An Active Knee Orthosis for Supporting the Elderly in Daily Life

An active orthosis was designed to support users with reduced muscle strength with an additional knee joint torque to improve the independency in everyday activities. In two persons the hypothesis was tested that less muscle activity is necessary when standing up with the active support of a motorized orthosis. The orthosis is a custom-made knee-ankle-foot orthosis and is equipped with a series elastic actuator. A reduced EMG activity in the m. rectus femoris was found when supported by the active orthosis in the sitto-stand task. The unchanged kinetics and kinematics show that the subject's sit-to-stand (STS) strategy is not influenced by the external torque; therefor amplifying torque generation seems to be a promising way of support.