Optimization on Planning of Trajectory and Control of Autonomous Berthing and Unberthing for the Realistic Port Geometry

TL;DR

This paper presents an advanced optimization method for autonomous ship berthing and unberthing in realistic port environments, considering obstacles, wind disturbances, and practical constraints to improve safety and efficiency.

Contribution

It introduces a collision avoidance algorithm with variable ship domain size, accounts for wind disturbance, and extends optimization techniques to unberthing, enhancing real-world applicability.

Findings

Effective collision avoidance in complex port geometries

Feasible trajectories considering wind disturbances

Applicable to both berthing and unberthing operations

Abstract

To realize autonomous shipping, autonomous berthing and unberthing are some of the technical challenges. In the past, numerous research have been done on the optimization of trajectory planning of berthing problems. However, these studies assumed only a simple berth and did not consider obstacles. Optimization of trajectory planning on berthing and unberthing in actual ports must consider the spatial constraints and maintain sufficient distance to obstacles. The main contributions of this study are as follows: (i) a collision avoidance algorithm based on the ship domain which has variable size by the ship speed is proposed, to include the spatial constraints to optimization; (ii) the effect of wind disturbance is taken into account to the trajectory planning to make a feasible trajectory based on the capacity limit of actuators; (iii) showing that the optimization method for berthing is also eligible for the unberthing, which has been almost neglected; (iv) waypoints are included to the optimization process, to make optimization easier on practical applications. The authors tested the proposed method on two existing ports. The proposed method performed well on both the berthing and the unberthing problem and optimized the control input and the trajectory while avoiding collision with the complex obstacles.