Robust Adaptive Time Delay Control For Permanent Magnet Linear Synchronous Motor Servo System

Permanent magnet linear synchronous motor(PMLSM)has been widely used in servo control,numerical control processing and other fields,for the advantages of fast response speed,high accuracy,simple structure,etc.However,because the intermediate transmission mechanism is omitted,it is vulnerable to uncertain factors such as friction,parameter changes,external disturbances,unmodeled dynamics,etc.therefore it is difficult to achieve high precision servo control.The control proble ms of the PMLSM servo system were studied as follow.First of all,the basic structure and working principle of the PMLSM were introduced,the dynamic mathematical model of PMLSM with uncertain factors was established.At the same time,the causes of uncertainties in PMLSM and their influence on system control percision were analyzed.Then the basic principle of time delay control(TDC)was elaborated,which laid the theoretical foundation for the use of TDC scheme.Then,TDC scheme was proposed for the large tracking error in the PMLSM servo control system,which affected the accuracy of servo control.The time delay controller was designed by introducing a delay link into the system,the controller was used to suppress the impact of uncertain factors,it no t only simplified the control structure of the system,but also improved the robust performance and tracking performance of the system.The validity of the proposed scheme was verified by system simulation.Finally,although the time delay controller suppr esses the influence of uncertain factors effectively,it has the disadvantages of fixed gain control and inability to suppress the effects of the discontinuous nonlinear uncertain factors.Therefore,the robust adaptive control gain was designed by combining sliding mode control and adaptive control,and then the robust adaptive time delay controller was designed by combining TDC and robust adaptive control gain,the controller reduced the time delay estimation error by adjusting the control gain online,thereby the shortcoming of fixed gain control was overcomed.At the same time,the sliding mode control also enhanced robustness of the system,thereby the influences of discontinuous nonlinear uncertainties was suppressed.In addition,Lyapunov stability analysis was used to verify that the controller was a globally asymptotically stable controller.Finally,simulation results proved the feasibility of the controller.