Development and testing of a passive ankle exoskeleton

This study proposes the development and initial testing of a passive ankle exoskeleton intended to provide a plantarflexion torque assist during the push off phase of gait. The design incorporates a Pneumatic Artificial Muscle as a non-linear elastic element to store and release energy during walking. The device also integrates a novel clutch mechanism design to engage and disengage the spring element about the ankle joint during walking such that it does not impede the ankle motion during swing phase. Mechanical testing demonstrated the prototypes ability to function adequately over the natural range of an ankle joint and generate an ankle torque equal to at least 25% of natural ankle torque during normal walking. Using motion capture and electromyography systems, human testing was performed to examine the gait kinematic and muscle activation when the device is worn, unilaterally. The preliminary results show that the exoskeleton is able to reduce the activation of the calf muscles on the limb wearing the device. However, a decrease in ankle joint range of motion is noted in the limb with the device, and, to a much lesser extent the leg without the exoskeleton.
Source: Biocybernetics and Biomedical Engineering - Category: Biomedical Engineering Source Type: research