Adaptive practical prescribed-time fault-tolerant control for autonomous underwater vehicles trajectory tracking

This article investigates the practical prescribed-time trajectory tracking control problem for AUVs with parametric uncertainties under tracking error constraints and velocity constraints. A settling time regulator is combined to construct the performance function, with which we build a new adaptive fault-tolerant control scheme upon the transferred error, ensuring that the tracking error converges to an adjustably small residual set within the prescribed time with a continuous control action. Furthermore, with the specific velocity transformation techniques, the problem of velocity constraints is transformed into the boundedness of new variables, thus the feasibility conditions are eliminated, and the requirements of constrained boundary functions are relaxed. Theoretical analysis shows that the proposed control method is an effective way to achieve pre-given tracking precision within the prescribed time, while avoiding the issue of explosion of complexity. The prescribed time is independent of system initial conditions and other parameters, and the tracking error will converge asymptotically. Simulation results further demonstrate the effectiveness of the proposed approach.