Anti‐Disturbance Anti‐Swing Control Based on Improved Back‐Stepping Method for Overhead Cranes

ABSTRACT As a typical underactuated system, the overhead crane is highly susceptible to oscillations and instability under external disturbances. To address this issue, an anti‐disturbance control strategy is proposed by integrating the back‐stepping method with a nonlinear disturbance observer. First, the crane system is reformulated into a novel strict‐feedback form without linearization or approximation, and the lumped disturbances are defined accordingly. Subsequently, a nonlinear disturbance observer is designed to estimate these disturbances in real time. Based on the estimation results, a back‐stepping‐based controller is constructed, and a robust enhancement term is added to suppress the influence of observation errors. Lyapunov stability theory is then employed to rigorously prove that the closed‐loop system is uniformly ultimately bounded under various disturbances, ensuring that the state errors remain within a prescribed bound. Finally, simulations in MATLAB/Simulink demonstrate the effectiveness and robustness of the proposed control strategy.