Docking Control Method Using LEDs Detection by Hovering AUV “Hobalin” for Deep-Sea Research

The Autonomous Underwater Vehicle (AUV), which is a cableless ocean observation vehicle, has been developed to achieve more advanced underwater observation. A hovering AUV, here as a H-AUV, is a type of AUV capable of optical observation with approaching seafloor at a slow speed. It is difficult however to observe around the sea floor too vast. In order to have a wide area optical observation covering vast seafloor, the authors have been developing an underwater charging technique for H-AUV to focus on the method of extending observation time. At this time, it is necessary that high precision localization for docking to the electrical devices. The localization by Inertial Navigation System (INS) and Ultra Short Base Line (USBL) have a position error about a few meters. The authors try to develop the localization by image processing and docking control method. In this study, Deep sea terminal as the underwater base station which has the electricity supply device is mounted some guidance lights, and H-AUV is localized by relative position to the terminal using detecting the guidance lights. It approaches to the terminal by tracking waypoints created for docking while slowing down and decreasing altitude. The authors verify the effectiveness of the docking method by experimental tank test.