Research On Terrain Adaptive Coordinated Control And Autonomous Operation Of Tractors In Hilly Mountains

The development of intelligent and efficient agricultural machinery equipment is an important measure to improve agricultural production efficiency and relieve labor pressure.It is also the only way for the development of agricultural mechanization in my country.But for a long time,the hilly and mountainous areas have been affected by factors such as rugged terrain and land fragmentation,and the development of agricultural machinery and equipment has been relatively lagging behind.Therefore,research on hilly and mountainous tractors with high terrain adaptability,high passability and intelligence has important academic significance and huge social and economic value.Aiming at the actual problems faced by agricultural machinery and equipment in hilly and mountainous areas,this paper aims to improve the adaptability and autonomy of tractor terrain in complex environments.The existing tractors are integrated design and transformation,and the key common problems involved are studied..The main contents are as follows:(1)Aiming at the problem of rugged arable land in hilly and mountainous areas,which affects the safety and efficiency of vehicle operation,a coordinated control system for body-machine attitude is designed.The dynamic model of hydraulic components in the system is studied,and a parameter adaptive neural network PID control algorithm is proposed.The test results show that under severe working conditions with a slope of ±15°,the horizontal deviation of the lateral inclination of the vehicle body is less than 0.6497°,and the following deviation of the lateral inclination of the implement is less than 1.7620°.The control accuracy and stability of the algorithm can meet the actual operation requirements.(2)Aiming at the problems of large undulations on the road surface and soft soil,which may cause vehicle skidding and reduced trafficability,an active torque distribution system is designed.The four-wheel independent wheel speed detection system is studied,the dynamic mechanism and suppression methods that cause wheel slip are analyzed,and the wheel speed-based slip determination mechanism and torque active distribution strategy are proposed.A slip test bench was designed,and torque distribution tests were carried out for three typical working conditions: single wheel,two wheels on the same side and two wheels on the opposite side.The test results show that using the proposed control strategy,the output torque of the vehicle is increased by 126.90%,122.56%and 208.79% under the above three working conditions respectively,which significantly improves the passability of the tractor on complex roads.(3)Aiming at the problem of low intelligence of tractors in hilly areas and strong dependence on labor,an autonomous operation system is designed.The overall architecture and implementation principles of the system are studied,and the sequential logic of each key operation action during the autonomous operation of agricultural machinery is analyzed.Combined with the mechanical performance and characteristics of the experimental prototype,an autonomous operation path planning method suitable for tractors in hills and mountains is proposed.Taking advantage of the characteristics of smooth B-spline curve,guideability everywhere and low calculation amount,a method of planning agricultural machinery obstacle avoidance bypass path is proposed.Aiming at the problem of the time-varying speed of agricultural machinery operation,the RBF network is used to approximate it,and an automatic driving control algorithm is proposed.The test results show that the curve tracking accuracy and robustness of the proposed algorithm are relatively ideal,and the autonomous operating system has certain practicability.(4)Aiming at the problems of decentralized functions,low visibility and inconvenient operation of the transformed tractor,a vehicle-mounted management and remote control system was developed.The connection reliability and data transmission accuracy problems that may occur in the system data communication process are analyzed,and the heartbeat packet mechanism and CRC check method are used for data verification to ensure the high security of system operation and the high availability of various functional modules.Provide users with a set of convenient,intuitive,interactive and friendly monitoring and operation terminals.