Actuation timing strategies for a portable powered ankle foot orthosis

Emily A. Morris, K. Alex Shorter, Yifan Li, Elizabeth T. Hsiao-Wecksler, Geza F. Kogler, Timothy Bretl, William K. Durfee

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

Abstract

Ankle-foot orthoses (AFOs) are used to assist persons with lower-limb neuromuscular impairments. We have developed the portable powered AFO (PPAFO). This device uses a bidirectional pneumatic actuator powered by a CO2 bottle to provide dorsiflexor and plantarflexor torque assistance. The PPAFO operates tether-free, allowing for use outside of the laboratory. This system has been tested on one impaired and multiple healthy subjects. Timing of the assistance provided by the PPAFO has been determined by: 1) direct event detection using sensor feedback with threshold triggers, and 2) state estimation in which gait events are estimated using a cross-correlation based algorithm. Direct event detection, while simple to implement, can be unreliable for subjects with certain gait impairments. State estimation, while more complicated to implement, provides access to state information that cannot be directly measured by the AFO, which allows for greater flexibility in assistance timing. Current hardware limitations and future work are also discussed.

Original languageEnglish (US)
Title of host publicationASME 2011 Dynamic Systems and Control Conference and Bath/ASME Symposium on Fluid Power and Motion Control, DSCC 2011
Pages807-814
Number of pages8
DOIs
StatePublished - Dec 1 2011
EventASME 2011 Dynamic Systems and Control Conference and Bath/ASME Symposium on Fluid Power and Motion Control, DSCC 2011 - Arlington, VA, United States
Duration: Oct 31 2011Nov 2 2011

Publication series

NameASME 2011 Dynamic Systems and Control Conference and Bath/ASME Symposium on Fluid Power and Motion Control, DSCC 2011
Volume2

Other

OtherASME 2011 Dynamic Systems and Control Conference and Bath/ASME Symposium on Fluid Power and Motion Control, DSCC 2011
CountryUnited States
CityArlington, VA
Period10/31/1111/2/11

ASJC Scopus subject areas

  • Fluid Flow and Transfer Processes
  • Control and Systems Engineering

Fingerprint Dive into the research topics of 'Actuation timing strategies for a portable powered ankle foot orthosis'. Together they form a unique fingerprint.

  • Cite this

    Morris, E. A., Shorter, K. A., Li, Y., Hsiao-Wecksler, E. T., Kogler, G. F., Bretl, T., & Durfee, W. K. (2011). Actuation timing strategies for a portable powered ankle foot orthosis. In ASME 2011 Dynamic Systems and Control Conference and Bath/ASME Symposium on Fluid Power and Motion Control, DSCC 2011 (pp. 807-814). (ASME 2011 Dynamic Systems and Control Conference and Bath/ASME Symposium on Fluid Power and Motion Control, DSCC 2011; Vol. 2). https://doi.org/10.1115/DSCC2011-6170