Underwater target encirclement by multi-UUV based on finite-time event-triggered time-varying formation

This paper studies underwater target encirclement control for underactuated Unmanned Underwater Vehicles (UUVs), with a focus on improving system convergence speed, overcoming the disturbance of ocean currents and limitations of underwater target velocity measurement, and conserving resources. Firstly, to avoid the degradation of control performance due to inaccurate target velocity measurement, a finite-time observer is designed based on the target’s position to estimate the target’s velocity. Secondly, a velocity error observer is designed to observe the velocity error between the UUVs and the target. Finally, a finite-time controller is designed based on the event-triggered mechanism to ensure that multiple UUVs encircle the target in a time-varying formation within a finite time without the need for global information of the system. The non-existence of Zeno behavior in the system is mathematically proven, and the effectiveness of the method is validated through numerical simulations.