An ankle based soft active orthotic device powered by pneumatic artificial muscle

Soft robotics are made by materials which have similar modulus with human musculoskeletal system. They can be used to augment the human performance without restricting the natural behavior. This paper presents a bio-inspired, ankle-based soft active orthotic device which can assist the ankle dorsiflexion during walking. This device implemented a silicone-based, fast actuating Pneumatic Artificial Muscle (PAM) to provide angular assistant force at the ankle joint. This PAM is based on the pneumatic network structure. Specific design have been made to make the PAM ergonomically compile with foot-ankle structure and facilitate the underlining application. An initial testing was first carried out to characterize the PAM. The control strategy was planned based on ankle angle information within each gait cycle. A pilot study was carried out for evaluation. The results show that this soft active orthotic device can improve the dynamic stability of the ankle joint. This device can be potentially used as real time argumentation for frail and fall-prone elderly and benefit their walking stability.