Asymptotic Stabilization of USVs With Actuator Dead-Zones and Yaw Constraints Based on Fixed-Time Disturbance Observer

This paper investigates the problem of asymptotic stabilization of underactuated surface vehicles (USVs) with actuator dead-zones and yaw constraints. By transforming the system model into two subsystems, a backstepping control method based on a Barrier Lyapunov Function (BLF) is introduced to stabilize the transformed system and prevent the USV from reaching the boundaries of yaw angle and velocity constraints. A fixed-time disturbance observer is involved in the USV controller to deal with actuator dead-zones and disturbances. The method is extended to cover the case in which the yaw constraints are time-varying and the initial states exceed the constraint regions. Numerical simulations have shown the effectiveness of the presented method.