Research On Disturbance Rejection Control Theory And Application For Motion Control Systems

With the rapid progress of power electronic technology,manufacturing technology in integrated circuit,and modern control theories,it requires the increasing higher con-trol performance for motion control system such as in special robot,medical equipment,automotive manufacturing,machinery parts processing.Due to its complicated me-chanic structure,motion control system is a high coupling,multi-variable and nonlinear system.It is difficult to satisfy application requirement for such systems just using the conventional linear control methods.In recent years,the research and application is-sues of motion control system using nonlinear control methods have attracted the more and more attention.However,there are still many problems need to be investigated in this field.This dissertation discusses the disturbance rejection control problem of motion control system based on permanent magnet synchronous motor servo system and robot,which is the speed control problem of permanent magnet synchronous motor servo system based on continuous sliding mode control,the speed control problem of permanent magnet synchronous motor servo system based on continuous terminal slid-ing mode control,the finite-time output feedback control problem based on disturbance compensation and its application to rigid robot,the finite-time output feedback posi-tion control problem of compliant robot based on disturbance compensation,the position control problem of compliant robot for matched/mismatched disturbance compensation based on continuous sliding mode control,and the position control problem of compliant robot for matched/mismatched disturbance compensation based on continuous terminal sliding mode control.The main results and contributions of this dissertation can be summarized as follows:(1)For the speed control of permanent magnet synchronous motor servo system,two composite control methods are proposed.One method is based on continuous sliding mode control and generalized proportional integral observer.The other is based on continuous terminal sliding mode control and extended state observer.Both of composite control methods have the advantages of reducing the chattering caused by high switch function in conventional sliding mode control law and obtaining small steady state speed fluctuations by feed-forward disturbance compensation and small control gains.The advantages that are different between two methods are the following.The first composite control method can deal with time-varying disturbances,while the second is targeted to improve convergence rate of states.Moreover,the simulation and experimental results demonstrate the effectiveness of the two proposed composite control methods.(2)For a class of uncertain nonlinear systems subject to unknown time-varying disturbances,a robust finite-time output feedback control framework is proposed,and tested on rigid and compliant robots,respectively.The design process of the proposed control method consists of two steps:the design of a continuous finite-time state observ-er,and design of a finite-time output feedback controller.The continuous finite-time state observer is used to estimate the lumped exogenous and endogenous disturbance and simultaneously deliver the estimate to a corresponding controller for on-line distur-bance compensation.The finite-time output feedback controller is completed with the estimates of the states,which are delivered from the same finite-time observer.The finite-time stability of the closed-loop system is also guaranteed.The simulation and ex-perimental results on the position tracking control of rigid robot and compliant robot are given to validate the promising performance of the proposed control approach compared with the traditional asymptotical control method based on generalized proportional in-tegral observer.(3)For the position control of compliant robot in the presence of unknown matched/mismatched time-varying disturbances,two controller design schemes are introduced.The first approach is based on continuous sliding mode control and generalized propor-tional integral observer.The design process is described as follows.First,based on continuous sliding mode control,a position controller is proposed.Second,in order to tackle mismatched time-varying disturbances acting on different channels from the con-trol input in compliant robot,a composite position control method is devised based on continuous terminal sliding mode control and generalized proportional integral observer.Experimental results under three different test conditions are provided to illustrate the promising tracking performance of the proposed control strategy.For further improving the performance of the position tracking for compliant robot with unknown matched/mismatched time-varying disturbances,the second method is proposed based on the control structure of the first method,by using continuous terminal sliding mode con-trol and finite-time state observer.The design process of this method is described as follows.A position controller is firstly proposed based on continuous terminal sliding mode control.Then,a composite position controller is given via continuous terminal sliding mode control and finite-time state observer.This proposed composite control scheme can deal with matched/mismatched time-varying disturbances,and improve the tracking performance compared with the first method.Simulation results also verify the promising tracking performance.