the self-power supply of the sensors in real application. MFC uses microbes as biocatalysts, which can transform carbohydrates into electrical energy. In order to improve the efficiency of MFC, lots research has been done. The maximum power output of MFC has been gradually improved. However, the output open-circuit voltage of MFC is low，about 0.7 V, and the internal resistance is large, so it is impossible to ensure the MFC working at the maximum power point. Based on the polarization curve and output power density of the MFC reactor, a power management module is designed to improve the efficiency of MFC in this paper. The output power management module consists of an energy harvesting circuit and a secondary booster circuit. The energy harvesting circuit consists of a DC-DC converter, hysteresis compactors (ADCMP609 and 74HC32) and a large capacitor, which has a function of the maximum power point tracking (MPPT). The circuit can boost the output voltage of MFC at the maximum power point, which improves the system energy conversion efficiency. The secondary booster circuit consists of an Ener Chip energy processor (CBC915), a charge pump (IC S882Z24), an Ener Chip solid state battery module (CBC51100). The secondary booster circuit can improve the voltage on the large capacitor connected with the output of the energy collection circuit and the working voltage of the wireless temperature sensor, and provide a stable power supply for the next stage circuit. The wireless temperature monitor system is powered by the proposed power management module. MSP430 and CC2500 chips are used in the temperature monitor system to collect the environmental temperature and send the real-time temperature data to the remote terminal. The measured results show that the output voltage of MFC in the system is maintained in the range from 316 to 390 mV, and the function of maximum power point tracking is realized. The output voltage of the energy harvesting circuit and the secondary booster circuit are 1.1 and 3.5 V, respectively. By using MFC as the power supply, the wireless temperature sensors deliver the environment temperature data to the remote terminal at a period of 13 ms. The proposed energy harvesting circuit for MFC with MPPT function provides an innovative solution to solve the problem of the power supply for sensor nodes, and has great potential in agricultural environmental monitoring system. [ABSTRACT FROM AUTHOR]