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In industry 4.0, the paradigm of technologies has been actively changing in fields of artificial intelligence and autonomous system. Shipbuilding industry is also investing autonomous navigation system, including collision avoidance supporting system and navigation assistance system using leading-edge technologies such as deep learning, sensor fusion, and augmented reality (AR). Hyundai heavy industry has developed advanced navigation assistance system called Hi-NAS, which uses radar ARPA, AIS as well as a forward-looking camera. The output of Hi-NAS is an AR-based display overlayed information on own ship’s and other ships status and indices of collision risk. It is expected that the display can assist crews to navigate safer.

In this study, we propose a new approach for solving the weather routing problem with an efficient speed schedule that minimizes fuel consumption. The procedure used to solve the problem comprises two phases. The first phase aims to obtain the optimal route at each time step using the A* algorithm. During this phase, the speed of the ship is fixed and only the heading angle is optimized. The safety regulations published by IMO are applied as constraints during the first phase. The second phase is the speed scheduling phase. The original problem is highly nonlinear and nonconvex optimization problem and it can be converted into a geometric programming problem. By solving the geometric programming problem, we can determine the optimal speed schedule for the ship. The optimal speed obtained using this procedure guarantees the global optimum because the problem is convex. This method can produce an almost optimal solution to the weather routing problem more efficiently than existing methods.

In this paper, we employ a dynamics modeling method for investigating a multi-body dynamics system of semi-submersible autonomous underwater vehicles consisting of a towing vehicle operated near the water surface, a tow cable, and a towfish. The towfish, which is towed by a marine cable for the purposes of exploration or mine hunting, is modeled with a Six-Degree-of-Freedom (6-DOF) equation of motion that reflects its hydrodynamics characteristics. The towing cable, which can experience large displacements and deformations, is modeled using an absolute nodal coordinate formulation. To reflect the hydrodynamic characteristics of the cable during motion, the hydrodynamic force due to added mass and the drag force are imposed. To verify the completeness of the modeling, a few simple numerical simulations were conducted, and the results confirm the physical plausibility of the model.