Research On Model Predictive Control Algorithm For AC Servo System With Disturbance And Friction

Permanent magnet synchronous motor(PMSM)has many advantages such as small torque ripple,high efficiency and high torque inertia ratio,so it has been more and more widely applied in AC speed regulation system.However,under the actual working conditions such as low speed friction and disturbances like load mutation and parameter changes.Therefore,more and more advanced control algorithms are applied to servo system.The main work of this paper is to apply the very mature model predictive control algorithm in the industrial process control to the permanent magnet synchronous motor speed control system,and the optimal control sequence under the comprehensive performance target is obtained through the rolling optimization of model predictive control.Considering the actual working condition of strong disturbance and low speed friction,the model predictive control based on GPIO and model predictive control based on friction model are designed respectively to improve the performance of the motor under different complex conditions.Firstly,the paper introduces the current development of AC speed regulation system,the characteristics of several main control algorithms of current AC speed regulation system,the mathematical model of PMSM and the implementation of PMSM speed regulation system based on vector control.After that,the theory of model predictive control is introduced,and the speed loop model predictive controller is designed for PMSM speed regulation system.Simulation and experimental research on its parameter adjustment law and control performance are carried out.Then,aiming at the characteristics of motor load mutation and parameter changes under strong disturbance,the design and simulation of speed loop model predictive control based on GPIO is studied.The simulation results show that the designed model has stronger anti-disturbance performance than the conventional model predictive control.Finally,taking into account the performance deterioration brought by friction in high-precision servo applications such as CNC machine tools and industrial robots,the speed loop model predictive control considering the friction model is proposed.The Stribeck friction model is identified offline and the output of the predictive model is compensated online.The simulation results show that the position tracking "flat roof" and velocity "dead zone" are effectively improved under low speed of servo system.