Research On Automatic Driving Of Tractor Based On Beidou Navigation

With the continuous development of China's industrialization,more and more young workers have participated in industrial manufacture.However,agricultural modernization has become a short board in China because of the loss of labor force and the aging of population.Precision agriculture developed in some countries has reduced the number and pressure of workers and improve productivity by combining advanced science and technology with agricultural production.The autonomous navigational tractor can be located by satellites in precision agriculture.At present,BDS was promoted in the market,and research of autonomous navigational tractor based on BDS could give the upgrading of traditional agriculture and the development of BDS.Control system of autonomous navigational tractor based on SL704 tractor was studied in this paper,focused on path tracking control system,positioning system,speed adaptive control system and automatic steering system.The research contents of this paper are as follows:Firstly,the problems of steering system and path tracking control system of autonomous navigational tractor were proposed and research scheme and technical route were determined after consulting literatures and analyzing the current research methods and technologies at home and abroad.Secondly,the overall control scheme and upper computer system were determined.The selection and modification of electromagnetic proportional directional valve and components were completed by analyzing the automatic steering oil circuit system.The equipment of automatic brake and throttle were designed to improve the tracking precision in the case of turn round.The steering controller and brake throttle motor controller were designed and the test platform of autonomous steering tractor was constructed based on modified mechanical structure.Thirdly,the kinematic model and dynamic model of tractor were established by analyzing the longitudinal and lateral movement of the tractor.The path tracking method was proposed based on pursuit algorithm by analyzing the common tracking algorithm.A modified Smith predictive control method was used to improve the delay problem of traditional PID controller.The simulation model of the whole system of autonomous navigational tractor was established by using Matlab/Simulink and Carsim.Finally,in order to examine the actual effect of the designed controller,the path tracking experiment was conducted and results were analyzed based on the built SL704 tractor platform.