A Bio-Inspired Pursuit–Evasion Game and Fixed-Time Safety Control Method for USV Swarm Encirclement

Unmanned Surface Vehicle (USV) swarms face significant challenges during dynamic target encirclement in complex marine environments, particularly regarding strong target maneuverability and strict safety constraints. To address these issues, this paper proposes a novel encirclement and capture method. The proposed approach integrates a bio-inspired pursuit-evasion dynamic game with fixed-time safety control. Drawing on the behavioral mechanism of dynamic cooperative blocking and escape space compression in group predation in nature, a multi-pursuer single-evader dynamic game model is established. The payoff functions of pursuers and the evader are constructed to characterize the strategic interaction between both sides, and adaptive cooperative encirclement strategies for the USV swarm are generated based on dynamic game equilibrium. To address environmental disturbances and the requirement of rapid response in complex marine environments, a fixed-time safety controller is designed. Taking the desired encirclement positions generated by the dynamic game as control objectives, a safety constraint mechanism is constructed by introducing control barrier functions, which achieves rapid convergence and cooperative collision avoidance of the USV swarm. Furthermore, the fixed-time convergence of position errors and the satisfaction of safety constraints for the control system are proven via Lyapunov stability theory. Finally, dynamic target encirclement numerical simulations under ocean current disturbances verify the effectiveness of the proposed method. The results demonstrate that the USV swarm can adapt to continuous target maneuvering, realize stable encirclement and capture, and satisfy safety constraints.