Qualitative Assessment of a Clutch-Actuated Ankle Exoskeleton

Among the growing number of different exoskeletons, passive and quasi-passive solutions hold the upper-hand compared to powered solutions in price, accessibility, complexity, weight and user acceptance. This paper evaluates a modification of an originally passive ankle exoskeleton with an active clutch, making it quasi-passive. We developed an electric quasi-passive clutch to improve the performance of the original exoskeleton design, with the aim of mitigating the problems on the clutch engagement timing and user physiological variability. In order to evaluate the exoskeleton and the clutch operation, we performed a study where 7 users wore the exoskeleton and performed trial walks. Qualitative user feedback that focused on the device comfort, users perception of exoskeletons effect and smoothness of the clutch operation was collected, along with quantitative data on clutch operation during walking on a flat surface. Results show improved and more reliable exoskeleton clutch operation which was also expressed in qualitative user feedback.