Abstract
In recent years, coral predation by crown-of-thorns starfish has become a serious problem. Therefore, authors have been developing an underwater robot to capture the starfish. The robot has two vertical thrusters, which are used for vertical movement control of the robot. The robot can lift a underwater object by a thrust of the thruster. In the case of conventional fixation method, however, lifting force is lost. Because the vertical thruster is locked rigidly to body of the robot. For that reason, we propose the passivity posture maintenance mechanism for a thruster, in order to use a thrust of the vertical thruster effectively. In the lifting force measurement experiment, we confirmed the effectiveness of this mechanism.
