Practical Fixed-Time Aperiodic Intermittent Path-Following Control of Underactuated USV With Dynamic Collision Avoidance

In this article, to address the path-following control problem for an underactuated unmanned surface vehicle (USV) under aperiodically intermittent measurement and control, a new predictor-based fixed-time collision-free control strategy is proposed. To solve the external disturbances, an improved fixed-time predictor with aperiodically intermittent prediction of tracking errors is constructed. Based on the established predictor, the fixed-time intermittent line-of-sight (LOS) guidance law is developed to obtain the expected heading angle, and the convergence of the tracking error can be ensured. For collision avoidance, the velocity obstacle method is utilized to obtain the optimal collision avoidance for a single USV. Furthermore, two improved aperiodically intermittent fixed-time controllers are developed with sliding mode control, and the desired heading angle and surge velocity can be tracked. The aperiodically intermittent control strategy is first utilized in the design of the predictor, LOS guidance law, and controllers for unmanned surface vehicles, thus the number of measurements is reduced. The effectiveness of the designed algorithms is verified by simulation examples.