Robust trajectory tracking control of underactuated surface vehicles with prescribed performance

In this paper, a robust sliding mode tracking controller with prescribed performance is developed for an underactuated surface vehicle (USV) with time-varying external disturbances. Firstly, to guarantee the transient and steadystate performance of the closed-loop system, the error transformation technique is presented. Further, the design of the prescribed performance function implements predefined tracking performance constraints, which eliminate the requirement for prior knowledge about the initial errors. Then, a Lyapunov stability synthesis shows that all closed-loop signals remain bounded and the tracking errors remain strictly within the predefined bounds. Finally, simulations and a comparative study are performed to illustrate the robustness and effectiveness of the proposed robust sliding mode control scheme.