Leader-Follower Formation Tracking Control and Stabilization of Underactuated Unmanned Surface Vessels via Event-Triggered Mechanism

This paper addresses the control problems of formation trajectory tracking and formation stabilization simultaneously for multiple underactuated unmanned surface vessels (USVs) under a directed communication network. Firstly, because only a subset of followers has access to the leader’s information, a distributed observer is presented for each follower to estimate up to second order time derivatives of the virtual leader’s states. Then, an error state transformation scheme is introduced to overcome the difficulties caused by the off-diagonal terms in the inertia matrix and the underactuated dynamics. Based on the above results, a distributed formation control strategy is designed for multiple underactuated USVs to achieve formation trajectory tracking and formation stabilization simultaneously, where the event-triggered control mechanism is applied to reduce the communication burden and decrease switching frequencies of inputs. Some comparative simulations are performed to illustrate the effectiveness of the proposed method.