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.
International Journal of Robust and Nonlinear Control, EarlyView. Read More
