Dynamics Computation of Soft-Rigid Hybrid-Link System and Its Application to Motion Analysis of an Athlete Wearing Sport Prosthesis

TL;DR

This paper introduces a motion analysis framework for athletes with flexible prostheses using a soft-rigid hybrid-link system, enabling accurate motion reconstruction and force estimation.

Contribution

It develops a unified modeling approach combining soft robotics and rigid-body dynamics for analyzing prosthesis-assisted athletic motion.

Findings

Achieved approximately 12% error in ground reaction force estimation.

Enabled muscle force estimation considering amputation and prosthesis interaction.

Validated the framework through human subject experiments.

Abstract

This paper presents a motion analysis framework for an athlete wearing sport-specific flexible prosthesis based on the soft-rigid hybrid-link system. Such a motion analysis is a challenging problem because we need to consider the interaction force between the rigid human skeleton system and a flexible prosthesis. However, most of human musculoskeletal models are based on the computation framework of a rigid-body multi-link system. Recently in soft robotics research field, fast and efficient modeling methods were developed for a flexible rod deformation, which allows us to build a hybrid-link system that integrates rigid-link and soft-bodies in a unified formulation. We apply inverse kinematics of the hybrid-link system to motion reconstruction from a motion captured data, and also present the estimation of the joint torques and ground reaction force by inverse dynamics. Through a human subject experiment, we show that the inverse dynamics achieved approximately 12% error on the ground reaction force estimation. Furthermore, we provide the muscle force estimation considering muscle amputation and interaction force with the prosthesis leg deformation.