Development of energy-harvesting unit and propulsion unit for a robotic buoy system

In this paper, we described about development of a robotic buoy for Internet of maritime thins (IoMT) technology. For IoMT, stand-alone data conllector is a key technology. The energy harvesting robotic buoy is proposed in the context. The proposed system is composed of three components: propulsion system, energy harvesting system, and buoyancy control system. The proposed system can hold its position within an uniform bound without mooring, and harvests wave energy. As a preliminary study, we developed hydrodynamic model for the whole system, and conducted simulation. Through the simulation, we implemented station keeping algorithm, and investigated optimal design parameters. To verify the simulation results we constructed prototype and carried out a series of experiments: station-keeping test, and power generation test. As a result, the whole system was proved that the propulsion system has sufficient manoeuvrability for station keeping within 3 m, and peak power generation was 8 W.