Research On The Plowing Depth Automatic Control Of Tractor Hydraulic System Based On Electronic Control

Based on the Dongfanghong 804 agricultural tractor as the research prototype, we have designed a set of electric hydraulic suspension system. Using electro hydraulic proportional directional valve and control panel to replace the original distributor and operating mechanism. The status parameters of tractor were collected by sensors, and sent out to the controller, then the controller sent out the corresponding instruction to the electro hydraulic proportional directional valve according to the received message.Eventually, the function of force control, position control and force-position combined control were realized in the upgraded tractor.In this paper, the overall design of the controller is discussed from two aspects of hardware circuit and software, which contains the design of minimum system circuit,signal acquisition circuit, CAN communication circuit, RS232 serial conversion circuit and LCD display circuit, system main program and various types of subroutine. Finally,the controller is designed according to the relevant design. In addition, this paper analyzed the relationship between the traction force and the plow depth, and then introduced a resistance coefficient, the introduction of this coefficient can significantly reduced the deviation between the online tillage depth and the target depth in the force control and comprehensive control of force position, and improved the precision of the depth control.The P-control scheme was applied to the suspension depth control strategy, effectively enhance the response speed of the control system, the P- fuzzy control scheme can reduce the fuzzy range of the domain, improve the system accuracy.In order to verify the feasibility of the system design, the control precision and stability of the system, we carried out the relevant field experiments. Through the analysis of experimental data, the electronic control hydraulic suspension system can meet the requirements of the tractor in the aspects of operation response rate and operation stability.