Adaptive fixed-time dynamic surface path following control for underactuated ships with input delay

Abstract

This paper proposes a novel fixed-time path-following control strategy for underactuated ships with input delay. Firstly, the fractional power is employed in the controller design to obtain the fast system convergence. Then, a fixed-time dynamic surface control (FTDSC) technique is presented to approximate the analytic derivatives of the virtual controller. Furthermore, to achieve timely system response, an input delay auxiliary system (IDAS) is introduced to effectively compensate the delayed signal between control commands and actuators. A concise adaptive law is developed to eliminate the negative impact induced by system uncertainty and ocean disturbance. Through the Lyapunov stability analysis, all tracking errors of the closed-loop system are converged to the neighborhood of origin within fixed-time setting. Finally, the effectiveness and superiority of the proposed controller is exemplified by numerical simulations.