Multi-Layer Formation Maneuvering Pursuit–Evasion Control for Underactuated Unmanned Surface Vehicles with Uncertainties and Collision Constraints

Pursuit–evasion tasks involving multiple unmanned surface vehicles (USVs) in complex maritime environments present significant challenges in terms of adaptability, intelligence, and robustness. This paper proposes a novel multi-layer formation control method to significantly improve the maneuverability of USV formation in dynamic pursuit scenarios. The primary contributions of this work are threefold: (1) The development of a maneuverable pursuit–evasion decision layer that enables strategic encirclement of the evader is proposed, which can flexibly adjust the encirclement strategy for the evader and reduce the resource consumption of USVs based on the Apollonius circle-based multiple-angle encirclement strategy and the artificial potential field (APF). (2) A coordination layer based on the trajectory prediction of the evader is designed. This layer introduces a Head-Guidance (HG) operator into the APF to dynamically predict the evader trajectory with motion constraints and assist the Pursuit team to complete tasks. (3) A novel pursuit–evasion distributed Model Predictive Control (MPC) layer that ensures robust formation tracking and collision avoidance is proposed. This layer is specifically engineered to handle not only dynamic obstacle constraints but also lumped uncertainties. The overall performance of the proposed multi-layer framework is verified via abundant numerical simulations under complex marine disturbances and multiple obstacle environments, and the developed fixed-time extended state observer is validated with a real-water field experiment with a single self-developed USV prototype.