Research On Steering Control Of Agricultural Wheeled Robot Based On Semi-physical Simulation

Agricultural wheeled robots can effectively improve farmland operation efficiency and reduce labor costs.It is an important development direction for agricultural machinery in the future.However,the high development cost of agricultural robots,insufficient reliability,and slower response of the chassis steering system restrict its further development.Promotion and application.Improving the control accuracy and response speed of the steering system is the key to improving the stability and flexibility of the robot.To this end,this paper designs an adaptive robust controller based on continuous friction compensation to reduce the impact of friction,clearance and wheel vibration between steering actuators on the steering system and improve the control accuracy of the steering system.And stability.Finally,a semi-physical simulation bench test were carried out on the designed controller to verify the effectiveness of the controller.The specific work is as follows.(1)Construction of the semi-physical simulation test bench of the steering system: The semi-physical simulation test bench of the steering system is built according to the robot’s chassis structure and technical indicators,which is mainly divided into two parts: hardware and software.The hardware part mainly includes the design of the mechanical structure of the test bench,the selection of measuring components and actuators,and the design of input and output circuits.The software part includes startup and monitoring program design,realtime control program design,and data display program design.(2)The mathematical model of the semi-physical simulation test bench of the steering system is established: first complete the mathematical model of the permanent magnet synchronous motor of the main actuator of the test bench,and then draw the structural block diagram of the control system according to the mathematical model,study the vector control of the permanent magnet synchronous motor,and design the three-loop control It establishes mathematical models of steering angle closed-loop and torque closed-loop systems,and finally completes the establishment of the test bench model through coupling.(3)Design of compound control algorithm based on feedforward compensation:Combine feedforward compensation with PID algorithm,and compare the control effect of PID control algorithm and feedforward PID compound control algorithm on the system through simulation.The simulation results show that the compound control algorithm based on feedforward compensation has obvious effects on suppressing the overshoot of the controlled system and reducing the steady-state error,but the control effect on external interference is not good.(4)Design of adaptive RISE(a robust integral of the sign of the error)controller based on continuous friction compensation: establish the system nonlinear equation based on the continuous friction model,and use the backstepping design method to design the controller based on the system nonlinear equation,and pass the definition of Lyapunov The function verifies the stability of the designed controller.Simulations are carried out under three working conditions to verify the feasibility of the algorithm.In order to further prove the accuracy of the controller,a bench test was carried out.The results show that the designed control algorithm has better performance and the built test bench can test the steering control system more accurately.