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In order to better realize the combination of agricultural machinery and agronomy, the design of precision rice hill-drop drilling machine was further optimized and tested. The precision rice hill-drop drilling machine that was powered with high speed transplanter chassis was composed of frame, furrowing and ridging device, height and horizontal profiling mechanism system, power transmission system, seeding device and hydraulic lifting frame. It could meet the rice direct seeding agronomic requirements which are furrowing and ridging synchronously, adjustable sowing rate and hill space, optional row space, profiling seeding mode and stubble burying before seeding. The combined hole-type metering device included small and big type holes was used for the precision rice hill-drop drilling machine, so that it could meet the sowing rate requirement of conventional rice and hybrid rice simultaneously and adjust the seeding rate quickly. On the basis of the combination of agricultural machinery and agronomy as well as the experimental verification, the frame, reduction gearbox, horizontal profiling mechanism, height profiling system and installation angle of slide plate were optimized. The new frame could protect the main bar from being bended. The new reduction gearbox made the hill space to match the speed of the chassis more accurately and also could change the rotation direction to fit different kinds of chassis. The height and horizontal profiling mechanism made the seeding machine more floatable, so it could adapt more complicate ground. Furthermore, the related experiments proved that profiling system is conducive to the seedling emergence of rice. The seedling emergence rates of the rice varieties XS134 and PZTF, which were seeded by the precision rice hill-drop machine with horizontal profiling mechanism, were 7.8% and 8.7% higher than that without horizontal profiling mechanism, respectively. In order to protect the atmosphere environment, the government introduced the relevant policies and laws to prohibit the burning of straw, and promoted the comprehensive utilization of crop straw. Many farmers returned straw residue to field to improve soil fertility and reduce environmental pollution, but it could be more difficult for the direct seeding machine and rice transplanter working in the field as well. To overcome this difficulty, the stubble-burying seeding was studied. The angle of the slide board was confirmed as 4° by the experiment result, while the efficiency of stubble burying was 91.6% and the furrowing and ridging effect under 4° was relatively better than that under other degrees. In this paper, some verification tests involved the main technical indices of the seeding machine and its reliability. Results showed that, the pure work efficiency was 0.67 hm2/h, the qualified rate of hill space was up to 100%, the variable coefficient was as low as 2.5%, the qualified rate of the seeds number per hill reached 95% and the cavity rate was 0; furthermore, the variable coefficient of the consistency of seeding quantity per row and the stability of total seeding quantity were 3.8% and 1.5% respectively; after seeding with horizontal profiling mechanism, the height difference between the left and the right field surface was about 2.0 cm; more important, the average of assignment before first-time fault (MTTFF) was 30.4 hm2/h, and the validity reached up to 98.2%. Therefore, on the basis of these results which all meet the national standard and the requirements of the combination of agricultural machinery and agronomy, and the reduction gearbox makes the machine+ more universal. The performance of the optimized precision rice hill-drop drilling machine is reliable and has exciting application foreground. [ABSTRACT FROM AUTHOR]

In the process of planting Anthurium andraeanum, people need to transplant the seedling from small pot to big pot to get more growth space. This work will not only spend much time, but also increase the cost of planting. Our research group has finished a design of the transplanting machine to realize the automatic transplanting of Anthurium andraeanum. However, during the usage of the machine, we found that the transplanting manipulator cannot take out the soil matrix completely from the small pot sometimes. Once the incomplete soil matrix is watered after the transplanting, the seedling will tilt. It will lead to the difficulty of sale. So taking out the soil matrix completely from the small pot will be one of the most critical technical problems in the transplanting mechanical system for potted anthurium. Operation objects can be regarded as rigid body in the traditional mechanism design, however, the potted soil matrix, as the operation object of transplanting manipulator, belongs to the discrete body, although the potted matrix can be condensed as a certain shape under the limitation of the pot. In the process of sinking the needle into the soil matrix and taking it out, it is hard to keep the original stable shape and take out the matrix completely due to the lack of the cohesion of matrix itself and the adhesion effect between the pot and matrix. This condition will lead to the failure of transplanting. Based on the discrete element analysis method, this paper established discrete element simulation model among mechanism (transplanting manipulator), action object (matrix with rootstock), and action condition (pots) by EDEM (enhanced discrete element method) software to analyze the whole process of transplanting. In the simulation, we found that when the transplanting manipulator takes out the soil matrix, a fault happens inside the soil matrix. After the analysis for this simulation phenomenon, we knew that when the total resistance force is greater than the maximum cohesive force that soil matrix can offer, the matrix will be broken and become the incomplete matrix. According to the above analysis, we started to use the Su-Field analysis method to solve this problem. By using the component analysis and functional model, the transplanting mechanical system was known more, and we focused the key point on the harmful adhesion effect between small pot and soil matrix. With the help of Su-Field model and standard solution, we fully analyzed the resources of the mechanical system and translated the Su-Field model into the solution of pot pressing mechanism finally. And for this solution, we also done the discrete element simulation by EDEM and found that the pot pressing mechanism can make a crack and reduce the friction between the soil matrix and pot. With the reduction of friction in this way, the total resistance force cannot be greater than the maximum cohesive force that soil matrix can offer most of the time. It will effectively avoid the appearance of incomplete soil matrix. So the solution of pot pressing mechanism is reasonable and feasible. On the basis of the solution, we done the optimization for the original transplanting mechanical system. The transplanting experiment of 3 groups of pots (100 pots each group) was carried out respectively for the transplanting manipulator before and after the optimization. We found that the success rate of taking out soil matrix completely is improved from 84.67% to 97.67%. In this study, the discrete element analysis and Su-Field analysis method in TRIZ (theory of inventive problem solving) are combined to apply to the mechanism optimization design process, which can provide reference for the research and development of automated transplanting equipment about potted plant. [ABSTRACT FROM AUTHOR]

Tillage practice is one of the energy-consumed links in agricultural production, while the energy can be saved through proper management of blade geometry. In case of rotary tillage, the geometry of sidelong edge, lengthwise edge and transition edge plays a pivotal role in the energy consumption and working performance in the field. The continuous development of the conservation tillage puts forward higher requirements for the performance of rotary blade. In order to manage the rotary tillage process reasonably, the power consumption and working performance of blade should be better understood. In this paper, the sidelong edge and lengthwise edge of the national standard blade were designed as serrated ones and the bionic-shape transition edge was devised according to the arrangement of mole's toes, and later the power consumption and working performances of the bionic serrated blade and the national standard blade were investigated in the field. Meanwhile, the performances of both blades were also studied in soil with and without straw covered via discrete element method (DEM) simulation. A torque sensor was installed between the PTO (power take-off) shaft of tractor and the cardan of straw returning machine to measure the power consumption, while the straw burying rate, the soil crashing rate and the proportion with straw length ≤15 cm were used to evaluate the working performance of blade. Both simulation and experiment were performed with the rotational speed of 300-350 r/min and a constant forward speed of 0.5 m/s. The simulation was performed under 2 conditions with 0% and 100% straw covered, and the results showed that the horizontal and vertical force both increased from 0 to the maximum value and then decreased to 0, while the side force nearly remained constant in one tillage cycle. The directions of horizontal force and side force were the opposites of the working direction of blade and the blade edge, respectively, and the vertical force would change its direction when the maximum tilling depth was reached. It was also observed that the forces and torques of blade in soil with 100% straw covered were larger than those in soil without straw covered because of the extrusion and shear effects between the blade and straw. The field experiments were conducted under 3 soil conditions with kilogram of 0, 0.375 and 0.75 kg (0%, 50% and 100%) on field surface with 0.5 m×0.5 m. The torque and power consumption of the bionic serrated blade and the national standard blade were 404.05 and 389.27 N·m, 20.08 and 18.52 kW with 0% straw covered, 438.33 and 443.79 N·m with 50% straw covered, and 557.92 and 507.34 N·m with 100% straw covered, respectively. The working performances of both blades showed that the performances of bionic serrated blade were better than those of national standard blade in the straw burying rate, the soil crashing rate and the proportion with straw length ≤15 cm under all straw covered conditions. Both simulation results and experimental results revealed that the torques of bionic serrated blade were larger than those of national standard blade with 0% and 100% straw covered. Although the torque and power consumption of the bionic serrated blade appeared better than those of national standard blade only with 50% straw covered, the working qualities after the bionic serrated tillage were always better under all 3 soil conditions. It can be inferred that the bionic serrated blade will perform well with some straw removed from field to compensate for the disadvantages of higher torque and power consumption. The study provides a reference to achieve soil-rototilling and stubble-shattering by using one kind of blade. [ABSTRACT FROM AUTHOR]

Corn seed bionic thresher was designed based on the principle of first discretizing and then threshing, which imitated the process of chicken beak discretizing corn grain and bare hand threshing, and had the advantages of low damage, low broken rate, and so on. In order to optimize the parameter of corn seed bionic threshing system, and then reduce the damage in the course of threshing of corn seed, this paper adopted the method of the quadratic regression orthogonal rotation combination design. Grain broken rate and removal rate were taken as the main performance indicators, differential roller speed, discrete roller speed, threshing roller speed, discrete roller gap, and threshing roller gap were selected as experimental factors, and the performance test of the corn seed bionic thresher was carried out. According to the test results, the influence of discrete roller speed and threshing roller speed on the broken rate and removal rate was respectively analyzed, as well as the influence of discrete roller gap and threshing roller gap on the broken rate and removal rate. Analysis results showed that when the threshing roller speed was fixed at a certain level, and the discrete roller speed increased from 150 to 350 r/min, the broken rate first increased and then decreased; when the discrete roller speed was fixed at a certain level, with the increasing of the threshing roller speed from 150 to 350 r/min, the broken rate decreased gradually; when the discrete roller speed was in 150-180 and 310-350 r/min, and the threshing roller speed was in 270-350 r/min, the broken rate was 0, which reached the lowest. The threshing roller speed was fixed at a certain level, and the discrete roller speed changed in the range of 150-350 r/min, the removal rate first increased and then decreased; when the discrete roller speed was fixed at a certain level, with the increase of threshing roller speed, the removal rate decreased gradually; when the discrete roller speed was in 230-330 r/min, and the threshing roller speed was in 150-300 r/min, the removal rate reached 100%, which was the highest. When the discrete roller gap was in 0-4 mm, and the threshing roller gap was in 5-9.2 mm, the broken rate was 0, reaching the lowest. When the discrete roll gap was fixed at a certain level, and the threshing roller gap reduced from 9.2 to 0 mm, the removal rate continued to increase; when the threshing roller gap was in 0-2.2 mm, the removal rate was 100%, which was the highest. On the basis of the experimental curve, through the optimization with the comprehensive evaluation method, the optimal combination of parameters was obtained: the differential roller speed of 90 r/min, the discrete roller speed of 350 r/min, the threshing roller speed of 350 r/min, the discrete roller gap of 4.6 mm, and the threshing roller gap of 4.6 mm. The verification test was carried out on the basis of these optimal conditions. It was found that the breaking rate was 0.226%, the net removal rate was 99.317%, and the corncob integrity was 100%. All the results meet the requirements of the national standard. [ABSTRACT FROM AUTHOR]

Wheel swivel angle is regarded as a critical parameter in agriculture automatic navigation system, and it can always be measured by using angle sensor. In engineering practice, angle sensor is difficult to fix, and the shaft is easily broken. In order to solve the problem, displacement indirect measurement method and four-bar indirect measurement method are proposed in this paper. Wheel rotation depends on steering cylinder piston movement, and the movement of steering cylinder piston causes the movement of steering trapezoidal mechanism. Therefore it is available to apply displacement sensor in measuring the position of the steering cylinder piston rod, and the displacement sensor is parallel fixed with the steering cylinder. Referring to the motion of steering trapezoidal mechanism, it is proposed to use the front axle, knuckle arm, connecting rod and pendulum rod to form a four-bar linkage. According to the fixed location of the displacement sensor and four-bar angle sensor, it is available to establish measurement models for those 2 indirect measurement methods, and calibrate the relation between sensor measurement and wheel swivel angle, but those 3 measurement methods are incapable to measure the real wheel swivel angle. In the 2 kinematic models of wheel vehicle, wheel swivel angle is the angle between wheel axis and vehicle body axis, and thus Ackerman transformation must be used for converting the test angle into wheel swivel angle. However, different vehicles are different in the transformation of Ackerman, and the ideal Ackerman transformation cannot be used. In fact, the rotation angles of left and right wheels have little bias with the wheel swivel angle when the wheel swivel angle is being in a small range in the middle of the pair. Therefore it is supposed that the measurement angle is the wheel swivel angle. Through automatic navigation precision comparison experiment, the advantages and disadvantages of different measurement methods are compared. The experiment is performed on basis of the LOVOL tractor M800, in which the self developed automatic navigation system was used, and an experiment platform was built. The experiment is completed on the asphalt pavement and the field, and the platform can be utilized to compare the accuracy of 3 measurement methods of wheel swivel angle and compare the accuracy of navigation through statistical analysis. The result shows that the four-bar angle sensor can provide the highest angle measurement accuracy and navigation accuracy. When the vehicle keeps the speed of about 4.2 km/h, the mean value of lateral deviation is -0.028 2 cm by using the four-bar angle sensor in the field, and the mean value of lateral deviation is -0.014 6 cm by using the hall angle sensor and 0.109 0 cm by using the displacement sensor in the same experiment environment. Therefore the four-bar indirect measurement method offers almost a navigation accuracy equal with the direct angle measurement, but the standard deviation of lateral deviation for automatic navigation of the four-bar indirect measurement method is 1.297 5 cm, which is less than the direct measurement method. But considering the displacement sensor wear, when the sensor has been used for about 50 h in the same environment, the mean value of lateral deviation is -0.656 1 cm. Thus the displacement angle measurement is incapable of replacing the direct angle measurement, while the four-bar angle sensor is capable to replace direct angle measurement method and can be further applied in practice, which is easily fixed and protected. [ABSTRACT FROM AUTHOR]

The large-scale harvester chassis is usually made up of 2 long stringers and several crossbeams by welding, and most important parts of harvester are mounted on its upper surface, such as engine, cab and gearbox. Because of the welding thermal stress, the upper surface of chassis cannot be a perfect plane, and the important parts would not be in the pre-set position. If the error is too big, the harvester would not run smoothly as hoped. So it is important to get the flatness error before chassis goes toward the production line. Three-coordinate measuring machine, laser measuring machine and 3D (three-dimensional) camera are traditional flatness error measuring devices, and their precision is high, but they cannot measure such a big chassis with fast enough speed; in addition, their price is very high. In this paper, a test system equipped with laser ranging finders is proposed to measure the flatness error of chassis. The system includes a hydraulic lifting platform and a reference platform. Hydraulic lifting platform is made up of positioning devices, clamping devices and shearing mechanism, and it can lift chassis to a certain height and keep still. The reference platform is a 0 stage precision granite platform, 2 parallel linear guide rails are mounted on its surface, and 2 groups of laser ranging finders (3 finders for each group) will move along the guide rails to get the distance between reference platform and measuring point on chassis. In this system, hydraulic lifting platform is just used to fix chassis, and the position error between hydraulic lifting platform and reference platform can only change the coordinate value of measuring point, and has nothing to do with the flatness error result. The measurement process is carried out in 3 steps. First, hydraulic lifting platform lifts the chassis to the position where stringers are under the laser ranging finders. Second, laser ranging sensors scan the chassis to get the coordinate values of measured points on chassis. At last, computer calculates the flatness error result, and the chassis is put down and took away at the same time. After measuring, the chassis plane is transformed into a great number of spatial coordinates with the same rectangle distribution, and then software will call the MATLAB to calculate the error result. The measurement and control software above-mentioned based on LabWindows/CVI (C for Virtual Instrumentation) is developed to control the system, which can make the test system autonomous or semi-autonomous working, and all the data are stored in an excel file. The system is tested by 9 times on one chassis of a certain type corn combine harvester. The length is 4 000 mm, the width is 1 110 mm, and 66 measuring points are measured along the 2 stringers. The flatness error of 10.27 mm is obtained with the least square method, which takes all the measuring points into account, and the uncertainty degree of this result is just ±0.05 mm. All these show that the result is authentic and credible, and the system and error evaluation method can meet the accuracy and speed requirements of the test, so there is a great significance to ensure the assembly quality of large-scale harvesters and improve the competition of the products. [ABSTRACT FROM AUTHOR]

In order to improve the seeding performance of pneumatic cylinder-type precision direct seed-metering device for rice, the single factor and central composite experimental experiments were conducted in this paper. The effects of the main working parameters (rotational speed of seeding cylinder, vacuum degree in vacuum gas chamber, air-blowing velocity and clearing blockage positive pressure of chamber) on seeding performance of the direct seed-metering device were analyzed by means of the JPS-12 type performance test rig of metering device. The study object was “Huanghuazhan”, which was pre-germinated and its moisture was 21.65%-23.73% (wet basis). Qualified rate, miss-seeding rate, replay rate, average hole distance and variation coefficient of hole distance were regarded as the performance evaluation indexes. The result of single factor experiments showed that rotational speed of seeding cylinder, vacuum degree in vacuum gas chamber and air-blowing velocity had significant influence on the qualified rate, miss-seeding rate and replay rate of metering device, respectively. The clearing blockage positive pressure of chamber had no significant influence on qualified rate, miss-seeding rate, replay rate, the average hole distance and the variation coefficient of hole distance of metering device, respectively. So, it was only necessary to provide the positive pressure chamber with suitable strength of clearing blockage positive pressure to ensure the suction hole not be blocked during the metering device working. The three-factor and five-level quadratic regression rotation design optimization experiment of the 3 influence significant factors on metering device showed that the order affecting qualified rate was rotational speed of seeding cylinder > vacuum degree in vacuum gas chamber > air-blowing velocity, and the order affecting miss-seeding was vacuum degree in vacuum gas chamber > rotational speed of seeding cylinder > air-blowing velocity. The variance analysis of experimental results had a significant affecting of experimental factors on performance evaluation indexes. Through the analysis of effect of various factors on the metering device, the seeding performance of the metering device was better under the condition of low rotational speed of seeding cylinder, high vacuum degree in vacuum gas chamber and higher air-blowing velocity. The optimal combination working parameters of metering device were seeding cylinder rotational speed with 10 r/min, vacuum degree in vacuum gas chamber with 4.6 kPa and air-blowing velocity with 21.88 m/s. All of those were obtained by optimization solution of all factors by use of quadratic regression model equation of performance evaluation indexes in the range of experimental parameters constraints. The results of verification test were consistent with the results of optimization solution. Under the condition of the optimal combination working parameters, the qualified rate, miss-seeding rate, cavity rate and replay rate were 87.73%, 2.93%, 0.53% and 9.34%, respectively. Meanwhile, the seed breakage rate was 0.91%, the average hole distance was 200.07 mm (theoretical hole distance was 200.00 mm), the variation coefficient of hole distance was 4.75%, the apiece row consistency variation coefficient of seeding quantity was 3.07%, the stability variation coefficient of the full seeding quantity was 2.08%. This seeding quality met the direct seeding requirements of hybrid rice. The field sowing experiment of the direct seed-metering device was carried out in the modern agricultural science and technology experiment base of Huazhong Agricultural University. When the average forward speed was about 1.79 km/h of direct seeder, the average vacuum degree in vacuum gas chamber was about 4.6 kPa and the average air-blowing velocity was about 21.88 m/s, the qualified rate, miss-seeding rate, cavity rate and reseeding rate were 79.42%, 15.11%, 3.88% and 5.47%, respectively. Meanwhile, the average hole. [ABSTRACT FROM AUTHOR]

With the increasing use of agricultural plastic film, the pollution it bringing is becoming more and more serious. It has become a problem which needs to be solved urgently. In China, the plant areas of peanut were expanded to 460.6 hm2 in 2014, which accounted for about 17.9% of the global area of peanut crops. And its output reached to 16.481 7 million tons in the same year, which accounted for about 38.9 % of the global production of peanut yields. Therefore, design and experiment on plastic film collector of ridged peanut means a great deal to us. The collecting film teeth residue plastic film collector of ridged peanut was designed, and the whole structure and working mechanism of the machine were introduced. Therefore, the main operation components of it were designed and the structure parameters were determined at last. To solve the problem of residual film recycling after peanuts harvest, we designed the plastic film residue collector, and then optimized its parameters. The key structural parameters were determined by mechanism analysis and tests. The collecting film teeth diameter of the first row, the second row, and the third row were set as 10, 8 and 8 mm, respectively. The harrowing tooth was made of No.65 manganese steel, and the harrowing tooth's lug angle ranges from 10° to 35°. The collecting film teeth space on the first row, the second row, and the third row were 120, 100 and 80 mm, respectively. The four-dimensional slice of MATLAB and response surface analysis was done on the machine speed, the harrowing tooth's lug depth and its radius of curvature. The quadratic regression model between film removing ratio and machine operating speed, the embedded depth of the rake, tooth curvature radius was built. The optimal structure parameters of plastic film residue collector were obtained by response surface analysis. The response surface analysis of the model was optimized, and the effect of 3 factors on the recovery of the residual membrane was significant. The order of strength is: machine operating speed> embedded depth of the collecting film teeth > collecting film teeth curvature radius. The machine was optimized by parameter optimization. The machine operating speed, depth of collecting film teeth, tooth's radius of curvature of machine was 1.2 m/s, 11mm, and 222 mm, respectively. And film recycling rate was about 93% through the field test. Its relative error was 2% compared with the predictive value. In conclusion, the optimization scheme was feasible. This paper could provide theoretical basis for optimization of related machines. With the preliminary experiment, the collecting film teeth residue plastic film collector of ridged peanut has good film quality, which meets the design requirements of plastic recycling machine. Removing mechanism on the collecting film teeth residue plastic film collector of ridged peanut is the further research. [ABSTRACT FROM AUTHOR]

Residual film not only affects the crop emergence and yield but also causes serious soil and environmental damage and affects the smooth operation of the agricultural machinery, so residual film recovery is imperative. Ridge tillage residual film recovery has the same characteristics with the residual film recovery equipment, and it has higher requirements for ridge width of residual film recovery equipment. The plastic film has not been fully utilized and the ridge body is relatively high. Furrow residual film recovery is difficult and a lot of plastic films used can not be completely recovered. A lot of plastic films are buried very deep. As one of the key means to control plastic film residue pollution, mechanically collecting technique of plastic film residue has shown a good developing prospect. But, there are many problems in the existing residual film recycling machines, such as high rate of film wrapping, incomplete recovery of residual film, and so on. Shovel screen type plastic film residue collector has a recycling capacity to the film in soil. It has a good application prospect in the field of ridge tillage plastic film recycling. The high rate of film wrapping for plastic film transport mechanism and the high rate of soil content in residual film after harvest are the major problems in the promotion of shovel screen type plastic film residue collector. To reduce the high film wrapping rate and soil containing rate in residual film after harvest, and improve the working quality of plastic film transport mechanism, single-factor test was used to get the best form of the screen surface structure in this paper. The Box-Benhnken central composite experimental design principle was adopted on the basis of single factor experiment to research the working parameters of the plastic film transport mechanism of shovel screen type plastic film residue collector. The vibrating screen's vibration frequency, vibrating screen amplitude, and distance between jagged pieces were taken as 3 factors which influenced the working quality, and a three-factor and three-level response surface experiment was conducted. In the experiment, when the vibration frequency of vibrating screen was less than 2.3 Hz, the separation effect was poor; when the altitude of vibrating screen was less than 40 mm, the film conveying performance was poor; when the distance between jagged pieces was less than 8 mm, the separation effect was poor; when the vibration frequency of vibrating screen was higher than 4.3 Hz, the resonance phenomenon was serious; when the altitude of vibrating screen was more than 80 mm, the effect of separation was poor; and when the distance between jagged pieces was more than 20 mm, the residual film phenomenon was serious. Therefore, the vibration frequency of vibrating screen was selected from 2.3 to 4.3 Hz, the altitude of vibrating screen from 40 to 80 mm, and the distance between jagged pieces from 8 to 20 mm. The mathematical model of the response surface was established. And the influence of each factor on the working quality was analyzed and each factor was optimized comprehensively. The results showed that the significant effects of vibration screen frequency, distance between jagged pieces and vibrating screen amplitude on reducing the rate of film wrapping were in a decreasing order, and the significant effects of distance between jagged pieces, vibrating screen amplitude and vibration screen frequency on reducing the rate of soil content were in a decreasing order. The best work parameters were as bellow: when the vibrating screen's vibration frequency was 3.9 Hz, the vibrating screen amplitude was 42 mm and the distance between jagged pieces was 15 mm, the rate of film wrapping was 1.72%, and the rate of soil content was 32.81%. Through comparing the mathematical model and the experimental result, it turned out that the relative errors of all the property indices between the two were less than 5%, which meant that the model established was useful and could be used for prediction and optimization. The research results can provide the references for the plastic film transport mechanism of plastic film residue collector and the optimization of working parameters. [ABSTRACT FROM AUTHOR]

Rice is the most important crop in China, which has the largest planting area, the highest per unit area yield and the most total output. The production scale of rice has important significance to the development of grain production safety. Solid ridge is important guarantee for irrigation and rice growth. It can improve the yield of grain crops and reduce the waste of water resources, which is conducive to the construction of standardized farmland in China. At present, the ridge are built still by manual labor in some regions. The ridge building by manual labor have some problems such as poor quality, long operation period, and repeated labor intensity. Ridging operation belongs to a part of tillage operation in the whole production process. With the development of paddy field mechanization, the paddy field machinery ridging technology has become the bottleneck problem for production. Paddy field mechanization ridging is constructed by agricultural machinery to meet the production requirements of rice irrigation and ridge technology. Some Chinese scientific research institutes and agricultural machinery enterprises have carried out researches and designed paddy field ridge machines. These machines take the soil on both sides through the plow or rotary blade and other parts, and compact soil to build ridge by double disc rolling, but they have shortcomings of heavy body, poor flexibility, high power consumption, and limits to the sampling position, which affect the follow-up planting and soil leveling operations. This kind of machine can not fully meet the actual production demands in China. In order to improve the quality and the efficiency of ridging operation in paddy field, and to reduce the labor intensity, the 1DSZ-350 type hanging unilateral rotary tillage compacting ridger was designed, in view of meeting the agronomic requirements of rice planting in the northeast region of China. The overall structure and working principle of the ridger were illustrated and analyzed. The structural design and the theoretical analysis were conducted for key components, such as partial traction hanging adaptive mechanism, rotary tillage ridging adjustable depth transmission assembly, rotary tillage soil- collecting roller assembly and compacting ridging circular assembly. To improve the working performance of ridger and to obtain the best operation parameters, the quadratic general rotary unitized design experiment was carried out with the forward speed and the rotational speed as the impact factors, and the average value of ridge density and the variation coefficient of ridge height as the response indices. Based on experimental data, a mathematical model was built by using the Design-expert 6.0.10 software, the experimental factors were optimized, and the best combination was achieved. Test results showed that the forward speed of the ridger was 1.33 km/h, the rotational speed was 525 r/min, and the average of ridge density was 2 160 kPa, the variation coefficient of ridge height was 4.01%. On the basis, the field test was carried out, and the test results showed that the ridger was characterized by its compact-sized reasonable structure and simple operation. And its ridge had good quality, which was solid and smooth and could meet the requirement of paddy field production. The research results in this paper can provide the theoretical basis and direction for the research of mechanical ridger and its key parts for paddy field. [ABSTRACT FROM AUTHOR]

With the improvement of the farm mechanization level, the more corporate’ style farming emerges. For example, more than one harvester collaborated with each other completes the task of harvesting operations. The new corporate style farming creates several new challenges for the agricultural machinery navigation, and the group navigation is the trend of agricultural machinery navigation technology. Group positioning and collaborative navigation control are the 2 critical technical problems to be resolved. In order to solve the slave positioning problem, a slave positioning method based on visual servo was proposed. Firstly, the combine group based on mater-slave structure was introduced, and the slave positioning scheme was proposed. In order to fulfill the automatic measurement of the slave position, the relative positioning device was designed. The structure and measurement process of the positioning device were introduced in detail. The positioning device was composed of laser ranging sensor, PTZ (Pan Tilt Zoom) controller and monocular camera. The monocular camera was used to guide the laser ranging sensor to aim at the target. The laser ranging sensor was used to measure the distance between the master and the slave. The laser ranging sensor guaranteed high precision of the measurement data. The position measurement process could be divided into 2 steps. The first step was to measure the relative position posture between the master and the slave. According to the deviation between the target's center and the image center, the system adjusted the platform's direction to change the posture of the camera, so that the 2 centers in the target and the image could coincide approximately. After aiming at the target, the laser sensor was triggered to measure the distance between the master and the slave. The second step was to calculate the slave positon. A global localization model was built up to show the relative location relationship between the master and the slave, and the slave’s coordinate under global coordinate system could be calculated. Secondly, in order to solve the 2 key problems in the process of the position measurement, 2 methods were proposed. A method of automatic identification for motion target based on dual windows was proposed to reduce the visual feedback delay. This target identify method filtered out most of the identified area by setting dual windows, and searched the target point only in a small area of the image. A variable-scale variable-universe fuzzy control method was proposed to improve the target control accuracy. This method introduced the contraction-expansion factor to improve the granularity of fuzzy rules without increasing the number of control rules, and introduced the variable scale factor to improve the adaptability to the change in the distance between the master and the slave. Finally, in order to verify the effectiveness of the proposed model and method in this paper, the slave positioning experiments were carried out. When the slave ran at the speed of 0.8, 1.0 and 1.2 m/s, the average positioning error was 0.127 9, 0.128 6 and 0.132 1 m respectively. The experimental results show that the slave positioning accuracy is independent of the forward speed, and can meet the slave positioning requirement. [ABSTRACT FROM AUTHOR]

The plastic film mulch has the function of increasing soil temperature and preserving moisture, and it also can suppress weeds and maintain soil structure. Because of these special physical and chemical properties, agricultural mulching is extensively applied to cotton and other crops. Xinjiang is currently the largest cotton planting region in China, and all cotton cultivation involves film mulching. However, because plastic film itself is difficult to degrade and without scientific management and recovery in long-term use, a large amount of residual plastic film is left in the fields after harvesting, which has caused serious pollution problem to both the soil and the ecological environment. The mechanical collection of the plastic mulch is one of the effective ways to resolve plastic mulch pollution at present. Therefore, it is significant and urgent to study the residual film recovery methods and operation machines. Many kinds of mulching residues recovery machines have been developed and used, but there are some problems with the machines such as bad adaptability, low recovery rate, poor work efficiency in removing the collected film, and plastic films being easy to wind in cotton straw chopping, which needs further improvement for the machines. With a view to solving the above problems, a new method of operation step by step was proposed, which could collect plastic film in strip at first and then recover it, and a cotton straw chopping and plastic film strip-collection combined machine was designed. The machine mainly consisted of suspension device, power transmission system, straw chopping device, straw conveying device, strip-collection device, stripping device, and so on. Compared with the existing cotton straw chopping and plastic film collection combined machines, the machine proposed in this paper was simplified and efficient. The machine adopted the way of throwing cotton stalk into a certain height and distance to create a condition to separate cotton stalk from the residual film. Moreover, because of the ground profile modeling, this machine could be adapted to complex operating environments and operating requirements, and had a good performance on the strip-collection ratio. It could not only realize the straw chopper returning and the straw separation with plastic film, but also collect plastic film in strip with one operation, which ensured that it was easy to recover plastic film and recycle it. Based on the underlying theory analysis and experimental study, its basic structure and main parameters were determined, and the rational kinematic relationship among the knife-roller speed, the forward speed of unit, and the speed of strip-collection device was obtained by experiments. Field trials were conducted in Manas County of Xinjiang. The experiment results showed that the working efficiency could reach 1.15 hm2/h, plastic film collection stripe ratio was 92.6%, the straw chopping qualification rate was 97.5%, and the film-straw separation ratio was 90.5%, when the machine operating speed was 5-7 km/h, the cutter shaft speed was 1 880 r/min, and the speed of strip-collection device was 150-160 r/min, which could satisfy not only the agricultural requirements but also national standards. The research results can provide a reference to solve the problem of plastic film pollution in cotton-growing areas of China. [ABSTRACT FROM AUTHOR]

In the intertillage of sugarcane, the fertilizing with a low evenness and stability will lead to many problems, such as losing a lot of sugarcane seedlings, soil hardening, fertilizer wasting, lower fertilizer use efficiency, and higher input with lower output. So the research on the fertilizing device is vital to control the evenness and stability of fertilizing. This paper focused on improving the fertilizing evenness of 3ZSP-2 type sugarcane intertillage fertilizing hilling machine. The innovational scraper fertilizing device was independently designed. The single-factor experiment on the diameter of disk, rotation speed of disk, gap of scraper, angle of scraper, width of scraper and advancing velocity was conducted in the Tropical Agricultural Machinery Research Institute, Chinese Academy of Tropical Agricultural Sciences, Zhanjiang in April 2014. The pivotal parameters of technology in this study were that the tractor motive power ranged from 22 to 36 W, the working speed ranged from 2 to 5 km/h, the overall dimension was 2300 mm × 1100 mm × 1640 mm, the diameter of fertilizer box was 730 mm, the diameter of disk was 700 mm, the rotation speed of disk ranged from 6 to 14 rpm, the width of scraper was 45 mm, the angle of scraper ranged from 15° to 19°, and the advancing velocity ranged from 0.7 to 1.1 m/s. The results showed that, the width of scraper, the angle of scraper and the advancing speed had a significant impact on the fertilizing evenness, and the value ranges of the 3 factors were identified. The mathematical model between the 3 experimental factors of the fertilizing device and the evaluation index of fertilizing evenness was established by the experimental method of Box-Behnken design. The influence law of those parameters on the evenness of fertilizer ejecting was analyzed through the Statistical Analysis System. The result concluded that the evenness of fertilizer ejecting increased at first, and then decreased respectively with the increasing of the 3 parameters (the width of scraper ranging from 30 to 50 mm, the angle of scraper ranging from 15° to 19° and the advancing speed ranging from 0.7 to 1.1 m/s). The order of the factors affecting the fertilizing evenness was the width of scraper > the angle of scraper > the advancing velocity. When the interaction was considered, the width of scraper and the advancing velocity had a tremendous impact on the target value, and the width of scraper and the angle of scraper also had a significant effect on the fertilizing evenness. Under the conditions of the width of scraper of 48.4 mm, the angle of scraper of 16.5° and the advancing velocity of 1.09 m/s, which were the optimal parameter combination, the fertilizing evenness was 92.97%, the stability of furrow opening depth was 92.9%, and the coverage rate of fertilizer was 100%. The verification test of optimized fertilizing device was performed in an experimental field whose area was 0.12 hm2. Results indicated that, the test result of the optimized machine was consistent with the results of the response surface analysis. The fertilizing deepness of this machine was 17.8 cm, the fertilizing evenness was 92.97%, and the coefficient of stability was 92.9%. All these indices were much higher than the design indices and the original machine, and met the requirements of cultivating, fertilizing and hilling in sugarcane tillage. The optimized mechanism parameters of fertilizing device were found to be technically viable. This study provides a starting point for further research on the optimization design of 3ZSP-2 type sugarcane intertillage fertilizing hilling machine. [ABSTRACT FROM AUTHOR]

Grafting has been widely used in production of melon vegetables, which can effectively prevent vegetable diseases and ensure the quality of vegetables. Different from manual grafting method with low efficiency and low survival rate, vegetable grafting machine significantly reduces the labor intensity and improves the productivity. Insert-type machine does not need to fix the plant that is grafted, and only needs to insert scion directly into the stock, which is easy to operate. It can avoid removing the cotyledon of stock and retain the nutrients, which make the plant more likely to survive after grafting. It has been widely applied at present. Removal of growing point of melon vegetable stock is one of the key problems which need to be solved for this kind of grafting machine designing. The incomplete removal of growing point will lead to the regrowing of growing point, which will affect the joint of scion and stock, even need to use artificial method to remove the growing point again. In this paper, the growing point removal mechanism of melon vegetable grafting was designed. By imitating human finger in conjunction with each joint, the growing point was removed from the stock without being damaged. Through analyzing the trajectory of the removal of growing point, the implementation of growing point forming principle, and establishing the growing point removal model, the stock growing point removal mechanism was designed in order to solve the problems of incomplete removal of growing point and the stock easy to be damaged in removal process. Finger has good flexibility in the removal of the growing point, and the force is automatically reduced through joint buffer when the force is too large, so the finger does not hurt the cotyledons. Finger can instantly bend when it reaches the bottom, which is resulting from the action of removing growth point and makes the growing point divorced from stock. This provides the design basis for the growth point removal mechanism. The movement of the growing pointer removal finger is driven by the crank connecting rod mechanism. When the growing point removal mechanism is close to the growing point, the arc movement is instantly generated and the removal of the growth point of the stock is realized. Because the expansion joint is designed, the removal mechanism of the growth point can realize the removal of the growth point flexibly and avoid the damage of the stock. Under the given conditions, 9 groups of stocks were selected in experimental study. And the experiment results showed that the mechanism could remove the growing point easily, the success rate of the growing point removal reached more than 90%, and the injury rate was less than 5%, which confirmed that the growing point removal mechanism could effectively solve the problems of stock growing point’s incomplete removal and stock easy to be injured. Thus, the new growing point removal mechanism can satisfy the requirements for vegetable grafting. It provides a new kind of structure and design ideas for solving the problem of stock seedling damage and growing point removal difficulty. The main reason to the failure of the growing point removal is individual stock stem’s serious distortion, and clamping and positioning being very difficult for the grafting machine. In addition, there is individual growth point deviating from center point obviously, which interferes with the removal mechanism, so it is hoped that the mechanism design will get further improvement in the future. [ABSTRACT FROM AUTHOR]

In a corn field with an unstructured environment, for the images collection by monocular vision, conventional path recognition algorithms are difficult to guarantee their robustness due to illumination variation, background reflection, shadow noise, and so on. In addition, the increase of the calculation amount of the algorithms caused by the complicated background information of the corn field environment affects the quickness and the real-timeliness of the corn harvester autonomous navigation, which leads to the difficulty of meeting the requirement for the operation efficiency of the corn field harvester and impedes the practical application of the mobile robot technology in agricultural production. The significant premise of visual navigation for a corn harvester is the precise and rapid detection of the navigation route. Unfortunately, some interferences will affect the extraction of the navigation route and the judgment for the edge of the corn field due to the corn shadow and weeds. The vision navigation has many technical advantages of adapting to the complicated field operating environment, has wide detection range, and has rich and complete information. This paper put forward the detection algorithms of the operation routes of the corn harvester and the judgement of the end of the corn field by analyzing the different color features of the visual navigation image. Here we studied the region of interest where lies the target straight line. To improve the rapidity of the navigation path recognition and meet the real-time requirements of autonomous navigation operations, for the color characteristic of the corn field environment, the clustering segmentation of the image was performed based on the analysis of red (R), green (G) and blue (B) components to achieve the respective clusters of the path and the corn field information. We used these color components to extract the target features of the inner and outside of the corn field respectively, and smooth the image using the moving average method with the set length. First, to remove the shadow interference of the corn columns, we compared the G component and the B component of a color image and smoothed the image using the moving average method. For the first frame, we used the distribution of the G component to find the alternate point; for other frames, we connected them with the previous frame to calculate the skew angles of the target line. Then, we extracted the navigation routes based on the Hough transform passing a known point. At last, it would be determined whether the corn harvester reached the end automatically according to the continuous mutation of the R component. The test proved that the processing time of detecting line was 50.1 ms per frame and the detection of the end was accurate and reliable, which could meet the demand of the real operation of a corn harvester in the field. It can be concluded that the navigation routes are extracted and the edge of the corn field is judged accurately, which satisfy the requirement of the practical application of the corn harvester in the field. In addition, the work can also provide the reference for the vision navigation routes' detection of sorghum and some high pole crops with mechanized harvesting. [ABSTRACT FROM AUTHOR]

In recent years, corn has become the first major crop in place of wheat and rice, which has an important influence on the national life with its production increasing. Corn snapping device is a main component of corn harvesting machine, and has an important effect on the quality of corn harvest. Currently, according to the way of working, there are 2 types of snapping devices: snapping rolls and plate type. The existing snapping device is easy to cause the corn ear nibbling and grain loss. In order to solve the above problems, the test device of corn ear picking by pulling stack upwards was studied, the principle of which was imitating artificial snapping action, and pulling stalk upwards to pick corn. It mainly included corn ear picking device, clamping feeding device, corn roots cutting device, high-speed photography and computer data acquisition system. When corn plant was fed to the ear picking device by the clamping feeding device, the corn stalks were cut off through the corn roots cutting device, then the snapping rollers pulled up the corn stalks and the corn ear encountered the snapping rollers, and finally the corn ear was bent and broken off. In the process of picking corn ears, the force of stalk was a resultant force of the force of pick ear buckle and the force along spiral line, which made stalk move backward and upward. This paper also analyzed the force relationship of corn ear. When the corn ear encountered the snapping rollers, the snapping rollers only overcame connection force and connection torque to bend and break off the corn ear. The test was done at the laboratory of agricultural machinery. The grain moisture content was 21%, and the grain loss rate was taken as the index to estimate the performance of the harvesting device. Through the single factor experiment, the impacts of the roll's rotational speed, the roll's interval and the angle between roll and horizontal surface on the rate of grain loss were analyzed. The process of harvesting was captured through the high-speed photography, which was helpful to the comprehensive analysis in the late period. Through the single factor experiment and the analysis of variance, it was found that the grain loss rate reduced at first and then increased gradually, when the rotational speed was changed in 6 levels of 500, 600, 700, 800, 900 and 1 000 r/min in turn and other factors were changeless. The rotational speed had significant effect on the grain loss by the analysis of variance. The average grain loss rate was the least (0.293%) when the rotational speed was 700 r/min. When the roll's interval was selected to 5 levels including 4, 6, 8, 10 and 12 mm in turn, the grain loss rate was decreasing gradually in general. The grain loss rate was the least when the roll's interval was 10 mm, which was 0.33%. But, if the interval was too large, it had some problems such as the grasping ability was weakened and the corn head was gripped. The effect of the angle between roll and horizontal surface on the grain loss rate was not obvious, which was set at 5 levels of 0°, 10°, 20°, 30° and 40°, and the grain loss rate was 0.28%-0.31%. It was found that corn ear picking by pulling stalk upwards had good performance, and the corn grain loss rate was less than the national industry standard (2%) and also less than the traditional snapping roller. This way of picking corn can improve the corn grain quality and reduce the grain loss, and provide a thought for corn harvesting. [ABSTRACT FROM AUTHOR]

A hydrostatic drive system scheme for the high clearance self-propelled corn detasseling machine was proposed and the dynamic performance of the system was simulated and tested in this paper. Although detasseling machines have much higher working efficiency than manual detasseling, they have just been used for a few years in China and mostly were imported from abroad at a high price. Since the machine demanded a high ground clearance, the closed volumetric speed control loop with one pump and four motors was adopted. The engine directly drives the pump to output high pressure fluid to the four-wheel motors, and then the motors drive the hub reducers to turn the wheels. It can be concluded that the vehicle can achieve 3 gears of I, II and III by choosing the appropriate maximum and minimum displacements of motors and reducer gear ratios. To better analyze the performance of the drive system, a detasseling machine model with 15 degrees of freedom was built according to the vehicle structure features. The vehicle model included vehicle body model, wheel model and four-wheel independent suspension system model. Meanwhile, the mathematical model of the hydrostatic drive system was derived, which included pump model, motor model and reducer model. Then, the simulation model of vehicle dynamics of detasseling machine was presented using the software Matlab/Simulink based on the mathematical models. The simulation model was used to study the performance of speed and system pressure of the vehicle at 3 gears. And the results showed that the vehicle could get a maximum travel speed of 15.8, 19.7 and 26.1 km/h, and a steady system pressure of about 6.29, 7.30 and 8.94 MPa at the 3 gears of I, II and III, respectively, which could meet various application conditions. As a special component of detasseling machine, the effect of the suspension system on the drive system was testified. By exerting a road excitation on one wheel, the system pressure of the vehicle with the suspension was contrasted with the one without suspension. The results showed that the pressure of the one with the suspension fluctuated much narrower and smoother than the other, which meant the suspension could effectively improve the performance of the drive system. To verify the mathematical model and to further research the drive system, a high clearance self-propelled corn detasseling machine was designed to conduct the tests. During the process of changing the displacement of pump from the minimum to the maximum value at each gear, the maximum travel speed was recorded, and the variations of the inlet and outlet pressure of the pump and motor were measured. The main test devices contained oil pressure sensors, acceleration sensors, data acquisition card of National Instruments, switching power supply and laptop, and the software LabVIEW was used for data processing. The vehicle tests showed that with the increase of pump displacement, the system pressure of the high pressure side first trended to increase sharply and then decreased to a stable value of 6.361, 7.286 and 8.717 MPa at the 3 gears of I, II and III, respectively, which was consistent with the simulation results. And the pressure of the low pressure side was about 2.4 MPa, which was equal to the system charge pressure. In addition, the maximum driving speed of the machine at the 3 gears was 15, 19 and 24 km/h respectively, which was lower than the theoretical values. That was mainly due to the leakage loss of hydraulic components and the mechanical friction loss. The simulation and test results showed that the vehicle drive system had a rapid response and a good performance, and the correctness of the mathematical model of the machine was also verified. The study can provide a technical reference for the independent research and development of the high clearance self-propelled corn detasseling machine in China. [ABSTRACT FROM AUTHOR]

The development of garlic harvest mechanization still lags relatively behind, restricting the development of China's garlic industry. In recent years, garlic combine harvester has been designed by Chinese research institutes, realizing the garlic digging, soil cleaning, stalk cutting and garlic bulb gathering. The main garlic combine harvester in the developed countries is bundling type or cutting seedling type harvester. The garlic combine harvester, which can finish the processes of root cutting, is few. Root cutting is the core technology of garlic harvest, and also the most difficult technical operation. The fresh garlic has thin and tender skin and different size, and its roots are mixed with sediment, which have a wide but disorderly distribution. Therefore, in the process of harvesting, how to ensure technical performance, such as high rate of one-time root clearance and low rate of bulb damage, has been a difficult technical problem of garlic root cutting mechanized operation. In view of the lower rate of root clearance and the higher damage ratio, a root cutting device of garlic combine harvester was designed, which realized the root cleaning and pre-cutting, the garlic sorting and arraying, and the second cutting of root. The root cutting device of garlic combine harvester consists of clamping delivery device, hairbrush roller, front revolving cutter, rank-alignment device and floating cutting device. The clamping delivery device carries out the clamping of garlic upper stalk and the transport. The clamping style of garlic is changed from chain-chain clamping to chain-board-hairbrush clamping. The rank-alignment device mainly achieves the functions of stalk fixation and garlic bulb alignment, which provides ancillary work to root cutting. The floating cutting device adopts the principle of floating rotary cutting to adapt different sizes of garlic bulb, which can realize shape cutting along the spherical trajectory under the garlic bulb. The spiral protection railings are installed outside the cutter of floating cutting device, which stay on the outside of cutter turning trajectory and keep the free state. This structure reduces the impact force when garlic bulb contacts the spiral railings, and thus solves the problems of hurting garlic bulb effectively. Combining theoretical analysis with experimental research, this paper has determined the key structure parameters and the key working parameters, and at the same time, synthetically optimized the main factors affecting root cutting quality. The results showed that the importance sequence of various factors affecting root cutting quality was as follows: conveying speed > clamping angle > cutter rotational speed. Under the 95% confidence level, conveying speed was highly significant for root cutting quality; clamping angle and cutter rotational speed were significant for root cutting quality. The optimum parameters were that the conveying speed was 1.05 m/s, the clamping angle was 79°, and the floating cutter rotational speed was 2 200 r/min (The cutting linear velocity was 17.3 m/s). Under the conditions, the rate of cutting root was 96.1%, and the damage ratio of garlic bulb was 2.39%. The results provide the technical basis for the design and optimization of the root cutting device. [ABSTRACT FROM AUTHOR]

Mechanical precision seed-metering device has low price, compact structure, good manufacturability and other advantages. However, in recent years, the pneumatic precision seed-metering device has occupied the dominant position, mainly because of the fatal flaw of the hole filling rate declining rapidly in high speed for mechanical precision seed-metering device, which resulted in grievous decline in the quality of operation and serious seed-leakage phenomenon. Due to the structure characteristic of seed-metering device and mixing characteristic of granular soybean seeds, the value of filling force in the form of compressive stress was limited. For this reason, how to improve the filling force was a crucial factor for mechanical precision seed-metering device. In this paper, the model of filling force of hole was built. And an opposed inclined seed-metering device was innovatively designed by theoretical analysis, which combined the advantages of a variety of mechanical seed-metering devices. It could improve seeding frequency by using double-plate to seed in single line. It changed the seed filling pattern from structure, made full use of the structure of the shell space, improved the compaction force and the filling force type, and further improved the qualified rate and its performance under high-speed operation to adapt to the modern high-speed operation requirements. Relying on gravity cleaning of seed, it effectively avoided the injury of seeds. The double-cavity composite vertical seed-metering device was chosen as a comparison, which also had high speed operation ability. The mathematical models were established according to the working principle. The filling force of the vertical disk seed-metering device and opposed inclined-plate seed-metering device was contrasted and analyzed. Through analyzing the filling force changing rule of the seed-metering device in different angles, and drawing the function image by Matlab (MATrix LABoratory) software, the effective ways to improve the filling ability were found and the best angle was determined to 20°. The single-factor experiments were carried out under the condition of different inclined angles, and the operation indices under 20° were better, which proved the accuracy of the theoretical analysis. The seed-metering device structure both retained the advantages of traditional vertical seed-metering device and solved the problems of seed-leakage increasing phenomenon under high speed. The simulation was done for opposed inclined-plate seed-metering device and double-cavity composite vertical seed-metering device by EDEM (engineering discrete element method) software, and a physical prototype test was performed to verify the superiority of this kind of structure further. The results showed that the simulated and experimental values of variation trend of filling rate were basically the same, and the relative error was small. At the low speed section of 5-8 km/h, the qualified rate was increased by 3% on average, and in 8-12 km/h high speed section, the average qualified rate was increased by 5%. The results of simulation and experiment showed the performance of opposed inclined-plate seed-metering device was significantly optimized when its speed was increased and the speed range of mechanical allowing operation was improved. This verifies the gravity and interaction force between seeds as composite force can make a contribution to filling seeds and can be obviously helpful for seeds to come into the hole when increasing the rotational speed of seed-plate, and provides the guidance for the design and development of high-speed precision mechanical seed-metering device. [ABSTRACT FROM AUTHOR]

Huang-Huai-Hai region is the main production area of peanut, where currently exist some outstanding problems, such as multiple operations of multiple machines in routine machine sowing work, high production cost, high energy and time consumption, and missing farming season. In addition, the traditional way of no-till seeding is not fit for peanut no-till seeding under the coverage of the wheat straw, and 3 major technical problems exist: soil-buried parts of machine are blocked with grass, which can't guarantee the smooth operation; the seeds may be planted on the wheat straw, causing the seeds are above the soil and not into the soil; soil-covering is unreliable, causing the seeds are not covered by soil. In this paper, a no-till peanut planter under the coverage of the wheat straw based on "cleaned area seeding" was developed. Firstly, smash the wheat straw on the surface of the fields which would be seeded, then pick up and collect them, and spread backwards after loading; secondly, finish stubble cutting and seed-bed preparation before the straw fell down, and finish fertilization and seeding work in "cleaned area"; finally, the smashed straw was evenly covered on the fields after planting, and the whole process, including crushing the wheat straw, cleaning the field, fertilizing, and covering the seed bed with wheat straw, was all finished in relatively "cleaned area". With the combination of analytical calculation and experimental optimization, 4 parts of the whole machine were involved to be designed based on the working principle of the machine, and Y typed cutting device was adopted in the link of crushing and collecting straw. In order to meet straw smashing and picking requirements, the optimized working parameters and structure parameters of knife roller were obtained by analyzing the absolute speed of the swung knife, which was synthesized by the machine forward speed and the rotary speed of knife shaft. Meanwhile, the parameters such as the rotary speed of the horizontal screw feeder were determined through wheat straw pushing volume. Impeller type lifting and throwing structure was used during the links of straw loading, throwing and evenly covering. According to the energy conservation law, combined with the configuration of the machine, the main structural and motional parameters such as throwing impeller, pipes, and lifting height were designed by calculation. According to the principle of non dynamic passive rotation, the impeller type evenly throwing mechanism was designed, achieving high speed rotation of the impeller through the wind force generated by the fan, which was installed in the machine, and then the straw was scattered and spread to the surface of the field evenly. The reverse shallow rotary tillage method was designed to break the stubble and soil during the seeding bed preparation. Compared with traditional rotary parameters, the smaller the shallow rotary tillage tactical diameter and rotational speed were, the better the stubble and soil breaking effect would be, and meanwhile, the energy and power consumption were eased. Matched with the designed peanut no-till planter during fertilizing and seeding session, the furrow opener, one of the key soil-buried components, was designed to prevent the soil blocking, solving the clogging problem of seed spout. Peanut no-till planter under the coverage of the wheat straw, affiliated with high-powered tractor of over 75 kW, had the working width of 2400 mm and the pure productivity over 0.53 hm2/h. The field tests and measurement results showed that the average length of straw was 115 mm after work, the uniformity ratio of straw mulching was 83%, the average depth of sowing and fertilizing was 46 and 59 mm respectively, the qualified rate was 98% and 89% respectively, and the yield was about 5 749.5 kg per mu. This machine is suitable for the coverage of the straw, which can crush the wheat straw, clean the seedbed, fertilize, and cover the soil and seed bed with wheat straw at one time; the operation is smooth and reliable and has high seeding quality, and all the operating indices can meet the requirements for main peanut producing areas. Meanwhile, the research on the method of “cleaned area” seeding may be applicable for other dryland crops such as wheat, corn, and soybean, providing appropriate equipment to promote the mechanization of prohibiting straw burning. [ABSTRACT FROM AUTHOR]

Potato is the fourth staple food product in China, and Chinese potato planting area of 6.7 million hm2 ranks first worldwide in 2013. However, the mechanized potato seeding percentage in China is only 23%, which is limited by poor performance of potato planter. Cup-chain metering device is the most commonly used for potato planting, whereas it is troubled with high miss-seeding and re-seeding problems. To solve these problems, the simulation model of potato planter is firstly built, and this model is used to analyze potato seed movement during metering process; then a new type of metering device with double-deck seed tank is designed, and finally the parameters of seeding speed, seed cup diameter and seed filling height are optimized. 1) Potato planter simulation: Potato cup-chain metering planter is simulated based on the software of EDEM (enhanced discrete element method). On the one hand, Hertz-Mindlin non-sliding contact model between 2 seeds is built with the recovery coefficient of 0.3, static friction coefficient of 0.56 and dynamic friction coefficient of 0.15; on the other hand, the model between seed and seeder is built with the recovery coefficient of 0.52, static friction coefficient of 0.5 and dynamic friction coefficient of 0.1. 2) Potato seed movement analysis: During the metering process, movement is originated from only a small part of seeds instead of most of them that are immobile. The small part of moving seeds determine the seed charging performance. The major movement area of potato seed is around the chain presenting the shape of inverted cone, which contains 3 areas of high-efficiency charging area, low-efficiency charging area and no seed area. The seed charging performance is directly affected by the volume of high-efficiency charging area and the seed mobility. 3) Seed planter design: Aiming to enlarge high-efficiency charging area and enhance seed mobility, planter with double-deck seed tank is designed, which doubles the volume of high-efficiency charging area and enhance seed mobility. A planter test platform with double-deck seed tank is modified from a 1 220 type potato planter provided by Zhongji Meno Polytron Technology. 4) Performance evaluation and parameter optimization: 2 indicators are employed to evaluate the planter performance, including miss-seeding percentage and re-seeding percentage. The influence of seeding speed, seed cup diameter and seed filling height in the seed tank on seed charging performance is studied. Regression equation and multi-objective optimization method are employed for parameter optimization. In the Chinese national standard for potato planter, miss-seeding percentage is no more than 10% and re-seeding percentage is no more than 20%, the designed planter can operate at the seeding speed of 0.96 m/s to satisfy this national standard. To balance the planting performance, including miss-seeding percentage and re-seeding percentage, and planting efficiency of seeding speed, the parameters of seeding speed, seed cup diameter and seed filling height in the seed tank are optimized as 0.67 m/s, 48.6 mm and 0.28 m, respectively, showing the miss-seeding percentage of 3.8% and re-seeding percentage of 8.8%. This paper demonstrates the potential for a high-performance cup-chain metering device with double-deck seed tank for potato planting. [ABSTRACT FROM AUTHOR]

Air pressure maize precision planter is suitable for high-speed planting which needs to work under ensured and stable air pressure. However, significant problems exist in the air supply system such as high pressure loss and velocity loss, serious heating and uneven pressure and flow supply. Air supply system seriously affects the working stability of planter. Reasonable allocation of the air flow is one of the most important factors to air pressure maize precision planter. The importance of the allotter in the air supply system cannot be ignored. To solve the problems of high loss in air pressure and velocity, this paper supplies a new type of air allotter which contains one inlet, four outlets and a connection segment with gradient combined curve. According to the theory of steady incompressible flow in pressure conduits, the phenomena of high air loss and uneven flow distribution can be interpreted. The pressure and velocity loss are usually insignificant in comparison with the loss due to pipe friction when the length of pipe or channel is very long. But if the length of pipe or channel is very short, these so-called minor losses may actually be major losses. As long as the air pressure and velocity at the inlet and outlet of the air allotter are known, pressure and velocity loss can be analyzed easily. Therefore, 4 types of air allotters with different airflow directions are designed by analyzing the relationship between loss and structure in turbulent flow. Because of the difficulty in measuring the velocity in real condition, computational fluid dynamics (CFD) is applied to obtain ideal data which can be simulated by software such as Gambit, Fluent and Tecplot. In order to find the optimal pathway and direction of the air flow, 4 different types of air allotters were simulated. The result indicated that the paralleled axis of the inlet and the outlet was the best way. In order to find the ideal parameter of the allotter, the simulation experiment was carried out further. Compared with all factor experiments, orthogonal experiment is better and faster to select the optimal structure. So, 3 factors including the shape of connection segment of the allotter, the inlet-outlet diameter ratio and the center distance between inlet and outlet were chosen to test and find out the most significant factors. The simulation result of the range analysis and variance analysis showed that the inlet-outlet diameter ratio and the distance between inlet and outlet's axis in the allotter should be as small as possible within the permitted range. Besides, the results also indicated that the shape of the curve had significant influence on the pressure loss, whereas there was few influence on velocity loss. Structures such as sudden expansion and bends could lead to more pressure and velocity loss which should be avoided in the design of allotters. Thus, the optimal structure of the air allotter consisted of coaxial inlet and outlet and a concave-convex combined curve. Through the dimension driven in SolidWorks, the shape of the concave-convex combined curve could be ensured. An optimal structure with related parameters was estimated finally through the simulation of different types of allotters with different shapes of concave-convex combined curve. The experiment and simulation results indicated that the length of the connection segment of the allotter and the ratio of concave curve to outward curve were 2 significant parameters. Field experiment was conducted with 2 different types of allotters installed on air pressure maize precision planter to validate the result of simulation. The pressure and velocity of the balance and low-loss air allotter were measured by air flow meter KA33 made by KANOMAX. Results proved that the performance of the balance and low-loss air allotter was better than that of other widely used allotters. Comparative experiment showed that the rate of pressure loss of the designed allotter was kept within 10% under different working pressures, while the loss of another allotter was over 30%. The pressure consistency variation coefficient of 4-row seed metering device was less than 4%. The research shows that the allotter cannot be ignored in the research of maize precision planter. Appropriate structure of air allotter can significantly reduce energy consumption and ensure uniform air pressure when the planter works. [ABSTRACT FROM AUTHOR]

In order to reduce the decay of the droplet carrying capacity and increase the droplet coverage on hidden area of the foliage, a double air-assisted electrostatic spraying system which included anelectrostatic nozzle, a centrifugal blower, an axial fan and a diaphragm pump was proposed in this study. The power of double air-assisted electrostatic orchard sprayer was from power take off (PTO) of tractor to drive hydraulic pump (CBH-G563-AFHL).There were three hydro-motors in hydraulic system to drive centrifugal blower, axial fan and diaphragm pump separately. The indoor and outdoor tests including charge to mass (CTM), air velocity distribution, vertical distribution of spray volume and canopy droplet coverage was conducted. The faraday cylinder was used to collect spray volume, Key sight 34 410 A digital multi-meter was used to test current, and the CTM was calculated. The result showed the CTM at 0.2 m was reached to 1.0 mC/kg with damping along air direction, but the current could also be tested at 1.8 m. The air velocity distribution, vertical distribution of spray volume was based canopy biomass of spindle type fruit, the two maximum heights were between 0.5 and 1.5 m. The field experiment was carried out in Shanxi during October 14 to 16, 2015. The objective of this experiment was to evaluate the effect of electrostatic charge on foliar spray deposition in a high spindle apple orchard using the double air-assisted electrostatic sprayer. The temperature was 25 °C, relative humidity was 55%. Experiment plot was a modern standard apple orchard which was 350 m long and 200 m wide, the tree was spindle type apple fruit, three years older, 3.2 m in height, 3.5 m row spacing and 1 m spacing in the rows. Trimming was done every year after harvest. There are iron wires at 0.5,1.5 and 2.5 meters high which had different canopy width of 1.0, 0.6, and 0.3 m, and the foliage density was 7.8, 3.6, 1.97 m. The test was strictly followed the quality of air-assisted orchard sprayer (GB/T 24683-2009). The electrostatic system was switched on and off, in order to evaluate its effect on deposition on exposed and hidden face of the foliar. The flow rate at the nozzles was maintained unchanged across the tests, and the main environmental parameters were measured during the tests, they were air temperature, wind speed, and relative humidity. The water sensitive paper as collectors, the profile sampling strategy was adopted. The sprayer’s working velocity was set at 0.84 m/s, spraying pressure was 0.5 MPa, rotation rate of axial fan and centrifugal blower were 1 400 and 1 800 r/min. Each test condition was replicated three times in the same position. Experimental plot consisted of four adjacent rows sprayed under real conditions, i.e. by passing with the sprayer in all the three inter-rows; foliar sampling was carried out in the central inter-row. Blocks were separated by three unsprayed inter-rows in order to avoid possible overlapping due to spray drift. The test was conducted to determine effects of electrostatic spraying on hidden droplet coverage and droplet distribution on canopy. All statistical analysis and graphical representations were performed using Microsoft excel 2010. Results showed the droplet coverage on exposed and hidden foliage were 115 and 47 dot/cm2 at single spraying at the condition of the spray volume 3.5 L/min and driving velocity 0.84 m/s. This illustrated the single spraying was enough for insect prevention, and double spraying was suggest for preventing disease. The droplet coverage was improved 20% at the outside of tree closed to sprayer using electric spraying, while 7.2% was improved at the outside of tree away from sprayer at beyond. The research can provide technology support for air-assisted electric orchard sprayer designing and spraying standard setting. [ABSTRACT FROM AUTHOR]

In the rice-wheat crop rotation and other type of double cropping system areas, a large number of straws were left in filed after harvesting. Most areas need the twice field preparation for crop production so that straw could be returned to soil. In order to solve the problems of straw-returning and soil preparation in the rice-wheat crop rotation, the plowing and rotary tilling compound soil preparation machine was designed. The compound soil preparation machine mainly included plough mechanism, rotary tilling mechanism and rack. There were four plough bodies installed in the plough frame of the compound soil preparation machine and two rotary tilling knife rolls divided by the auxiliary gear box installed in the rotary tilling frame of the machine. There were 26 couple rotary tilling blades installed in the left and right knife roll and ranging by double helical line. The interaction of the plowing mechanism and the rotary tilling mechanism when the compound soil preparation machine was working was mainly considered in the designing process. For balancing couples of ploughing, the rotary tilling frame was offset 210 mm to right. For making the soil was shatter better, the distances that two rotary blades of close to the auxiliary gear box on the left and right knife roll to the auxiliary gear box were 50 mm. The compound soil preparation machine was studied in this paper based on the theory of discrete element method (DEM). The dynamical model of the compound soil preparation machine was established based on its working principle. The DEM model of the compound soil preparation machine was established by the discrete element software EDEM and the virtual simulation of working situation was carried out. The simulation results showed that the broken rate of soil of the compound soil preparation machine was 91.4% and the surface roughness of the machine was less than 2 cm. A field experiment was conducted to validate the rationality of designing methods and working performance of the compound soil preparation machine. The results of field experiment showed that working condition tillage deep and working condition tillage wide were 21.6 cm and 1.98 m, and working condition tillage deep stability and working condition tillage wide stability were 91.3% and 96.7%. The results showed that working situation of the compound soil preparation machine was stable. The surface roughness of the compound soil preparation machine was 1.87 cm and the broken rate of soil and vegetation coverage of the machine all were greater than 90%. The results showed that quality of soil preparation met requirement of agriculture production in the rice-wheat double cropping system area. The fuel consumption and productivity were 15.9 kg/hm2 and 0.38 hm2/h. The control group that plough machine and rotary tilling machine were secondary tillage operations was set up. The results of control group experiment showed that the various experimental results of the compound soil preparation machine were better than the results of control group. Especially in fuel consumption and productivity index, the compound soil preparation machine was far better than the control group. The control experiment explained that the compound soil preparation machine was energy conservation and efficient to the traditional cultivation method. [ABSTRACT FROM AUTHOR]

Licorice is not only an important Chinese herbal medicine, but also widely used as an additive in food industry.With the increasing demand of licorice, wild licorice resources can not meet the needs of the market.Artificial cultivation of licorice has become an effective way to solve the problem between the supply and demand of licorice resources.Direct seeding method leads to dredge difficult and large labor consumption when harvest because of its low seedling survival rate, large quantity, long growth cycle, and deep roots.Research shows that seedling transplanting can be used for licorice planting.By this way, the licorice roots can grow strongly and healthily with good quality and high yield; and it is also easy for mechanized harvesting.Seedling transplanting is an ideal cultivation model for artificial cultivation of licorice.At present, the cultivation of licorice in China is still in the manual operation stage, from which exist many problems, such as large labor input, high cost, low production efficiency, poor transplanting quality, etc.Due to the impact of the above problems, the scale of the cultivation of artificial transplanting of licorice has been greatly restricted.A lot of relevant research documents show that the development trend of the cultivation of licorice is the mechanization of transplanting.However, the research on the transplanting machine of licorice in China is still in its early stage, and there is no mature and practical application of the licorice root transplanting machine.In this paper a licorice tilt transplanting opener was proposed.The analysis and experiment of the structure and work parameters of the opener were carried out, which provided the research foundation for the design of the licorice transplanting machine.In order to analyze the forming mechanism of the tilt transplanting furrow opener, the soil backflow model and seedling position parameter model were built.Through analyzing results of the mathematical model, a multi factors orthogonal test for the opener was executed by changing the soil backflow port angle, the space between two wing plates, velocity, the furrower operating depth and the soil repose angle.The opener orthogonal test results showed that main influencing factors of the inclined V type groove tilt angle was the soil backflow port angle.The primary and secondary order of the factors affecting the length of the ditch was:the furrow opener operating depth, the soil backflow port angle, the space between two wing plates, the soil repose angle and the velocity.The results also showed that the formula built by mathematical model could be used for design the opener to make V type inclined groove.Under the agronomic condition of 30° inclined transplanting with 300 mm long licorice roots.When the lag seedling coefficient value less than 1, the licorice angle decreased with the lag seedling coefficient value decreased, and decreased with the increase of the opener velocity.When the lag seedling coefficient value was equal or greater than 1, the licorice angle fluctuated between 28°-31°.The opener had the advantages of stable working performance. [ABSTRACT FROM AUTHOR]

In order to investigate the general rule of soil conditions and working parameters on power consumption of disc type ditcher, LS-DYNA software which transient dynamic finite element analysis using explicit time integration was employed to simulate the process of soil cutting in this paper, and MAT147 model was used as constitutive model to build soil model, then with given specific parameters, the characteristics of yellow loam in north China was simulated.Due to the complexity of construction for ditching part, the model was initially set up in Soildworks, then imported into LS- DYNA. In order to shorten the operation time, the secondary characteristics such as chamfer, fillet and connection, etc, was omitted. Aiming to study the physical process of soil cutting, we stimulated the finite element model of soil cutting by using Smoothed Particle Hydrodynamics. The deformation of soil was generated when subjected to extrusion of blade. As the amount of deformation was big enough, the soil would be broken. According to the results of simulation, the relationship between power consumption and time of ditching part in soil cutting process was obtained. Any two blades mounted in disk were simultaneously used to assure cutting smoothness and steady. As such, the second blade has been inserted into soil before the first one departed from soil. The total power assumption included kinetic energy from rotational motion of ditching part and internal energy from interaction with soils. At the beginning of soil cutting, power consumption increased quickly, which was caused by a great deal of power consumption needed during the process of soil deformation and broken. According to the results of simulation, it was found that the cutting power consumed was from 0 to 24.2 kW during the time of 0 to 13 ms, the consumption reached maximum 36.26 kW, when cutting motion arrived at the time of 26 ms. After that, the power consumption tended to be stable, indicating that the binding force tended to be less after the soil particle was destroyed. The cutting force was then maintained at steady state, so the power consumption subsequently changed slowly and maintained about 32.5 kW. Orthogonal simulation experiment was carried out with soil firmness, rotation speed of cutting wheel and ditching depth as experiment factors and with power consumption of rotary ditching part as assessment index. It can be concluded that soil firmness, rotation speed of cutting disk and ditching depth had a larger effect on power consumption. Using range analysis method and variance analysis method to determine the importance index for power consumption, the results were:soil firmness, ditching depth, rotation speed of cutting disk. The mathematical model of impact factor and performance index was then established using MATLAB software, the minimum power consumption was 32.5 kW when the parameters of soil firmness, rotary velocity and ditching depth were 120 N/cm2, 225 r/min and 405 mm, respectively. Finally, the field test was conducted to verify the accuracy of simulation results and optional parameters, it has shown that the relative error between theoretical and testing values was 5.68% showing that the simulated value was basically coincided with testing value, which proved that the modeling and simulating methods adopted met the content requirement. The results provide reference for the product designers to select economic power consumption parameters and working conditions with different working parameters. [ABSTRACT FROM AUTHOR]

Ploughing with rear-driving tractors plays an important role in agricultural production during which the electronic-hydraulic hitch system is regularly adjusted for desired performance. In operation, severe driving wheel slip easily occurs because of the complex terrestrial environment and the frequent changing of operating load. Studies show that tractors have a higher traction efficiency when slip ratio is between 0.1 and 0.15; however, when slip ratio is larger than 0.2, the efficiency drops dramatically while the soil texture is destroyed, the tires are worn faster and the energy consumption is increasing. Therefore the effective control of the 2WD tractors’ driving slip is highly desired. In this paper, both the structure of the electro-hydraulic hitch and the working principle of 2WD tractor’s driving slip system are firstly analyzed. Then the integrated control of traction and slip-rate based on PID (proportional integral differential) is proposed. The integrated control method that contains a control factor with 2 detailed control objectives is presented. The automatic control system mainly performs the traction control while constantly monitoring the changes of slip ratio. When the slip ratio is in the desired range mentioned above, the traction control continues; when the slip ratio is out of range, the controller switches to slip rate control, which outputs a voltage signal to the electromagnetic proportional control valve (if the slip ratio is smaller than 0.1, proportional descent control valve works with an input voltage of 0.5 V; if the slip ratio is greater than 0.2, proportional lift control valve works with an input voltage of 4.5 V); and it returns to traction control once the slip is addressed. According to the characteristics of heavy tractor electro-hydraulic hitch，taking account of the complex operating condition of ploughing, an integrated automatic controller is developed for the electro-hydraulic hitch system based on microprocessor MC9S12XS128 of Freescale. At the same time, the software is designed using CodeWarrior. Taking the heavy tractor with electro-hydraulic hitch system as the test platform, after the successful selection and installation of the sensors, in order to verify the effectiveness of the joint controller, contrast experiment was carried out after wheat harvest in the farm of Xinli Machinery Company in Shunyi District, Beijing. First of all, we measured the actual traction with cultivated land operation in homogeneous soil conditions. Actual tractor traction was measured by force sensor, in which ploughing depth was set to 20 cm, tractor was geared to B2, and speed of tractor was set to 7.5 km/h. In the end, we identified the target of traction was 6 000 N. With the slip ratio between 0.1 and 0.2, traction of 6 000 N and sampling time of 50 s, the maximum of slip ratio changed from 0.2766 to 0.2112, the minimum changed from 0.0419 to 0.0786, the range reduced by 41.71% and the effective control of time range increased by 20.55%; ploughing depth’s average error changed from 1.69 to 1.15 cm, and root-mean-square error changed from 4.07 to 2.09 cm; traction’s average error changed from 426.38 to 270.73 N, and root-mean-square error changed from 503.18 to 366.23 N. The results demonstrate that the joint controller has not only the effectiveness, but also the efficiency, precision and stability. The proposed integrated controller raises the traction efficiency, improves traction performance and can serve as a guidance to field production. [ABSTRACT FROM AUTHOR]

The on-line mixing is a process with higher productivity and safer operating conditions, and can reduce waste production. In order to optimize the spraying performance of orchard air-assisted sprayer, a real-time mixing system for pesticide precision control using peristaltic pump and static mixer was developed. The components of the mixer prototype were pesticide tank, peristaltic pump, pesticide flowmeter, electromagnetic valve, water tank, filter, pressure regulator and static mixer. An electro-hydraulic proportional valve was used to continuously vary the sprayed flow rate of sprayer prototype according to a control signal depending on the canopy volume. The static mixer was used to homogenize the fluid of pesticide and water by redistributing them in the radial and tangential directions. Three insert-type configurations of static mixers named SK, SX and SD type static mixers were analyzed. Their difference was the design of stationary inserts for redistributing the fluid in the directions transverse to the main flow. With the SIMPLEC(SIMPLE-Consistent) algorithm and k-ε turbulence model, the internal flow fields in the mixing process of 3 mixers were characterized and quantified using the Fluent software for the two-phase flow mixture. The distributions of volume fraction were analyzed in detail from the cross-sections perpendicular to the main flow direction. Simulations were also conducted while varying the number of static mixing elements. Comparing the cloud map of the secondary phase volume fraction of the 3 mixers, it was found that the SX static mixer had several mixing advantages compared to other mixers, and the optimum number of elements was 5. The reason for the high productivity of SX static mixer was the multilayer design splitting the fluid in multiple layers. Taking into account the optical visibility of on-line mixing process, the glycerol solutions with carmine stain to follow the fluid motion were used as the pesticide fluids in the experiments and the SX static mixer was made of identical elements inserted in a transparent pipe. It was observed that the mixing test results of SX static mixer were in good agreement with the simulation results. It was clear that the computational fluid dynamics(CFD) analysis used in this paper could properly reveal the complicated flow characteristics in the static mixer. To assess the performance of pesticide flow control, the step rising and step falling of 84 mL /min flow rate signal sent to the peristaltic pump and the responses of the pesticide flowmeter were recorded. The time between the control signal step and the attainment of the stabilized value was approximately 0.3 s for the rising case. Similarly, the response of flowmeter required approximately 0.28 s to reach the stabilized value for the falling case. For smaller steps, the response time would be shorter. As an indication of mixing stability and mixing homogeneity, the droplets were collected and measured using the collectors, which were allowed to dry completely between successive spraying tests. The results of mixing stability test showed that the maximum error between the actual and referential concentration was less than 4.33%. The results of mixing homogeneity test showed that the coefficient of variation was no larger than 4.98%. This work can provide a reference for the design of real-time mixing mechanism and performance optimization of orchard air-assisted sprayer. [ABSTRACT FROM AUTHOR]

As an important part of the agricultural equipment, high clearance agricultural machinery is usually equipped with suspension system to reduce the vibration from uneven road. However, most of the suspensions have not been equipped with dampers and the vibration attenuation mainly depends on the damping of springs and tires. When the machine runs at a higher speed or works on some bad roads, the damping effect of the suspensions will become worse. In this paper, an independent strut type air suspension system with friction damping was designed according to the operating characteristics and requirements of high clearance agricultural machinery. The suspension system uses the Firestone 1T15L-4 air spring as the antivibration element and the nylon 66 resin slider as the damping element. When the suspension works, the vibration energy is consumed via the relative slippage between the nylon slider and the guide frame of the air spring. Since the high clearance agricultural machinery commonly uses the vacuum intertillage radial tire, the impact of tire damping on suspension antivibration cannot be ignored. Based on this, the vertical dynamic model of the suspension system was established, including the tire damping model and the viscous yielding resilience friction damping model, and then the state equation of the system was obtained. On the basis of the state equation and the filtered white noise random road excitation model, the simulation model of the system was created in Matlab/Simulink R2012a. And the designed suspension system was equipped in a high clearance emasculation machine and the field test was carried out in Jiuquan City, Gansu Province in August 2015. Before testing, the internal pressure of the air spring was adjusted to assure the height of the spring close to 280 mm. And the friction damping force was regulated by adjusting the bolt preload using the torque wrench. The Lancetec ULT1001 piezoelectric acceleration sensor was used to measure the acceleration signal of the sprung and unsprung mass. The MIRAN KTC-325 displacement sensor was applied for measuring the suspension dynamic deflection signal. During the test, the emasculation machine was set to run on the field at a constant speed of 8 km/h, and the sampling frequency was set to 200 Hz. The data acquisition card NI USB-6216 and the software LabVIEW were applied to collect the signals of acceleration and displacement. The main purpose of the simulation and experiment was to study the influence of the changing friction damping force on the vibration characteristics of the suspension, and verify the correctness of the mathematical model. The simulation and test results showed that when the friction damping force was equal to zero, the acceleration root mean square (RMS) and the suspension dynamic deflection of the sprung and unsprung mass were relatively large. At this time, the suspension system depended merely on the self-damping of the air spring and rubber tire to attenuate vibration. The suspension was in an underdamped state and the damping effect was poor. With the increase of friction damping force, the RMS of sprung and unsprung mass reduced firstly and increased afterward, which reached the minimum value at the force of 1 800 N and got the best damping effect, and tended to be equal when the force exceeded 5 000 N. That was because the force was too large and the suspension was locked, leading to the direct transmitting of pavement impact load to the vehicle body and thus the worse damping effect. In addition, the RMS of the suspension dynamic deflection continued to decrease in the whole process of friction damping force increasing. According to the time domain and frequency domain analysis of the acceleration data, when the friction damping force was set to 1 800 N, the RMS values of the sprung and unsprung mass accelerations were approximately equal to 1.874 and 8. 953 m/s2 respectively in simulation, while the vehicle test results were 1.604 and 9.653 m/s2 respectively. Meanwhile, the resonance frequencies of the masses were approximately equal to 1.2 and 10.7 Hz respectively in simulation, while the vehicle test results were 1.1 and 11.4 Hz respectively. The above data showed that the natural frequency of the designed suspension system was far away from the most sensitive frequency range of human body that is from 4 to 8 Hz. And the acceleration RMS of sprung mass was significantly decreased in contrast with the unsprung mass. In summary, the designed suspension has a good vibration property and the developed mathematical model is reasonable to reflect the dynamic performance of the suspension. [ABSTRACT FROM AUTHOR]

Ride comfort is of great importance feature for the heavy truck, its optimization can improve the driver's driving conditions to reduce fatigue, and make the goods safer. Primary factors that can influence ride comfort are form and parameters of suspension, which are suspension stiffness, suspension damp and their combination. When the form of suspension is confirmed, more reasonable parameters can be selected by optimization method to improve ride comfort. Ride comfort optimization analysis belongs to the combinatorial optimization problem, at the same time, the nonlinear characteristics in optimization is essentially a nonlinear multimodal optimization problem. In this paper, at first, a nine degree of freedom vehicle vibration model was established; Vehicle driver seat acceleration simulation tests were conducted with different vehicle speed. Also, both time and frequency domain analysis was implemented with MATLAB software development platform. On the whole, with the increase of the speed of the vehicle, the acceleration root mean square of vehicle driver seat became larger, so the vehicle ride comfort performance reduced. Especially at low speed and high acceleration change is more obvious. But in 40~80 km/h, the acceleration change quite gentle. That means to achieve the better economy and the vehicle ride comfort performance, the vehicle speed keeping in a medium speed is better. Based on C level road and the speed of 70 km/h, with an eight by four dump truck as experimental object, the ride comforttests were conducted, moreover the test results compared with the results of simulation. The compared results showed that the simulation and the test were very close. And then, today technology was coming to a stage of intersection, infiltration, and interaction with multi subjects. More and more issues on complexity, non linearity, and system have come to us. To deal with such complexity of system, conventional techniques have become incapable, and to seek an optimization algorithm, which adapt to large scale parallel with intelligent characteristics, has been a primary research target of related subjects. The artificial fish algorithm was proposed to optimize ride comfort. The artificial fish swarm algorithm (AFSA), anew method based on animal behaviors and the typical application of behaviorism artificial intelligence, was proposed byan internal scholar in recent years. It used the operators such as prey, swarm, follow and random behavior. The algorithm parameters, such as population, step size, sense of distance, the largest try number, crowded degree coefficient and the largest number of iterations, has a great impact on the performance of the convergence. At the end, the artificial fish algorithm was used to optimize ride comfort by reasonable selection of the suspension parameters. The objective function was the acceleration root mean square of vehicle driver seat to be minimized. The decision variables were front suspension stiffness and damp. Moreover AFSA need to set up the appropriate algorithm parameters. For example, population scale, step size, sense of distance, the largest try number, crowded degree coefficient and the largest number of iterations was 100, 100, 20 000, 100, 9 and 50. Where the population scale N was called the number of possible values of suspension parameters within the value range, step size was suspension parameters increasing or decreasing the amount of each iteration, and sense of distance visual was variables scope of each iteration. Optimization results show that the acceleration root mean square average fell by 16.82%, the biggest fell by 21.24% in 60 km/h, so it effectively improves the ride comfort h performance of heavy vehicles. [ABSTRACT FROM AUTHOR]

The hydraulic steering-by-wire system abandons the mechanical connection between hand wheel and front steering wheels, and thus the driver′s intent is delivered via electrical signal. The actuator of hydraulic steering by wires system is the hydraulic cylinder. ECU (electronic control unit) generates the corresponding electric current to control the opening of electro hydraulic proportional servo valve after receiving the steering signal, which correspondingly leads to the displacement of steering hydraulic cylinder. The displacement direction determines the steering direction and the magnitude determines the steering angle. At present, asymmetric hydraulic cylinders are mostly adopted. However, due to the piston areas are varied as the piston rod moves in different directions, even if the opening of electro hydraulic proportional servo valve and the pressure are fixed, the displacements of the piston rod vary under stretch and retracting condition. Combining hydraulic steering by wire system with asymmetric hydraulic cylinder, we know that accuracy adjustment of steering is essentially the adjustment of the hydraulic cylinder piston rod's displacement on the left or right side. Therefore, the traditional PID(proportional integral derivative) control of hydraulic steering by wire system is not efficient for precise control of steering angle. Considering the error is either positive or negative in steering angel, to improve control accuracy, the hydraulic cylinder can be regarded as different hydraulic cylinders with different piston areas working alternately. This paper presented the idea of dual channel PID control, in which way the 2 hydraulic cylinders (positive or negative error) used different channels with different PID parameter values. The characteristic of dual channel control was that when the errors, whose magnitudes were same and positivity and negativity were different, were adjusted with different PID values, the control current of electro hydraulic proportional servo valves was not same. However, the difference of cavity work area finally guaranteed the same displacement of hydraulic cylinder piston rod, namely the accuracy of adjustment. In addition, in order to avoid the low accuracy of a simplified mathematical model as well as the time consuming defect of other software, we used SimHydraulics to build the physical model of hydraulicsteering by wire system conforming to the real platform, whose preferences consulted the reality; the simulation of following response and steering angle pulse test of the steering wheel was completed, the test rig of hydraulic steering by wire system was set up, and then IPA15F2K61S2 chip of STC was chosen, which was written to the dual channel control program to be a controller of the hydraulic steering by wire system platform. The steering wheel angle was the input signal of controller, and the product of the actual angle and the steering ratio was a feedback signal. The output signal of the controller was the current controlling the electromagnetic proportional servo valve. The experiments of the steering wheel were completed under the control of single channel and dual channels on platform; and the effect of dual channel PID control on the system was analyzed by combining simulation and experiment results. Under the dual channel PID control, the simulation results showed that, the following error was 0.473° and the step response time was 0.273 s, the errors indifferent directions were almost the same, and they were both superior to the performance of the traditional PID control, for which the following error was 1.315° and the step response time was 0.334 s. Moreover, compared with single channel PID control, the error of dual channel PID control decreased by 64%, and the response speed increased by 18%. The results of experiments on platform were consistent with the simulation, which indicated that under the control of dual channel PID, the response of hydraulic steering by wire system was faster, the following error was smaller, and the errors in positive and negative direction were almost the same. Thus, it is concluded that the system under the control of dual channel PID has superior following performance and control precision as well as more desirable stability and reliability. [ABSTRACT FROM AUTHOR]

There is a large area of low productive soil, many soil types, and different low productive reasons in Heilongjiang Province. So improving low productive soil has important significance for agriculture. Subsoil fertilization is a comprehensive soil improvement technology which can improve subsoil′s bad physical and chemical properties. Studying team has done research on improving planosol with subsoil fertilization, and this technology has the effect of continually increasing yield, but there is lack of the research on other soil types, and the practical mechanical tools. In this paper, the subsoil fertilization plow was researched according to the subsoil fertilization technology requirements, and applied on the improvement of carbonate meadow chernozem and thin layer black soil, which was aimed to clarify its soil improvement effect on soil physical and chemical properties and corn yield, and provide the mechanical and technological support for its wide application in low production soil. The field contrast method was applied in this study, and 3 treatments were set which included deep loosing(DL), subsoil fertilization(SF) and control(CK). The result showed that the effects of subsoil fertilization and deep loosing on soil physical and chemical properties, yield characteristics and yield were not consistent. The lasting effect of deep loosing and subsoil fertilization on deceasing soil shear strength was obvious. For carbonate meadow chernozem and thin layer black soil, the soil shear strength was decreased by 7.14 and 5.41 kPa under DL treatment, and by 12.16 and 8.20 kPa under SF treatment respectively compared with that of the CK in the first year after soil improvement; the soil shear strength was decreased by 0.68 and 2.25 kPa under DL treatment, and by 6.65 and 11.31 kPa under SF treatment respectively compared with that of the CK in the second year after soil improvement. The bulk density and hardness were the same as the above change. Subsoil fertilization could improve soil air permeability and saturated hydraulic conductivity; the air permeability coefficient was respectively 3.22 and 15.28 times higher than the CK on the 10-30 cm soil layer of carbonate meadow chernozem and thin layer black soil in the first year after improvement, and 5.17 and 3.78 times after the second year; the saturated hydraulic conductivity was respectively 8.93 and 7.68 times higher than that of the CK after the first year, and respectively 12.62 and 3.38 times after the second year. The effect of deep loosing was not obvious. The DL and SF treatment could improve water consumption of subsoil, and the order of water consumption was CK>DL>SF in 0-30 cm soil layer, and SF>DL>CK in 30-60 cm soil layer. The water consumption in subsoil layer was 30% of total water consumption, and 10% more than the CK. The total phosphorus and available phosphorus were increased by 0.05 g/kg and 3.21 mg/kg under SF treatment compared with the CK in 20-30 cm soil layer of carbonate meadow chernozem, and by 0.01 g/kg and 1.92 mg/kg in 30-40 cm soil layer, and the phosphorus offering intensity of the 2 layers was improved by 5.17 and 17 times compared with the CK; The total phosphorus and available phosphorus were increased by 0.09 g/kg and 15.05 mg/kg under SF treatment compared with the CK in 20-30 cm soil layer of thin layer black soil, and by 4.19 g/kg and 4.96 mg/kg in 30-40 cm soil layer, and the phosphorus offering intensity of the 2 layers was improved by 5.17 and 17 times compared with the CK. Subsoil fertilization and deep loosing could promote the corn growth, increase the length and width of ear, grain number per spike, 100-seed weight and yield. The yield was increased respectively by 18.01% and 14.28% under subsoil fertilization and deep loosing in the first year after soil improvement for carbonate meadow chernozem, and respectively by 6.82% and 2.87% in the second year after soil improvement; the increased yield was respectively 6.45% and 1. 80% in the first year after soil improvement for thin layer black soil, and respectively 11.18% and 5.11% in the second year. The effect of increasing yield for carbonate meadow chernozem is more obvious than that for thin layer black soil. [ABSTRACT FROM AUTHOR]

In order to improve the blocking issue of logistics system in sugarcane harvester, by the methods of simulation analysis and experimental research, the cutter spiral lifting mechanism and the effects of friction coefficient and working parameters on the sugarcane material flow were studied and discussed. The average residence time of sugarcane in the transmission device of the screw conveyor was considered as test index and the virtual prototype simulation model was established by the software ADAMS and Unigraphics. Simulation results indicated that increasing friction coefficient of cutter spiral lifting mechanism could improve the delivery rate of the sugarcane and effectively inhibit the clogging problem. The high-speed photography results of experimental prototype showed that while a tyre rubber with high friction coefficient was used as the covering layer for the cutter spiral lifting mechanism and the cutter speed was about 750 r/min, the retention time of sugarcane was shortened by 17% compared to original rebar spiral lifting mechanism. This characteristic could improve the congestion problem of logistics system, and verify that the friction coefficient was exactly the main affecting factor. Based on this principle, this paper worked out the structure improvement of the cutter spiral lifting mechanism. The helical circular cross section was changed into a helical rectangular cross section, which made the contact way of the cutter spiral lifting mechanism and sugarcane change from point contact originally to line contact. The computer simulation experiments under different structures’ transmission speed, displacement, force and so on were conducted, and the analysis indicated that for the 20 mm cutter spiral lifting mechanism that was improved, the sugarcane residence time was shortened by 32% comparing with the original cylindrical spiral. Meanwhile, after the sugarcane head entered the spirals, the loading time from the spiral to the sugarcane head relatively decreased and the time of the loading process was shorter, and the universal impact force for the sugarcane was bigger, which made the cane’s feeding into the system more easily and rapidly. Before the sugarcane tail left the spiral, the favorable impact from spiral still existed, its impulse changed by 11.1 N·s, and the backward displacement of the sugar cane increased. And in the comparison of different width of spiral plane, the spiral retention time of sugarcane decreased by 18.5% when the plane width increased from 12 to 20 mm. If the width of spiral plane continued to increase to 24 mm, the trapped time of sugarcane increased by 17.6% compared to 20 mm width. When sugarcane tail left the spiral, the spiral with 12 and 24 mm width would have an adverse impact on sugarcane, which was unfavorable to the sugarcane conveying, while the spiral with 16 and 20 mm width would not only make the time of cane heading into the spiral shorter, but also produce more favorable impact when sugarcane tail left the spiral. Consequently, the experimental results showed that it could increase the friction conveying force and reduce the sugarcane retention time by appropriately widening the cutter spiral lifting mechanism width. It was advantageous to improve the transportation performance of sugarcane. Compared with 16 mm wide spiral, 20 mm wide spiral offered the equivalent total impulse after the sugarcane head entered the spiral. That made it easier for the sugarcane to enter the feeding roller, and before the sugarcane’s tail left the spiral, the loading time from the spiral to the sugarcane’s tail was more concentrated, the impact force was more balanced, and the backward transmission of the sugarcane was faster and more stable, which could effectively restrain the blocking problem of the front end of conveying system. The results provide the design basis for the construction of the late test platform and the development of the physical prototype. [ABSTRACT FROM AUTHOR]

In 2014, soybean production was 179 million tons, and planting area was 102.1 million square hectare in China. China has become the fourth largest soybean production country after the United States, Brazil and Argentina over the world. However, the green soybean harvest still rely on manual power, what’s more, harvesting has taken up the large part of labor force in green soybean planting, accounting for over 40% of the total labor force. The operation of pod taking off is a key link in the process of green soybean mechanization harvest, and meanwhile, it is a core factor and technology which seriously influences the equipment performances. The structure style of the device of pod taking off and its parameters selected for working directly determine its harvest capability of fresh soybeans and other legume crops. Therefore, a green soybean separation experiment device of 5TDS-00 type manufactured by Nanjing Research Institute for Agricultural Mechanization was designed to research the separation properties of green soybeans based on striking, in order to seek the optimal combination of the factors influencing the separation effect. This experiment device of pod taking off consisted of rollers of pod taking off , conveying mechanism, angle adjuster, distance adjuster, driving speed-adjusting motor, roller speed-adjusting motor and so on. The device was driven by motor and fed by chain conveyor, and could realize step-less speed regulation under the coordination of angle adjuster, distance adjuster and adjustable speed motor. After striking, the green soybean would generate the variable motion inertia force, which could overcome the pod-handle connection force so as to achieve the objective of separation. The energy collision model of the separation process and the mechanical model of pod-handle separation were constructed based on the principle of energy conservation. Quantitative analysis was done to verify the energy collision model and the mechanical model. The roller speed, feeding speed and roller distance were supposed to be the main influence factors. In the end, focusing on “Xiaonongqiuyan” and “Doutong 6” varieties, the experimental investigations were carried out. The test green soybean was derived from Hentang Export Vegetable Base in Changshu City, Jiangsu Province, and the sample collecting dates were from August 1st to 7th in 2014. Under the same climatic condition, the samples possessing the similar shape and quality could be chosen. After that the rapid refrigeration was needed and the storage temperature was set at -2-0℃. Moreover, the research should be completed within 24 h. The results showed that the crop variety had little impact on damage rate and separation rate. The order of the aggregative indicators according to their influence from major to minor was the roller speed, the feeding speed and the roller distance. When the roller speed was set at 600 r/min and the roller distance was set to 18 mm, and at the same time, the feeding speed was set at 0.3 m/s, the harvest rate could attain 99.0% and the damage rate could be reduced to 2.4%, achieving a good comprehensive property. The prototype field experiments showed that the production efficiency could be up to 3-5 mu every hour, which was more than 20 times the manual operation. The result of this paper can provide a theoretical foundation for the design of the green bean harvest device. [ABSTRACT FROM AUTHOR]

The application of the path tracking technology on agricultural vehicle makes the robot replace farmers for field operation, and the accuracy, production efficiency and dependability about farming automation are improved effectively. Meanwhile the labor time, labor intensity of drivers and the production cost are saved. The path tracking of agricultural vehicle was studied in an operating condition, and a variety of sensors were installed on the car features of the external environment. Then it generated a four-element in state space by the target path which was given for controling the agricultural vehicles to track the target path automaticly according to the theory of optimal navigation control. The location method of GPS/INS was selected, the navigation system was developed, and the experiment was finished in 2014. According to the needs of automatic walking positioning system, a variety of sensors has been chosen, including the inertial sensor, angle sensor and GPS sensor. Then the serial program was writen to collect the signal from the sensors and calibrate them. In order to meet the requirements of vehicle navigation system, the positioning system with low cost and high precision was developed. The hardware of the system consisted of two GPS modules, two Zigbee wireless transmission modules and an inertial sensor. The data from the sensors are filtered and fused, and finally accurate, reliable vehicle position data was got. The tracking controller based on preview control was designed to obtain the future values and target values of the vehicle. With the target path and its curvature, the feed forward control value was got. There was an error between the current state and the state of vehicle target path that was needed to use LQR for elimination. The performance of the path following controller was simulated by Matlab, then the maximum lateral error was 0.16 m and 0.27 m at the speed of 0.5 m/s and 1 m/s respectively. The results showed that the control method was feasible. The steering control system was designed based on steer-by-wire(SBW) after the study of vehicle navigation control principle. SBW removed out mechanical connection between steering wheel and steering front wheel. It used motors to control front wheel angle and simulated force characteristic. Compared with traditional steering system, SBW had characteristics of ideal steering ratio and active steering control according to vehicle state parameters, and improved safety of driving and handling stability. The strategy of BLDCM was designed in order to make actual front angle follow the desired angle better. PID control and sliding mode variable structure control were applied in strategy of BLDCM and the result of simulation showed that sliding mode variable structure control was better than PID control. This paper designed the electronic control unit of SBW based on chip of MC9S12XET256, mainly including peripheral circuit of MCU, CAN communication circuit, drive circuit of BLDCM, power circuit, signal acquisition and processing circuit, current sampling circuit of motor. Based on the requirement of joint simulation, we designed a bench test for control strategy and hardware, software of ECU in 2015. The results of test bench showed that angle correction was similar with the result of simulation and sliding mode variable structure control was better than PID control in following front angle. Finally, the vehicle steering control test and the vehicle path tracking control test were carried out based on vehicle test platform, which was built personally. The vehicle path tracking system was based on the Windows platform, using Microsoft Visual Studio as the development environment. The integrated navigation system was validated and the test data showed that the integrated navigation system had a high positioning accuracy and the steering system had a reliable tracking performance. The final navigation and positioning accuracy of integrated navigation system was around 0.1 m to 0.5 m and the response speed of the whole system was about 0.1s . The results proved that the system could meet the requirements of agricultural vehicle path tracking control system. [ABSTRACT FROM AUTHOR]

Although great development has taken place in agricultural mechanization since reform and opening up, China still faces the big challenge in improving agricultural resource utilization as well as promoting the sustainable development of agriculture at present. As we all know, it is mainly the 5 factors, i.e. water, soil, fertilizer, pesticide and seed that affect sustainable development in the construction of China’s agricultural modernization. The overall development of agriculture in China will be impeded if the resource utilization stays low. There exist some phenomena: 1) the irrigation water use is 360 billion m3 each year, while canal-system water use efficiency is only 0.4~0.6; 2) high-quality cultivated land is lacking; 3) nitrogen use efficiency is about 30%~35%, which is 20% less than developed country; 4) pesticide utilization is merely about 30%, while leads to severe environmental pollution; 5) the demand of seeding quantity is high while there are shortage of high-quality seeds and serious waste of seeds. Accordingly, several technologies and machines in PA (precision agriculture) were put forward in this article so as to meet the requirement of agricultural sustainable development: precision irrigation, precision plow, precision fertilization, precision spraying, and precision sowing. By reviewing the researches at home and abroad, the current situation of PA was analyzed and thus the methods to achieve the 5 mentioned key technologies were presented. Meanwhile, some other suggestions were proposed to push the agricultural mechanization to play a greater and more important role on the utilization of agricultural resource and agricultural sustainable development: 1) further strengthen the combination of agricultural machinery and agronomy as well as the basic study of related theory; 2) carry out in-depth studies on key technologies of maximum utilization of agricultural resource, especially in precision irrigation, precision plow, precision fertilization, precision spraying, and precision sowing; 3) enhance the capacity of independent innovation, namely, the capability of equipment design and manufacture related to PA; 4) accelerate extensive application of precision agricultural machine and equipment. Above all, this paper has provided a scientific guide and policy direction for improving utilization of agricultural resource, promoting agricultural mechanization and agricultural sustainable development. [ABSTRACT FROM AUTHOR]

China is one of the major rapeseed production countries in the world, but the harvesting mechanization is still backward, and high mechanical harvest loss is a key inhibiting factor for rapeseed production. In order to reduce the harvest loss ratio, the effects of the parameters of air-screen cleaning device of rapeseed combine harvester on cleaning loss ratio and percentage of impurities in grain under the actual field harvest operating condition are needed to understand. In this paper, a Plackett-Burman test and a response surface test were designed to study the 4 parameters: vibration screen amplitude, crank revolving speed, fan revolving speed, and fan dip angle based on a two-roller and air-screen field mobile harvest testbed. The Plackett-Burman experiment results showed that the vibration screen amplitude and the crank revolving speed had significant influences on the cleaning loss ratio, and the effect of the amplitude was greater than that of the crank revolving speed, but the fan revolving speed and the fan dip angle had not significant impact; the results also showed that the fan revolving speed had significant influences on the percentage of impurities, while the other 3 parameters had not significant impact. The response surface regression variance analysis showed that the effects of the 4 parameters were not the linear relation but the interaction; the predicted values of quartic polynomial regression model were consistent with the measured values in the experiment, and the regression models of the cleaning loss ratio and the percentage of impurities were solved and the values of R2 were 0.9559 and 0.9660 respectively. The single factor and two-factor analysis results indicated that the vibration screen amplitude had a little impact on cleaning loss ratio near zero level, reducing the crank revolving speed could remarkably lower the cleaning loss ratio, and increasing the fan revolving speed could remarkably lower the percentage of impurities. A group of optimal parameter combinations under the constraint condition could be acquired by solving these regression equations, and a checking test was carried out by using an approximately optimal parameter combination: vibration screen amplitude of 35 mm, crank revolving speed of 392 r/min, fan revolving speed of 1 750 r/min, and fan dip angle of 29°. The cleaning loss ratio and the percentage of impurities were 0.90% and 0.45% respectively in the test, but when these parameters were applied into the regression mathematical models, the cleaning loss ratio was 0.38% and the percentage of impurities was 0.48%, and the absolute errors were 0.52% and -0.03% respectively. Compared with the field result that was based on the common parameters, the cleaning loss ratio dropped by 61% and the percentage of impurities dropped by 58%. The analysis results indicated that the relationship between the parameters of cleaning device and the cleaning loss ratio and grain percentage of impurities was correct and the precision of regression mathematical model could meet the need for optimizing the parameters of air-screen cleaning device. The results can provide theoretical basis and technical references for the parameter selection and optimization of air-screen cleaning device of rapeseed combine harvester. [ABSTRACT FROM AUTHOR]

Calculation process strongly amplifies the relative error of input signal, which makes it difficult to measure the sliding rate. The key to obtain the accurate value of the sliding rate lies in the real-time and accurate measurement of the tractor speed and the theoretical speed of the driving wheel. Multi sensor information fusion algorithm based on Kalman filtering can effectively improve the measurement accuracy. Due to the development of controller area network, sliding rate measuring node can share the information of other sensors on the bus based on ISO11783 protocol, which provides a convenient condition for realizing multi sensor fusion. However, the measurement noise variance of the sensor signals of the tractor is unpredictable, which is the problem that the algorithm must solve. Aimed to this problem, the adaptive data fusion algorithm with noise observer is proposed in this paper. Multi sensor signals from wheel speed sensor, angular acceleration sensor, vehicle body accelerometer and global positioning system are integrated by this algorithm, and at the same time, the noise variance of the sensor signal is calculated online, so as to accurately estimate the tractor driving wheel’s sliding rate online without the prior noise measurement signal variances. The simulation results show that the sliding rate estimated by the proposed algorithm is almost coincident with the theoretical value. The average error of the sliding rate estimated by adaptive data fusion algorithm is about 1/10 of that by the median filtering method, and 1/5 of that by the Kalman filtering method. The algorithm has good robustness. The noise observer of the algorithm can estimate the white noise variance of the measured signals in real time, and there is no significant difference between the average estimated variance of steady state and the Kalman data fusion algorithm with exact prior error. The algorithm has the mechanism of the fusion according to the weight of the signal covariance, and the distortion signal can be modified by other related signals in the fusion process, so the algorithm has good robustness. Under the special condition that driven wheel speed signal is disturbed by colored random noise, the information fusion mechanism of the algorithm can compensate for the errors caused by the disturbance of colored noise. Experiments show that the estimated value of driving wheel sliding rate is very close to its true value, and for the estimated value, the mean error is 0.012 and the maximum error is 0.027. Under the condition of stable working of tractor, the mean value of the noise variances of the measured signals is within 5%. So the mean value can be used to replace the real-time estimation, so as to improve the real-time performance of the system. This algorithm can estimate the noise variance of the sensor signal online, which provides the technical basis for the measuring nodes on the bus network to share the sensor signals from other sensors on the bus. The precise sliding rate by the algorithm can reflect the real-time traction efficiency of the tractor, and provide the basic parameter for the control system of the tractor. [ABSTRACT FROM AUTHOR]

A flexible chassis is a four-wheel-independent-drive and four-wheel-independent-steer electric vehicle chassis with 4 driving wheels. It can make omnidirectional motions and every driving wheel has an offset steering shaft, which means the rotating surface of the wheel is not coplanar with the steering axis, so that the chassis can make a turn using the force of the wheel. This paper presented a new type of test bench, which was built based on the working characteristics of the driving wheel, in order to resolve some key issues about the dynamics of the driving wheel based on offset steering shaft. The feature of this bench was that steering center of the offset shaft shared the same axis with the center of horizontal turntable below the wheel to simulate its moving on the ground. And a force sensor was connected between the forks of the wheel and the frame of the bench. The force analysis showed the traction force and the power for the steering of the offset shaft. And a record and display software was designed for the bench based on Visual Basic 6.0. First, we completed the whole structure design and analyzed the working principle of the device. Horizontal rotary table drove by the same driving wheel was installed, and its rotary center was the same axis with the steering shaft of the driving wheel which was connected to the frame through the bracket; the sensor was used to test the traction force of the driving wheel moving on the horizontal turntable, and keeping its levelness was supported by 4 small wheels connected to the frame. Second, a test system based on Visual Basic 6.0 was developed to show and record the data of the rotation speed, current and force. And according to the working characteristics of this bench, we analyzed the forces for the driving wheel and its fork, and a model was built and the simulation was carried out based on MATLAB/SIMULINK to make a comparison with the test data. Finally, by testing the bench, we recorded variables, such as the time, rotation speed and current of the driving wheel, and the force of force sensor. We tested the performance of the driving wheel on the bench through loading different weights on the wheel. We analyzed the indices such as the force changing progress and the time spent by stabilization of speed. The result showed that the time spent by the rotation speed of driving wheel changing from zero to stable value was not irrelevant with loading; it was 0.667 s on average. And the force, which could supply power for the offset shaft to steer, had linear relationship with loading. And when the 500 N loading was applied, the turning force was 77.24 N. The various performance indicators met the design requirement, which could make the performances satisfy the requirement of flexible chassis. The test results can provide the reference for the study of flexible chassis and also prove that the bench is feasible and efficient. In addition, the research provides the theoretical and technical references for the control design of four-wheel-independent-drive and four-wheel-independent-steer vehicles. [ABSTRACT FROM AUTHOR]

Plug seedlings transplanting, which has comprehensive benefits including high and stable yield, climate compensation and improving land utilization, is an important part in the process of dry land crops production. At present, the crops, such as maize, sugar beet, rapeseed, cotton, tobacco and vegetables, apply dry land seedlings transplanting in China, with total planting area of nearly 50 million hm2 in 2014 which goes in advance in the world. At the same time, semi-automatic transplanting machine is the main equipment for dry land crops transplanting domestically, and the work of picking up and delivering seedlings is finished manually. It results in high-intensive labor and high producing cost. Aiming at some existing problems in China, such as low level of automation in vegetable transplanter and high rate of injuries during picking up and delivering seedlings, a system for picking up and delivering seedlings in automatic transplanter is designed in this paper. In this tester, step mechanism is used to realize the vertical and horizontal movement of plug seedlings, row type of seedlings pushing up mechanism and clamps are adopted to implement the work of pushing up and clamping plug seedlings, and seedlings catching, seedlings stirring up, seedlings delivering, seedling dropping mechanism, etc. are applied to finish the task of delivering plug seedling from bowl plate to transplant instruments. During the whole operation all actions of the system are finished through the programmable logic controller(PLC), which controls pneumatic cylinders and hydraulic motors. Theoretical analysis and MATLAB simulation have been done, and the results show optimum working pressures of 2 drive cylinders which drive seedlings pushing up mechanism and control the opening-closing of clamps’ clamping piece are 0.2-0.4 and 0.1-0.3 MPa respectively for pepper seedlings. In order to verify optimization results, single-factor experiment is carried out respectively. The results show that the optimal working pressure of the drive cylinder driving seedlings pushing up mechanism is 0.4 MPa and that of the drive cylinder controlling the opening-closing of clamps’ clamping piece is 0.25 MPa. The functional relationship among 3 parameters which are the frequency of picking up seedlings, the speed of delivering seedlings, and the forward speed of transplanting machine are obtained through theoretical analysis. Besides, levels of these 3 factors are optimized, the 4 groups of best combinations of the factors are achieved, and orthogonal experiment is conducted, in which experimental indices are missing ratio of seedling transplanting, seedling repeated planting ratio, seedling lodging ratio, and seedling damage ratio. Using an experimental automatic vegetable high-speed transplanting machine cooperatively developed by College of Mechanical Transportation of Xinjiang Agriculture University, the experiment is conducted in the farm of Regiment 22, Division 2 of Xinjiang construction Corps in Hejing County, Xinjiang. Pepper seedlings which come from the farm of Toudun river, Urumqi, Xinjiang serve as the test sample. The age of seedlings is 52 days, and their plant height is 142 mm. Through analysis on the experiment result, it reflects that the system achieves the best quality of seedlings picking up and delivering when the frequency of picking up seedlings is 7 times/min, the speed of delivering seedlings is 42 m/min, and the forward speed of transplanting machine is 20 m/min. [ABSTRACT FROM AUTHOR]

In order to solve the problem of high traction resistance of the traditional subsoiler, a forced-vibration subsoiler was designed and developed. This paper introduced the structure and described the working principle of this forced-vibration subsoiler. What was more, the motion process of the vibrating deep loosening shovels was analyzed and the motion equation of the shovel point was established. Type of forward velocity, vibration frequency and vibration angle were selected as 3 factors of the orthogonal simulation experiment to evaluate their effects on traction resistance, total power and torque in the soil-bin experiment. The sequence of factors in affecting the traction resistance was vibration frequency > forward velocity> vibration angle. The traction resistance was reported to increase consistently with the increasing of forward velocity. The sequence of factors in affecting the total power was forward velocity > vibration frequency > vibration angle, and the total power values firstly increased and then decreased with the increasing of vibration frequency while the total power values firstly decreased and then increased with the increasing of vibration angle. The sequence of factors in affecting the torque was vibration frequency > forward velocity > vibration angle, and the torque values firstly increased and then decreased with the increasing of forward velocity while the torque values consistently increased with the increasing of vibration frequency. The optimal combination of the performance parameters was the forward velocity of 2 km/h, the vibration frequency of 10Hz and the vibration angle of 12°. For further validating the rationality of optimal combination of parameters, the test on working performance of the forced-vibration subsoiler was carried out in the experimental field, and soil properties (bulk density and water content), soil bulkiness, soil disturbance coefficient and traction resistance were selected as the evaluation indicators to compare with non-vibration subsoiler. The results showed that the bulk density of all soil layer decreased after forced-vibration sub-soiling and that at 0-15 cm soil layer decreased by 21.74%. At the same time, the water content at 15-25 cm increased by 16.02%. The variation coefficient and stability coefficient of sub-soiling depth, which were the indicators to the change quantity and degree, were 7.37% and 92.63% respectively. Meanwhile, the variation coefficient and stability coefficient of the depth reached the requirements of the Ministry of Agriculture, and the land surface was smooth and flat after sub-soiling. Moreover, soil disturbance coefficient was 57.11% after subsoiling and soil bulkiness was 36.96%. Both soil bulkiness and disturbance coefficient reached the requirements of the test indicators. In addition, the traction resistance was reduced by 9.09% compared with non-vibrating subsoiler, so the effect of reducing traction resistance was obvious. These results provide a reference for further optimization of the mechanical structure and improving dynamic and economic performance of the whole machine. [ABSTRACT FROM AUTHOR]

In China, corn harvest gradually tends to mechanization, and corn threshing is the most important section in the process of corn harvest, which is directly affecting the damage level of corn seed. Manual threshing often chips away a row of corn ear with an awl firstly, and then it’s easy to thresh other kernels. Based on this, some agricultural experts put forward a process of “pre-dispersion and post-threshing”. Besides, the study found that after the long-term evolution, beak has not only excellent ability to insert into corn kernels, but also strong ability of dispersing kernels with low damage. To explore the movement law of corn ear kernels and low damage in the discrete process of corn ear, this paper had an experimental study on the beak to peck the corn kernel using the discrete test system with high-speed photography. The variety of experimental corn was Zhengdan 958 and the common domestic chicken was selected for testing. Self-made corn discrete test system was used in this experiment. The whole system consisted of mechanical data acquisition system and high-speed photography system. Due to the randomness of chicken pecking corn, firstly, the high-speed camera was fixed to the bracket, and then the best angle was selected to shoot at the beginning of discrete process. The shooting in the test was mainly from the ahead, the side and the back side of the test equipment with the shooting angle of 45°. The sensors were installed on the fixture to measure the forces in 3 directions respectively. Through observing the photos, we found that the closer the kernel was from beak, the larger the horizontal component of thrust was, the more obvious the movement was, and the easier kernel was to disperse from ear; on the contrary, the further the kernel was from beak, the smaller the horizontal component of thrust was, and the more difficult kernel was to disperse from ear. The kernels followed the “arrangement law” to deliver forces, whose range was approximate to a “tower”, and the movement of kernel separated from corn ear was similar to oblique throwing movement. According to the data measured, the maximum force on the corn ear was in x direction, second in y direction, and the force in z direction was the minimum. The resultant force of x and y direction had a great influence on the number of the kernels separated from the corn ear. The results of verification test were that the average discrete rate was 67.53% and the damage rate was 0.16%, which showed that the beak had a significant effect on dispersing corn ear, and the damage rate was low. The study will provide a bionic thought on designing corn threshing system with low damage [ABSTRACT FROM AUTHOR]