State Feedback H∞ Control for Trajectory Tracking of an Unmanned Surface Vehicle

Aiming at the sway velocity and uncertainties such as wind, wave, and current, a state feedback H∞ control method is proposed to improve the dynamic and steady-state performance with line of sight (LOS) law for trajectory tracking of an unmanned surface vehicle (USV). First, a novel LOS is proposed for trajectory tracking with the position error to obtain the references of surge velocity and heading angle. Second, the LPV model is established with varying parameters of the sway velocity for the USV. Third, the closed-loop system for the LPV model is established by the state feedback H∞ control method to design the controller. Since the coupling term of system coefficients in the Lyapunov stability condition is difficult to solve directly, a novel variable is introduced to decouple the stability condition, which can be solved with MATLAB LMI tools for the controller parameters. Finally, the simulation result shows that the proposed method has super performance on the dynamic and steady-state indices.