Tracking control of surface vessel systems with disturbances and deferred full state constraints

This paper studies the tracking control of surface vessel systems with unknown disturbances and deferred full state constraints, employing a continuous controller and a dynamic event-triggered controller, respectively. To ensure the tracking performance while accommodating deferred full state constraints, a continuous controller with a nonnegative time-varying gain is constructed. By adjusting the value of nonnegative time-varying gain (i.e., κ≥0), both the asymptotic tracking performance (κ>0) and the practical tracking performance (κ=0) can be realized. Compared with existing studies on state constraints, the proposed controller in this paper guarantees the stability of the closed-loop system. On that basis, a dynamic event-triggered mechanism is further developed to decrease the number of controller updates without compromising system control performance. Compared with the existing dynamic event-triggered mechanisms, the proposed dynamic event-triggered mechanism removes a certain stringent restriction. Illustrative results exhibit the feasibility and effectiveness of the presented control schemes in this paper.