Objective An improved dynamic window method is proposed to solve the obstacle avoidance problem of intelligent ships in offshore waters, which cannot be effectively avoided when facing pinch and mixed dynamic-static encounters.

Methods In order to obtain the constraints of ships navigating in offshore waters, the factors affecting ship obstacle avoidance in offshore waters are analyzed, and the minimum obstacle avoidance requirements for ship navigation in offshore waters are proposed. The objective function of the Dynamic Window Approach (DWA) is then optimized, improved and correlated with the distance between the ship and obstacles to enhance the safety of the ship in the navigational chart, while the heading weights in the objective function are introduced into the judgment of the ship's encounter posture so as to enable the target ship to effectively judge its obstacle-avoidance responsibility. Finally, the effectiveness of the improved algorithm is verified through simulation.

Results The simulation results show that the proposed improved algorithm can clearly judge the ship's obstacle-avoidance responsibility and reduce the steepness of speed change in the sailing process, and the planned ship sailing path can effectively improve the safety of ship operation in case of encountering pincer attacks and complex encounters respectively. Conlusion The proposed obstacle avoidance algorithm can provide useful references for solving the collision avoidance failure problem of intelligent ships encountering complex encounter scenarios in offshore waters.