Bearing-based prescribed-time formation control of underactuated autonomous surface vehicles with the interception of attackers

This paper studies the bearing-based prescribed-time formation keeping control problem of collaborative underactuated autonomous surface vehicles (ASVs) systems subject to malicious attacks, model uncertainties and external disturbances. For the leader-follower formation control structure, the leaders usually serve as pacemakers and play dominating role in generating the reference trajectory. On this account, it is imperative to ensure the safety of the leaders when attacks occur. To prevent the breakdown of the formation system from attacks, our control strategy mainly focuses on the following two points: 1) assigning defenders from the collaborative underactuated ASVs system to intercept the oncoming attackers, and 2) ensuring the formation keeping maneuvers of the remaining ASVs to be isolated from the influence arising from the interception mission. With these in mind, a defender allocation algorithm is developed to switch the formation keeping control mode to the interception control mode smoothly when the attackers get close to the leaders. Meanwhile, a bearing-based formation interception control strategy is developed, in which a formation keeping control scheme and an interception control scheme are designed under a unified framework by sharing the same control form and different tracking objectives. Besides, for the sake of a faster convergence rate of the resulting closed-loop system, a dynamic control gain is introduced into the formation keeping control scheme to endow the formation keeping system with a prescribed-time convergence capability. Numerical simulations are conducted to illustrate the efficacy of our approach.