Abstract:Mechanized seeding is an important part of agricultural mechanization. The planter mainly transports seeds from the seedbox to the seedbed obeyed a reasonable agronomy position, which would create a suitable environment and uniform space for seed germination and plant growth of individual and group. For this purpose, the precision planter applied precision seeding technology and reposeful seed migration technology to guarantee the seed placed in the reasonable seedbed position by singulating the seed orderly from seedbox and maintaining the singulated state to delivery to the seedbed. The seed migration process was a process of organizing multiple links in series. The seed guiding step was a connecting link between the preceding step of seed discharging from the seed metering device and the following step of settling in the seedbed, which affected the orderly state of seeds in the presequence process and determined the uniform distribution of subsequent seeds in the seedbed. The research of seed guiding technology and the device of the planter was reviewed. According to the concept of object degree of freedom constraint, the seed guiding was generalized into three types: seed unconstrained, seed underconstrained, and seed fullyconstrained. The seed movement constraints, technical characteristics, and applicable objects of the three technical principles and devices were analyzed systematically. Combining the research progress of domestic and foreign technical equipment and the technical requirements of mechanized seeding, the development of seed guiding technology and device was discussed. The research provided a reference for the research of seed guiding technology and the innovative design of seed guiding devices.

Abstract:Picking trajectory planning is one of the important research aspects of apple picking manipulator. The unstructured natural environment leads to low training efficiency for picking trajectory planning based on deep reinforcement learning. A deep deterministic policy gradient algorithm (DDPG) based on a stepwise migration strategy was proposed for apple picking trajectory planning. Firstly, a progressive spatially constrained stepwise training strategy based on DDPG was put forward to solve the problem of hard converging in natural environments. Secondly, the transfer learning idea was utilized to migrate the strategies obtained from the obstaclefree scenario to the simple obstacle scenario, from the simple obstacle scenario to the hybrid obstacle scenario, to accelerate the training process in an obstacle scenario from prior strategies and guide the obstacle avoidance trajectory planning of the apple picking manipulator. Finally, the simulation experiments on the multidegreeoffreedom apple picking manipulator for picking trajectory planning were carried out, and the results showed that the stepwise migration strategy can improve the training efficiency and network performance of the DDPG algorithm. It was validated that the trajectory planning method for apple picking manipulator based on stepwise migration strategy was feasible. 

Abstract:According to the existing problems of no/minimumtill wheat seeding in maize straw covered field in doublecropping system area in the NorthChina Plain, such as residue blockage, low cleanness of seedbed, a strip tillage interrow residue sidethrowing device for antiblocking and seedbedcleaning was developed. The blade tilt angle, tilt line angle and rotary radius were identified as the key parameters influencing seedbed cleaning in the straw throwing process during seeding operation. Through BoxBehnken central composite rotatable design experiment conducted by discrete element method (DEM) simulation, the optimal parameter of blade tilt angle was 25°, and tilt line angle was 30°, rotary radius was 250mm, when torque requirement was 47.2N·m, seedbed cleaning index was 80.5%, and soil throwing index was 15.8%. An seeding and fertilizing opener was designed with a fixed blade in the front which could coordinate with the rotating blade to recut residues for antiblocking; a Vtype board for soil guidance was designed with the angle of 130° which could rebound soil return to seedbed; and an antitwinning board was designed which could increase rotor radius for antiresidue twinning. Field experiments showed that the seedbedcleaning and antiblocking device had a good antiblocking performance, its seedbed cleaning rate was 82.7%, and torque requirement was 2982N·m. The seeding and fertilizing quality satisfied the national and standard agronomy requirement.

Abstract:Aiming at the problems of large surface straw coverage after mechanical harvesting of corn and returning straw to the field and surface soil mixed with straw after rotary tillage and the impact on subsequent seeding quality, combining the planting patterns and agronomic requirements of the wheat and maize for double cropping area in Huang-Huai-Hai region, a telescopic finger stalk burying device was designed based on commonly used rotary tillers. The device was mainly composed of a rotary tiller roller, a fence and a stalk tooth equipped with an eccentric telescopic finger set. The eccentric telescopic finger group first contacted the straw and then threw the straw close at a low speed. After the rotary cutter touched the soil that was cleared of the straw and threw the soil far at high speed and covered the straw, then the separate burial “the straw was under the soil” was achieved. The theoretical analysis of the motion of rotary tiller and telescopic finger in the straw burial device determined the relationship between the speed of the rotary tiller. Besides, the telescopic finger and the structure and parameter design of key components such as the eccentric telescopic finger group, the fence and the stalk teeth were completed. By using the multibody dynamics RecurDyn software to track the motion trajectories of the end points of rotary cultivator, telescopic finger and pressing stalk teeth and analyze the speed and angular velocity motion rules of the three end points, it was found that the motion laws were consistent with the theoretical analysis. Field comparison tests were performed on the straw burial device and the conventional rotary cultivating device, and the straw burial rate of the surface below 50 mm was measured. The results showed that the burial rate of the straw burial device was 83.25%, which was 10.05 percentage points higher than that of the conventional rotary cultivating device. 

Abstract:Arch blocking is an important factor that affects the stability of fertilizer apparatus performance. It is of great significance to analyze the mechanism of arching, anticlogging and arch breaking mechanism of the fertilizer discharge to improve the performance of the fertilizer discharge and the quality of fertilizing. In order to further explore the mechanism of anticlogging and arch breaking by spiral cone centrifugal fertilizer apparatus and provide theoretical basis for later optimization, the theoretical analysis and simulation tests of the designed spiral disturbance cone centrifugal centralized chemical fertilizer apparatus were conducted to explore the mechanism of anticlogging and arch breaking by spiral cone centrifugal fertilizer apparatus. And the anticlogging performance of the fertilizer apparatus was further tested by highspeed photographic test and a bench test. The movement model of granular fertilizers during the process of fertilizer removal by the designed spiral cone centrifugal fertilizer apparatus was constructed and the mechanism of disturbance anticlogging and arch breaking was analyzed. The positive effects of spiral disturbing blades on anticlogging and arch breaking and the feasibility of fertilizer apparatus disturbance anticlogging were clarified. By using the EDEM discrete element simulation software, the effects of the fertilizer apparatus with and without the spiral disturbance cup on the movement of the fertilizer were simulated. Spiral blades can provide rolling disturbance for the granular fertilizer at the junction of the fertilizer box outlet and the fertilizer apparatus, at the same time, increasing the downward movement speed of the granular fertilizer can prevent arching and clogging at this location. The highspeed photographic test showed that the granular fertilizer at the junction of the fertilizer box outlet and the fertilizer apparatus with a spiral disturbance cup was moved downward and in the same direction as the speed of the cambered cone disk. The process of granular fertilizer movement was smooth and there was no problem of fault falling. The granular fertilizer at the connection between the fertilizer apparatus without a spiral disturbance cup and the fertilizer box outlet made a slow downward movement, and the problem of fault falling during the movement of granular fertilizer. The bench test showed that when the rotation speed of the cambered cone disk was the same, the coefficient of variation of fertilizing amount stability of the spiral disturbance cup fertilizer apparatus was lower than that of the nonspiral disturbance cup of the fertilizer apparatus, and the coefficient of variation of fertilizing amount stability of two types of fertilizer apparatus was decreased with the increase of cambered cone disk rotating speed. When the rotation speed of the cambered cone disk was low, the coefficient of fertilizing frequency stability in the same row of the nonspiral disturbance cup fertilizer apparatus was lower than that of the spiral disturbance cup of the fertilizer apparatus. With the increase of the rotating speed of the cambered cone disk, the coefficient of fertilizing frequency stability in the same row of the fertilizer apparatus with and without the spiral disturbance cup were increased. When the speed was the same, the coefficient of fertilizing frequency stability in the same row of the spiral disturbance cup fertilizer apparatus was higher than that of the nonspiral disturbance cup of the fertilizer apparatus. The coefficient of variation of fertilizing amount stability of the spiral disturbance cup fertilizer apparatus was above 96%, the variation curve of coefficient of variation of fertilizing amount stability was not more than 5.57%, which can fully meet the quality requirements for field discharge of fertilizer.

Abstract:Aiming at the situation of pesticide residues and less spraying under the conventional field quantitative spraying method, at the same time, in order to improve the timeliness of the existing variable spray control system and solve the lag of fuzzy decisionmaking, the BP neural network PID variable spray system was designed. Based on the multisensor realtime monitoring of speed, flow rate and pressure, the system used neural network selflearning ability to modify PID parameters toprecisely control the return flow of the liquid. It solved the technical problems such as large overshoot, large steadystate error and long response time in the existing variable application control algorithm, and realized the purpose of constant application amount per unit area in the field. In order to verify the superiority of the system algorithm in accurate variable application, the conventional PID, fuzzy PID and neural network control mode were modeled and simulated under the Simulink platform. Through comparison, it can be seen that the neural network PID control was superior to the other two control modes in terms of rising time, overshoot and steadystate error. The field experiment showed that the standard deviation of droplet deposition number was less than 1.4 per square centimetre, the coefficient of variation of longitudinal uniformity was less than 6%, and when the speed varied randomly in the range of 4~11km/h, the average adjustment time of the system was 0.72s, the average overshoot was 2.1%, and the difference between the dosage and the setting was 1.3%. 

Abstract:Different from traditional cultivation techniques of sowing in lines for wheat, precision seeding technology ensures the most reasonable distribution of wheat seeds in the field through precisely controlling seeding quantity and uniformity. Precision seeding technology can ensure the balance of nutrition in the growth process of wheat and achieve high quality and yield. The main component that affects the sowing precision of wheat seeder is seed metering device. The uniformity and stability of sowing are affected due to the pulsating of seed arrangement at low speed or small amount of sowing. However, in high speed operation, the diameter of the outer groove wheel seed metering device is small, when the speed is increased, the seed filling rate would be reduced, and the seed damage rate would be increased, it is difficult to achieve the goal of precision seeding of wheat. In order to realize the wheat single grain seeding technology, reasonable allocation of row spacing for wheat sowing, and improve the sowing quality of wheat seeder, a kind of differentspeed single grain seedmetering device with seedfilling groove for wheat was designed, and a 7.5cm row spacing narrow row wheat seeder was produced, the structure of “one seedmetering device with two seed rows” was realized, double row single grain sowing was realized, it provided technical support for close row spacing and uniform seed spacing. The design of the differential filling groove single grain seedmetering device with seedfilling groove for wheat was completed. EDEM discrete element software and Design-Expert 8.0.6 software were used to carry out simulation tests on the seed device and optimize the parameters of the differential filling groove single grain wheat seed device. A single factor experiment was completed by using EDEM discrete element software, it showed that the relative motion between the two sides alternate seedfilling and rotating seed wheel and stationary curved baffle was better for the seeding performance, the qualified rate was higher, which was 77.58%. The orthogonal experiment of the effect of the length, width and height of the seedfilling groove on the seeding performance was completed by using EDEM discrete element software, the simulation results showed that when the length between seed groove baffles was 8.00mm, the width of seed groove was 6.00mm, the height of seed groove was 5.00mm, the optimal results can be obtained. Based on these studies, the orthogonal combination test of multiple quadratic regression rotation was carried out on the basis of rotational speed, width of filling groove and raised slope angle of stationary curved baffle, then the DesignExpert 8.0.6 software was applied to analyze the test data, the relationship between the regression model and the influence of factors on indicators was obtained, the factors influencing the qualified rate of seeding were determined, the importance descending order was that rotational speed, width of filling groove and raised slope angle of stationary curved baffle, and the pair wise interaction cannot be ignored, the important factors influencing the variation coefficient of seeding uniformity, in order of importance, were the width of filling groove, rotational speed and raised slope angle of stationary curved baffle. Multiobjective parameter optimization was carried out based on regression model, the results showed that when the rotational speed was 1r/s, the width of filling groove was 6mm, and the raised slope angle of stationary curved baffle was 42.68°, it was predicted that the qualified rate of the seeding was 76.73%, and the variation coefficient of the seeding uniformity was 28.23%. The sample of seed metering device was made. Then some bench tests were carried out to verify the results, the results of bench tests showed that when the rotation speed was 1r/s, the qualified rate was 81.67%, the reseeding rate was 12.50%, the miss seeding rate was 5.83%, and the variation coefficient of the seed uniformity was 32.32%. The results were consistent with the simulation results. Field experiments were carried out on the wheat seeder trialproduced by using the differential filling groove single grain seedmetering device for wheat. The test results were consistent with the simulation test and the bench test results: the qualification rate of grain spacing was 82.50%, the replay rate was 9.17% and the missed replay rate was 8.33%, the mean value of the variation of sowing uniformity was 30.12%, which met and exceeded the national standards. 

Abstract:In order to improve the mechanization and automation level and accuracy of the soybean plot test, aiming at the bottleneck problem of soybean plot seeder cleaning and replacing technology, a kind of threeleaf type airsuction seed meter with automatic clear and replace seeds features for soybean plot test was designed. The motor was used as the power source to drive the gear seed plate and the threeleaf auxiliary seed filling and cleaning and replacing mechanism to quickly complete the nonstop seed cleaning, seed replacing and seed filling between neighboring plot. The basic structure and working principle of the seed meter were described, and key components were theoretically analyzed to determine the structural parameters based on the requirements of the breeding test. Combined with the requirements of breeding test, the structural parameters were determined through theoretical analysis of key components with the spatial analysis principle of TRIZ theory. The EDEM virtual simulation of the threeleaf auxiliary seed filling and cleaning and replacing mechanism was performed to analyze the auxiliary seed filling process and determine the blade inclination angle of the best auxiliary seed filling effect. According to the agronomic requirements of community breeding, a threefactor fivelevel quadratic orthogonal rotation center combination test was carried out, and the working speed, vacuum degree, and cleaning and replacing seed time were taken as test factors, and the eligibility index, replay index, missed index, and cleaning and replacing distance were selected as the test indicators. The result showed that when the optimal parameter combination was as follows: working speed was 5.3km/h, vacuum degree was 4.6kPa, and cleaning and replacing seed time was 0.3s, the eligibility index was 95.29%, replay index was 3.29%,missed index was 1.42%, and the cleaning and replacing distance was 554.6mm, which met the sowing requirements of soybean plot test.

Abstract:Quinoa as an emerging healthy food of rich nutrition has developed rapidly in recent years, but there is little research about the farming equipment of quinoa. Considering the shortage of research on dedicated sowing machine of quinoa in China, a film mulch precision quinoa seed sowing machine was developed. Based on the planting requirements of filmcovering precision quinoa, the drip irrigation pipes were buried in the trench (45mm wide and 20mm deep) between rows dug by the obtuse furrow opener. A layer of film was laid by the adaptive profiling film covering device on the surface flattened by the leveling device. A wingspoon seed storage tank was designed with specified structure and sizes of the spoon, side holes and seed chamber. Six drumtype hole sowing devices (with the radius of the seed metering device as 210mm) were used to dig holes and sow seeds through the film. The whole precision sowing process was completed by covering rows with soil conveyed via the earthing roller. With a white variety of quinoa “Long Quinoa No.1” as the test object, using orthogonal test method of three factors and four levels, the influence of operating speed, length of the seed chamber and seed depth on the seeding result was studied. The result indicated that the factors for the qualification of the sowing machine rank from top to down were operating speed, the length of the seed chamber and seed depth. By optimization, when the moving speed of the machine was 1.0m/s, the length of the side hole was 10mm and the seed depth was 140mm, the machine achieved its best performance. Specifically, the machine had a qualified rate (2~4 seeds per hole) of 85.4%, empty rate (no seed) of 1.7%, shortage rate (less than 2 seeds per hole) of 52% and repetition rate (over 4 seeds per hole) of 9.4% with rate of qualified depth of 88.1%. All these indicators either matched or exceeded the design requirements and related standards, perfectly in line with the growing requirements of quinoa. The research result can provide theoretical reference for film mulch precision quinoa sowing and promote the mechanization of growing quinoa. 

Abstract:Rapeseed is the most important oil crops in China. Rapeseed seedling transplantation is a chief cultivation pattern in the crop rotation area of rice and rapeseed. The existing transplanter took the soil mobility as a prerequisite for transplanting, which was not suitable for the sticky soil of rice stubble field. In addition, the working efficiency of transplanter was low. In order to improve the present situation of rapeseed mechanized transplanting, a 2ZY-6 type rapeseed carpet seedling transplanter which could finish ditching, transplanting and compacting all at once was designed with the reference principle of the rice transplanter. The efficiency of the rapeseed carpet seedling transplanter could reach up to 10 times higher than that of a traditional rapeseed transplanter. The rapeseed carpet seedling transplanter got rid of the limitation of soil mobility and had strong ability to adapt the soil environment of paddy stubble field. Rapeseed carpet seedling transplanter consisted of a furrow opener, seedling feeder mechanism, planting mechanism and compacting mechanism. The furrow opener adopted the design of corrugated disc. The stubble breaking ability was strong and the furrow type was stable which was beneficial to the subsequent planting of seedlings into the gap. The mechanical hydraulic copying mechanism was designed to control the planting depth under the condition of uneven soil. The Vshaped compacting mechanism was designed, and the suppressing wheel which adopted the V type symmetrically to arrange through a longitudinal deflection angle was used to cut the soil at the sharp angle and push the soil at side direction. The soil on both sides of the seedling ditch was squeezed around the seedling through the suppressing wheel, and the seedlings were compacted and kept upright. At the same time, the key components and parameters of the planting system were optimized according to the agronomic requirements of rapeseed transplanting, and the requirements of large area and the low number of cutting block and picking seedling of rapeseed carpet seedling were realized. The performance test of the rapeseed carpet seedling transplanter was carried out under the paddy soil and dry stubble soil. The test results showed that the transplanting effect was outstanding when the moisture content of paddy soil was 25%~30%, and the average transplanting qualified rate was up to 85.66%. The best transplanting quality was obtained in dry stubble field when the moisture content of dry stubble soil was 17.6%~26.8%, and the highest transplanting qualified rate was 87.01%. The transplanting speed of paddy soil should be kept within 1.15m/s, and the transplanting speed of dry stubble soil should be kept within 0.8~1.2m/s, which can directly satisfy the requirements of rapeseed transplanting agronomy. This study provided a reference for users to use rapeseed carpet seedling transplanter and select suitable transplanting conditions. 

Abstract:The shape of the work trajectory and the pose requirements of the transplanting arm in a specific position are the primary problems to be considered in the design process of the transplanting mechanism. A noncircular gear planetary gear train transplanting mechanism based on approximate multipose was presented in order to obtain multiple desired positions and take into account the specific shape of the work trajectory. The information matrices of eight expected poses were transformed into threedimensional space by quaternion using kinematics mapping theory, and the general solution space was expanded by introducing eigenvectors after the singular value decomposition of the matrix. A fourbar mechanism was formed by selecting two sets of suitable twobar groups, whose coupler trajectory can approximately go through all the prescribed poses. The transmission ratio of noncircular gear was solved based on the kinematic characteristics of the selected twobar group. Moreover, after establishing the circurity function and determining the design parameters, the shape of the noncircular gears was optimized by using the genetic algorithm. Finally, the prototype of the transplanting mechanism was manufactured for the primary test. A testing result that had an identical shape and operating poses with that of theoretical calculation was obtained, as well as the qualified picking success rate, which effectively verified the correctness of the motion synthesis and design method. This method can be used for reference in the design of transplanting mechanism with multipose requirement.

Abstract:Peanut seedlings has many advantages as husbandry forage, such as rich nutrition, soft texture and low price. However, residual film on the harvested peanut seedlings that mulching cultivated would seriously affect the digestive system functions of livestock and reduce the feed utilization value of peanut seedlings. Therefore, it’s an urgent issue to carry out the research on removing the residual film from peanut seedlings. There are significantly differences on the components and suspension velocities of mixture materials that shredded by peanut seedlings shredding and residual film sucking machine, which make it difficult to separate residual film out from peanut seedlings. The suspension velocities of shredded materials are the basic characteristics during the research of improved design and parameters optimization for the device of separate residual film out from peanut seedlings. In view of the outstanding problems at present, for example, it’s hard to separate residual film form peanut seedlings and the materials loss rate is higher than that was expected. The suspension velocity measurement experiment was designed and conducted by using DFPF-25 type suspension velocity testing equipment, the physical characteristics and suspension velocities of materials that shredded by peanut seedlings shredding and residual film sucking machine were studied, and a kind of residual filmseedlings separating device of which combined centrifugal fans and vibrating sieve was designed, with the functions of grading, dust cleaning, material conveying and residual film sucking. The rotational speed of upper fans were designed to be 700~900r/min adjustable, that of lower fans were 500~700r/min adjustable, and the frequency of vibrating sieve was 3~4Hz adjustable. By using the peanut seedlings shredding and residual film sucking machine as the experimental platform, the performance test and parameters optimization of the residual filmseedlings separating device were carried out. The quadratic regression orthogonal test of threefactor and threelevel was designed by taking the rotational speed of upper fans, lower fans and the frequency of vibrating sieve as experimental factors, and residual film removal rate and materials loss rate as response values. The quadratic polynomial response surface regression models were established and optimized via the optimization modules of DesignExpert 8.0.6. The results showed that the significance order of the influence of test factors on residual film removal rate was as follows: the rotational speed of lower fans, the rotational speed of upper fans, and the frequency of vibrating sieve; the order of the influence on materials loss rate was as follows: the rotational speed of lower fans, the frequency of vibrating sieve, and the rotational speed of upper fans. The validation test results presented that the residual film removal rate was 91.24% and the materials loss rate was 8.51% when the rotational speed of upper fans was 760r/min, the rotational speed of lower fans was 670r/min, and the frequency of vibrating sieve was 4Hz. The relative error between the validation test results and the predicted values of the models was less than 5%, which proved that the models were reliable. The research result can provide reference for design and optimization of the residual film-seedling separating device of peanut seedlings shredding and residual film sucking machine. 

Abstract:Aiming at the problems of cavity and single hole rate in rice seedling planting, in order to further improve the qualification rate of 2~3 grains per holes, a visual inspection technology of seeding quality was presented, and an efficient intelligent reseedling decision system was designed. The visual collection and image processing system were used to check the quality of seeding, and a population distribution database was established. The convolution calculation method was adopted to intelligently decide the reseeding scheme of the cavity and the single hole, and the dynamic coordinates of the replanted acupoints were positioned. The relevant parameters of seed suction were calculated to ensure its reliable performance. Finally, the combination of the servo motor and the pneumatic combined suction needle was used to form the reseeding mechanism, which realized an accurate, efficient and continuous dynamic reseeding process. According to the statistics of the test results, the average reseeding time per hole was 1.51s when the rice seed replenishment rate was 2%, and the intelligent seed replenishment system can meet the production requirements of 420 dishes per hour. The intelligent replanting decision greatly improved the working efficiency of the replanting system, and which can provide a theoretical basis for lowseeded reseeding technology of rice, vegetables, flowers and other crops in the factory. 

Abstract:In field operation, the boom must be kept parallel to the ground or crop canopy, resulting in unwanted movement of the boom due to the unevenness of the soil surface. The most important vibrations, affecting the spray distribution pattern, are rolling (rotational motion around an axis along the driving direction) causing spray boom motions in the vertical plane. In order to reduce the unevenness in spray deposit, the majority of current agricultural sprayers are equipped with a vertical suspension system to attenuate roll of the boom. The suspension tries to keep the boom at right angles to gravity by isolating the boom from vibrations of the tractor or trailer. Aiming at the problem of low accuracy and poor stability caused by parameter uncertainties and random disturbances in the passive and active pendulum type suspension system, the adaptive robust control algorithm based on model compensation was developed. Firstly, the nonlinear dynamic model and geometric equation of the pendulum active and passive suspension were established by using the dynamic analytical modeling method. Then, based on the nonlinear model of the suspension system, the design of adaptive robust controller was carried out, which integrated many parameter uncertainties existing in the suspension system and the electrohydraulic position servo system model, and also took into account of uncertain nonlinear factors such as uncompensated friction and disturbance of the system. It was proved theoretically that the designed controller can guarantee the transient performance and steadystate accuracy of the output tracking control system when the model parameters were uncertain and nonlinear. In order to make the designed control algorithm easier to understand and apply, the active and passive suspension of 28m large boom driven by single rod hydraulic actuator was used as an example. The platform was tested and verified by the control algorithm, and the Stewart sixdegreeoffreedom motion platform was used to simulate the motion interference of the chassis. The proposed controller and feedback linearization controller, robust feedback controller, and PID controller were compared on the test bench. The maximum tracking error of the designed adaptive robust controller based on model compensation was 0.148°, while the feedback linearization controller was 0.201°, the robust feedback controller was 0.51°, and the PID controller was 0.48°, which verified that the design of the controller can ensure the asymptotic tracking performance and steadystate tracking accuracy of the control system by using a smaller feedback gain coefficient in the presence of parameter uncertainty and disturbance.

Abstract:Drifting and settling of droplets are important factors affecting the effect of spray machinery. In order to reduce the drift of droplets and the ineffective settlement in nontarget areas, a conical wind field antidrift device was designed. The effect of conical wind field on droplet deposition was clarified by three factors and three horizontal indoor droplet drift deposition tests. The experimental results showed that these three factors had significant influence on the deposition characteristics of droplets, and the degree of influence was as follows: conical wind speed, natural wind speed, and spray pressure. As an example of natural wind speed of 2m/s, the mean diameter of droplet volume was decreased by 11.7%, and the coverage, deposition density and deposition volume was increased by 21.9%, 26.7% and 22.6%, respectively. The optimization results of response surface model showed that when the spray pressure was 0.34MPa, the conical wind speed was 16.53m/s, the optimal droplet deposition can be 3.14μL/cm2 when the natural wind speed was 2m/s. If the natural wind speed was more than 2m/s, the spray pressure should be reduced and the conical wind speed should be increased, so as to ensure the better droplet deposition. The test verification results were basically consistent with the model prediction. The research result can provide a reference for further promoting the application of airflow assisted technology in plant protection field. 

Abstract:Aiming to meet its operational challenges, the parameters of a wheat flour equalpitch screw feeder are mainly based on empirical design, but systematic research of its optimization is lacking. Thus, an optimization method was presented based on particle swarm optimization. Firstly, to improve the accuracy and rationality of the algorithm optimization results, the large error between the empirical calculation formula of the mass flow rate was mitigated, and actual tests were done. The differences between the response value, pitch S, inner shaft diameter d, and rotational speed n, which had significant influences on the flow difference, were taken as variables. The orthogonal experiments were designed by using DesignExpert software, a secondorder regression equation between the three variables and the response value was established and the modified formula of wheat mass flow rate was obtained. Then, according to the modified formula, based on particle swarm optimization, with maximum mass flow rate and smallest screw weight as the optimization goals, the outer diameter of the blade, pitch, outer diameter of the inner shaft, and inner diameter of the inner shaft were taken as variables. The two goals were then transformed into singleobjective optimization problems in a proportional way for optimization. Finally, tests were carried out according to the optimization results, showing that the optimized mass flow rate was 3.0546t/h, which was 18.15% higher than the empirical design value of 2.5853t/h, and the screw weight was 6.2779kg, which was 29.39% lower than its empirical design. The theoretical mass flow rate of the modified optimization result was 2.8647t/h and the error for the actual measured flow value of 3.0546t/h was 622%. The result demonstrated the reliability of the modified mass flow rate calculation formula and optimization design method, which provided a reference for the design of a wheat flour equalpitch screw. 

Abstract:In order to solve the problems of complex structure and poor stability of transverse sealing device for ultrathin selfadhesive film, a set of pneumatic transverse sealing device based on the existing fresh food packaging machine was designed, which can complete the transverse sealing problem of ultrathin selfadhesive film. And the device completed the transverse sealing operation through the cooperation of six main mechanisms, including vertical conveyor, two up wind boxes arranged in parallel in front and back, cutting mechanism, unpowered idlers and lower folding mechanism which was composed of rollers, a cylinder and a lower wind box, which combined movement of pneumatic and mechanical structure to complete the transverse sealing operation. Then the mechanical model of packaging materials and transverse sealing device were established during transverse sealing process. After that, the structure of the lower wind box which was the key part of device was analyzed by Fluent software. The optimal parameters of the lower wind box were obtained as follows: the position of the air inlet and air outlet in the horizontal direction was symmetrically arranged, the height of the air cavity was 14mm, the size of outlet of the lower wind box was 3mm in diameter, and the number of outlets was 10. Furthermore, aiming to obtain the best parameters of the rear transverse sealing, the outlet pressure of the rear up wind box, the pressure of the horizontal air outlet of the lower wind box, the distance between the lower folding mechanism and the bottom of the packaging box were chosen as the experimental factors, and the transverse sealing rate was selected as the experimental index. Through the experimental research and the result analysis, the optimal aggregative index could be obtained under the condition that the outlet pressure of the rear up wind box was 113.3Pa, the pressure of the horizontal air outlet of the lower wind box was 85Pa, the distance between the lower folding mechanism and the bottom of the packaging box was -3mm. By verification of experiment, the maximum value of the transverse sealing rate was up to 99%, and the transverse sealing effect was flat and beautiful, which indicated that pneumatic transverse sealing device could satisfy operation demand of the fresh food packaging machine. 

Abstract:Aiming at the problems in the combine harvester manufacturing industry, including the low automation level of the combine harvester manufacturing quality inspection, the lack of a complete inspection system and other problems, combined with relevant national standards and the actual needs of the enterprise, two kinds of combine harvester manufacturing quality inspection plans were proposed, one was multistation pipelined inspection system, the other was multifunctional cellline inspection system. The virtual models of the two combine harvester manufacturing quality inspection systems were established through digital means, the models included combine harvester, inspection equipment and instrument, sensors, workshop and virtual workers. The two inspection systems were simulated in the Visual Components environment respectively to analyze the applicable scope, work intensity, the efficiency of the equipment and instrument, and other workshop operation parameters. And the simulation results showed that the multifunctional cellline inspection system was more suitable for combine harvester manufacturing quality inspection. On the basis of modeling and simulation, with the electrical system of combine harvester as the object, a set of inspection system based on virtual instrument technology was developed to realize the fast testing of the electrical working conditions, starting performance and other working parameters, which improved the inspection efficiency. The research results show that the construction of digital workshop simulation model can provide effective evaluation methods for inspection process evaluation and system development, thereby providing strong support for manufacturing process optimization. 

Abstract:Mengjin County was selected as the case study area to construct the evaluation system of ecological importance for territorial space from the aspects of ecological service, landscape integrity and ecological sensitivity. And a quantitative analysis was made on the evolution of cultivated land in different ecological functional areas from 2001 to 2018. With the ultimate goal of promoting the restoration of ecological functions and the development of highquality agriculture in the Yellow River shoal area, a classified regulation scheme was put forward in combination with relevant planning. The results showed that the national spatial ecological importance of Mengjin County can be divided into high important area (104.61km2), middle important area (245.26km2) and low important area (384.90km2), the high important area was mainly located in the Yellow River beach area, which played a key role in maintaining the water ecological security of the Yellow River basin. To promote regional highquality development, it was necessary to combine the existing advantageous space and social and economic foundation to work out differentiated farmland regulation plans. In the high important area, it was important to actively promote the return of farmland to the beach and implement the ecological tillage model. In the middle important area, it was necessary to intensify the improvement of cultivated land which was not convenient for cultivation to create conditions for largescale farmland construction. In the low important area, the social platform should be used to promote the compound utilization of cultivated land. It was determined that the area needed to be converted to farmland in the Yellow River beach area of Mengjin County was 12.67km2, the orderly withdrawal of cultivated land in the beach area was conducive to magnifying the superposition effect of the national Yellow River strategy. 

Abstract:Since 2000, drought has occurred frequently in Southwest China, which has seriously affected social production and ecological environment. Therefore, studying the temporal evolution characteristics of meteorological drought and its impact on vegetation growth can provide theoretical basis for scientific management of regional water resources and ecological control. Based on the monthly precipitation and temperature data of Southwest China from 2000 to 2018, the standardized precipitation evapotranspiration index of different time scales was calculated. The linear trend method and Mann-Kendall (M-K) test were used to analyze the temporal variation characteristics of meteorological drought in Southwest China. The effectiveness and difference of solarinduced chlorophyll fluorescence (SIF), normalized differential vegetation index (NDVI) and enhanced vegetation index (EVI) in vegetation stress monitoring were evaluated. Furthermore, the response of vegetation to drought was also explored. The results showed that SPEI values showed a weak increasing trend in all time scales from 2000 to 2018. From 2000 to 2013, SPEI-12 showed a downward trend (the trend rate was -005/(10a), R2=0.295), and from 2014 to 2018, SPEI-12 time series showed an increasing trend (the trend rate was 004/(10a), R2=0.094), indicating that the drought trend in Southwest China was alleviated in recent years under the background of climate change. The turning point of SPEI-12 time series occurred in 2016 and 2017 respectively. Compared with NDVI and EVI, SIF showed obvious negative anomalies for both longterm and shortterm drought events during vegetation growing season, and it can quickly obtain the information of vegetation photosynthesis under water stress. The correlation between SIF of forest, farmland and grassland and meteorological drought index at different time scales was higher than NDVI and EVI, which meant that the sensitivity of SIF of forest, farmland and grassland vegetation ecosystem to drought monitoring was better than that of traditional vegetation greenness index. The correlation between SIF of grassland and SPEI-1 was higher (R=0.859, P<0.01), which indicated the grassland photosynthesis was more sensitive to shortterm water stress. The research results can provide scientific basis for comprehensive drought coping, water resources management and ecological control in Southwest China. 

Abstract:Leaf area index is an important indicator of crop growth evaluation, so it is crucial to estimate LAI quickly and accurately. The imaging data of the three growth stages of winter wheat was obtained through the imaging hyperspectrum carried by the UAV, and the plant height (Hcsm) was extracted from it. Firstly, the correlation between vegetation indices, Hcsm and LAI was analyzed, and the optimal vegetation index was selected; then the LAI linear estimation model of a single parameter was constructed separately; finally, taking the vegetation indices and vegetation indices combined with Hcsm as the model input factor, the partial least squares regression method was used to construct LAI estimation model. The results showed that the height of the plant height Hcsm extracted from the UAV hyperspectral remote sensing image was highly accurate (R2=0.95); the correlation between most vegetation indices and Hcsm at different growth stages and LAI was at 0.01 significant level; the accuracy of estimating the LAI based on the optimal vegetation index combined with Hcsm was better than that based on the optimal vegetation index or Hcsm only; taking vegetation indices and vegetation indices combined with Hcsm as input variables, the LAI estimation model constructed by partial least square regression achieved the highest accuracy during flowering stage, so partial least squares regression can improve the estimation effect, and the ability to estimate the LAI with the vegetation indices combined with Hcsm as the independent variable was better (modeling R2=0.73, RMSE was 0.64). The research was based on the Hcsm extracted from the UAV hyperspectral remote sensing image combined with the vegetation indices, which can improve the accuracy of estimating LAI and provide a reference for agricultural managers. 

Abstract:In order to quickly and accurately obtain aboveground biomass (AGB), potato was taken as research object, and the hyperspectral images of unmanned aerial vehicle (UAV) and measured aboveground biomass were obtained in budding period, tuber formation period, tuber growth period, starch accumulation period and mature period. Firstly, the canopy reflectance data of potato at each growth stage were extracted from hyperspectral image. Secondly, the 0~2 order differential (the interval was 0.2) of canopy spectral reflectance were calculated by fractional differential method. The correlation between canopy spectral data and aboveground biomass was analyzed, and the first 9 differential bands with high correlation were selected. Finally, the potato AGB estimation model of the whole, different varieties, densities and fertilization based on fractional differential spectrum was constructed and compared by using multiple linear regression (MLR), random forest (RF) and artificial neural network (ANN). The results showed that the order of the maximum absolute value of correlation coefficient in〖JP2〗 each growth stage was different, the maximum value in budding stage was 0.8 order differential (470nm), the maximum value in tuber formation stage was 1.8 order differential (710nm), the maximum value in tuber growth stage and starch accumulation stage was 1.6 order differential (718nm, 722nm and 766nm), and the maximum value in mature stage was 10 order differential (622nm). The correlation between hyperspectral fractional differential and AGB was higher than that of integer differential, and fractional differential can improve the estimation accuracy of potato AGB. Comparison and analysis of potato AGB estimation models at different growth periods, different varieties, densities, and fertilization were carried out. AGB estimation by three methods with 9 differential bands as independent variables all performed best in the tuber growth period. The model obtained by MLR under each condition had the highest accuracy and the strongest stability, followed by the RF model, and the ANN model had the worst performance. The accuracy of AGB model constructed by three methods in different growth stages were as follows: tuber growth period, tuber formation stage, starch accumulation period, budding stage and mature stage.

Abstract:The number of wheat ears per planting area is one of the key agronomic index to evaluate wheat yield. In the field scene, there are usually great differences in the shape, size and posture of wheat ears, and there are serious occlusion between leaves and ears and between ears and ears. At the same time, wheat awn, curly wheat leaves, weeds and uneven illumination introduced a lot of background interference. These complex factors led to a high false detection rate in traditional methods based on color and texture features. The detection method based on deep learning has a high missed detection rate for smallsize rice ear images in practical application. To solve these problems, a wheat ear detection method FCS R-CNN based on deep learning was proposed. Taking Cascade R-CNN as the basic network model, a feature pyramid network (FPN) was introduced to fuse shallow detailed features and highlevel rich semantic features, and online hard example mining (OHEM) technology was added to increase training frequency for highloss samples, the network was fused by the IOU threshold. Finally, a SVM classifier was trained based on the circular LBP texture features to carry out the reinspection of wheat ear detection results to further reduce the detection error. In the wheat field image test, the detection accuracy of FCS R-CNN model reached 92.9%, the average precision (AP) was 81.22%, the average time to identify a single image was 0.357s, and the AP was 21.76 percentage points higher than that of the original Cascade R-CNN. The results showed that the proposed method had better detection results for wheat ear detection in complex scenes, which provided a new idea for wheat yield estimation. 

Abstract:In order to obtain the external phenotypic parameters of the leaves and grasp the growth status of the plants quickly and efficiently, a threedimensional estimation method of leaf length, leaf width and leaf area was proposed based on a geometric model by using the leaves of money plant. The Microsoft Kinect V2 camera was used to obtain the local point cloud of the leaf from the 80cm height vertical pose and perform preprocessing such as passthrough filtering, denoising and simplification of the bounding box. The shape parameters of the point cloud were measured, and the preestablished SAE network classification prediction was used to obtain the geometric model parameters. The geometric model of the blade was established based on the surface parameter equation. The particle swarm optimization algorithm was used to calculate the spatial distance between the discrete point cloud and the local point cloud of the geometric model for spatial matching. The genetic algorithm was used to solve the internal model parameters of the optimal matching model, and the leaf length, leaf width and leaf area of the optimal matching model were output, were used as the estimation result. A total of 150 point cloud data were collected from the experiments. The estimated results and real values were analyzed by mathematical statistics and linear regression analysis. The average errors of the estimated leaf length, leaf width, and leaf area were 0.46cm and 0.41cm and 3.42 cm2, respectively. The R2 and RMSE of estimated leaf length were 0.88 and 0.52cm, the R2 and RMSE of leaf width were 0.88 and 0.52cm, and the R2 and RMSE of leaf area were 0.95 and 3.60cm2, respectively. It can be known from the experimental results that this method had good estimation effect on the shape parameters of money plant leaves, and it had high practical value. 

Abstract:Aiming at measuring the number of main stem nodes of soybean plants quickly and efficiently, a statistical method of soybean main stem nodes was proposed based on image processing and clustering algorithm. Firstly, multiple perspectives of the soybean plants were obtained by using a camera, the initial image collection interval and sampling step were set, and then some of the plants were extracted as the train set and validation set. Secondly, through the operations such as plant segmentation, skeleton extraction, and denoising of the main stem nodes, the soybean main stem nodes to be detected were obtained. Meanwhile, the multiple dimensional scaling (MDS) was used to convert the data into a space which was easy to cluster. Then, the hierarchical densitybased spatial clustering of applications with noise (HDBSCAN) clustering algorithm was used to cluster the soybean stem nodes to be detected from multiple perspectives, and the recognition accuracy of the number of main stem nodes were recorded. Finally, the optimal collection interval was used to determine the number of main stem nodes of the remaining sample plants and conduct statistical analysis. The experiments were carried out based on the above method by using 63 samples which variety was called Zhonghuang 30. 21 plants were selected as the training set, and it turned out that, under the condition of 90° interval, and four soybean images were captured and fused with the minimum cluster of 2, the node number recognition results were mostly distributed in the effective range. To identify and analyze the main stem node number of the remaining 42 sample plants, the corresponding soybean main stem node number recognition accuracy rate can reach 98.25%. The experiment results showed that this method can meet the needs of soybean plant test requirements.

Abstract:The drawbacks of traditional crop and weed identification algorithms include low accuracy, poor realtime and weak robustness，resulting in weeding operations inefficient in the natural environment. In order to solve these problems，corn and its associated weed were taken as research object，and an improved single shot multibox detector （SSD）model was proposed. Firstly, a light weight feature extraction unit was constructed through the use of depth separable convolution and squeezeandexcitation networks （SENet）module. On this basis, a light weight basic network formed with dense connection was adopted to replace the VGG16 network of the standard SSD model, so as to improve the speed of image feature extraction. Based on the mechanisms of different classification feature layer fusion, the deep semantic information in extra feature layers was fused with shallow detail information. The fused feature map would have enough resolution and strong semantic information, which can improve the detection accuracy of smallscale crops and weeds. Experimental results showed that the mean average precision and recognition speed of the proposed model were 88.27% and 32.26f/s, respectively, and the parameters size was 8.82×10.6. Compared with that of standard SSD model, the identification accuracy and speed of this model were increased by 2.66 percentage points and 33.86%, respectively, and the parameters were decreased by 66.21%. In addition, the improved SSD model performed good robustness ability under the condition of smallscale targets and overlapping of crop and weed leaves. The proposed method could identify crop and weed accurately and rapidly, which provided a technical support for agricultural automatic precision weeding. 

Abstract:Lanzhou lily is the only kind of sweet lily in China and it is one of the famous specialties of Gansu Province. However, its yield and quality were decreased significantly in recent years due to gray mold disease, bulb rot disease and other diseases and insect pests. In order to improve the antiinterference ability of Lanzhou lily diseases diagnosis model, the three full connection layers of VGG-16 convolutional network was replaced with capsule network module to construct convolutional capsule network. And the effects of capsule size and route iteration times on training time and model accuracy were analyzed systematically. The result of the experiment showed that the diagnosis accuracy of Lanzhou lily diseases via convolutional capsule network was 9920% when the capsule size was 8 and the route iteration time was 3. And the capsule size and the number of routing iterations had no significant effect on the accuracy of the model. In addition, the accuracy of VGG-16 model was slightly higher than that of convolutional capsule network when the affine transformation grade was 0.04~0.08. But the antiinterference ability of convolutional capsule network was obviously better than that of VGG-16 model for Gaussian noise, saltandpepper noise, speckle noise and other grades of affine transformation. So it was possible to use the convolutional capsule network for dealing with the realworld examples of Lanzhou lily diseases recognition. 

Abstract:Film mulching can change radiation transfer, increase soil temperature, reduce soil evaporation and so on. Potato has good nutritional value and produce more dietary energy than rice, maize and wheat. Potato has shallow roots and is sensitive to hydrothermal conditions. Field hydrothermal environment can be regulated through the combination of film mulching and drip irrigation. Drip irrigation with film mulching can increase potato yield and water use efficiency and improve potato quality. Optical properties of film are important factors affecting field thermal conditions and potato growth. The effects of film mulching on field thermal conditions and potato growth are also different in different regions with different climatic conditions. The experiments were conducted in Gansu Province from April to August 2015 and Shandong Province from March to July 2017, respectively. Effects of different film mulching (clear film, CF; no film, NF; black film, BF) on heat conditions and potato growth under drip irrigation were studied. Canopy net radiation, soil heat flux and soil temperature were monitored automatically during the whole growth period. Potato yield, tuber grade, water consumption and water use efficiency were measured. The results suggested that net radiation of BF treatment was greater than that of NF and CF treatments, while net radiation of CF treatment might be higher or lower than that of NF treatment. The maximum net radiation of BF treatment was 12% greater than that of NF treatment during sprout development stage and seedling stage in 2015 and 22% and 15% greater than that of NF treatment in 2017, respectively. The differences of soil heat flux and soil temperature between treatments were great during sprout development stage and seedling stage, decreased during tuber initiation stage and tuber bulking stage, and increased during maturity stage. The maximum soil heat flux at 10cm soil depth of CF treatment was 66% and 129% greater than that of BF and NF treatments in 2015, respectively, and it was 57% and 91% greater than that of BF and NF treatments in 2017, respectively. The soil temperature of CF treatment was greater than that of BF and NF treatments, while it might be lower than that of BF and NF treatments during tuber initiation stage and tuber bulking stage. In 2015, the daily maximum soil temperatures at 10~50cm soil depths of CF treatment were 29% greater than that of BF treatment, and 31% and 29% higher than that of NF treatment during sprout development stage and seedling stage, respectively. In 2017, the daily maximum temperatures at 10~50cm soil depths of CF treatment were 22% and 4% greater than that of BF treatment, and 21% and 9% greater than that of NF treatment during sprout development stage and seedling stage, respectively. The difference of soil temperature among different treatments in Shandong Province in 2017 was smaller than that in Gansu Province in 2015. Film mulching significantly improved potato yield and water use efficiency in Gansu Province and the evapotranspiration of CF treatment was significantly lower than that of BF treatment. However, film mulching did not significantly improve potato yield and water use efficiency in Shandong Province in 2017. The evapotranspiration of CF treatment was lower than that of BF treatment in Gansu Province. The effects of film mulching on thermal conditions and potato yield and water use efficiency were more remarkable in Gansu Province than that in Shandong Province. Clear film mulching was favorable for potato cultivation in Gansu Province. 

Abstract:In order to explore the effect of soil water, temperature and nutrient characteristics under autumn tillage with mulching practices on the growth and yield of dryfarming potato, a field experiment was conducted to study different tillage with mulching measures after the autumn crop harvest in potato cultivation of southern Ningxia between 2013 and 2016. Soil water at 0~200cm layer, topsoil temperature at 0~25cm layer and soil nutrient content at 0~40cm layer, the growth and yield of potato were investigated. The results showed that the tillage methods, mulching measures, and their interactions had highly significant effects on the soil water storage during the potato sowing season, and treatments of notillage with straw mulch and subsoiling with straw mulch had the best effect of soil conservation. Notillage with straw mulch and subsoiling with straw mulch significantly increased the mean soil water storage by 14.4% and 14.7%, respectively, compared with the plowing with no mulch. The tillage methods, mulching measures, and their interactions had significant effects on the soil water storage, and the improvement effect of subsoiling with straw mulch on soil water was the best. Subsoiling with straw mulch significantly increased the mean soil water storage by 207% compared with the plowing with no mulch. The tillage methods, mulching measures, and their interactions significantly affected topsoil temperature, while a reduction in their effect as the growing season of potato was advanced. Among the tillage methods, the film mulch plots increased the mean topsoil temperature by 3.6℃, whereas the straw mulch plots reduced the temperature by 1.4℃ during each potato growing season. Over the three years of the autumn tillage with mulching experiments, the interactions between tillage methods with mulching measures highly and significantly affected the indexes of soil nutrient. Among all of the treatments, the higher mean soil organic matter, total N, alkalyzableN, available P and available K at 0~40cm layer was obtained in the notillage with straw mulch and subsoiling with straw mulch treatments and the minimum in the PT×NM treatment. Among the tillage methods, the warming effect of subsoiling with film mulch treatment significantly promoted the growth of potato in the early stage, while the higher temperature during the later stage in subsoiling with film mulch was not conducive to the reproductive growth of potato. However, the stable temperature and cooling temperature effects of subsoiling with straw mulch treatment significantly promoted the growth of potato in the later growth period. Among all the treatment combinations, the mean potato total yields and net incomes under the subsoiling with straw mulch and notillage with straw mulch were the highest. The mean potato total yield was significantly increased by 49.4% and 383% under the subsoiling with straw mulch and notillage with straw mulch treatments, respectively, and the mean net income was increased by 129.1% and 103.3% when compared with plowing with no mulch treatment. However, the best marketable tuber rates were obtained under subsoiling with film mulch and subsoiling with straw mulch, which were significantly higher by 18.4% and 16.2% than that of plowing with no mulch. Taking together, in consideration of soil environmental and economic feasibility, it was recommend that the notillage and subsoiling combined with straw mulch practice was a more favorable practice for improving soil water, temperature and nutrient environment and potato productivity, and it had certain practical values in dryland potato cultivation of southern Ningxia. 

Abstract:In order to quantify the impacts of soil input parameters on the sensitivity of CERES-Wheat output variables, the extended Fourier amplitude sensitivity test (EFAST) method was used to study the global sensitivity analysis. The most sensitive parameters for yield, tops biomass and harvest index of winter wheat were soil field capacity (SDUL), followed by soil pH (SLHB) among the soil parameters. SDUL was also the most sensitive parameter for nitrogen content in grains, while SLHB was the most sensitive parameter for nitrogen content in tops biomass of winter wheat. Among the soil parameters, the most sensitive parameters for nitrogen content in root and leaf of winter wheat were both total nitrogen in soil (SLNI), with the first order sensitivity index value of 0.67 and 0.59, respectively. The runoff curve number (SLRO) and SDUL were more sensitive for the plant uptake nitrogen content than other soil parameters. Soil drainage rate (SLDR) was the most sensitive parameter for nitrogen leached during season, while SLNI was the most sensitive to total soil nitrate nitrogen and ammonium nitrogen content. SLNI was also the most sensitive parameter for nitrogen mineralization content and nitrification content, while the nitrogen denitrification content was most affected by SLDR. The ammonia volatilization content was sensitive to SLNI, SLHB and SLDR. Furthermore, all 15 soil parameters that should have been measured can be simplified to four parameters when the research focus on the simulation of winter wheat production and crop nitrogen, and all the soil parameters can be simplified to nine parameters when the research focus on the simulation of soil nitrogen transformation and distribution. The research result provided a feasible method to decrease the difficulty in obtaining soil data for CERES-Wheat model, which can benefit model localization and regional application.

Abstract:Coastal soil was taken as an object in order to clarify the influence of straw coverage amount on soil evaporation resistance in Binhai area, and dynamic model of soil moisture evaporation and coverage resistance model under different straw coverage amount conditions (0kg/m2, 0.3kg/m2, 0.6kg/m2, 0.9kg/m2 and 1.2kg/m2, expressed as CK, S1, S2, S3, S4,respectively) were established, moreover, the measured and calculated evaporation data were evaluated. Results showed that the surface soil moisture was decreased exponentially with time, and the more amount of straw coverage, the higher surface soil moisture; both the soil evaporation rate and cumulative soil evaporation were increased exponentially with the increase of soil moisture. The decrease of soil moisture showed a linear increase trend with time, the determination coefficient R2 of the fitted line was greater than 0.9, and both the average soil evaporation rate and cumulative soil evaporation amount were decreased with the increase of straw coverage quantity. Coverage resistance under different straw coverage treatment had a large difference, while the difference for coverage resistance in the same straw coverage treatment was small, and the coverage resistance was increased linearly with the increase of straw coverage amount, moreover, the relationship between coverage resistance and straw amount showed a significant positive correlation (R2=0.9114, p<0.05). The RMSE, MAE and NS between the simulated and the actual soil evaporation was 4.18×10-4mm/min, 3.85×10-5mm/min, and 0.90, respectively, and the slope k for the simulated and actual soil evaporation fitted line was 0.926, indicating that the calculated straw coverage resistance model can accurately estimate the soil evaporation under straw coverage conditions. 

Abstract:In order to study the characteristics of sunflower canopy development and its absorption and use of radiation in saline fields, two years of field experiments were conducted in Hetao Irrigation District of Inner Mongolia in 2015 and 2016. Three salinity levels were set according to the average ECe of 0~60cm depth: mild (S0: 0~3dS/m), moderate (S1: 3~6dS/m) and severe (S2: >6dS/m); the 〖JP2〗nitrogen application rates were set at four levels, referred as N0, N1, N2 and N3, which were 45kg/hm2, 90kg/hm2, 135kg/hm2 and 180kg/hm2, respectively. The dynamics of LAI, extinction coefficient, light interception and radiation use efficiency (RUE) of sunflower were measured under different salinity and nitrogen levels. The results showed that salt stress obviously inhibited the increase of CLAI at seedling and bud stages, and its effect were more severe under N3 treatment, which decreased the CLAI at S1 and S2 levels by 48.3% and 64.6%, respectively, compared with S0. However, the effect of S1 level on canopy development could be alleviated before the end of vegetative growth, whereas the compensatory growth of sunflower occurred after entering mature stage at S2 level. The daily fraction of light interception (fPAR) and RUE of each treatment were increased constantly from seedling to bud stage, and reached the peak value in flowering stage, and then decreased in mature stage. Among them, the fPAR and the cumulative intercepted PAR of S0N3 treatment were higher than those of the other treatments during the crop cycle, but the maximum RUE appeared in S1N3, which reached 2.26g/MJ in the same year. The research result also slowed that the extinction coefficient of sunflower in this experiment was 0.729. By combining the modified Logistic equation with the linear correlation between LAImax and the effective nitrogen application rate (ENA), a model describing the dynamics of LAI with normalized developmental index under different salinity and nitrogen levels was established. These results proved that applying N2 and N3 rate at S1 level could alleviate salt stress, promote leaf growth and light interception, and increase RUE and seed yield accumulation. However, at S2 level, the N2 and N3 rate had no benefit on canopy development and yield accumulation, but could even reduce the RUE before mature stage. The conclusion helped determining the reasonable rates of nitrogen fertilizer under different saline conditions.

Abstract:Heavy metal pollution of soil and water has seriously threatened human life and health, and Pb2+ is one of the most difficult heavy metals to deal with because of its strong toxicity, difficult degradation and easy enrichment. Corn straw was used as raw material to prepare hydrochar and pyrochar at different temperatures (280℃ and 320℃), respectively. The structural differences of the two kinds of biochar were compared and analyzed, and based on this, Pb2+ adsorption mechanism of hydrochar and pyrochar from straw was studied by combining isothermal adsorption model and adsorption kinetic model. The results showed that the dehydrogenation effect of hydrochar was more significant, forming rich surface oxygen functional groups and disordered crystal structure with the increase of hydrothermal temperature. The porosity of hydrochar was firstly increased and then decreased, finally presenting a regular and dense appearance; however, the deoxidization effect of pyrochar was more remarkable, it had fewer surface oxygen functional groups, forming a more ordered crystal structure. The porosity of pyrochar continued to increase, showing a rough porous surface morphology. Adsorption equilibrium of straw hydrochar and pyrochar was reached at 4h and 10h respectively, and the theoretical equilibrium adsorption capacity was 214.16mg/g and 133.99mg/g; Pb2+ adsorption of straw pyrochar was in accordance with pseudo firstorder kinetic model and Freundlich isotherm adsorption model, indicating that the adsorption reaction was a multi molecular layer adsorption process; however, Pb2+ adsorption of straw hydrochar conformed to the pseudo secondorder kinetic model and Langmuir isotherm adsorption model, indicating that the adsorption reaction was a single molecular layer adsorption process. Combined with the structural characteristics of the two kinds of biochar, it was found that straw pyrochar mainly relied on the diffusion movement of Pb2+ within its pores to remove Pb2+ from water, and the existence of largescale mesopores was more conducive to Pb2+ to overcome the space barrier and enter the pores, however, the physical adsorption capacity was relatively weak and easy to desorb; in addition, complexation reaction was the main Pb2+ removal mechanism of straw hydrochar, in other words, the oxygencontaining functional groups exchanged with Pb2+ to form complexes, and chemical adsorption capacity was strong and not easy to desorb. 

Abstract:To maximize the performance of the aircooled condenser heat collection and release system, with the goal of improving heat transfer rate and COP, three key influencing factors, i.e., the air and circulating water temperature difference (air and water temperature difference), water flow velocity and air velocity were selected as independent variables, and the best control parameters were obtained through the threefactor threelevel response surface method (RSM). The results showed that under the condition of constant water flow velocity and air velocity, heat transfer rate and COP were increased linearly with the increase of air and water temperature difference. Under the condition that the air and water temperature difference was constant, the heat transfer rate was increased with the increase of the water flow velocity or air velocity, but the COP tended to increase first and then decrease. Further, the RSM was used to draw the significance order of the three factors on heat transfer rate as descending order was as follows: water flow velocity, air velocity, and air and water temperature difference, the significance order of the three factors on COP as descending order was as follows: air velocity, water flow velocity, and air and water temperature difference. The optimal control parameters of the system were: air velocity of 1.91m/s, water flow velocity of 1.23m/s, and air and water temperature difference of 5.8℃, under this operating condition, the heat transfer rate was 5.88kW, and the COP was 4.9. Therefore, it was feasible to use the RSM to optimize the parameters of the greenhouse heat collection and release system. This study provided an optimization method of the operating parameters for the efficient and energysaving operation of this type of heat collection and release system. The full play of the performance of the aircooled condenser heat collection and release system provided data support. 

Abstract:With the aim to solve the problem of low detection speed and precision of beef tenderness, a fast nondestructive detection method for beef tenderness based on airpuff and structural light 3D imaging technology was proposed. The structural light 3D scanning technology was used to obtain the threedimensional point cloud information on the surface of the beef and the point cloud processing technology was combined to extract the depth, area, surface area and volume parameters of the stressed depression area on the beef. In point cloud processing, denoising, point cloud segmentation, greedy projection triangulation, Delaunay triangulation, surface fitting and other algorithms were used to extract the characteristic parameters of beef samples. The modeling method was used to establish the prediction model of beef shear force which about the least squares support vector machine regression (LS-SVR), back propagation (BP) and general regression neural network (GRNN). The results showed that the GRNN model performed the best with the correlation coefficients of prediction set of 0.975, and root mean squared error of 5.307N. The GRNN neural network based on K-fold cross validation was used to predict the tenderness grade. It was worth noting that the results showed that the method had a better grading effect on the tender beef of 100% and a slightly worse grading effect on the tougher beef of 91.3%. The results demonstrated that the proposed airpuff combined with structured light method was effective in beef tenderness detection nondestructively. The research result provided a method for poultry meat tenderness detection and a basis for online poultry tenderness detection which had broad application prospect not only in meat tenderness but also in fruit hardness and ripeness detection.

Abstract:Aiming to use the cavitation jet treatment technology to effectively increase the soluble protein content and improve the physicochemical properties of the soybean residue produced by enzymatic oil production, twodimensional, threedimensional fluorescence, sodium dodecyl sulfatepolyacrylamide gel electrophoresis (SDS-PAGE), and scanning electron microscopy were used to analyze the effects of different cavitation jet treatment times (0min, 5min, 10min and 15min) on the structure and morphological changes of soybean residue protein, and its solubility, emulsification, amino acid analysis, particle size distribution and ζpotential were used to characterize its physicochemical and functional characteristics, and finally the cavitation jet effect on the structure and physicochemical properties of protein from soybean residue produced by enzymatic method was clarified. The results showed that the cavitation jet can promote the unfolding of the soybean residue protein structure and the intermolecular interaction was enhanced, and its subunit structure was transformed from high molecular weight to low molecular weight. When the cavitation jet was treated for 10min, the particle size distribution of the soybean residue protein was stable and the volume average particle diameter D[4,3] reached the lowest value (470.10±8.70) nm, the absolute value of ζpotential reached the maximum value (27.4±0.83) mV, and the dissolution characteristics and interfacial properties were the best; in particular, amino acid analysis revealed that the amino acid composition of the enzymemade oil soybean residue protein and soy protein isolate (SPI) was similar, with hydrophobic amino acids reached 33.03%. 

Abstract:In order to improve the light stability of vitamin D3 (VD3), the soy protein isolatevitamin (SPI-VD3) nanoparticles were prepared by high pressure homogenization. The influences of homogenization times on the SPI structure and VD3 light stability in SPI-VD3 nanoparticles were investigated. The results showed that when the times of high pressure homogenization was 2, compared with the sample without high pressure homogenization, the loading efficiency of SPI-VD3 nanoparticles was increased to 27.7%; the average particle size was reduced from 145.20nm to 82.00nm, the turbidity was gradually decreased and the particle size distribution was more uniform. Two times highpressure homogenization can increase the hydrophobicity of the surface of the SPI-VD3 nanoparticles and enhance the fluorescence intensity of the endogenous fluorescence spectrum. The results of Fourier transform infrared spectroscopy showed that the secondary structure of SPI-VD3 nanoparticles was changed after high pressure homogenization. When the number of homogenization times did not exceed 2, αhelix and βfold were gradually changed into βturn. When the number of times were 3 or 4, the sample may undergo insoluble aggregation. After twice highpressure homogenization, the photostability of VD3 in the sample was also improved. Compared with the VD3 control alone, the remaining amount of VD3 was increased to 166.6% after four hours of UV irradiation. Proper highpressure homogenization was a useful method for making SPI-VD3 nanoparticles with improved VD3 photostability. 

Abstract:High internal phase Pickering emulsions stabilized by foodgrade particles have received much attention in recent years. However, the stabilizing mechanism in the continuous phase of high internal phase Pickering emulsions stabilized by proteins is not well understood. Soy protein isolate (SPI) gel particles were constructed and used to stable high internal phase Pickering emulsion. The SPI gel particles and high internal phase Pickering emulsion were studied with particle size, ζpotential, cryoscanning electron microscopy, optical microscope observation, analysis of formation characterization and rheological properties of the emulsions. The results showed that the SPI particle size and ζpotential of gel particles were varied along with the change of pH value. When the pH value of SPI gel particles was 4.0~5.0, it was near protein isoelectric point, the absolute value of ζpotential was the minimum, and particles were gathered at this time. It cannot be successful preparation of stable high internal phase emulsion. At pH value 9.0, the SPI particles were tightly bound together in a gel network structure. Under alkaline conditions, high internal phase Pickering emulsion can be stabled with the soy protein concentration of 1.00% and the internal phase volume fraction in 78%~82%. By increasing the volume fraction of the internal phase, the Pickering emulsion system stabilized by SPI gel particles was more evenly distributed and less prone to aggregation, forming a finer and denser porous structure to make it more stable. And it had stronger properties of elastic gel emulsion. 

Abstract:Synchronous adjustment of the body and implement posture of hilly mountain tractors helps to improve the safety and efficiency of their operations. The current research on the attitude adjustment of hilly tractors is mainly focused on the body or implement attitude control. Its accuracy and reliability are difficult to meet the actual requirements. A synchronous control system for tractors in hilly and mountainous areas was designed based on the neural network PID algorithm. Specifically, according to the different attitude adjustment requirements of the body and implement, a corresponding attitude adjustment system was designed respectively and its dynamics was modeled. And then a synchronous control algorithm based on neural network PID was adopted. Comparisons with the conventional PID control algorithm was conducted, and simulation analysis was performed. The simulation results verified the effectiveness of the proposed neural network PID algorithm, and its control performance was better than that of the PID control algorithm. Finally, experimental verifications were carried out on fixedslope and random pavement operations. The experimental results showed that the accuracy and stability of the proposed neural network PID control method were better than those of the PID control method. On a road with a fixed slope of about 14°, the maximum error of the vehicle lateral inclination angle was 0.8640°, the maximum error of the absolute value difference of the left and right swing mechanism was 0.9600°, and the maximum error of the machine lateral inclination angle was 0.6497°; the vehicle lateral inclination was the largest on a random slope road, the error was 2.8740°, the maximum error of the absolute value of the swing angle of the left and right swing mechanism was 4.2800°, and the maximum error of the machine lateral inclination angle was 1.7620°. It can be seen that the proposed method had good control accuracy and stability, and can meet the actual needs of hilly and mountain tractors.

Abstract:To eliminate the deviation between the actual pressure and the ideal pressure of the wet clutch of a highpower tractor during the power shifting process, a model free adaptive predictive control strategy (MFAPC) based on the compactform dynamic linearization (CFDL) was proposed to achieve the tracking control of the pressure. Considering the parameter uncertainties of the hydraulic actuators and external disturbances, a nonlinear dynamic model of the wet clutch control system was established and verified in AMESim. Taking the cylinder pressure as the control target, the nonlinear wet clutch actuator system was equivalently converted into a dynamic linearized data model by CFDL. Furthermore, an online MFAPCbased controller was designed to control the clutch pressure in real time. The closedloop clutch pressure control system was built in Matlab/Simulink and the simulation experiments were performed to verify the correctness of the dynamic linearization model and the reliability of the control strategy. Compared with the commonly adopted control strategies such as PID and MFAC, the proposed control algorithm performed better in terms of robustness. MFAPC was proved to output the varying expected pressure accurately and quickly by adjusting the control parameters. Specifically, the response time under the square wave signal was 0.119s, while the steadystate error under sinusoidal signal kept at ±0.0281MPa, which appeared 48.91% lower than the conventional PID. In addition, MFAPC has better antiinterference capability than MFAC, which was reflected by the smallest jerk (16.57m/s3) among PID and MFAC. The results proved that MFAPC generally had better dynamic performance and superiority, and is conducive to improving the shifting quality and guaranteeing the power performance of highpower tractors under continuous operating conditions. 

Abstract:A wallclimbing robot can be used for the rust removal task of fishing vessels. And the robot is inevitably required to surmount weld seam when operating on the hull plate. For the wallclimbing robot with inflatable wheels and suspended magnet, the compression of the tires is decreased after surmounting weld seam, which leads to an increase in the air gap between the magnet and the hull plate with a following decrease in the magnetic adsorption force. Thus the load capacity of wallclimbing robot is weakened, which affects the reliability of wallwalking. In order to solve the problems mentioned above, a research on the dynamic process of the wallclimbing robot surmounting weld seam was carried out. Firstly, based on the drivewheel tires simplified as spring dampers, a dynamics model of the wallclimbing robot surmounting weld seam was established, and the weldseam surmounting process of the drivewheel was divided into different stages. Secondly, a numerical method was proposed to solve the dynamics model. Meanwhile, the motion state of the wallclimbing robot with different values of tire pressure when surmounting weld seam was analyzed. Finally, experiment was carried out and the experimantal results were basically consistent with the numerical simulation ones, which verified the rationality and correctness of the established dynamics model. 

Abstract:It is difficult to mathematically describe the metamorphic process of gearshift and identify its own transmission characteristics of planetary shifting mechanism. Therefore, the metamorphic theory was interpreted aiming at planetary shifting mechanism firstly. Based on the mechanism conversion method, the constraint function, which described the dynamics traits of kinematic pair between two adjacent parts was transformed into the space of relevant revolving speed. And its transformation rule was defined. The adjacent matrixes of components and their each correlation was constructed aiming at planetary shifting mechanism, whose elements were constraint functions. And according to the operation logic rule of gear shift by operating clutch and brake, the metamorphic function of shifting configuration evolution was separately deduced based on configuration adjacent matrix. The principle of configuration evolution was revealed with an example to be analyzed. The identification formula of special configurations, including neutral position and direct position were established. After the construction of relative speed functions and the identification of characteristics parameters, the automatic identification method of system transmission ratio and torque function was presented based on configuration metamorphic function eventually. It was used to automatically analyze the transmission characteristics of planetary shifting mechanism. The application of this method wasdiscussed aiming at the planetary shifting mechanism of one tractor. It was indicated that this method was feasible and effective. And it supplied the theory references for computer innovative design of the vehicle power train. 

Abstract:Aiming at the position control system of active suspension electrohydraulic servo actuator with uncertain load mass and load force, the internal model control method was used to control the position of the actuator. Firstly, according to the characteristics of the system, the linear mathematical model of the electrohydraulic servo actuator position control system was established, and then the internal model controller was designed based on the model. In order to verify the control effect of internal model controller, the simulation analysis and bench test were compared with PID controller. The step signal was used as the input signal for simulation analysis. The simulation results showed that the unit step response of the system under internal model control was fast, stable, no overshoot, and its dynamic characteristics were better than that of PID control. When the system was disturbed by external interference, it can return to the steady value more quickly and stably than PID control. The bench test included changing the frequency of sinusoidal input signal and changing the load quality. There were three kinds of experimental schemes. The experimental results showed that when the frequency of sinusoidal input signal was increased from 0.1Hz to 2Hz, the tracking performance of the system based on internal model control had no obvious change, while the tracking performance of the system based on PID control was obviously deteriorated when the sinusoidal input signal frequency was 2Hz; the test results of changing load quality showed that when the load quality was changed, the system based on internal model control had no obvious change. The variation range of tracking error was obviously smaller than that of PID control. The tracking response performance of electrohydraulic servo actuator position control system based on internal model control was better than that of PID control, and can meet the requirements of active suspension system.

Abstract:In view of the complexity of design problems, the variety of projects, the difficulty of parameterized deformation design and the high requirements for the professional quality of designers in the design process of combine harvester, appropriate parameterized design methods were sought, and the interactive design system of threshing device was studied based on Skeleton Design. This method only needed to obtain the overall design information of combine harvester equipment, and it can automatically complete the personalized design of combine harvester related parts. Taking the typical component of combine harvester—striprod drum threshing device as the research object, the concepts of Skeleton Design and process body were introduced to realize the personalized. Combined with the overall design process of striprod drum threshing device, the reasoning machine based on rules, examples and models was used to determine the values of design parameters, to establish a threshing device matching relation between structural parameters and working parameters, and then to lay a foundation for the realization of interactive design system. Meanwhile, according to the example tree of threshing device process and Skeleton Design philosophy, the personalized and parameterized design and modeling of threshing drum were completed. Visual Studio was used as the development language, providing technical support for the system, and to achieve interactive design system, and computer aided tridimensional interface application (CATIA) was applied to realize the visualization of this method on the digital interface. The application of SQL database management data realized the objectoriented language environment product design, data sharing and exchange foundation. Taking combine harvester threshing device as the research object, the process of instance design was analyzed, the relationship between instance tree and parameter configuration of threshing device was defined, and the interactive design system was completed through the integration of Skeleton Design, Visual Studio and CAITA secondary development. System test results showed that the system can reduce the specialization of researchers and improve the accuracy of the developed products at the same time, improve the design efficiency, shorten the design cycle, and easy to understand and apply, which can enhance knowledge inheritance and reusability of the model, and make it meet the grain rod roller personalized design requirements, and it can also provide reference for this kind of intelligent design problem. 

Abstract:The knotter bracket supports a series of executive parts of the knotter, and its quality directly affects the knotters knot rate. In order to eliminate the influence of casting deviation of bracket blank on machining quality, based on threedimensional scanning technology, the deviation distribution rule and deviation size of the same batch of casting bracket blank were obtained. A method of adjusting the machining position of bracket axle hole deviated from the ideal position was put forward by deducing the coordinate transformation rule of axle hole center under different space coordinate system. Aiming at the five different space axle holes and one cam surface, the five axis NC machining technology and special fixture of the bracket were designed. The machining method of five shaft holes with different spatial surfaces and one cam surface by onetime installation and clamping was designed. The processed bracket was assembled by this method and other parts into knotter, a series of executive parts cooperated accurately, and the square bale tying test was completed. The test result showed that based on the five axis NC machining method, the proposed deviation compensation method and the designed special fixture, the machining of the five different space axle holes and one cam surface can be realized by onetime installation. The relative position and angle of each axle hole on the knotter bracket were accurate, and the knotting action was accurate and reliable, the finished rate of the bracket processing was 99%, and the square bale knotting rate was 100%. 