ABSTRACT The paper presents a collision avoidance algorithm for ship open sea navigation, based on an ad hoc modified version of the Rapidly-exploring Random Tree (RRT*) algorithm. The proposed approach is designed to act as the high level layer of the navigation control structure for an autonomous ship. Collision and grounding still represent the primary source of sea accidents, thus an automatic system able to detect static and moving obstacles and plan an evasive route could significantly improve safety during navigation, especially in crowded areas. Focusing on the maritime field, a review of the scientific literature dealing with collision avoidance is presented, showing potential benefits and weaknesses of the different approaches. Among the several methods, details about the RRT and RRT* algorithms are given. The ship path planning problem is introduced and discussed, formulating suitable cost functions and taking into account both topological and kinematic constraints. The algorithm is able to manage multiple moving obstacles with variable speed and course. Eventually, a time-domain ship simulator is used to test the effectiveness of the proposed algorithm over a number of realistic operation scenarios. The obtained results are presented and critically discussed.

中文翻译：

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一种用于船舶制导应用的避碰算法

摘要 本文基于快速探索随机树 (RRT*) 算法的临时修改版本，提出了一种用于船舶公海航行的避碰算法。所提出的方法旨在充当自主船舶导航控制结构的高层。碰撞和搁浅仍然是海上事故的主要来源，因此能够检测静态和移动障碍物并规划规避路线的自动系统可以显着提高航行期间的安全性，尤其是在拥挤的地区。以海事领域为重点，对涉及避碰的科学文献进行了回顾，展示了不同方法的潜在优势和劣势。在这几种方法中，给出了有关 RRT 和 RRT* 算法的详细信息。介绍和讨论了船​​舶路径规划问题，制定了合适的成本函数并考虑了拓扑和运动学约束。该算法能够以可变的速度和路线管理多个移动障碍物。最后，使用时域船舶模拟器来测试所提出算法在许多实际操作场景中的有效性。所获得的结果被提出并批判性地讨论。