Linear time-varying identification of ankle mechanical impedance during human walking

Hyunglae Lee, Hermano Igo Krebs, Neville Hogan

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

5 Scopus citations

Abstract

This paper presents a new method to investigate the multivariable time-varying behavior of the ankle during human walking, and provides the first experimental results from treadmill walking. A wearable ankle robot with an ensemblebased linear time-varying system identification method enabled identification of transient ankle mechanical impedance in 2 degrees of freedom, both in the sagittal and frontal planes. Several important issues of the ensemble-based identification method in practical measurements are discussed, especially a strategy to solve the limitation of the method which assumes that the system undergoes the same time-varying behavior on every stride. The suggested method was successfully applied to 15 minutes of human walking on a treadmill. Experiments with 10 young healthy subjects showed clear time-varying behavior of ankle impedance across the gait cycle, except the mid-stance phase. Interestingly, most subjects increased ankle impedance just before heel strike in both degrees of freedom. Interpretation of impedance changes was consistent with analysis of electromyographic signals from major muscles related to ankle movements.

Original languageEnglish (US)
Title of host publicationASME 2012 5th Annual Dynamic Systems and Control Conference Joint with the JSME 2012 11th Motion and Vibration Conference, DSCC 2012-MOVIC 2012
Pages753-758
Number of pages6
DOIs
StatePublished - Dec 1 2012
Externally publishedYes
EventASME 2012 5th Annual Dynamic Systems and Control Conference Joint with the JSME 2012 11th Motion and Vibration Conference, DSCC 2012-MOVIC 2012 - Fort Lauderdale, FL, United States
Duration: Oct 17 2012Oct 19 2012

Publication series

NameASME 2012 5th Annual Dynamic Systems and Control Conference Joint with the JSME 2012 11th Motion and Vibration Conference, DSCC 2012-MOVIC 2012
Volume1

Other

OtherASME 2012 5th Annual Dynamic Systems and Control Conference Joint with the JSME 2012 11th Motion and Vibration Conference, DSCC 2012-MOVIC 2012
CountryUnited States
CityFort Lauderdale, FL
Period10/17/1210/19/12

ASJC Scopus subject areas

  • Control and Systems Engineering

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