Anti-sway sliding-mode with trolley disturbance observer for overhead crane system

Abstract

Moving the suspended load along a predefined trajectory as fast as possible is not an easy controlling task due to the residual swing at the end of travelling. In this paper, the overhead crane is fully automated with the high speed trajectory. Robust scheme, namely anti-sway sliding-mode with trolley disturbance observer (DOB), are implemented with overhead crane systems. The anti-sway sliding-mode is specially designed for underactuated nonlinear systems which is derived from Lyapunov law. The asymptotic stability of switching function is proved theoretically. The controller can eliminate the error toward their sliding surfaces. Furthermore, trolley disturbance observer is also implemented to enhance the robustness. An obvious advantage of this kind of controller is based on simple control scheme however it can guarantee the robustness, speed convergence and swing suppression. In this paper, Experiment results are presented to show the superiority of the anti-sway sliding-mode with actuator's disturbance observer by comparing the effectiveness with PD controller assisting with Lyapunov based anti-sway controller and anti-sway sliding mode without disturbance observer. Not only that, but also the filtering technique is employed to eliminate chattering effect.