This study focuses on the problem of finite-time tracking control for underactuated surface vessels (USVs) through sliding-mode control algorithms with external disturbances. Considering the nonexistence of relative degree caused by the underactuated property, the initial tracking error system is firstly transformed to a high order system for the possibility of applying a sliding-mode control algorithm. Subsequently, a finite-time controller based on an integral sliding surface (ISMS) is designed to achieve trajectory tracking. With the aid of this controller, the tracking errors converge to a steady state in a finite time. In contrast to the backstepping-based approach, the proposed method makes it possible to integrate controller design of position tracking and attitude tracking in one step, thus ensuring simplicity for implementation. Finally, theoretical analysis and numerical simulations are conducted to confirm the effectiveness of the proposed method.

This paper investigates the problem of distributed dynamic event-triggered formation control for multiple unmanned surface vehicles (USVs) subject to external disturbances. Firstly, a novel event-based distributed formation control scheme is proposed, under an undirected communication graph. Wherein, a dynamic event-triggered data transmission mechanism is designed for communication resource reduction. The time-varying dynamic parameter ensures fewer triggering instants and a larger triggering time interval compared with the traditional static one. The adaptive laws are incorporated into the formation control scheme to address the effects of external disturbances and uncertainties. Subsequent to the theoretical analysis, it can be concluded that the relative tracking errors can converge to the origin, and all closed-loop signals are bounded. Moreover, it is proved that the triggering time sequences do not exhibit Zeno behavior. Finally, a numerical simulation is performed to verify the effectiveness of the proposed distributed formation controller.