Research On Auxiliary Driving System For Tractor Based On Beidou Satellite Navigation

Tractor auxiliary driving technology is the development of agricultural machinery automation and intelligent requirements,which is of great significance to the realization of precision agriculture.Tractor auxiliary driving system can not only reduce the driver's work intensity,but also can improve the job accuracy and production efficiency.This paper studies the automatic steering and path tracking algorithms in tractor assisted driving technology,Taking DF904 tractor as the research object,combined with Beidou satellite high precision positioning equipment,using PID algorithm control to achieve automatic steering,variable universe fuzzy algorithm to achieve path tracking.The PID parameter values are optimized by genetic algorithm,and verified by simulation and experiment.The main research work and results are as follows:(1)The overall scheme and the hardware selection of the automatic navigation system of the tractor are determined.The satellite navigation auxiliary driving system is composed of two parts: the path tracking system and the automatic steering system.According to the functional requirements of these two systems,respectively,the hardware selection and integration.(2)The automatic steering control algorithm is designed.By analyzing the bench test data,the tractor steering mathematical model is obtained,According to the steering model,the appropriate PID parameters are determined by genetic algorithm in Matlab environment,and the steering simulation experiment is carried out in Matlab/Simulink environment.The genetic algorithm is used to optimize the PID parameters to control the accuracy of automatic steering.(3)The path tracking control algorithm is designed.In view of the fact that the tractor has strong non-linearity and uncertainty when traveling on the scheduled path,and the control accuracy is low when the path deviation is small,this paper is concerned with the fuzzy control Based on the theory of fuzzy control,the fuzzy controller is used to dynamically change the input and output domain,that is,the initial domain changes with the input change when the fuzzy rule is invariant,and thefuzzy control is solved at the "zero point"(The deviation is very small)near the control accuracy of the problem.And the path tracking simulation experiment is carried out in Matlab/Simulink environment.The simulation results show that the fuzzy control of variable universe can effectively track the tractor.(4)Experimental Research.The tests included bench test and path tracking test.The bench test was carried out under the control without any algorithm and PID control.The steering model of the tractor and the steering performance under the PID control were determined by experiment.The path tracking test is a straight path tracking when the speed is 3km / h and 4km / h on the flat road and the potholes.The results show that the average error in the lateral position on the flat surface is less than3 cm.The trapping on the pavement pavement can quickly and accurately correct the deviation and return to the predetermined path.This paper completes the development of the auxiliary driving system of the tractor based on the Beidou navigation,and tests the performance of the system through simulation and experiment.Experiments show that the satellite navigation assisted driving system can be achieved by the tractor according to the scheduled path automatically.