Design and control of a wearable active knee orthosis for walking assistance

In the past decades, many wearable powered orthoses have been developed with the aim of augmenting or assisting motion activities in daily life. Among many applications, they are particularly used to provide lower-limb moving assistance in locomotion-related rehabilitation tasks. This paper presents a wearable active knee orthosis consisting of an active knee joint, a double-tendon-sheath transmission system and a control system. The active knee joint and the double-tendon-sheath transmission system are applied to reduce the weight of the orthosis and achieve preferable maneuverability. A PID controller is used to validate the feasibility of the orthosis, and a fuzzy controller is developed to perform the walking assistance experiments. Finally, two groups of EMG signal tests were conducted to verify the assisting effectiveness of the orthosis. The results obtained from the two EMG evaluation experiments demonstrate that the proposed orthosis can reduce muscular power consumption during walking and proved the usability of the whole system.