Advanced APF-based collision avoidance and route restoration for large commercial ships under COLREGs

To address the key gap in existing artificial potential field (APF)-based ship collision avoidance (CA) research—specifically the lack of methods that concurrently account for large-ship maneuverability and COLREGs compliance while ensuring reliable post-CA route recovery—this study proposes an advanced CA approach for large commercial ships by enhancing the APF framework within the International Regulations for Preventing Collisions at Sea (COLREGs). The proposed method aims to ensure the safe and timely return of a ship to its planned route after adhering to COLREGs and successfully passing and clearing other ships and/or obstacles. Considering the characteristics of large commercial ships, including hull inertia, rudder response delay, and maneuvering lag, this study refines the route-plan-guided APF (RPG-APF) method. A route-based goal retrieval mechanism is developed to account for both the maneuvering capabilities and dynamic motion characteristics of the vessel. Moreover, a yaw-restoring force and an enhanced repulsion model are introduced to enable large commercial ships to perform the navigation tasks of ''route keeping'', ''autonomous CA'', and ''return to the original route'' in a stable and realistic manner. Simulation experiments demonstrate that, after executing CA in compliance with COLREGs, the ship can safely and efficiently return to its predefined route while remaining within the prescribed cross track limit (XTL). This proposed approach effectively addressed several limitations of traditional APF theory and provides a robust foundation for developing autonomous navigation systems (ANSs) for large commercial ships.