Command Filter Backstepping based Trajectory Tracking Control of Underactuated Surface Vessels

This paper focuses on the trajectory tracking control problem for underactuated surface vessels with ocean environment disturbances. To overcome difficulty caused by the underactuation, an output redefinition method is adopted to redefine the vessel position outputs. An adaptive law is designed to estimate the upper bounds of the ocean environment disturbances. On the basis of the above, a trajectory tracking control law using the command filtered backstepping control method is proposed and the "differential explosion" problem could be avoided comparing with the conventional backstepping method. Theoretical analysis and simulation results show that the proposed control law can force the underactuated surface vessels to track the desired trajectory, while all signals in the trajectory tracking closed-loop control system are proved to be uniformly ultimately bounded.