Successful Repeated Docking under Fluctuating Current Disturbances in Real Sea

To extend the persistence time of an underwater operation of Autonomous Underwater Vehicles(AUVs) in the sea, many studies have been performed worldwide. The docking function takes place as an important role not only for battery recharging but also for other advanced applications. In the previous studies, the repeated sea docking using a Remotely Operated Vehicle(ROV) was succeeded. However, during the experiment in the sea, ROV sometimes failed the docking due to the ocean current disturbance since ROV is hard to correct large error of orientation around z-axis. Therefore, we develop an autonomous rotary station that defects the ocean current direction for correcting the error between the ocean current direction and the docking direction. This paper presents the details of an autonomous rotary station and the analysis of the repeated sea docking experimental result.