Multistage Vessel Berthing Position and Attitude Planning Based on Improved RRT* Algorithm

This paper proposes a trajectory planning method under uncertainty to address the berthing planning task for inland ports. A maneuvering model group (MMG) model is established, considering the influence of the port environment. Subsequently, a trajectory planning method is proposed, segmenting the berthing process into three temporally continuous stages. The avoidance phase generates a path based on an improved Rapidlyexploring Random Tree Star (RRT*) algorithm with vessel motion position and attitude constraints. Then, based on the planned path, a smoother trajectory is created by using Bezier curves to stabilize the vessel as it approaches the berth stationary point, before completing the final berthing phase. These three berthing processes are interconnected through vessel motion constraints, integrating a speed and heading allocation mechanism. Finally, comparing with mainstream planning algorithms, and employing a proportional-integral-derivative (PID) control method, the proposed trajectory planning method is validated and comparatively assessed, demonstrating its adaptability to the port environment and vessel maneuverability, thereby providing an effective solution for inland port berthing.