Position and orientation control of passive wire-driven motion support system using servo brakes

Wire-driven haptic devices can easily achieve highspeed operation because of the low inertia of light and thin wires. Therefore, it is expected to be widely used as a motion support system in fields such as sports training. However, usually these wires are driven by controlling each wire's tension using servo motors, which raises concerns about the safety in human-robot interaction. Thus, we propose to support the user by controlling servo brakes instead of motors, which can ensure safety. In this paper, we introduce a passive wire-driven system without any motors for realistic motion support in sports training. The system can measure the user motion and support the user while following a target form by a novel passive control method considering the orientation as well as the position using 7 wires' lengths and the brake tensions. We also conduct error evaluation experiments and show that a tennis beginner using this system can accurately follow the target form.