A Conceptual High Level Controller to Walk with Active Foot Prostheses/Orthoses

In this paper, the goal is to develop a high level controller for active prosthetic feet that can continuously estimate the ankle motion based on the shank motion. The proposed controller does not require speed determination, gait percent identification, input data manipulation, look-up tables or switching rules. To do this, the Gaussian process (GP) regression is used. The performance of the controller has been tested for walking speed of 0.6, 0.9, 1.2, 1.4 and 1.6 m/s. The results showed that the controller had lower estimation quality when input was only shank angular velocity or shank angle. However, the aggregated angular velocity and angle input resulted in high output estimation quality. Furthermore, for each speed, the estimation quality was more acceptable when the controller was trained for it. Accordingly, when the high level controller was tested without previous training, the estimation quality was less acceptable.