Multiple obstacle collision avoidance path-following dynamic surface control of underactuated ship with unknown ocean interference

This paper studies the path following problem of underactuated ships under unknown ocean disturbances, multiple obstacles and state constraints. An improved Stanley collision avoidance guidance law based on reduced-order extended observer (EISCGL) is proposed. In dealing with the traditional path tracking problem, this method optimizes the navigation effect on the large curvature route. At the same time, a collision avoidance guidance mode considering the International Regulations for Preventing Collisions at Sea (COLREGs) is designed. The collision avoidance space is dynamically adjusted according to the relative speed of obstacles, and the switching strategy is designed to avoid multiple obstacles in the path tracking process. In addition, the back-stepping method is used to construct an underactuated ship controller considering unknown environmental disturbances and state constraints. Stability analysis shows that the proposed control scheme can ensure that all signals in the closed-loop system are semi-globally uniformly stable. Finally, the effectiveness of the strategy is verified by comparative simulation experiments.