Anti-disturbance control problem is studied for ship dynamic positioning systems with disturbances and thruster faults. The disturbances include slowly-varying environmental disturbances and norm bounded disturbances. For the slowly-varying environmental disturbance, a stochastic disturbance observer is established to give the online estimation. For thruster faults, a fault diagnosis observer is designed. Then, a composite anti-disturbance control (CADC) strategy is raised, which ensures asymptotic mean-square boundedness of the closed-loop system. Finally, the simulation example proves the validity of the controller.

Anti-disturbance control problem is studied for ship dynamic positioning systems with model uncertainties and ocean disturbances under thruster faults. For the ocean disturbance, a stochastic disturbance observer (SDO) is established to give the online estimation. For thruster faults, an adaptive law is used to evaluate, which is obtain from Lyapunov function. For model uncertainties, a robust control term with adaptive technology is used to attenuate it. Then, a composite anti-disturbance control (CADC) strategy is raised by combining disturbance observer-based control (DOBC), adaptive technology, and robust control term, which makes the position and yaw angle of ship reach the desired values. Finally, the simulation example proves the validity of the controller.

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This work provides an adaptive trajectory tracking control scheme for the unmanned surface vessel. The adaptive tracking control scheme builds on incorporating the fuzzy logic systems with the adaptive backstepping technique. By employing fuzzy logic systems as the approximations of ship dynamic uncertain term, the fuzzy trajectory tracking controller does not require the a priori knowledge of ship motion model dynamics. Furthermore, by using the adaptive backstepping control design, the trajectory tracking control law is derived to force the ships position and heading to track the reference trajectory. The effectiveness of the adaptive fuzzy control strategy is verified by simulation study based on a supply ship.