Application of Piece-wise Constant Strain Model to Flexible Deformation Calculation of Sports Prosthesis and Stiffness Estimation

In this study, we present an application of the Piece-wise Constant Strain (PCS) model to a flexible deformation analysis of a sports prosthesis leg. Dynamic motion analysis of an athlete wearing a sports prosthesis is important to clarify a relationship between the prosthesis characteristics and the performance of an athlete, which contributes to training of an athlete or design of the prosthesis. However, there are few studies on modeling of the three-dimensional deformation of the sports prosthesis. In soft robotics, the PCS model was proposed for calculating a flexible deformation of a beam or rod structure with a low computational cost. We employ the PCS model to calculate the flexible deformation of the prosthesis, assuming that its structure can be discretized into a finite number of segments. Moreover, we propose an estimation method of the prosthesis stiffness using optical motion capture data and calculating the semi-definite programming.