Command Filter-Based Backstepping Sliding mode Control for the Position tracking of the AC Asynchronous Motor Using Disturbance Observer

In order to improve the position tracking control performance of the alternating current (AC) asynchronous motor under the uncertainties caused by parameter perturbations and load disturbance, a command filter-based backstepping sliding mode control strategy is proposed using nonlinear disturbance observers (NDOs). Firstly, NDOs are designed to observe the system uncertainties, which improve the position tracking control precision of the system effectively. Secondly, the rotor flux linkage-oriented vector control scheme is adopted, and the backstepping sliding mode controllers are designed for the position subsystem and the flux linkage subsystem, respectively, which improve the dynamic and static performance and the robust stability of the system effectively. Besides, during the design processes of backstepping sliding mode controllers, command filters are adopted to estimate the virtual control inputs and their first time derivatives, which eliminate the "explosion of complexity" problem. Theoretical analysis shows that the resulting closed-loop system is bounded stability. Finally, simulation results show the superiority of the proposed control strategy in comparison with the proposed strategy without NDOs and the command filter-based backstepping control strategy.