0
research-article

Estimation of the 2-DOF Time-Varying Impedance of the Human Ankle

[+] Author and Article Information
Ficanha Evandro

Department of Mechanical Engineering-Engineering Mechanics, Michigan Technological University, Houghton, MI 49931, USA
emficanh@mtu.edu

Aramizo Ribeiro Guiherme

Department of Mechanical Engineering-Engineering Mechanics, Michigan Technological University, Houghton, MI 49931, USA
garamizo@mtu.edu

Knop Lauren

Department of Mechanical Engineering-Engineering Mechanics, Michigan Technological University, Houghton, MI 49931, USA
lknop@mtu.edu

Rastgaar Mo

Department of Mechanical Engineering-Engineering Mechanics, Michigan Technological University, Houghton, MI 49931, USA
rastgaar@mtu.edu

1Corresponding author.

ASME doi:10.1115/1.4039011 History: Received September 20, 2017; Revised November 21, 2017

Abstract

This paper describes the estimation of the time-varying mechanical impedance of the human ankle in both Dorsiflexion-Plantarflexion (DP) and Inversion-Eversion (IE) during walking in a straight line. The impedance was estimated using a 2-DOF vibrating platform and instrumented walkway. The perturbations were applied at 8 different axes of rotation combining different amounts of DP and IE rotations of four male subjects. The observed stiffness and damping were low at heel-strike, increased during the mid-stance, and decreases at push-off. At heel-strike it was observed that both the damping and stiffness were larger in IE than in DP. The maximum ankle stiffness was 5.43 Nm/rad/kg at 31% of the Stance Length (SL) when combining plantarflexion and inversion and the minimum was 1.14 Nm/rad/kg at 7% of the SL when combining dorsiflexion and eversion. The maximum ankle damping was 0.080 Nms/rad/kg at 38% of the SL when combining plantarflexion and inversion and the minimum was 0.016 Nms/rad/kg at 7% of the SL when combining plantarflexion and eversion. From 23% to 93% of the SL, the largest ankle stiffness and damping were either when combing plantarflexion and inversion or dorsiflexion and eversion. These rotations are the results of the motion of the ankle's subtalar joint, suggesting that the role of this joint and the muscles involved in the ankle rotation are significant in the impedance modulation in both DP and IE during gait.

Copyright (c) 2018 by ASME
Your Session has timed out. Please sign back in to continue.

References

Figures

Tables

Errata

Discussions

Some tools below are only available to our subscribers or users with an online account.

Related Content

Customize your page view by dragging and repositioning the boxes below.

Related Journal Articles
Related eBook Content
Topic Collections

Sorry! You do not have access to this content. For assistance or to subscribe, please contact us:

  • TELEPHONE: 1-800-843-2763 (Toll-free in the USA)
  • EMAIL: asmedigitalcollection@asme.org
Sign In