Evaluation of inertia matching of trans-femoral prosthesis based on Riemannian distance

A method to quantify the matching of inertia property of a trans-femoral prosthesis to a given user´s skill will be explored for better design of the prosthesis. Advancements in the mechanism and the control method of trans-femoral prostheses have drastically improved the gait of amputees. However, realization of a natural gait has not been investigated in detail even though such smooth gait is important to increase the amputee´s activities of daily living (ADL). Inertia of the prosthesis plays an important role in natural and smooth gaits during the swing phase. We suppose that goodness of gait or easiness of walking is strongly related to effective use of the prosthesis inertia. In this paper, we will attempt to quantify matching of inertia property of the prosthesis to a given user´s skill / condition from the effective use of the prosthesis inertia during gait in the swing phase. Gaits of an expert prosthesis user will be measured by changing inertia properties. Effective use of inertia property of the prosthesis in gait is evaluated by closeness of the gait to the inertia-induced motion using inertia-induced measure. In addition gait of a novice prosthesis user will be measured to compare with the expert´s results.