In this paper, the formation control problem is investigated for a team of uncertain underactuated surface vessels (USVs) based on a directed graph. Considering the risk of collision and the limited communication range of USVs, the prescribed performance control (PPC) methodology is employed to ensure collision avoidance and connectivity maintenance. An event-triggered mechanism is designed to reasonably use the limited communication resources. Moreover, neural networks (NNs) and an auxiliary variable are constructed to deal with the problems of uncertain nonlinearities and underactuation, respectively. Then, an event-triggered formation control scheme is proposed to ensure that all signals of the closed-loop system are uniformly ultimately bounded (UUB). Finally, simulation results are presented to demonstrate the effectiveness of the proposed control scheme.

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The leader–following consensus issue is investigated for multiagent systems under external disturbances and denial-of-service (DoS) attacks. DoS attacks are considered to be designed according to an unknown attack strategy and would block the communication network. First, a novel triggering mechanism is designed to save communication resources during normal communication periods by event-triggered strategy and to detect the end of attack periods by time-triggered strategy. Then, a set of estimators is constructed to predict the states of the agent itself and its neighbors when the attack occurs. The estimators do not contain the control signals, which only correct the prediction when the actual system states are received. As a result, a distributed switching controller is designed that includes event-triggered states during normal communication periods and predicted states during attack periods. Finally, the proposed secure control protocol is proven to ensure that the system states are eventually consensus and the Zeno behavior is not exhibited. Moreover, a simulation example is given to illustrate the effectiveness of the presented strategy.