Workspace control system of underwater tele-operated manipulators on an ROV

This paper presents a control technique for structured undersea tasks that require a high degree of precision. The overall efficiency of tele-operated underwater manipulation is improved by reducing the burden on the human operator. A new workspace-control system composed of a computer and input devices in workspace was developed to support the operator. The computer transforms the desired velocity of end-effector in workspaces to desired joint angles by solving the inverse kinematics of the slave manipulators. The desired joint angles are transferred to the slave controller through RS-485 serial communication, and be followed by the slave manipulator. The developed master system provides advantages in conducting structured tasks(coring, drilling, underwater connector mating, etc.) that require precise control of the end-effector’s motion and attitude. The existing master system, however, is more useful for unstructured tasks than newly developed master system. By combining the two master systems, the work efficiency of the underwater tele-operated manipulator system was improved. This paper presents the development of the workspace-control system and a working strategy to alleviate operator’s burden in underwater works. Experimental results are presented to evaluate the effectiveness of the proposed method using underwater manipulators mounted on the KORDI deep-sea ROV Hemire.