Fixed-time Trajectory Tracking Control of a Full State Constrained Marine Surface Vehicle with Model Uncertainties and External Disturbances

This paper addresses the fixed-time trajectory tracking control problem of a fully actuated marine surface vehicle with full state constraints and system uncertainties. A continuous fixed-time convergence tracking controller is proposed based on fixed-time control and adding a power integrator methods, which achieves system stabilization within a finite time independent of system initial conditions. Moreover, a novel barrier Lyapunov function with a power integrator is designed to ensure the full state tracking error within the constraints. To accurately estimate the lumped disturbances of the vehicle system, a fixed-time disturbance observer is designed to guarantee the settling time of the disturbance observer bounded by a time constant independent of initial estimation errors. Finally, the proposed control scheme is proved to be fixed-time stable via fixed-time Lyapunov stability theorem and the full state constraints can never be violated. A numerical simulation is provided to illustrate the effectiveness and superiority of the proposed control scheme.