Nonlinear Stable Transportation Control for Double-Pendulum Shipboard Cranes With Ship-Motion-Induced Disturbances

From the practical perspective, with large-scale cargoes or nonnegligible hook masses, the centers of gravity of cargoes and hooks do not coincide with each other, and shipboard cranes usually exhibit complex double-pendulum effects during ship-to-ship or ship-to-harbor transportation, which dramatically increase the complexity of dynamic characteristics and make the control issue very challenging. At present, there is no reported work on control of double-pendulum shipboard cranes yet. To tackle such problems, this paper obtains the dynamic model of double-pendulum shipboard cranes and then provides an effective nonlinear antiswing feedback controller to achieve stable cargo transportation. Specifically, new state variable signals are generated by combining the original state variables with the ship motion (induced by sea wave perturbations). Based on this, by adding some elaborately designed nonlinear terms, an antiswing feedback controller is proposed, which can achieve stable transportation with suppressed swing, and the closed-loop asymptotic stability is proven without any linearizations or approximations to the original complex nonlinear dynamics, with rigorous theoretical analysis. As far as we know, the paper provides the first solution for both controller design and stability analysis of double-pendulum shipboard cranes. Also, several groups of hardware experiments are implemented on a self-built hardware experiment platform, which verify the effectiveness of the proposed method.