Abstract: In order to solve the problem that ships were affected by both river boundaries and movement of surrounding ships during collision avoidance process in restricted waters, a decision-making method for ship collision avoidance was proposed, which combined thought of velocity obstacle with theory of artificial potential field. Velocity obstacle method was applied to avoid collision with other ships and static obstacles under constraint of inland river collision avoidance rules. Then, artificial potential field was constructed on navigable waters boundaries to realize collision avoidance. Finally, collision avoidance scenarios such as crossing, meeting and overtaking of ships under straight channel and curved channel were set up, and the method was verified in simulation environment. The results show that the proposed method can help ships make decisions of avoiding obstacles and approaching ships in different directions under constraints of rules, and ensure that collision avoidance path keeps safe distance from boundaries of navigable waters, so as to meet requirement of limited maneuvering in process of collision avoidance.

Key words: velocity obstacle, artificial potential field, restricted water, collision avoidance decision-making, rule constraints