Coordination strategy for coarse motion control in biorobotics

Human coordination strategy for coarse motion control in operating a telerobot is investigated for efficient human-telerobot interaction. Two types of major coordination strategy, end effector control (EEC) and point angle control (JAC), were examined by performing placement tasks requiring large/coarse motion as opposed to small/fine motion of a joystick-controlled telerobot. In fine motion control, EEC is in general superior, since JAC demands that the human operator determine the mapping between the robot joint angles and the robot hand Cartesian space. In experiments on coarse motion control, however, the superiority of EEC disappeared, resulting in no significant difference in task success rate or completion time between EEC and JAC. It turns out that: (i) the disadvantage of EEC, difficulty in visualizing the joint angle limitations, sometimes emerged in coarse motion control, causing EEC to take longer to complete the task than JAC, and (ii) the disadvantage of JAC, difficulty in determining the precise movement of the telerobot hand from the joint angle command, was not critical in coarse motion