Fixed-Time Three-Dimensional Formation Control for Underactuated Autonomous Underwater Vehicles via Event-Triggered Mechanism

This research presents a fixed-time three-dimensional formation control strategy for underactuated autonomous underwater vehicles (AUVs) utilizing an event-triggered mechanism. The study introduces virtual AUVs to transform the formation control problem into a trajectory tracking challenge. A virtual velocity regulation law is developed for virtual AUVs, enabling follower AUVs to track the reference position through virtual AUVs without requiring the leader autonomous underwater vehicle’s velocity information. To manage system uncertainties, the research implements a fixed-time disturbance observer based on AUV dynamic models, providing accurate estimations of parameter uncertainties and external disturbances. Through the backstepping approach, an expected velocity regulation law is formulated for underactuated AUVs, ensuring position tracking error convergence within a fixed time. Additionally, a fixed-time dynamic controller is implemented to facilitate rapid achievement of expected velocity by the follower AUV, while the event-triggered mechanism reduces control input triggering frequency. The stability analysis, based on Lyapunov theory, demonstrates that the closed-loop system’s tracking error converges to a compact residual set within a fixed time. Comparative simulation results confirm the proposed algorithm’s enhanced performance.