Study on Development of the Automatic Navigation System for Ships

为了防止海上事故的发生，对航行安全提出了很高的要求。然而，最近为了降低总运输成本而强制削减人员费用，这意味着拥有优秀技能的海员的保障变得困难。本研究假设利用DGPS(Differential Global Positioning System)获取的位置信息，利用模糊推理对船舶周围存在的障碍物进行碰撞风险评估和避碰对策的研究，设计了基于数值模拟的船舶自动导航系统，并通过数值模拟和模型试验验证了系统的有效性。模型试验结果表明，该系统能很好地控制船舶改变航向或避免与航道上的障碍物相撞。仿真结果与模型试验结果吻合较好，说明本文的仿真模型对船舶运动估计具有较高的精度。为了验证系统的有效性，对多艘有碰撞风险的船舶进行了数值模拟。观察到，该算法对于模拟研究中使用的场景工作得很好。因此，基于模糊推理的船舶自动导航系统对船舶安全航行具有一定的指导意义。

Navigational safety is highly demanded in order to prevent marine accidents. However reduction of personnel expenses is enforced recently to reduce total transportation cost and it means that securement of the sailors who have an excellent skill becomes difficult. So increase of sea disaster accident originated with degradation of skill of a sailor is concerned in the future and introduction of an automatic navigation device is one of solution of such a problem.In this study, supposing to utilize positional information which is derived using DGPS (Differential Global Positioning System), research on development of automatic navigation system which utilize fuzzy inference to evaluate the risk of collision and to define countermeasures to avoid collision with other ships obstacles which exists in circumference of own ship was carried out.The systems were designed based on a numerical simulations and verification of effectiveness of the systems was done by comparing results obtained by numerical simulation and by model test. The model test results shows that the system can control ship well to change her course or to avoid collision with obstacles on course. Comparison between simulation results and model tests results agree well, then our simulation model has high accuracy to estimate ship motion.Numerical simulations assuming several encounter situations of plural ships in collision risk were made to confirm validity of the system. It was observed that the algorithm works well for the scenarios utilized in the simulation study. Then the automatic navigation system using fuzzy inference may be useful to navigate ship safely.