Hybrid Sliding-Mode Position-Tracking Control for Servo System With External Disturbance

In this article, the issue of position-tracking control of servo system with external disturbance is studied. A novel hybrid second-order sliding-mode control (HSSMC) strategy is proposed. To be specific, first, the uncertainties of motor parameters and load torque are considered as lumped disturbance, and an adaptive extended sliding-mode disturbance observer (AESMDO) is designed in order to estimate the disturbance. Second, a new terminal sliding-mode function is presented, and a super-twisting controller based on AESMDO is designed. In which, a nonlinear switching term is brought to weaken the chattering of the system. Furthermore, the convergence of terminal sliding-mode surface and the stability of controller are proved. Finally, the simulation and experiment are executed to verify the effectiveness of the proposed method.