Adaptive robust tracking control for an offshore ship-mounted crane subject to unmatched sea wave disturbances

• Published in: Mechanical systems and signal processing Vol. 114; pp. 556 - 570
• Main Authors: Qian, Yuzhe, Fang, Yongchun, Lu, Biao
• Format: Journal Article
• Language: English
• Published: Berlin Elsevier Ltd 01.01.2019; Elsevier BV
• Subjects: Adaptive control; Adaptive robust control (ARC); Computer simulation; Disturbances; Mechanical properties; Nonlinear systems; Offshore; Offshore crane systems; Parameter robustness; Parameter uncertainty; Robust control; Sea currents; Tracking control; Tracking control systems; Unmatched disturbances; Vertical orientation; Offshore crane systems; Unmatched disturbances; Tracking control; Adaptive robust control (ARC)
• ISSN: 0888-3270; 1096-1216
• DOI: 10.1016/j.ymssp.2018.05.009

•The paper firstly achieves adaptive robust tracking control for offshore ship-mounted cranes.•Unmatched sea wave disturbances are taken into consideration.•Comparative hardware experiments verify the effectiveness of the proposed method. An offshore ship-mounted crane consisting of a trolley, a wire, and a payload, is a typical nonlinear underactuated system, which suffers from unmatched disturbances mainly caused by sea waves and currents. Besides, unknown or uncertain parameters may cause vertical positioning errors or make accurate gravity compensation impossible, which may induce various risks during the transportation process. In terms of the aforementioned problems, this paper studies the adaptive robust tracking control problem for an offshore ship-mounted crane. In particular, a new adaptive robust coupling control approach, with adaptive laws included to deal with unknown parameters, and robust terms included to handle unknown disturbances, especially unmatched disturbances, is constructed in this paper, which achieves simultaneous load swing suppression and disturbances elimination. Without any approximation to the original nonlinear model, it is rigorously proven that the proposed method can ensure the stability of the overall crane system’s equilibrium point, as supported by Lyapunov techniques. Finally, some contrast simulations and experimental results are collected to verify the superior performance of the proposed controller.