Automatic Berthing Trajectory Planning for an Underactuated Ship Based on Extended Dynamic Window Algorithm and A* Algorithm

This paper proposes a real-time trajectory planning method for automatic berthing of an underactuated ship. This method considers the overall constraints of the ship’s dynamics model and obstacles, introduces a global planning algorithm to avoid falling into local optimum. First, the global optimal path is planned based on the A* algorithm and redundant points are deleted to obtain the reference waypoints for trajectory planning. Second, based on Extended Dynamic Window Algorithm (EDWA), the berthing trajectory of the ship, including the constant force phase and the deceleration phase, is predicted in real-time, and the desired heading is achieved through PID control. After performing the feasibility test on the predicted trajectories, the optimal trajectory is obtained by using the evaluation function that considers the constraints of the goal point, reference waypoints, and obstacles. This optimal trajectory is then used to guide the ship at the next sampling time. Finally, taking Rizhao Port as an example, this paper uses the proposed method to plan a smooth and reliable trajectory, successfully guiding the ship to the designated berth while meeting the requirements of speed and heading, and avoiding obstacles.