A new robotic approach to characterize mechanical impedance and energetic passivity of the human ankle during standing

Varun Nalam, Hyunglae Lee

Research output: Chapter in Book/Report/Conference proceedingConference contribution

1 Scopus citations

Abstract

This paper presents the quantitative characterization of ankle impedance and ankle passivity during upright standing. A novel multi-axis robotic platform allows for the quantification of these neuromuscular properties in two degrees-of-freedom of the ankle, specifically, dorsiflexion-plantarflexion (DP) and inversion-eversion (IE). For the slow sinusoid perturbations of low frequencies ranging up to 1.5 Hz, ankle impedance was accurately approximated by stiffness and damping, while the contribution of inertia and reflex feedback was minimal. Ankle stiffness and damping were found to be highly direction dependent, being much higher in the DP than IE direction. Ankle stiffness linearly increased with co-contraction of ankle muscles. While the same trend was evident for ankle damping in the DP direction, no significant changes were observed in the IE direction. In addition, the ankle behavior was found to be highly dissipative in both DOFs over a wide range of muscle activation for young healthy subjects. Characterization results in this study would not only provide an insight into the functional contribution of the ankle to the control of postural balance but also add valuable information in the development of neuro-rehabilitation and assistive devices.

Original languageEnglish (US)
Title of host publication2017 39th Annual International Conference of the IEEE Engineering in Medicine and Biology Society
Subtitle of host publicationSmarter Technology for a Healthier World, EMBC 2017 - Proceedings
PublisherInstitute of Electrical and Electronics Engineers Inc.
Pages4123-4126
Number of pages4
ISBN (Electronic)9781509028092
DOIs
StatePublished - Sep 13 2017
Event39th Annual International Conference of the IEEE Engineering in Medicine and Biology Society, EMBC 2017 - Jeju Island, Korea, Republic of
Duration: Jul 11 2017Jul 15 2017

Other

Other39th Annual International Conference of the IEEE Engineering in Medicine and Biology Society, EMBC 2017
CountryKorea, Republic of
CityJeju Island
Period7/11/177/15/17

ASJC Scopus subject areas

  • Signal Processing
  • Biomedical Engineering
  • Computer Vision and Pattern Recognition
  • Health Informatics

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    Nalam, V., & Lee, H. (2017). A new robotic approach to characterize mechanical impedance and energetic passivity of the human ankle during standing. In 2017 39th Annual International Conference of the IEEE Engineering in Medicine and Biology Society: Smarter Technology for a Healthier World, EMBC 2017 - Proceedings (pp. 4123-4126). [8037763] Institute of Electrical and Electronics Engineers Inc.. https://doi.org/10.1109/EMBC.2017.8037763