PMSM Position Tracking Based On Improved Sliding Mode Reaching Law And Nonlinear Disturbance Observer

Permanent magnet synchronous motor is widely used in positioning and tracking in aviation,aerospace and other fields because of its high power density and high reliability.In the field of high-performance servo control,the dynamic and static performance of permanent magnet synchronous motor is highly required,but the traditional PID three-loop control method is difficult to meet the control performance requirements because of uncertain interference such as parameter perturbation and external disturbance in actual operation,so it is of great theoretical and practical significance to study the strategy of high-performance servo control system.In engineering application,the most widely used method for permanent magnet synchronous motor position servo system is PID three-loop control.However,the speed loop will become a series delay link,reducing the tracking accuracy of the position loop,and uncertain factors such as parameter variation and load disturbance make the integral feedback suppression effect of PID control not obvious,affecting the anti-interference ability of the system and reducing the robustness of the system.Aiming at the above problems,this paper applies the inverse sliding mode control strategy to the position servo control of permanent magnet synchronous motor.Sliding mode control has the advantages of insensitivity to system parameter disturbance and external uncertainty disturbance and strong robustness.Inverse control has strong stability and good dynamic and static performance,but sliding mode control chattering is inevitable.At the same time,the influence of parameter change and the uncertainty of the upper bound of the system have not been solved,which will affect the response speed,tracking accuracy and robustness of the control system.In order to solve the above problems,the position and speed loop is designed as an integrated loop,and the controller is designed by using the improved backstepping sliding mode control.The sliding mode reaching law consists of exponential reaching law and power reaching law,and the sign function is replaced by hyperbolic tangent function,which ensures the smoothness of sliding mode control and weakens chattering.Adaptive control is introduced to the problem of disturbance upper bound uncertainty,and the upper bound of uncertainty can be estimated.Finally,a nonlinear disturbance observer is designed,and the load disturbance is applied to the system for observation and estimation,and feedforward compensation is made to the backstepping sliding mode.In order to prove the feasibility and effectiveness of the control method in this paper,the simulation is carried out in MATLAB/Simulink software environment,and the experiment is carried out on the hardware experimental platform of Links-RT.The improved inversion sliding mode control strategy,PID control strategy and traditional inversion sliding mode control strategy proposed in this paper are compared and analyzed in hardware and software experiments.The hardware and software experiments show that the compound control strategy of improved Inversion sliding mode control proposed in this paper has better position tracking accuracy and anti-interference ability compared with the other two control methods,and can effectively improve the motor control performance.