Recursive sliding mode control of dual-motor synchronous drive servo system based on disturbance observer

This article addresses the disturbance rejection problem in dual-motor servo systems subject to external disturbance torque by proposing a recursive nonsingular terminal sliding mode control strategy based on a finite-time disturbance observer. First, independent finite-time disturbance observers are designed for each motor, and the estimated values are directly incorporated into the recursive sliding surface for compensation. On this basis, a recursive nonsingular terminal sliding mode controller composed of four sliding surfaces is constructed, ensuring fast and smooth convergence of system states within finite time. Furthermore, a carefully designed reaching law effectively suppresses chattering, reducing actuator wear, while a synchronization feedback signal is introduced into the controller to ensure precise coordination between the two motors. Lyapunov-based stability analysis confirms the finite-time stability of the closed-loop system. Comparative simulation results demonstrate the proposed strategy’s superior performance in disturbance rejection, tracking accuracy, and synchronization precision, validating its effectiveness over existing methods.