Workspace control system of underwater tele-operated manipulators on ROVs

This paper considers the problem to increase working efficiency of tele-operated underwater manipulation by assisting human operator to reduce a burden in controlling manipulator precisely. A new workspace-control system composed of a computer and an input device for the velocity command in workspace was developed to support the operator. The velocity references commanded in workspace are transformed to the joint references by solving the inverse kinematics of the slave manipulators. The joint references are transferred to the slave controller through RS-485 serial communication to control the slave manipulator. The developed master system is advantageous in the tasks requiring accurate motion of end-effector such as coring, drilling and underwater connector mating while the existing master system is useful for the unstructured tasks. By combination of the two master systems, we achieve the improvement of the working efficiency of underwater tele-operated manipulator system. In this paper, the hardware and software of the developed workspace-control system is presented. Using the developed master system, we propose a strategy to improve the working efficiency of the underwater tele-operated manipulator system. Experimental results are presented to investigate the effectiveness of presented method using the implemented manipulator system embedded in the KORDI ROV Hemire.