Aiming at the potato cropping pattern in the hilly area of southwest China, a small digging device for potato harvester was designed. First, the overall structure of the harvester was determined according to the soil physical characteristic and cropping pattern of the test site. Then, the digging shovel, the key components of harvester were designed and was analyzed the relationship between the inclination of the digging shovel and the power loss under the conditions of different digging speed, digging depth and soil bulk density by MATLAB software, and the mathematical models were established. Finally, the three-dimensional model of the whole machine was established by SolidWorks, and the simulation experiment was carried out with the model of soil particles, potato particles and potato ridges created by the discrete element (DEM) software. The simulation results show that when the working speed of the harvester is 1 m/s, the digging depth is 170 mm, and the potato expose rate is 87.3%. Under normal working conditions of the digging device, appropriately reducing the digging depth can reduce the resistance and wear of the digging shovels.

[目的]针对大豆玉米气吸式精量播种机在作业过程中出现的漏播现象,设计一种实时的自动补种系统,并通过台架试验验证系统工作性能、确定补种系统的最优参数组合,以减少播种作业中的漏播指数.[方法]利用对射式光电传感器对播种情况进行检测,当检测到漏播时由步进电机驱动补种装置进行补种.[结果]以玉米种子为研究对象,通过多因素试验和响应曲面法分析,补种装置在真空度为4.3 kPa,补种盘转速为27 r/min、吸种孔直径为5 mm时补种效果最优.台架试验表明,当补种系统的参数为最优时,播种合格指数为93.68%、漏播指数为2.38%,合格指数较原排种装置上升2.34%,漏播指数较原排种装置下降3.09%.[结论]研究设计的补种系统能实现实时补种、提高播种合格指数、降低漏播指数.

In order to improve the automation level of the crawler tractor leveling system, an adaptive leveling control system was designed for the developed crawler tractor leveling device. The overall hardware of the leveling control system was determined and the software system of the leveling device was designed using the proportional algorithm. The designed leveling control system is composed of the real-time detection part, control part, driving part and display part. The system can realize the real-time detection of the tractor inclination angle, and complete rapid leveling of the leveling device. The test results of the leveling control system show that the leveling accuracy and leveling time of the lateral and longitudinal slope increase with the increase of the tractor inclination angle. The leveling accuracy and stability of the longitudinal slope are better than that of lateral slope leveling, and the leveling speed is higher than that of the lateral slope. The coordination leveling accuracy is higher than the independent leveling accuracy of the lateral slope and longitudinal slope, and the collaborative leveling accuracy of the longitudinal slope is better than that of the independent leveling accuracy. The developed leveling control system can independently complete the leveling work under the actual working conditions of the crawler tractor. The leveling accuracy can be in 1° and the leveling time is in 0-6 s. The leveling accuracy and time can meet the design requirements.

In view of the problems of the output power and operation, when the multi-function machine in hilly and mountainous areas driving in the field, the hydraulic control drive system of small multi-function agricultural hydraulic chassis is designed. The key components of the hydraulic drive system were selected and matched. The hydraulic system simulation model was established in AMESim simulation analysis software, and the dynamic analysis of the hydraulic system operation under different conditions is carried out. The simulation analysis results show that the hydraulic system has a large impact and vibration when it is started instantaneously, and the hydraulic system has smaller impact and vibration when it is started stably. It is consistent with the actual working state of the hydraulic chassis. Under the two starting controls, the maximum flow of the hydraulic pump is 50L/min, the motor torque is about 440N • m, and the motor stable pressure is 6Mpa, the motor speed is 96 r/min, which is within the bearing range of the hydraulic components. The simulation output parameters are basically consistent with the theoretical calculation results, and meeting the design requirements. The chassis performance test results show that the maximum crossing height of the chassis is 200mm, the crossing width is 300mm, the maximum deviation of high-speed straight driving is 2.57m, it can stably pass 20° slope, and the operation is stable and the steering is flexible. All performance parameters can better meet the requirements of chassis operation in hilly and mountainous areas.