Research On Chassis Control System Of Hillside Crawler Tractor

As the most widely used power machinery in agricultural machinery,the degree of automation of tractors is an important criterion for measuring the level of agricultural mechanization in a country.With the continuous development of science and technology,the process of tractor automation is accelerating,more and more electronic control technologies are applied to tractors.The new generation of chassis systems with hydraulic drives,electronically controlled steering,and electronically controlled actuators as actuators have been developed and become the trend of future tractor industry development.The emergence and development of the new generation tractor chassis system provides a good opportunity for the intelligent integration of the chassis control system.At the same time,the system structure is more complex,the coupling is more serious,and the control targets are more complex and diverse.So it’s more urgent to realize the integrated control of the tractor chassis system.This article takes the hillside crawler tractor independently developed by the team as the research object.According to its functional requirements,research and design the chassis control system suitable for hillside crawler tractors.The chassis control system adopts a layered coordinated control structure.First,independently design each subsystem in the chassis system,and then conduct coordinated control research on the chassis system to coordinate the work of each subsystem under different working conditions.The main research contents and conclusions of this article are as follows:(1)Scheme determination of the chassis control system of the hillside crawler tractor.According to the design requirements of the chassis control system of the hillside crawler tractor,the chassis control system structure of the hillside crawler tractor was determined by analyzing the advantages and disadvantages of the existing chassis control system structure.In order to enable the information exchange between the various subsystems and reduce the wiring harness,the CAN bus was used to realize the communication between the various subsystems of the chassis.The layered coordinated control system of the chassis of a hillside crawler tractor based on CAN bus was determined.(2)The design of chassis control subsystem of hillside crawler tractor.According to the functional requirements of the chassis control system of the hillside crawler tractor,the design scheme of software and hardware for each subsystem to realize automatic control was determined and the design of the software and hardware of each control subsystem was completed.(3)Research on coordinated control of Hillside crawler tractor chassis system.Based on the problems of mutual influence and mutual restraint among the various subsystems in the existing tractor chassis system,the mutual influence relations among the various subsystems were analyzed.A coordinated control strategy was formulated to improve the performance of the whole machine by setting the work priority of each subsystem and cooperating with each other.A coordinated driving speed control model through quadratic regression orthogonal test and machine learning method was established and the design and compilation of coordinated control software program was completed.(4)Performance test and analysis of the chassis control system of hillside crawler tractors.The test platform of the chassis control system was built on the basis of the hillside crawler tractor drive system test bench independently developed by this laboratory.The performance test of the engine throttle control subsystem was conducted and the test results showed that the throttle adjustment time ≤4s and the steady-state error ≤5.9%.The performance test of the HST angle control subsystem showed that the adjustment time ≤ 3.6s and the steady-state error ≤5%.Performance test of real-time information display and storage subsystem showed that the system was stable,can display real-time and accurate operating parameters and store data.The experiment of coordinated control of steering / braking,omnidirectional body leveling and farm implement adjustment subsystems showed them can coordinate work in an orderly manner according to priority and can be effectively avoided conflict.The experiment of coordinated control between the engine throttle and the HST angle control subsystem showed that the adjustment time of the system ≤4.5s and the relative deviation ≤8%,which can achieve stable driving speed control.