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A cam-displacement transducer device for measuring bi plane prosthetic motion

Twiste, M, Rithalia, S and Kenney, LPJ 2004, 'A cam-displacement transducer device for measuring bi plane prosthetic motion' , Medical Engineering & Physics, 26 (4) , pp. 335-340.

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    Abstract

    An electromechanical system is described that comprises a cam and two linear displacement transducers for measuring two-degree of freedom. This is aimed at quantifying the extent and pattern of both transverse rotation and longitudinal translation that takes place during amputee gait at what is sometimes termed a ‘‘torque-shock absorbing adapter’’ located between the prosthetic socket and foot. Both types of motion are measured independently by mounting the cam around the adapter and the two transducers orthogonal to one another with their spring loaded plungers moving separately against the cam’s perimeter and distal, flat face. The cam geometry should be an arc of a spiral and not a circle for the angular displacement measurement to be linear in response to rotation. Over a range of �18v for transverse rotation the maximum deviation of the ideal cam geometry away from an arc of a circle is less than �0.5% of the transducers’ 10 mm stroke. The transducer’s linearity is �2% and itcould therefore be assumed that this would be the dominant source of error. The theoretical predictions are supported by the calibration results, in which the pattern of errors that are found in the transducers’ calibration can also be seen in the calibration of the cam. # 2004 IPEM. Published by Elsevier Ltd. All rights reserved.

    Item Type: Article
    Themes: Subjects / Themes > R Medicine
    Health and Wellbeing
    Schools: Colleges and Schools > College of Health & Social Care > School of Health Sciences > Centre for Health Sciences Research
    Colleges and Schools > College of Health & Social Care
    Colleges and Schools > College of Health & Social Care > School of Health Sciences
    Journal or Publication Title: Medical Engineering & Physics
    Publisher: Elsevier
    Refereed: Yes
    ISSN: 1350-4533
    Depositing User: M Twiste
    Date Deposited: 21 Dec 2010 14:24
    Last Modified: 20 Aug 2013 17:43
    URI: http://usir.salford.ac.uk/id/eprint/12584

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