COLREGs-aware transit and docking for autonomous surface vessels*

This paper presents a novel approach to solving the docking problem for Autonomous Surface Vessels (ASVs) while considering the Convention on the International Regulations for Preventing Collisions at Sea (COLREGs). The proposed method combines computational geometry, numerical optimal control, and a collision avoidance (COLAV) system to generate a collision-free path from an initial location to the docking point. The proposed approach first performs Voronoi partitioning of the non-convex area to create waypoints, forming a roadmap that ensures safe distances from harbors and obstacles. A search algorithm then finds the waypoint sequence corresponding to the shortest collision-free path. Subsequently, a nonlinear optimal control problem (NOCP) further refines the optimal trajectory and generates control inputs corresponding to this trajectory. The efficiency of our approach is demonstrated by simulations. Our results indicate that the proposed approach is suitable for transit and docking applications, where intricate and safe maneuvering at low speeds is often a necessity.