In the case that underwater robots are floating, position/orientation of a robot-body is affected by reaction force when the robot contacts objects or environment. It makes underwater handling tasks difficult. To overcome this difficulty, we use a Negative-Pressure Effect Plates system. The system is composed of a thruster and a Donut-shaped aluminum plate. From Bernoulli's principle, we know the water pressure between an object-surface and the plate becomes negative when the thruster makes water flow. In this paper, we theoretically investigate the adsorption force mechanism and experimentally confirm performance of Negative-Pressure Effect Plates.
