An Adaptive Controller for Payload Swing Suppression of Ship-Mounted Boom Cranes

The ship-mounted crane is a typical system for completing marine projects, which often need to work in complex sea conditions. Besides, it has complex nonlinearity and is also a typical underdrive system. These factors increase the difficulty of the controller design. Traditional control strategies based on gravity compensation are mostly used in full-drive systems, which can effectively reduce the influence of gravity uncertainty on the system positioning error and save driving energy. However, the actuator oscillation problem of underdrive systems, such as the swing of the payload of ship-mounted crane systems, has not been fully solved. This paper proposes an adaptive swing suppression controller based on the gravity compensation of a (3-DOF) ship-mounted boom crane. Specifically, the influence of gravity on system stability is reduced by estimating unknow gravity parameters through adaptive functions. Combine the swing angle information of the payload with the control output to eliminate the remaining swing of the payload. The auxiliary term in the controller reduces the difficulty of subsequent stability analysis, and also has a certain resistance effect to steady-state oscillation. Next, with the help of the Lyapunov stability theory and LaSalle’s invariance theorem, the proof of the asymptotic stability of the closed-loop system is completed. Finally, this paper verifies the effectiveness of the proposed control method successively through numerical simulations, and the simulation data has the potential to improve the robustness of the proposed controller in different marine environments.