Development of an Electric Robotic Arm for the Hadal Zone

In this paper, we address the challenge of autonomous sampling in ultra-deep water, developing the hadal electric robotic arm. The prototyped three Degree of Freedom (3-DOF) robotic arm uses a newly developed full-ocean depth electric servo motor with a position control based on acceleration feed-forward. This method of Fers a light-weight and disturbance-resistant underwater robot arm even for hadal zone application. The experiment out of water and in the hydrostatic pressure tank shows the last deviation between the desired and feedback position was 0.1%. In ultradeep sea trials, the hadal robotic arm successfully reaches the target positions by an automatic control. Through these experiments, we confirmed that automatic sampling using the robot arm in the hadal zone is feasible.