Observer-based Composite Super-Twisting Sliding Mode Control for High-Precision Positioning Servo System

In this paper, an observer-based composite super-twisting sliding mode controller (STSMC) is designed for fast response and enhanced disturbance rejection ability for permanent magnet synchronous motor (PMSM). Towards this aim, a higher-order sliding mode observer (HOSMO) is first employed for the angular velocity and the lumped disturbance estimation. Subsequently, a novel integral-based terminal sliding mode (ITSM) surface is constructed by introducing the estimated information. Finally, a composite sliding mode controller is derived by integrating the super-twisting algorithm and disturbance feedforward compensation technique. The simulation results fully demonstrate the efficacy of the proposed approach.