Predictive Sliding Mode Control Of Maxwell Fast Tool Servo System

This thesis takes Maxwell fast tool servo(MFTS)system as the research object,which is based on sliding mode control(SMC)theory,and combines model predictive control(MPC)theory.Aiming at the uncertainty problem of parameter change and external disturbance in Maxwell fast tool servo system,the trajectory tracking control of Maxwell fast tool servo system is studied to meet the dual requirements of tracking accuracy and anti-interference performance of Maxwell fast tool servo system.The main research contents are as follows:Firstly,the basic structure,basic principle and moving process of Maxwell fast servo system are analyzed,and the mathematical model of the system is obtained according to its motion equation.Secondly,in the case of ultra-high precision machining,Maxwell fast tool servo system requires high tracking accuracy and anti-interference performance.In order to solve the problem of tracking accuracy decline caused by uncertainties such as parameter changes and external disturbances in Maxwell fast tool servo system,a control strategy combining integral sliding mode control method and model predictive control method was adopted to design the controller.On the one hand,the sliding mode control has strong robustness to system parameter changes and disturbances.On the other hand,the chattering problem of sliding mode is improved by replacing the switching control part of sliding mode control with predictive control,so as to improve the tracking accuracy and anti-interference performance of Maxwell fast tool servo system.The control system is modeled and simulated by using MATLAB/Simulink,and compared with the integral sliding mode control method.The simulation results verify the feasibility and correctness of the control strategy.Finally,the predictive terminal sliding mode controller is designed by combining the discrete terminal sliding mode control method with the predictive control method to solve the uncertainties such as parameter changes and external disturbances in the Maxwell fast tool servo system,so as to improve the tracking accuracy and anti-interference performance of the system.The terminal sliding mode control makes the state of the system converge to the equilibrium point in finite time by introducing the non-linear part,which improves the convergence speed of the system.The control system is modeled and simulated by using MATLAB/Simulink,and compared with terminal sliding mode control method and predictiveintegral sliding mode control method.The simulation results verify the feasibility and correctness of the control strategy.