Robust practical fixed-time leader-follower formation control for underactuated autonomous surface vessels using event-triggered mechanism

This paper investigates a practical fixed-time formation control strategy for underactuated autonomous surface vessels with unknown dynamics based on event-triggered mechanism. To deal with the leader-follower configuration without the information of leader velocity, the virtual vessel is designed to track the leader at desired bearing and distance. A concise adaptive law is developed to compensate the adverse effect of the unknown time-varying functions and unstructured uncertainty. Furthermore, the event-triggered mechanism is introduced to facilitate the smart triggering of control inputs. Different from most of the existing works, the proposed controller is with merits of smaller computation load and less energy consumption. Theoretical analysis proves that under the presented algorithm, all the tracking errors in the closed-loop system can converge to the neighborhood of origin within fixed-time settling. Meanwhile, the convergence time is independent with the initial states of the system. Finally, numerical examples are presented to demonstrate the feasibility and superiority of the proposed algorithm.