Improvement of a human-portable underwater robot for soil core sampling

Abstract

This paper describes improvement of a human-portable underwater robot for use in soil core sampling. We developed the soil sampling robot in our previous work. However, the efficiency of translational motion of that robot was low because of high drag force attributable to its shape. In addition, an operator had to control all motions of the robot manually using a controller. To overcome such shortcomings in this study, we first developed an attitude control system based on a parallel link mechanism that plays a role in reducing the frontal area of the robot facing the flow during vertical and horizontal motions to reduce the drag force acting on the robot and to enhance its motion performance. Secondly, we developed and added feedback control functions as functions of an operating device. We conducted experiments in a test tank and in Lake Biwa to verify the effectiveness of the developed attitude control system and the feedback control function for the soil core sampling robot.