Development of closed-fitting-type walking assistance device for legs and evaluation of muscle activity

A walking assistance device using a flexible shaft was developed. The combination of a flexible shaft with a worm gear was successfully adopted on this device to simplify its appearance and reduce its size. A hybrid - control system on this device controls both torque and angle at the ankle and knee joints. In this system, the torsional spring constant of the flexible shaft is taken into account by the motor in controlling the power and angle of rotation of the motor. To expand the area in which a person may use the device, it is equipped with a self-contained system powered by a Lithium-ion battery and controlled by an SH-4 microcomputer and actuators, consisting of motors and gears, all of which are carried in a small backpack. Consequently, persons using the device may walk freely in both indoor and outdoor environments.