Improved nonlinear sliding mode control based on load disturbance observer for permanent magnet synchronous motor servo system

This article presented an improved nonlinear sliding mode control based on disturbance observer for the permanent magnet synchronous motor servo system. The position transient response performances, such as fast response and non-overshoot, are enhanced by the introduction of novel nonlinear sliding surface in the design of sliding mode control law. In order to abolish the analysis necessity of changeable uncertainties and alleviate the system chattering, the nonlinear sliding mode control algorithm is improved by adaptive parameter estimation and saturation function. Since the improved nonlinear sliding mode control algorithm is sensitive to mismatched uncertainties which are mainly due to the load disturbance, a disturbance observer is put forward to estimate the mismatched uncertainties and is integrated into control law design to improve the positioning accuracy. The stability of improved nonlinear sliding mode control based on disturbance observer is proved based on the Lyapunov approach. The simulation results demonstrate the effectiveness and robustness of the proposed improved nonlinear sliding mode control based on disturbance observer for permanent magnet synchronous motor servo system with stationary and dynamic trajectory tracking