Abstract Manoeuvring in adverse weather conditions has significant challenges for the shipmaster especially when the ship is equipped with the smaller propulsion power. The automatic control methods for safe manoeuvring in severe weather conditions have not been studied extensively since manual control is applied in these conditions. Moreover, in most numerical simulations, PID control is used due to its simplicity. In this paper, the authors discussed the performance of a conventional PID autopilot under large external forces using the numerical simulation of a Handymax bulk carrier in various weather conditions. Then, a path-following control strategy was applied to eliminate the drifting problem found in the conventional PID autopilot alone. Moreover, Optimal Control (OC) based general-purpose trajectory optimization path-planner was proposed for obtaining obstacle-free optimal paths. Finally, the performance of the resulting path-planner-follower is analyzed under different severe weather conditions. A series of early small and precise continuous rudder commands are found to be used to execute the successful collision avoidance maneuver whereas a human operator may use discrete rudder angles with large steps. The head sea course is found to be the safest one in adverse weather conditions compared to the other oblique courses.

中文翻译：

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恶劣天气条件下机动控制策略研究

摘要 恶劣天气条件下的机动对船长来说是一个巨大的挑战，特别是当船舶配备较小的推进功率时。由于在恶劣天气条件下采用手动控制，因此在恶劣天气条件下安全操纵的自动控制方法尚未得到广泛研究。此外，在大多数数值模拟中，由于其简单性而使用 PID 控制。在本文中，作者使用大灵便型散货船在各种天气条件下的数值模拟，讨论了传统 PID 自动驾驶仪在大外力下的性能。然后，应用路径跟随控制策略来消除单独在传统 PID 自动驾驶仪中发现的漂移问题。而且，提出了基于最优控制（OC）的通用轨迹优化路径规划器，以获得无障碍最优路径。最后，在不同的恶劣天气条件下分析了所得路径规划器的性能。发现一系列早期的小而精确的连续舵命令可用于执行成功的防撞机动，而人类操作员可能会使用大步长的离散舵角。与其他倾斜航线相比，在恶劣的天气条件下，头海航线被发现是最安全的航线。发现一系列早期的小而精确的连续舵命令可用于执行成功的防撞机动，而人类操作员可能会使用大步长的离散舵角。与其他倾斜航线相比，在恶劣的天气条件下，头海航线被发现是最安全的航线。发现一系列早期的小而精确的连续舵命令可用于执行成功的防撞机动，而人类操作员可能会使用大步长的离散舵角。与其他倾斜航线相比，在恶劣的天气条件下，头海航线被发现是最安全的航线。