Technical Brief

Design of a Compact High-Torque Actuation System for Portable Powered Ankle–Foot Orthosis1

[+] Author and Article Information
Ziming Wang, Elizabeth T. Hsiao-Wecksler

Department of Mechanical Science and Engineering,
University of Illinois at Urbana-Champaign,
Champaign, IL 61801

DOI: 10.1115/1.4033780Manuscript received March 1, 2016; final manuscript received March 17, 2016; published online August 1, 2016. Editor: William Durfee.

J. Med. Devices 10(3), 030963 (Aug 01, 2016) (3 pages) Paper No: MED-16-1097; doi: 10.1115/1.4033780 History: Received March 01, 2016; Revised March 17, 2016

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Copyright © 2016 by ASME
Topics: Torque , Design , Orthotics
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Shorter, K. A. , Kogler, G. F. , Loth, E. , Durfee, W. K. , and Hsiao-Wecksler, E. T. , 2011, “ A Portable Powered Ankle-Foot Orthosis for Rehabilitation,” J. Rehabil. Res. Dev., 48(4), pp. 459–472. [CrossRef] [PubMed]
Winter, D. A. , 2009, Biomechanics and Motor Control of Human Movement, Wiley, New York.
Parsons, B. N. V , Walton, D. , Andrei, L. , and Andrei, G. , 2002, “ Non-Standard Cylindrical Gears,” VDI Ber., 1(1665), pp. 311–326.
Witte, K. A. , Zhang, J. , Jackson, R. W. , and Collins, S. H. , 2015, “ Design of Two Lightweight, High-Bandwidth Torque-Controlled Ankle Exoskeletons,” IEEE International Conference on Robotics and Automation (ICRA), Seattle, WA, May 26–30, pp. 1223–1228.
Malcolm, P. , Derave, W. , Galle, S. , and De Clercq, D. , 2013, “ A Simple Exoskeleton That Assists Ankle Extension Can Reduce the Metabolic Cost of Walking,” PLoS One, 8(2), p. e5613.
Ferris, D. P. , Gordon, K. E. , Sawicki, G. S. , and Peethambaran, A. , 2006, “ An Improved Powered Ankle-Foot Orthosis Using Proportional Myoelectric Control,” Gait Posture, 23(4), pp. 425–428. [CrossRef] [PubMed]
Mooney, L. M. , and Herr, H. M. , 2015, “ Biomechanical Walking Mechanisms Underlying the Metabolic Reduction Caused by an Autonomous Exoskeleton,” J. Neuroeng. Rehabil., 13(4), pp. 1–12.


Grahic Jump Location
Fig. 5

Back and side view of the modified PPAFO (linear actuator design)

Grahic Jump Location
Fig. 4

Side view of 3D-printed gearbox: (a) linear actuator mounting reinforcement/aluminum insert, (b) leg shell mounting holes, (c) gear rack, (d) yoke, (e) aluminum cylinder holder, (f) tapped front cover mounting hole, (g) compound driver gear, (h) compound-driven gear, and (j) sector gear

Grahic Jump Location
Fig. 3

Assembly view and exploded view of the powertrain

Grahic Jump Location
Fig. 2

Peak torques of the actuation systems compared with an 85 kg person's normal ankle torque profile [2]

Grahic Jump Location
Fig. 1

Back and side view of original PPAFO (rotatory actuator design)



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