Determining the rigid-body inertia properties of a knee prosthesis by FRF measurements

The precise evaluation of the rigid-body (RB) inertia proprieties of a prosthesis is important for its implantation in the patient. Nowadays, in the motion analysis of humans carrying prostheses, the RB inertia properties of the healthy limbs are used instead of the prosthesis ones due to their difficult evaluation. This forced approximation may yield significant errors in the motion-analysis results. In fact, the prosthesis is, in general, heavier and has a different center of gravity (COG) with respect to the healthy limb. Moreover, the computation of the forces applied by the muscles during motion (i.e., the inverse dynamics) cannot be correctly performed without the RB inertia properties of the prosthesis. In this paper, a prosthesis for transfemoral amputees is studied, namely C-Leg 3C-100. In particular, an experimental technique working in the frequency domain has been used for estimating prosthesis' inertia properties. Such a methodology evaluates the RB inertia properties from...