ABSTRACT

When a floating-type underwater robot is in operation, the robot's position and orientation is changed due to the reaction force created by the object, making it more difficult to perform the work Fig. 1. To solve this problem, this paper proposes a method of attaching a Negative Pressure Effect Plate to a moving thruster and effectively increase the adsorptive force of the target surface. First, a theoretical analysis of rigid Negative Pressure Effect Plate and flat surface is given. Next, the effectiveness of Flexible Negative Pressure Effect Plate, usable when the target object has a curved surface, is experimentally illustrated.

INTRODUCTION

Most underwater robots that have been developed to date carry out observation work using various sensors. Therefore, there is much research on the floating state in water. In the future however, work that requires mechanical contact between an object and an underwater robot, such as underwater construction and maintenance, inspections of dams etc., will be required. When a robot acts on an object with an arm or similar component, it receives a reaction force from the object. In the floating state, the position and orientation of the robot body changes due to the reaction force and this adversely affects the work. In order to solve this problem, when working on the seabed, the robot may be anchored on the seabed and cancel the reaction force the arm receives from the bottom of the ocean. In the case of underwater structures, dams, etc., it is necessary to mechanically make contact with the object and push the robot body against the object with just enough force, so the work is not disrupted by the reaction force. In order to generate such mechanical restraint, it is also possible to mount a dedicated arm, rope or something similar on the robot. However, in general, such a dedicated device for mechanical restraint causes the problem of enlarging the size, weight, and complexity of the entire robot. Moreover, with a mechanical restraint mechanism such as a gripper, on a plane, such as a dam wall, there is no place for the gripper to grasp and it cannot function.

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