Numerical Simulation of Motion-Controlled Fishery Boat With Harvesting Wave Energy

Numerical simulation of a motion-controlled ship was conducted. This ship is a catamaran, the motion of which is controlled with motors by an active control system, called Skyhook control. In addition, this ship can harvest wave energy by converting relative displacement between a cabin and floats to rotational motion, and then, to electrical energy by generators. Energy harvesting efficiency can be maximized by a technique, called MPPT (Maximum Power Point Tracking). The model of the ship was constructed on a circuit diagram with SPICE (Simulation Program with Integrated Circuit Emphasis) based on a mechanical-electrical analogy, called Mobility method, because mechanical system and electrical system are coupled through a motor/generator as a transducer in this ship. The results of the simulation based on this model were compared to those of the tank test already done by some of the authors, and its performance was evaluated. The results showed good agreement between the simulation and the experiment qualitatively, while quantitative gap could be found. There are some problems to be solved such as considering precise hydrodynamic force. Thus, the model needs to be improved more. It will be possible to design a new concept of fishery boats using the simulation based on this model in the future. This concept of fishery boats can be aimed at coastal fishery and offshore aquaculture.