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Copyright of Transactions of the Chinese Society of Agricultural Engineering is the property of Chinese Society of Agricultural Engineering and its content may not be copied or emailed to multiple sites or posted to a listserv without the copyright holder's express written permission. However, users may print, download, or email articles for individual use. This abstract may be abridged. No warranty is given about the accuracy of the copy. Users should refer to the original published version of the material for the full abstract. (Copyright applies to all Abstracts.)

Copyright of Transactions of the Chinese Society of Agricultural Engineering is the property of Chinese Society of Agricultural Engineering and its content may not be copied or emailed to multiple sites or posted to a listserv without the copyright holder's express written permission. However, users may print, download, or email articles for individual use. This abstract may be abridged. No warranty is given about the accuracy of the copy. Users should refer to the original published version of the material for the full abstract. (Copyright applies to all Abstracts.)

Copyright of Transactions of the Chinese Society of Agricultural Engineering is the property of Chinese Society of Agricultural Engineering and its content may not be copied or emailed to multiple sites or posted to a listserv without the copyright holder's express written permission. However, users may print, download, or email articles for individual use. This abstract may be abridged. No warranty is given about the accuracy of the copy. Users should refer to the original published version of the material for the full abstract. (Copyright applies to all Abstracts.)

Copyright of Transactions of the Chinese Society of Agricultural Engineering is the property of Chinese Society of Agricultural Engineering and its content may not be copied or emailed to multiple sites or posted to a listserv without the copyright holder's express written permission. However, users may print, download, or email articles for individual use. This abstract may be abridged. No warranty is given about the accuracy of the copy. Users should refer to the original published version of the material for the full abstract. (Copyright applies to all Abstracts.)

Copyright of Transactions of the Chinese Society of Agricultural Engineering is the property of Chinese Society of Agricultural Engineering and its content may not be copied or emailed to multiple sites or posted to a listserv without the copyright holder's express written permission. However, users may print, download, or email articles for individual use. This abstract may be abridged. No warranty is given about the accuracy of the copy. Users should refer to the original published version of the material for the full abstract. (Copyright applies to all Abstracts.)

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

Copyright of Transactions of the Chinese Society of Agricultural Engineering is the property of Chinese Society of Agricultural Engineering and its content may not be copied or emailed to multiple sites or posted to a listserv without the copyright holder's express written permission. However, users may print, download, or email articles for individual use. This abstract may be abridged. No warranty is given about the accuracy of the copy. Users should refer to the original published version of the material for the full abstract. (Copyright applies to all Abstracts.)

Copyright of Transactions of the Chinese Society of Agricultural Engineering is the property of Chinese Society of Agricultural Engineering and its content may not be copied or emailed to multiple sites or posted to a listserv without the copyright holder's express written permission. However, users may print, download, or email articles for individual use. This abstract may be abridged. No warranty is given about the accuracy of the copy. Users should refer to the original published version of the material for the full abstract. (Copyright applies to all Abstracts.)

The application of mechanical transplanting on crops can effectively increase the product of crops and reduce the labor intense as modern cultivation techniques. But the popularization and application are limited by the problem of lower upright degree to some certain extent. A new type cam-swing link type transplanting machine was designed to solve the problem of lower upright degree in current pot seedling planting machine. In addition, the receiving seedling stability of planting apparatus can be guaranteed well, owing to double parallel four-bar mechanism of this planting machine. In this paper, the kinematic model of the transplanting machine was established, including the equations of planting trajectory, planting velocity and planting acceleration for the planting device. For the purpose of high efficiency, interactive GUI design tool had been explored based on the MATLAB/GUI according to these mathematic equations. The influences on the transplanting trajectory of main parameters were analyzed based on MATLAB tool, including the length L1 and original phase angle Φ1 of crank CD, the length L2 and original phase angle Φ2 of swing AB, and the length L5 of link AG. The system parameters which had great effects on the planting trajectory were L1, L2, Φ1 and Φ2. These parameters were analyzed and optimized through the method of orthogonal experiment. The experimental scheme was designed according to orthogonal table off our factors and three levels. By analyzing the range table of residual, the parameter could be ranged as L2, L1, Φ1 and Φ2 from big to small, considering the degree of significant on upright degree of seedlings. The optimal combination could be selected that L1 is 118 mm, L2 is 52 mm, Φ1 is 256°, and Φ2 is 316°. Under the condition of this optimal combination, the motion model of transplanting machine was reestablished to generate a new optimized planting trajectory. The top of this trajectory was smooth to benefit the receiving seedling stability of planting device. As the total height of this trajectory was about 256 mm with 190 mm higher the ridge side, the planting device could avoid touching down seedlings planted effectively. When the planting depth reached 60 mm, the maximum residual of curve at planting seedlings parts was 0.465 mm, the mean residual was 0.253 mm, and penetration angel was 81.05°. The simulation results indicated that this optimized planting trajectory can improved the anteversion problem of seedlings that caused by compaction wheel and ensured the seedling planted higher upright degree. In order to verify the reasonability and accuracy of the theoretical model, the prototype was processed with the optimized parameters. Based on the prototype, field tests were carried out according to relevant standards in Yiyang county industrial park of China in March 2015. No crops were planted and the ridge film was mulched in the test plot before the testing, for simply obtaining test results without effects of the other crops. During the course of experiment, 30 horse-power tractor was selected as the only power. The total height of seedlings used was no more than 150 mm, and the height of seedlings substrate less than 60 mm. The plant vertical degree was considered as the main optimization indicator which influenced by the main parameters mentioned above. The data results showed that the mechanism proposed meet the requirements of pot seedling agricultural plant at the speed of 0.556 meter per second, and planting frequency was 60.7 plant percent minute. The qualified rate of upright degree with the variation coefficient of 2.03% was 95%, lodging rate was no more than 1.67%, and plant spacing error rate was only 0.22% with no lacking of seedlings. The results indicated that this machine had the good planting performances of high upright degree and low spacing error rate under the condition of high efficiency of planting. What this paper studied will provide theoretical reference for the subsequent transplanter research and development. [ABSTRACT FROM AUTHOR]

Copyright of Transactions of the Chinese Society of Agricultural Engineering is the property of Chinese Society of Agricultural Engineering and its content may not be copied or emailed to multiple sites or posted to a listserv without the copyright holder's express written permission. However, users may print, download, or email articles for individual use. This abstract may be abridged. No warranty is given about the accuracy of the copy. Users should refer to the original published version of the material for the full abstract. (Copyright applies to all Abstracts.)

Copyright of Transactions of the Chinese Society of Agricultural Engineering is the property of Chinese Society of Agricultural Engineering and its content may not be copied or emailed to multiple sites or posted to a listserv without the copyright holder's express written permission. However, users may print, download, or email articles for individual use. This abstract may be abridged. No warranty is given about the accuracy of the copy. Users should refer to the original published version of the material for the full abstract. (Copyright applies to all Abstracts.)

Copyright of Transactions of the Chinese Society of Agricultural Engineering is the property of Chinese Society of Agricultural Engineering and its content may not be copied or emailed to multiple sites or posted to a listserv without the copyright holder's express written permission. However, users may print, download, or email articles for individual use. This abstract may be abridged. No warranty is given about the accuracy of the copy. Users should refer to the original published version of the material for the full abstract. (Copyright applies to all Abstracts.)

Copyright of Transactions of the Chinese Society of Agricultural Engineering is the property of Chinese Society of Agricultural Engineering and its content may not be copied or emailed to multiple sites or posted to a listserv without the copyright holder's express written permission. However, users may print, download, or email articles for individual use. This abstract may be abridged. No warranty is given about the accuracy of the copy. Users should refer to the original published version of the material for the full abstract. (Copyright applies to all Abstracts.)

Copyright of Transactions of the Chinese Society of Agricultural Engineering is the property of Chinese Society of Agricultural Engineering and its content may not be copied or emailed to multiple sites or posted to a listserv without the copyright holder's express written permission. However, users may print, download, or email articles for individual use. This abstract may be abridged. No warranty is given about the accuracy of the copy. Users should refer to the original published version of the material for the full abstract. (Copyright applies to all Abstracts.)

Copyright of Transactions of the Chinese Society of Agricultural Engineering is the property of Chinese Society of Agricultural Engineering and its content may not be copied or emailed to multiple sites or posted to a listserv without the copyright holder's express written permission. However, users may print, download, or email articles for individual use. This abstract may be abridged. No warranty is given about the accuracy of the copy. Users should refer to the original published version of the material for the full abstract. (Copyright applies to all Abstracts.)

Copyright of Transactions of the Chinese Society of Agricultural Engineering is the property of Chinese Society of Agricultural Engineering and its content may not be copied or emailed to multiple sites or posted to a listserv without the copyright holder's express written permission. However, users may print, download, or email articles for individual use. This abstract may be abridged. No warranty is given about the accuracy of the copy. Users should refer to the original published version of the material for the full abstract. (Copyright applies to all Abstracts.)

A large amount of maize stalks are produced each year, due to the maize is serving as one of the main grain crop in China. Maize straw retention to the field after chopped is widely used in most disposal approaches. However, the currently used single shaft maize stalk chopping and retention machine can not meet the quality requirements of stalk chopping, such as too long maize stalk after chopping, and the low chopping pass rate of maize stalk, particularly when the amount of maize stalk was large, while the scarf skin of maize stalk was toughness. The shortcoming of maize stalk chopping directly determines the next seeding production, seed germination, and final crop yield. This paper aims to propose a novel chopping method, and thereby to design a double rollers type stalk chopping and retention device with different rotation speed and dynamic double support. The device mainly included the shell, supporting plate, suspension device, gearbox, transmission, chopping and collecting blade, shaft of chopping, collecting blade, blade shaft of slide-cutting supporting blade, and slide-cutting supporting blade. In operation, the chopping and collecting blade with anticlockwise rotation, firstly collected and chopped maize stalk in the field; then the maize stalk was chopped in dynamic support of side-cutting supporting blade with same rotation direction of chopping and collecting blade. A mechanical analysis of maize stalk was conducted under the effect of chopping and collecting blade, as well the slide-cutting supporting blade. The results showed that the rotation speed of chopping and collecting blade, and the slide-cutting angle of slide-cutting supporting blade were the main factors to affect the stalk chopping process. Furthermore, a motion analysis of chopping and collecting blade was carried out, including two L-type blades and a straight blade. The results revealed that the bend angle and length along the cutting-edge of L-type blade, and the rotation speed of chopping and collecting blade, were the main factors to affect the unpicking rate of maize stalk, and chopping pass rate, when the number of chopping and collecting blade and operation speed of device were fixed. In the slide-cutting supporting blade, the cutting-edge curvilinear equation was in the form of the logarithmic spiral equation. Moreover, the range of slide-cutting angle was 30º-60º, due to the slide-cutting angle can be more than frictional angle between maize stalk and slide-cutting supporting blade, according to slide-cutting principle. Importantly, the cutting edge of slide-cutting supporting blade with sawtooth was designed to increase the fraction of maize stalk and slide-cutting supporting blade. Prior to accurately coordinating between chopping and collecting blade, and side-cutting supporting blade, the rotating speed range of chopping and collecting blade was determined as 1 150 -2 500 r/min, to ensure the high stalk chopping pass rate. The rotation speed of slide-cutting supporting blade was one half that of chopping and collecting blade, to guarantee the speed of backward spread of chopped maize stalk. Simultaneously, the chopping and collecting blade, and side-cutting supporting blade, both were double helix arrangement to reduce machinery vibration, while increase machinery life. One device was installed 20 chopping and collecting blades, and 40 slide-cutting supporting blades. A quadratic rotation orthogonal combination test was used in the field research, to obtain the optimal structure parameters, where the chopping pass rate of maize stalk was set as test index. Some test factors were selected, including the cutting-edge bend angle of L-type blade (20º ≤γ≤60º), and cutting-edge length of L-type blade (30 mm ≤k≤60 mm), rotation speed of chopping and collecting blade (1200 r/min≤nY≤2 000 r/min), and slide-cutting angle of slide-cutting supporting blade (30°≤τ≤60°). The Design-Expert 8.0.6 software was applied to analyze the double factors interaction on stalk chopping pass rate, thereby to obtain the regression model between test factors and index. The primary and secondary factors that affect the maize stalk chopping pass rate were the rotation speed of chopping and collecting blade, the length of cutting-edge bend angle, the cutting-edge length of L-type blade, and the slide-cutting angle. In multiple objective optimization, the optimum ranges can be achieved, including the cutting-edge bend angle of L-type blade (41º≤γ≤57.64º), the cutting-edge length of L-type blade (41.7 mm≤k≤51.71 mm), the rotation speed of chopping and collecting blade (1 657.37 r/min≤nY≤1 889.97 r/min), and slide-cutting angle of slide-cutting supporting blade (36.55º ≤τ≤ 49.08º). In the field test, the rotation speed of chopping and collecting blade, the length of cutting-edge bend angle, and cutting-edge length of L-type blade, and slide-cutting angle were set as 1700 r/min, 40º, 45mm, and 45º, respectively. The field test results demonstrated that the maize stalk chopping pass rate was 92.58% under the optimal working parameters, while the error with the predictive value (93.96%) was less than 5%, indicating the reliable optimization of parameters. The finding can offer a sound reference to improve the chopping quality of maize stalk in the chopping and retention machine. [ABSTRACT FROM AUTHOR]

Precision seeding technology is one of the important technologies to realize cost saving and efficiency increasing in large-scale production. Precision direct seeding of rice has gradually become the main research direction of rice light and simplified planting. The real-time sowing monitoring system has an important contribution to improve the sowing quality of direct seeding machine, and can provide important support for the research and development of sowing rate real-time adjustment, real-time reseeding and the seeding evaluation quality system of rice precision direct seeding machine. At present, the methods of seeding monitoring are photoelectric-based, image-based and capacitance-based. However, image processing technology requires special equipment with high cost, and cameras are easy to be interfered by external light. For the capacitance-based method, when multiple small seeds fall simultaneously, the monitoring performance is not accurate enough. In order to monitor the sowing rate of precision rice hill-drop drilling machine in real time, in this paper, the surface-type photoelectric sensor installed in the seeding tube is used as the main monitoring element to design the monitoring system of precision rice hill-drop drilling machine. According to the structure and working principle of seed metering device, the installation modes of photoelectric sensor and rotary encoder are determined. In this system, the seeds flow in the seeding tube is taken as the research object. When the rice seeds pass through the photoelectric sensor monitoring area, it will cause the change of infrared beam intensity, which will lead to the change of photoresist voltage. The pulse signal from the photoelectric sensor is used as the time sequence to capture the interruption source, and then the monitored time sequence of rice seeds flow is obtained. The time division node is obtained by the synchronous monitoring of the seed metering time series and the rotation speed of the seed metering device. Based on the two adjacent time dividing nodes, the detecting time window of the seeds number per hill is obtained, each time window corresponds to one hill. The pulse width time of the rice seeds output in the monitoring time window is analyzed to get the seeds number per hill. Compared and analyzed the manual statistical data with the monitoring system statistical data, the test results show that the rotation speed of the seed metering device has a great influence on the monitoring accuracy of the average seeds number per hill, the variation coefficient of the monitored value of the average seeds number per hill grows up with the increase of the rotation speed of the seed metering device. When the rotation speed of seed metering device is 25-65 r/min, the relative error of seeds number per hill is less than 7.99% for Nanjing 46 (short grain variety), the monitoring errors of the number of hills is less than 6.07%; the relative errors of seeds number per hill is less than 24.07% for Xiangyaxiangzhan (long grain variety), the monitoring errors of the number of hills is less than 5.66%. The test results show that sowing rate monitoring system is applicable to different varieties of seed and has good detection accuracy, which can provide reference for improving the operation quality of precision rice direct seeder. [ABSTRACT FROM AUTHOR]

Mechanical precision seed metering device is widely used in precision seeding technology because of its simple structure and uniform seed metering. Seed filling process is the key link of the whole operation process of seed metering device. The precision metering device is mainly divided into internal filling, side filling, external filling, and the combination of side filling and external filling according to the seed filling mode. In the operation process, the internal filling mode mainly completes the seeding operation through the process of type-hole filling and gravity clearing, and the seed motion parameters close to the type-hole directly affect the seeding quality of the machine. The rotary type-hole cotton precision seed metering device is a kind of mechanical precision seed metering device. In order to solve the problem of missing seed in the process of filling, the influence of the motion parameters of rotary type-hole cotton precision seed metering device on the filling performance by establishing the kinematic model of the seed filling process in this paper. Using the discrete element simulation software to analyze the speed change trend of cotton seed falling into the type-hole and the influence of seed wheel vibration frequency on seed group disturbance. Taking the vibration frequency of seed wheel, vibration offset angle of seed wheel and rotating speed of metering device as the test factors, and taking the qualified rate of seed spacing, replaying rate and missing rate as the test indexes, three factors and five levels of positive traffic rotation combined test are carried out to explore the influence of each factor on seed metering performance. Design expert 8.0.6 software is used to analyze the test results and optimize the regression model. Single factor simulation test results show that the instantaneous speed of cotton seed increases with the increase of the rotating speed of the seed wheel, the instantaneous speed of the cotton seed is less than that of the seed wheel when it is filled into the type-hole, the cotton seeds with lower relative speed have better filling effect. When the vibration frequency of the seed wheel is 7 Hz, the average value of the normal force of the seed group is the smallest, which is 0.75 N, at this time, the internal friction of the seed goup is the smallest, the cotton seed is easy to be taken by the type-hole, and the seed filling performance of the seed metering device is improved. The simulation results of quadratic regression general rotation combination show that when the rotating speed of the seed metering device is 12.59 r/min, the vibration offset angle of seed wheel is 8.06° and the vibration frequency of seed wheel is 6.08 Hz, the qualified rate of seed spacing reaches the maximum of 94.5%, and the leak seeding rate is 2.9%, the repaly rate is 3.3%. On this basis, the platform validation test was carried out with Xinluzao No.61 cotton seed as the test object. The test results showed that when the rotating speed of the seed metering device was 12 r/min, the maximum qualified rate of the seed spacing was 94.65%, the error between the rotating speed of the seed metering device and the simulation test is 5.4%, which verifies the accuracy of the simulation results. This study can provide a reference for the structural optimization of the key components of the rotary type-hole cotton precision metering device. [ABSTRACT FROM AUTHOR]

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

Agricultural flexible chassis (FC) is a kind of in-wheel motor driving electric vehicle applied for greenhouse. The FC is composed of 4 identical off-centered shaft mechanisms, which can be controlled independently. Through this kind of mechanism, the FC can achieve various motion types. However, it is difficult to maintain the linkage relationship between the 2 front off-centered shaft mechanisms when the FC is in front wheel steering motion, and hard to accomplish smoothly turning. In order to solve this problem, a coupling control strategy for linkage motion was proposed in this study. Firstly, the contour error of the 2 wheel steering angle was deduced based on the Ackermann steering geometry and the cross-coupling control principle. To reduce the contour error during steering, a fuzzy PID control algorithm was designed, which could realize parameters self-tuning. As the electromagnetic friction lock was controlled by pulse width modulation (PWM) signal, the duty cycle of the PWM signal had to be adjusted according to turning situation. Thus, a fuzzy logic method was then introduced to regulate the duty cycle. Namely, the PWM signal duty cycle can be in line with the steering wheel signal size and its change rate, and the motion of the electromagnetic friction lock can match the steering speed of the off-center shaft mechanism. In this way, the coupling control of the 2 front off-centered shaft mechanisms can be achieved. The control strategy was then verified through simulation based on MATLAB/Simulink. To further verify the effectiveness of the control strategy, the control program was loaded into the steering system hardware, and tests were carried out on hard surface road. According to the traditional vehicle steering test methods, step steering test, snake steering test and random steering test were conducted. The effects of front wheel steering under the steering angle allocation control method were compared with coupling control strategy. The simulation results demonstrated that the proposed control strategy was effective and feasible. The test results on hard surface road showed that the FC had a fast steering response in step steering test. The response time of step steering was 0.8s and overshoot was 1.3° under coupling control method during front wheel steering of the FC. The overshoot under allocation control was larger than coupling control and its fluctuation was notable. From the results of the snake steering and random steering, it was obviously that the steering angles of the left and the right front wheels had good tracking performance for their target angles, respectively. The opening and closing of electromagnetic friction lock can match the steering motion of the electric wheel well. The maximum and average following errors of 3 steering modes were less than those under the allocation control method. The maximum and average contour errors of the linkage motion were 1.2° and 0.6° for step steering, 1.1° and 0.6° for snake steering, as well as 1.0° and 0.5° for random steering, respectively. All these errors were also smaller than the allocation control. Under the coupling control, the maximum steering error between simulation and test was 2.2°, and the contour error trend of them was consistent. The simulation model was reasonable and effective. The contour errors of the allocation control in these 3 kinds of tests had more fluctuations and larger range of fluctuations than coupling control. The steering performance under coupling control strategy was obviously better than the allocation control method. The steering angles of the 2 front wheels had maintained Ackerman steering geometry well. The coupling linkage control strategy proposed in this paper has good effectiveness and feasibility. This research can provide references for steering control or other applications of the FC. [ABSTRACT FROM AUTHOR]

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

Plastic film has been widely used to mulch soil in croplands, but its recycling rate is less than 60%. Since natural degradation of plastic film is slow, accumulative use of plastic films has resulted in soil structure degradation and environment deterioration. Recycling the film residuals is hence mandatory. Manual picking is labor intensity and inefficient, and mechanical recycling is thus called. Most machines available on market are unable to separate the film residuals from straw and large soil particles during pick-up process. To alleviate this problem, we designed and tested an machine equipped with an improved cleaning system. We optimized the working parameters of the system in attempts to improve the residual recovery efficiency. Analysis of the structure of the cleaning system, its working principle and conditions, as well as the factors affecting the machine operation revealed that the most important parameters were the advancing speed of the machine, the speed of the film-conveyer, position of the pick-up drum and the speed of the secondary impurity-conveyer. We investigated the recovery rate of the film residuals, rate of separating the film residuals from the straw, and transport efficiency of the impurity, using the regression orthogonal combination tests with four five-level factors. The response surface of the testing results was analyzed using the design-expert software, and the relationship between each impacting factor and the testing index was also analyzed. The results showed that the main and secondary factors affecting the picking-up rate were position of the picking drum and the advancing speed of the machine, and that the factor affecting the separation rate mostly was the speed of film transportation followed by rotating speed of the impurity conveyer. The transport efficiency was affected mostly by the rotational speed of the impurity conveyer, followed by location of the pick-up drum, speed of the film-conveyer and advancing speed of the machine. The regression model was optimized with multiple objectives, and the optimal working parameters for the cleaning system are: Advancing speed of the machine and equipment: 1.26 m/s, speed of the film transporter: 1.55 m/s, position of the pick-up drum: -17 mm (taking the center of the hole in the supporter and the center of the picking-drum in the vertical direction as the origin, adjusting 17 mm to the forward direction of the machine), speed of the secondary impurity conveyer: 205 r/min. Calculated using these optimal parameters, the pick-up rate of the film residuals was 90.19%, the separation rate of the film residuals from the impurities was 92.21%, the impurity transport efficiency was 89.6%. We verified these against field experiments, and the results showed that the picking-up rate was 91.54%, the separation rate was 90.37%, and impurity transport efficiency was 88.4%. This paper offers references to improving quality of the cleaning system in plastic-film pick-up machine. [ABSTRACT FROM AUTHOR]

The generation of power shift tractor promotes the automatic driving of agricultural machinery to the direction of unmanned, and the automatic obstacle avoidance of agricultural machinery has become a key issue to be solved. Most of the existing obstacle avoidance path planning adopts the shortest tangent method, which has the advantages of fast and simple path generation and short track, but the curvature of the path curve is discontinuous and there are corner inflection points, which make the tractor front wheel angle suddenly change and affect the obstacle avoidance accuracy. In this paper, for the curvature discontinuity of the shortest tangent path curve, poor tracking control accuracy and low precision of agricultural machinery model, the third-order bezier curve optimization method was used to form a continuous smooth agricultural machine obstacle avoidance path. The optimized curve curvature was continuous and the obstacle avoidance path was smooth with no turning points, which was conducive to the control of agricultural machinery driving. The linear control model of agricultural machinery movement was established by chain control theory, and the PI controller was used for corner compensation to improve the accuracy of agricultural machinery obstacle avoidance. The simulation of the path tracking control method was completed. The simulation results showed that the heading error angle of the agricultural machinery was mostly in the range of - 0.06-0.06 rad, the lateral position error was less than 13 cm, and the front wheel steering angle changed gently with no significant mutation, indicating that the control method of the obstacle avoidance path control method had a high precision, and the agricultural machinery can drive according to the preset trajectory. The ploughing operation test was carried out, and the Dongfanghong LF954-C power shift tractor was used, which can automatically start, stop, shift, and implement the lifting operation of the farm. The tractor was equipped with the Beidou agricultural autopilot with the straight running accuracy of ±2.5 cm. Ultrasonic radar and image recognition technology were used to perceive obstacles in the working environment. The farm implement was a 250 cm wide plow. A haystack obstacle was set on the machine working path with a contour radius smaller than the minimum turning radius of the tractor. The results of the plowing operation test showed that the machine can automatically complete the straight-line driving, farm implement lifting, automatic obstacle avoidance, farm implement falling, and continuous straight-line operation. The obstacle avoidance accuracy of the bezier curve was 5.21 cm, and the tracking control effect of the curve path was well. The accuracy of the agricultural machine continuing to travel in a straight line after obstacle avoidance was 1.98 cm, which indicated that the path tracking control method can ensure the tractor straight-line automatic driving after obstacle avoidance. The above results showed that the obstacle avoidance path and control method showed good robustness and adaptability in uneven ploughing land and can meet the obstacle avoidance requirements of tractor operation. [ABSTRACT FROM AUTHOR]

Copyright of Transactions of the Chinese Society of Agricultural Engineering is the property of Chinese Society of Agricultural Engineering and its content may not be copied or emailed to multiple sites or posted to a listserv without the copyright holder's express written permission. However, users may print, download, or email articles for individual use. This abstract may be abridged. No warranty is given about the accuracy of the copy. Users should refer to the original published version of the material for the full abstract. (Copyright applies to all Abstracts.)

Copyright of Transactions of the Chinese Society of Agricultural Engineering is the property of Chinese Society of Agricultural Engineering and its content may not be copied or emailed to multiple sites or posted to a listserv without the copyright holder's express written permission. However, users may print, download, or email articles for individual use. This abstract may be abridged. No warranty is given about the accuracy of the copy. Users should refer to the original published version of the material for the full abstract. (Copyright applies to all Abstracts.)

Rice-wheat rotation area, with heavy clay soil texture, that it is wheat planting area accounts for more than 37% of the total wheat sowing area in China as one of the major grain production bases, and rice-wheat rotation is the main cropping pattern in this region. Meanwhile, because of the shortage crop stubble and more rainfall in autumn, which lead to serious wet damage during the tilling and seeding stage for this field. Currently, most of the existing no-tillage and less-tillage seeding equipment for wheat sowing in rice stubble areas were optimized and developed on the basis of traditional contact-type wheat seeding technology, which lead to adhesion and serious blockage phenomenon, as well as increasing of operating resistance and power consumption during working. Therefore, a innovative technical proposal of non-contact type pneumatic seeding technology that could avoid contacting between sowing parts and soil was introduced in this paper, which in order to solve the problems of soil adhesion, blockage, drag increment as well as poor sowing quality for wheat seeders under the condition of sticky heavy loam clay in rice-wheat rotation areas. Experiment that utilized a self-made platform for wheat pneumatic seeding was conducted, which could rip wheat seed into the soil condition of clean seed bed without straw and stubble mulching by high pressure accelerating airflow. During the pneumatic seeding experiment, keeping a certain pneumatic seeding height HG and incident angle α between the accelerating tube and topsoil surface, high-pressure gas was injected from the upper apex of the air nozzle and ejected from the bottom of it, which a stable high-speed airflow was formed in the accelerator tube (the length of the accelerator tube is 600 mm and the diameter is 10 mm). Then wheat seeds were put into the seed entrance and absorbed at a high speed under the negative air pressure of the ejector, during which the rubber sleeve could protect wheat seeds from damaging. After mixing with airflow, wheat seeds were accelerated by high-speed air flow in the accelerating tube. Finally, the wheat seeds flew out and ripped into the soil at a certain incident angle and high pneumatic seeding velocity. At the same time, high-speed photography technology was used to study the parameters of pneumatic seeding velocity, vertical velocity and pneumatic seeding depth under six levels (15°, 30°, 45°, 60°, 75°, 90°) of incident angles, and pneumatic seeding experiments under five different accelerating air pressures of 0.2 MPa, 0.4 MPa, 0.6 MPa, 0.8 MPa and 1 MPa for each incident angle were carried out respectively. Pneumatic seeding experimental results showed that: For pneumatic seeding in soil without straw and stubble mulching, when the incident angle increases continuously, wheat seeds can achieve higher vertical component of pneumatic seeding velocity deeper and pneumatic seeding depth at the same accelerating air pressures, the probability of horizontal slip and bounce of wheat seeds after touching soil show an decreasing trend, and pneumatic seeding depth has a positive correlation with pneumatic seeding velocity under each incident angle. Moreover, wheat seeds show various pneumatic seeding depth and soil impact effect without damage after pneumatic seeding. When the incident angles and the vertical component of pneumatic seeding velocity were more than 45° and 25 m/s respectively, wheat seeds can be completely ripped into the soil and the emergence rate is more than 86%. The best pneumatic seeding effect achieved as incident angle is 90°. In order to realize wheat vertical pneumatic seeding in field operation, the horizontal component of pneumatic seeding velocity should be equal to the operating speed of seeder and the vertical component of pneumatic seeding velocity should be greater than 25 m/s, which the seeder operating speed shows positively and negatively correlated with pneumatic seeding velocity and incident angle, respectively. The experimental results can provide basic data and technical support for the development of non-contact wheat seeding equipment in rice-wheat rotation area. [ABSTRACT FROM AUTHOR]

In order to solve the problems of high resistance and high power consumption of rotary tillage and land preparation, the rotary blade is studied based on theoretical analysis, simulation and field experiment in this paper. First, a wedge drag reduction rotary blade is designed based on the theoretical force model of cutting tools in mechanical soil dynamics. Second , the three-dimensional model of the national rotary blade and the wedge drag reduction rotary blade is established by using the Inventor software and the simulation experiment is carried on. The cutting soil model of 2 kinds of rotary blades is established by using HyperMesh software, and the material parameters, boundary constraints and working parameters are defined. On this basis, the soil cutting process, stress and cutting resistance are analyzed. It is proved that the wedge drag reduction rotary blade design is reasonable. In order to verify whether the wedge drag reduction rotary blade meets the strength requirement, the stress of the rotary blades is analyzed, and the cutting resistance of the national rotary blade and the wedge drag reduction rotary blade are compared. Third, field comparative experiments are carried out on national rotary blade and wedge drag reducing rotating blade with the evaluation indexes of torque, power consumption and soil breakage. The results show that the cutting resistance of the wedge drag reduction rotary blade is smaller than that of the national rotary blade; the maximum stress of the national rotary blade is 35.68 MPa and the maximum stress of the wedge drag reduction rotary blade is 29.49 MPa, which is less than that of the national rotary blade and far less than the yield strength of the material 430 MPa. On the premise of ensuring the strength of the blade body, the weight of the wedge drag reduction rotary blade is reduced by about 50 g, which is about 8.3% lower than that of the national rotary blade. The maximum cutting resistance of the national rotary blade is 530 N, the average cutting resistance is 375.5 N, and the maximum cutting resistance of the wedge drag reduction rotary blade is 510 N, the average cutting resistance is 335.5 N, the average cutting resistance of the wedge drag reduction rotary blade is 10.65% lower than that of the national rotary blade, which proves the feasibility of the wedge drag reduction rotary blade designed; The average torque of the wedge drag reduction rotary blade is 11.35% lower than that of the national rotary blade. In the working process of rotary blades, the average power consumption of the national rotary blade is 74.2 kW, the average power consumption of the wedge drag reduction rotary blade is 67.3 kW, and the average power consumption of the wedge drag reduction rotary blade is 9.29% lower than that of the national rotary blade. The average breaking rate of soil of the national rotary blade is 75%, and the average breaking rate of wedge drag reduction rotary blade is 79%, which is 4% higher than that of the national rotary blade; After continuous 33 hm2 tillage, rotary blades did not break, and the average wear of the national rotary blade is 98.5 g, the average wear of the wedge shaped drag reduction rotary blade is 97.3 g, the wear difference is 1.3%, and the wear degree is the same. The wedge drag reduction rotary blade can effectively solve the problems of high resistance and high power consumption of rotary blade, which is helpful to accelerate the development of arable land machinery, improve the mechanization level of cultivated land, and reduce the production cost of crops. [ABSTRACT FROM AUTHOR]

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

Copyright of Transactions of the Chinese Society of Agricultural Engineering is the property of Chinese Society of Agricultural Engineering and its content may not be copied or emailed to multiple sites or posted to a listserv without the copyright holder's express written permission. However, users may print, download, or email articles for individual use. This abstract may be abridged. No warranty is given about the accuracy of the copy. Users should refer to the original published version of the material for the full abstract. (Copyright applies to all Abstracts.)

Copyright of Transactions of the Chinese Society of Agricultural Engineering is the property of Chinese Society of Agricultural Engineering and its content may not be copied or emailed to multiple sites or posted to a listserv without the copyright holder's express written permission. However, users may print, download, or email articles for individual use. This abstract may be abridged. No warranty is given about the accuracy of the copy. Users should refer to the original published version of the material for the full abstract. (Copyright applies to all Abstracts.)

Copyright of Transactions of the Chinese Society of Agricultural Engineering is the property of Chinese Society of Agricultural Engineering and its content may not be copied or emailed to multiple sites or posted to a listserv without the copyright holder's express written permission. However, users may print, download, or email articles for individual use. This abstract may be abridged. No warranty is given about the accuracy of the copy. Users should refer to the original published version of the material for the full abstract. (Copyright applies to all Abstracts.)

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

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

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

Fruit and vegetable picking grippers are important technology to achieve rapid and labor-saving harvest. However, most of the existing fruit and vegetable picking grippers still use traditional rigid or underactuated grippers, which often cause fruits and vegetables damage by the heavy mass and lack of high-precision control, and have poor compliance in the operation process. In recent years, inspired by soft creature’s tentacles, soft robotic grippers have appeared and been used in robotics due to the emergence of soft robots. Soft robotic gripper, which is made of flexible material, is a new type of gripper for general purposes with grasping and holding capabilities enabled by a simple control scheme. Under the infinite degrees of freedom, the soft robotic gripper can change its shape and size corresponding to the load in a large range. These advantages overcome the defects of traditional fruit and vegetable picking robots, such as rigidity and poor adaptability. Moreover, soft robotic gripper is easy to manufacture and can be integrated with manual operation without any large-scale safe requirement. This paper gives a research on limitations of the traditional grippers and summarizes the characteristics of ideal picking grippers of fruit and vegetable. In addition, the concept of soft robotic grippers is introduced in detail, and the current development status about soft robotic grippers is described. The manuscript also summarizes the progress and superiority of soft robotic grippers in fruit and vegetable picking as well as strong adaptability to the environment. The characteristics of the soft robotic grippers driven by the common driving mode including pneumatic, cable, shape memory alloy and electroactive polymer mode have been analyzed in the process of fruit and vegetable grasping and picking. Compared with the rigid grippers, in addition to the simple control and mechanism, the soft robotic grippers have high-degree flexibility, adaptability and versatility. Based on the related work, the problems of modeling and control of fruit and vegetable picking devices have been discussed, and possible solutions of soft robotic grippers are also summarized by means of analysis and classification. We can choose the appropriate control methods according to the surface characteristics of picked fruits and vegetables. Finally, we conclude that multi-sensing, variable stiffness, multi-functional composite materials, as well as control strategies of fusion intelligence will be future development directions of fruit and vegetable picking grippers with the progress of micro-sensors and biomaterials. This research will provide theoretical and technical guidance for the development of fruit and vegetable picking grippers. It is expected that more fruit and vegetable picking operations could be carried out by soft robotic grippers, and the application will effectively reduce the damage rate of fruit and vegetable picking. As a new-generation operating device, the soft robotic grippers involve the development of materials, chemistry, machinery and other multidiscipline. Further studies are required to improve its design, controllability, manipulating methods, and so on. [ABSTRACT FROM AUTHOR]

Yellow silage corn stover is taken as a kind of important feedstuff for animal husbandry. Corn stover pickup balers are used to collect the stover and bundle it into straw bale in the harvest process of yellow silage corn stover. But in Northeast China, the soil has strong adhesiveness when it is in high moisture content. And when the moisture content is low, the soil disperses into fine particles which are easily carried in the miscellaneous branches of stover. It is a fleeting moment when stover is gathered and transported into baler. Soil adhered to stover and carried by the branches can’t be removed in this short process. As a result, high soil content reduces feed quality of yellow silage corn stover. In order to solve the problem of high soil content of yellow silage corn stover, the paper proposed to remove the soil adhered and included in stover by means of vibration. The soil removal mechanism of stover pickup baler by vibration was fitted on the bottom of the machine. It is connected between the pickup unit and the cutting and rubbing unit. Stover can be picked up and delivered to the vibrating conveying screen to remove the soil. Then, the stover would be robbed, cut and bundled. The operating principle of the test-bed was clarified through the design of the test-bed and analysis of high-speed camera. Collision between stover and screen and internal friction of stover could release soil in the stover. Stover thickness, vibration time, vibration amplitude and vibration frequency were 4 influencing factors acting on performance of soil removal in the tests. Taking the soil removal rate and the stover loss rate as indices, single factor experiments were conducted to determine the value range of each parameter on the whole-plant stover (long stover) and chopped stover (short stover) on the ground respectively. The result showed that the soil removal rate and the stover loss rate increased with the increase of vibration time, vibration amplitude, and vibration frequency. But the soil removal rate and the stover loss rate dropped with the increase of stover thickness. It was given that the focus ranges of values of all parameters were vibration time from 10 to 14 s, vibration amplitude from 10 to 20 mm, vibration frequency from 4 to 6 Hz for long stover, and vibration time from 12 to 16 s, vibration amplitude from 10 to 20 mm, vibration frequency from 4 to 6 Hz for short stover. Through the three-factor orthogonal polynomial regression test, the author found the change laws of the soil removal rate and the stover loss rate determined by vibration frequency, vibration amplitude and vibration time. Four regression equations were induced according to experiment and analysis above. Then, a comprehensive index indicating soil removal rate and stover loss rate toward the optimum synchronously was made to evaluate the effect of soil removal. By analyzing the regression equations and the comprehensive index, an optimal solution was obtained. The optimal combination of soil removal from corn stover by vibration was as follows: For the long stover, the vibration amplitude was 15 mm, the vibration frequency was 4.5 Hz, and the vibration time was 14 s; for the short stover, the vibration amplitude was 20 mm, the vibration frequency was 4 Hz, and the vibration time was 12 s. Verification tests were conducted on the test-bed to verify the results above. Through calculating with the regression equations, the soil removal rate and the stover loss rate of long stover were 4.71% and 0.34%, respectively, and for short stover, the calculating results were 4.44% and 1.42% respectively. In the verification tests, the results were 4.80% and 0.38% for long stover and 4.72% and 1.53% for short stover. By comparing the simulated and the experimental result, it was found that the relative errors of the soil removal rate and the stover loss rate were acceptable. It was believed that the result of mathematical model matched the test result well. This study provides references not only for removing soil from stover by vibration, but also for the improvement of corn stover pickup baler design. [ABSTRACT FROM AUTHOR]

Electromagnetic friction lock is an important part of agricultural flexible chassis. When it is closed, flexible chassis will be driven forward, and will steer when opened. In engineering practice, flexible chassis needs to steer while advancing. Therefore, there is conflict between the opening and the closing of electromagnetic friction lock when the 2 motions need to be carried out at the same time. In order to solve this problem, a method based on pulse width modulation (PWM) technology was proposed to control the opening and the closing in this paper. The opening was achieved during low level of PWM wave, while the closing was achieved during high level of PWM wave. In this way, flexible chassis can be driven forward during steering. Further, some experiments were conducted to investigate the influences of PWM frequency and duty cycle on driving and steering performance of flexible chassis. Firstly, based on off-centered steering shaft test bench, two-factor experiments were performed to study the effects of frequency and duty cycle on pulse tightening torque, using a traction device which was composed of a lever and a force sensor. Then tightening torque was calculated from force sensor measurement and arm length value. Secondly, for the purpose of examining the characteristics of time-sharing steering related with the influence of frequency, duty cycle and initial speed of electric wheel, a quadratic orthogonal regression experiment was conducted on off-centered steering shaft test bench. In this test, steering motion was simulated by controlling the speed of horizontal turntable of test bench and electric wheel. Average steering angular velocity was taken as the evaluating indicator of steering characteristics, and it can be attained by measuring the steering time due to the same target angle of steering. Afterwards, results of two-factor experiment showed that frequency, duty cycle and their interaction had highly significant influences on tightening torque (P<0.01). In the process of rotation, the curve of tightening torque showed a pulse change, and the rotation angle of steering arm displayed a step-like rise. When frequency was 4-24 Hz and duty cycle was 20%-80%, the tightening torque of off-centered steering shaft varied from 6.822 to 40.046 N·m. The tightening torque declined as frequency increased when duty cycle was 20%-80% except a few duty cycles. Meanwhile, for the frequency ranging from 4 to 24 Hz, tightening torque rose with the increasing of duty cycle. Then regression analysis was carried out according to the results and a regression model was presented. Results of quadratic orthogonal regression experiment illustrated that the average steering angular velocity was remarkably influenced by the PWM frequency, duty cycle and their interaction as well as the initial rotation speed of in-wheel motor (IWM) (P<0.05). With the increment of duty cycle and the initial speed of IWM, the steering average angular velocity decreased rapidly but slowly increased with the increasing of frequency. When the frequency was 4-24 Hz and the duty cycle was 20%-80%, and the initial speed of IWM was 30-120 r/min, the average steering angular velocity varied from 0 to 0.514 rad/s. Therefore, through changing the PWM frequency, duty cycle and the initial speed of IWM, the process of pulse-driven and time-sharing steering for flexible chassis is able to be well achieved, and these results can provide a basis for cooperative control of flexible chassis [ABSTRACT FROM AUTHOR]

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In order to solve the difficulties of sowing for foxtail millet and improve the low germination rate of millet after sowing in dry land of North China, we firstly studied the agricultural requirements of precision drill of millet without thinning out seedlings. We prepared a mixed suspension of foxtail millet using water and agricultural super absorbent polymers, because the agricultural super absorbent polymers can promote crop growth. We did some experiments to find suitable super absorbent polymers and the optimal proportion for mixed suspension according to the requirement of fluid seeding. At the same time we designed a kind of seed metering device by small-amount liquid for foxtail millet. This paper determined the number of rollers, dimension parameter and combination form of tube. It also expounded sucking seeds, delivering seeds and metering seeds of this seed metering device. This device consists of seed box, delivery pump, pump tube, three-way tube, long bent tube, end drainage tube and short bent tube. The function of delivery pump is providing power for the seed metering device, the function of three-way tube is dividing and combining the mixed suspension, the long bent tube or the short bent tube can improve the uniformity of seeding, and the end drainage tube can decrease every drop volume of mixed suspension to ensure that every drop has 2-3 seeds. Because the delivery pump has impulsive motion, we greatly reduced the impulsive motion of this device by using 6 rollers of .delivery pump and designing the structural style of tube, which has long bent tube, short bent tube, three-way tube and end drainage tube. The length of long bent tube is 100 mm, and the length of short bent tube is 74.4 mm. We also chose the material and diameter of tube. The material of tube is silica gel, which has the advantages of good elasticity and long service life. The diameter of pump tube, long bent tube, short bent tube and end drainage tube is 4.8, 4, 4 and 4 mm, respectively. Finally we designed and conducted the experiments of the uniformity and steadiness for mixed suspension of millet, and the variability coefficient of seed number was adopted. And we performed the performance tests with 4 indices adopted, including the percentage of damaged seeds, qualified rate of hill distance, qualified rate of seed number per hill, and rate of no seed hill for seed metering device in laboratory. We also carried out the field experiment of sowing with 3 indices including the qualified rate of hill distance, qualified rate of plant number per hill and seedling emergence rate for this device. The results showed that the suitable agricultural super absorbent polymer was Anxin for preparing the mixed suspension of foxtail millet, and the quality ratio of super absorbent polymers, grain of millet seed and water was 1.1 : 10 : 200 in mixed suspension; the variability coefficient of seed number was 9.8% in this mixed suspension, and was 9.7%-10.4% within 5 hours, and the seeds in mixed suspension had no obvious settlement. The percentage of damaged seeds was less than 0.01%, the qualified rate of hill distance was greater than 86%, the qualified rate of seed number per hill was greater than 75%, and the rate of no seed hill was less than 4% in laboratory test. The qualified rate of hill distance was greater than 77%, the qualified rate of plant number per hill was greater than 74%, and the seedling emergence rate was greater than 87% in field experiment of sowing. The results provide a theoretical reference for the design and analysis of seed metering device by small-amount liquid for small grain seeds. [ABSTRACT FROM AUTHOR]

With the development of precision agriculture technology, agricultural robots which improve efficiency and save labors for agriculture are used for information collection in field, instead of the traditional manual recording and observation. At home and abroad, most of navigation researches of walking platform meet the requirement of tracking precision. However, they mainly use RTK-DGPS (real time kinematics - differential GPS) positioning system, and it is so expensive that it restricts the large-scale promotion of automatic navigation of walking platform to some extent. Consequently, aiming at uniform speed and line tracking problem in complex field environment for information collection platform, a motion controller with transverse correction and longitudinal constant speed control was designed. This paper constructed motion control hardware system using information collection platform as the carrier, STM32F4 32-bit microcontroller was as the control center and multiple sensors were used for obtaining the vehicle status information, including 3D (three-dimensional) electronic compass, low precision Beidou module, rotary encoder and angle sensor. The working principle of the controller could be described as follows: Firstly, 2 points were chosen to determine tracking path. Then, the current position information and the heading angle of the platform in the field were obtained by Beidou module and electronic compass. They were used to calculate the lateral offset and course deviation, which were 2 inputs of fuzzy controller, and the output of fuzzy controller was got through designing control algorithm to control steering angle of front wheel. It ensured information collection platform to always track the goal line. Meanwhile, speed information of the platform was measured by the rotary encoder, which was the input of PID (proportion, integral, derivative) controller. It realized constant speed walking through speed feedback regulation. On the other hand, in order to improve the positioning precision of Beidou module, a method was presented, which was that 3 Beidou modules of low precision were placed in the way of an equilateral triangle, and average positioning data of 3 Beidou modules were obtained at the same time. Then, they were used as the final location data of the center point of the equilateral triangle, which took advantage of compensatory principle of random error to reduce the random error and improve the positioning precision of the Beidou module. By this way, the average positioning precision of the Beidou receiving module was increased from 2.06 to 1.50 m, and the dynamic positioning precision was improved to within 0.78 m. The speed tracking experiment was carried out in the field of Modern Agricultural Science and Technology Experiment Site of Huazhong Agricultural University. The result showed that the control system could work steadily when the vehicle ran at the speed of 0.4 m/s; Proportion coefficient was 100, the differential coefficient was 40 and the integral coefficient was 50. The adjustment time was less than 3 s and the maximum error of speed was less than 7%. When running at the same speed, the initial lateral offset was set to 1.4, 2.0 and 2.5 m, the time required for stable tracking was 11, 15 and 25 s, respectively, and the maximum linear deviation after stabilization was all less than 0.31 m. The research of motion controller on information collection platform not only promotes acquisition ability of field information but also provides technical support for the efficient and intelligent operation of information collection platform in field. At the same time, it offers the possibility of greatly reducing cost in linear tracking, which is of benefit to the promotion of precision agriculture. [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]

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]

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]

Copyright of Transactions of the Chinese Society of Agricultural Engineering is the property of Chinese Society of Agricultural Engineering and its content may not be copied or emailed to multiple sites or posted to a listserv without the copyright holder's express written permission. However, users may print, download, or email articles for individual use. This abstract may be abridged. No warranty is given about the accuracy of the copy. Users should refer to the original published version of the material for the full abstract. (Copyright applies to all Abstracts.)

Copyright of Transactions of the Chinese Society of Agricultural Engineering is the property of Chinese Society of Agricultural Engineering and its content may not be copied or emailed to multiple sites or posted to a listserv without the copyright holder's express written permission. However, users may print, download, or email articles for individual use. This abstract may be abridged. No warranty is given about the accuracy of the copy. Users should refer to the original published version of the material for the full abstract. (Copyright applies to all Abstracts.)

Copyright of Transactions of the Chinese Society of Agricultural Engineering is the property of Chinese Society of Agricultural Engineering and its content may not be copied or emailed to multiple sites or posted to a listserv without the copyright holder's express written permission. However, users may print, download, or email articles for individual use. This abstract may be abridged. No warranty is given about the accuracy of the copy. Users should refer to the original published version of the material for the full abstract. (Copyright applies to all Abstracts.)

Copyright of Transactions of the Chinese Society of Agricultural Engineering is the property of Chinese Society of Agricultural Engineering and its content may not be copied or emailed to multiple sites or posted to a listserv without the copyright holder's express written permission. However, users may print, download, or email articles for individual use. This abstract may be abridged. No warranty is given about the accuracy of the copy. Users should refer to the original published version of the material for the full abstract. (Copyright applies to all Abstracts.)

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]