Adaptive Sliding-Mode Antisway Control of Uncertain Overhead Cranes With High-Speed Hoisting Motion

This paper proposes an adaptive sliding-mode antisway control law for uncertain overhead cranes with high-speed hoisting motion. Since the sway dynamics are disturbed by the trolley acceleration and hoisting velocity, antisway control law is designed based on the sliding mode control by defining a sliding surface in such a way that the trolley acceleration contributes to the sway dynamics as nonlinear damping in sliding mode. In addition, this nonlinear damping is designed such that it dominates the inherent damping coupled with the hoisting velocity so that the asymptotic stability of the sway dynamics can be achieved. To cope with system uncertainties such as system parameter variations, unknown actuator nonlinearities, unmodeled dynamics, and external disturbances, we design a fuzzy uncertainty observer and incorporate it into the sliding-mode antisway control law. Via the stability analysis and computer simulations, we show that the proposed control law guarantees the robust antisway performance of overhead cranes, regardless of hoisting velocity, even in the presence of system uncertainties.