Adaptive fuzzy controller design for dynamic positioning system of vessels

• An adaptive fuzzy controller has been developed for the DP system of vessels.
• Doesn't require a priori knowledge of vessel's model parameters and disturbances.
• Adaptive fuzzy system is used to approximate the uncertain term in the DP system.
• Vectorial backstepping method is used in the adaptive fuzzy controller design.

This paper develops an adaptive fuzzy controller for the dynamic positioning (DP) system of vessels with unknown dynamic model parameters and unknown time-varying environmental disturbances. The controller is designed by combining the adaptive fuzzy system with the vectorial backstepping method. An adaptive fuzzy system is employed to approximate the uncertain term induced by unknown dynamic model parameters and unknown time-varying environmental disturbances. It is theoretically proved that the proposed adaptive fuzzy DP controller can make the vessel be maintained at the desired values of its position and heading with arbitrary accuracy, while guaranteeing the uniform ultimate boundedness of all signals in the closed-loop DP control system of vessels. Simulation studies with comparisons on a supply vessel are carried out, and the results illustrate the effectiveness of the proposed control scheme.