Synthesis of motion-reproduction systems based on motion-copying system considering control stiffness

Following advancements in the field of visual and audio information, a third medium of information, namely, haptic information, is expected to become the basis of a key technology in the robotics industry. Haptic information includes position and force information, and such information is obtained through a motion-copying system (MCS). An MCS can store human motion in a motion database and reproduce the motion later at any other location. However, the MCS has a major disadvantage. The situations under which the motion-saving and motion-reproducing phases are carried out should be the same. If differences exist, the stored human motion will not be correctly reproduced. To solve this problem, the various motion-reproduction systems have been proposed previously. However, each motion-reproduction system proposed in previous research can provide a solution only for a particular problem. Therefore, in this study, motion-reproduction systems are unified in terms of control stiffness. By the integration of the motion-reproduction systems, it became clear that position and force control in an MCS can be realized only though compliance control, which was obtained conventionally. In other words, motion-reproduction systems can be synthesized depending on the situation and the associated problem can become solved. The validity of the concept proposed in this paper was confirmed by testing it for an application of the MCS.