Lower-Limb Soft Orthotic Device for Gait Assistance

In this paper, we present a soft wearable orthotic device for gait assistance. The components of the orthotic device are mainly made of soft materials and the device only has a mass of 680 g worn on the subjects lower extremity, which do not add significant inertia during walking. Fully soft pneumatic artificial muscles (PAMs) with low threshold pressures are utilized as actuators. A bundle of four PAMs are used to provide force for the plantarflexion of ankle joint in certain gait period. The gait cycle is detected by two inertial measurement units (IMUs) mounted on the calf and foot braces, respectively. The orthotic device applies a force of 65 N for ankle plantarflexion, which corresponds to 3.5% of the nominal biological force at the ankle joint during walking.