基于行船视距的船舶会遇安全距离研究

Study on safe distances of ships encounter situations based on sight distance

近年来船舶交通流量大幅增加,船舶会遇愈加频繁。为降低船舶会遇避让时的碰撞危险,在行车视距基础上,提出行船视距的概念,并引入航速、避让航向角等参数,构建基于行船视距的船舶领域模型,船舶采取避让操作时,可利用该模型判断应与他船保持的安全距离和最佳航速及避让航向角。从仿真结果发现:船舶追越时应尽量与他船保持3.5倍船长以上距离,并在船尾与他船达到2倍船长以上距离时回到原航向;对遇时应尽量与他船保持7倍船长以上距离采取避让,如果航道宽裕,避让时应尽量与他船横距保持1.8倍船长以上,如果航道较窄,也应尽量保证船舶在可航水域内进行大角度避让,并与他船横距保持0.72倍船长以上。研究结果可为实际船舶避让提供指导建议。

In recent years,the increasing ship traffic flow has led to more traffic congestion and ship approaches in waterways.Following that,the avoidance maneuvers in ship encounter scenarios would be a great risk.Drawing from the experience of driving sight distance on roads,this work proposes a concept called“ship sight distance”to reduce the collision risk.In addition,a novel ship domain model is constructed based on the conceptual framework of the quaternion ship domain,which incorporates the ship s sight distance and some operation parameters such as sailing speed and heading.Following that,with the proposed model dynamically changing in four quadrants,the own ship,which is represented by the mathematic model of ship maneuver motion,can always maintain a safer distance from other ships by adjusting the sailing speed and heading during the avoidance.It can be found from the simulation results of the overtaking encounter scenario that the own ship should maneuver before the time when the target ship is 3.5 times the ship length away from its bow,and recover the original course after the time when the target ship is 2 times the ship length away from its stern.And as for the head-on encounter scenario,the own ship should maneuver before the time when the target ship is 7 times the ship length away from its bow.Besides,for fully considering the large angle avoidance in navigable waters,there are also some suggestions about the lateral distance according to the results.The lateral distance should be more than 1.8 times or 0.72 times the ship length depending on whether the channel is sufficiently wide or not.Thus,this work can provide a reference for ship avoidance by taking a safe distance from other ships,and guiding the ship s sails with optimal speed and heading at the same time.The results can provide guiding suggestions for pilots to take avoidance maneuvers.