Anti-swing positioning and anti-disturbance control of the offshore crane using global sliding mode control

This paper is motivated by the control issues of offshore cranes in the existence of external disturbances. Compared with the sliding mode control methods, the proposed sliding mode control method is continuous and has global robustness with respect to disturbances. To our knowledge, this paper presents the first continuous global sliding mode control method for offshore cranes. Specifically, the dynamics of the offshore cranes system are given and rearranged through the model transformation for the convenience of control design first. Then, new state variables are constructed and corresponding error dynamics are derived. After that, a global sliding surface is designed and a corresponding continuous sliding mode controller is put forward for the regulation control and disturbance rejection control of the offshore crane system. Subsequently, based on Lyapunov technique and LaSalle’s invariance principle, we provide a comprehensive and rigorous stability analysis of the closed-loop system. Finally, simulation tests are carried out to demonstrate the efficiency of the proposed controller.