Yoshiaki Hirakawa

Motion compensator for acoustic device mounted on Autonomous Surface Vehicle

In recent days, the simultaneous operation of several AUVs is desired to realize widespread exploration in a navigation. As a method to realize the simultaneous operation, introduction the repeater vehicle called ASV (Autonomous Surface Vehicle) is proposed. The task of the ASV is to chase an AUV and to communicate with a support vessel. So, one ASV is needed for one AUV but several ASVs are monitored by one support vessel. The size of the ASV is similar to the AUV and is significantly smaller than the support vessel, so the seakeeping qualities are lower than the support vessel. Larger ship motion is expected than the support vessel and causes communication trouble. In this report, the new active motion compensator and the model experiment with this motion compensator is reported.

Development of Mini-Buoy for short term measurement of ocean wave

The authors have developed a small wave buoy as “Ultra-Small-Directional-Wave-Buoy” from 1997. In recent years, The demand of short term wave measurement such as verification of wave radar system and speed trials of new ships is increasing, but general wave buoys are large, expensive and for long term measurement. For such usages, smaller and lighter “Mini-Buoy” is developed.