A Valve-Less Electro-Hydrostatic Powered Prosthetic Foot to Improve the Power Efficiency During Walking
Bowen Li, Xin Li, Hongguang Xu, Qitao Huang
Abstract
Hydraulic systems have been widely applied in lower-limb prostheses, primarily for their compact actuation and inherent damping capability. However, when applied to powered prosthetic feet, valves and other damping elements cause unavoidable energy dissipation, thereby constraining their power density. To address this limitation, we propose a valve-less electro-hydrostatic powered prosthetic foot aimed at enhancing power efficiency. In addition, a gas accumulator's nonlinear elasticity is considered, forming a hydraulic series elastic actuator with passive stiffness comparable to the human ankle during walking. This configuration lowers the motor's required speed, consequently reducing its actual electrical power. The proposed design was evaluated through a treadmill walking experiment with a non-impaired subject walking at 1.1 m/s. The results showed that the prosthetic foot provided sufficient positive power relative to human reference values. Moreover, the prosthesis achieved a peak output power of 206.3 <inline-formula xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink"><tex-math notation="LaTeX">$\pm$</tex-math></inline-formula> 15.0 W, while the corresponding motor electrical power was only 147.5 <inline-formula xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink"><tex-math notation="LaTeX">$\pm$</tex-math></inline-formula> 29.5 W. Our study demonstrates that the electro-hydrostatic system holds significant potential for enhancing the power density of powered prosthetic feet.
BibTeX
@inproceedings{ral2026_avalvelesselectr,
title = {A Valve-Less Electro-Hydrostatic Powered Prosthetic Foot to Improve the Power Efficiency During Walking},
author = {Bowen Li and Xin Li and Hongguang Xu and Qitao Huang},
booktitle = {RA-L 2026},
year = {2026}
}