Fixed-Time Integral Terminal Sliding-Mode Control With Super-Twisting Nonlinear Extended-State Observer for Servo System With Disturbances

In this article, a novel composite sliding-mode control (NCSMC) scheme is proposed for the servo system with disturbances. First, the funnel control is provided to constrain the output state, which can construct the system with some original system properties. Second, a fixed-time integral terminal sliding-mode surface is developed to shorten the tracking error convergence speed. A super-twisting nonlinear extended-state observer is designed to estimate the load disturbances. Then, the robust integral of the sign of the error is incorporated into the observer design, which provides the feedforward compensation to improve the system robustness. The proposed control scheme can achieve efficient speed tracking and disturbance suppression. The stability analysis of the closed-loop system is rigorously given by the Lyapunov stability theory. The real-time experiments have been carried out on a permanent magnet synchronous motor platform to show the effectiveness of the proposed control approach.