Wire-type human support system controlled by servo brakes

In this paper, we propose a passive wire-type motion support system to guide a human hand through the use of servo brakes. This system is intrinsically safe because servo brakes cannot generate a driving force to control the system. On the other hand, this system may not generate sufficient force to guide the human hand along the desired path because of the use of servo brakes. To resolve this problem, the standard approach would be to increase the number of brake units to generate the desired force. However, the large number of wires attached to each brake unit might restrict the user´s motions, and there would be a potential for injury if the wires entwined around the user. Therefore, in order to safely guide the user´s motion, we need to decrease the number of brake units having wires. In this paper, we consider a feasible braking force region of the wire-type passive system with multiple brake units and discuss the number of brake units required to guide the user´s motion appropriately. We develop the wire-type motion support system that uses servo brakes and conduct path-following experiments considering table tennis as an example of sports training. In addition, we present experimental results that show the passive system with a small number of brake units can guide the user´s hand along the desired path.