Block disturbance observer-based sliding mode control for ship-mounted crane

The ship-mounted cranes are widely used to transfer heavy cargos between ships and other transportation devices. This paper proposes a block disturbance observer-based sliding mode control method for suppressing the payload sway and achieving accurate positioning. In particular, the proposed block disturbance observer availably estimates external disturbances due to ship rolling, pitching and heaving for ship-mounted crane systems, and which are fed back to the input as compensation signals. By designing nonlinear sliding surface, the payload can arrive at their desired positions quickly while suppressing the payload swing simultaneously. Simulation and experimental results show the effectiveness of the proposed control scheme. Using this method, oscillations are reduced to less than 10 cm during transfer.