Research Papers

Design and Evaluation of a Passive Ankle Prosthesis With Powered Push-Off

[+] Author and Article Information
Jacob J. Rice, Joseph M. Schimmels, Shuguang Huang

Department of Mechanical Engineering,
Marquette University,
Milwaukee, WI 53233

Manuscript received March 6, 2015; final manuscript received July 29, 2015; published online November 24, 2015. Assoc. Editor: Byung-Ju Yi.

J. Mechanisms Robotics 8(2), 021012 (Nov 24, 2015) (8 pages) Paper No: JMR-15-1052; doi: 10.1115/1.4031302 History: Received March 06, 2015; Revised July 29, 2015; Accepted August 08, 2015

Below-knee amputation is one of the most frequently performed types of amputation in the United States. This paper describes CamWalk, a novel passive ankle prosthesis that has mechanical behavior similar to that of a natural ankle. CamWalk generates rotational push-off to propel the walker forward using a compliant coupling between two degrees-of-freedom (DOFs) (deflection along the leg and rotation about the ankle). The design closely matches the ankle torque and ankle work characteristics of an average healthy ankle. Simulation results indicate that CamWalk generates 44.5% of the net rotational work performed by a natural healthy ankle when leg deflection is limited to 15 mm. Standard gait analysis of four amputees using CamWalk demonstrated that the device performance ranged from marginally dissipative to significantly active, generating 48.0% of the work performed by their natural ankle.

Copyright © 2016 by ASME
Your Session has timed out. Please sign back in to continue.



Grahic Jump Location
Fig. 1

Stance phase key positions

Grahic Jump Location
Fig. 2

Natural gait profiles for a healthy natural ankle. Average subject mass: 56.7 kg.

Grahic Jump Location
Fig. 3

Torque–angle curve for a healthy natural ankle. Average subject mass: 56.7 kg.

Grahic Jump Location
Fig. 4

Torque–angle curve for a passive prosthetic ankle. Subject mass: 63.7 kg.

Grahic Jump Location
Fig. 5

Novel 2DOF approach with compliant coupling. Ankle angle and leg deflection are zero at the no-load equilibrium configuration.

Grahic Jump Location
Fig. 6

CamWalk at key stance positions. Springs with dashed lines indicate that they are not providing force. (1) Heel-strike, (2) foot-flat, (3a) heel-off, (3b) heel-off, (4a) toe-off, and (4b) toe-off.

Grahic Jump Location
Fig. 7

CamWalk design parameters. Design parameters are specified in the no-load equilibrium configuration.

Grahic Jump Location
Fig. 8

Compactness envelope for CamWalk

Grahic Jump Location
Fig. 9

Average natural and simulated torque–angle curves

Grahic Jump Location
Fig. 10

CamWalk prototype

Grahic Jump Location
Fig. 11

Shock absorption spring, follower, and cam: (a) side view and (b) trimetric view

Grahic Jump Location
Fig. 12

Cam follower and track

Grahic Jump Location
Fig. 13

Torque–angle curves for the robot test and model simulation

Grahic Jump Location
Fig. 14

Ankle torque–angle curves for CamWalk with early drop timing. Subject 2 mass: 73.5 kg.

Grahic Jump Location
Fig. 15

Ankle torque–angle curves for CamWalk and the amputee's original prosthesis. Subject 4 mass: 88.0 kg.




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