Finite-time fast nonsingular terminal sliding mode path-following control for underactuated marine surface vehicles with input saturation

Abstract

In this paper, a finite-time fast nonsingular terminal sliding mode (FNTSM) control method based on predictive line-of-sight (LOS) guidance is designed for path-following control of marine surface vehicles (MSVs) in the presence of unknown external disturbances and uncertainties. First, predictive LOS guidance is designed to acquire the sideslip angle within a finite time by an error predictor. Second, a novel fixed-time lumped disturbance observer is developed to estimate the disturbances containing unknown environmental disturbances and uncertainties. Third, a finite-time FNTSM controller containing an auxiliary dynamical system is proposed to guarantee that the closed-loop system is finite-time stable. It can obtain a faster response and stronger robustness than asymptotic stability, and the auxiliary dynamical system is used to handle the system input saturation. Finally, the closed-loop system is proven to be uniformly finite-time stable (UFTS) by Lyapunov theorem analysis. The proposed control strategy is demonstrated to be effective via numerical simulation experiments.