Adaptive Fuzzy Control via Command Filtering and Backstepping for Ship Course-Keeping

With increasing marine transportation and logistics, the ship autopilot has become much more important not only to lower the seaman's operating intensions, but also to reduce the seaman's deployment. It is still a challenge to design ship coursekeeping controller because of ship's uncertain dynamics and time-varying environmental disturbance. This study focuses on backstepping adaptive course-keeping controller design for ship autopilot. Takagi-Sugeno (T-S) fuzzy approximation can formulate ship motion's uncertainties. Therefore, the proposed controller has no need of a priori knowledge about ship's system dynamics. Command filtering can bypass the iterative differential manipulations in adaptive backstepping controller for conventional ship course. The design can guarantee the ultimate uniform boundedness of the signals in closed-loop system. Finally, simulation study verifies the efficiency of the ship course-keeping design.