Evaluation of gait with trans-femoral prosthesis based on Riemannian distance

This paper presents a method to quantify the goodness of gait with a trans-femoral prosthesis in order to evaluate walking skill with the prosthesis and its application to its design. 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. Recently, inertia-induced measure has been proposed as a measure to quantify inertia-induced motion of a multi-body system based on the Riemannian distance. In this paper, we will attempt to evaluate the goodness or easiness of walking with a prosthesis leg by quantifying the effective use of the prosthesis inertia based on the Riemannian distance. Gaits with several different inertia properties will be measured. The results will then demonstrate the strong relevance between subjective evaluation of easiness of walking and effective use of inertia evaluated based on the Riemannian distance.