Abstract
Electric wrist rotation has been available with electric hands for approximately 20
years. Although it is integrated with the Otto Bock electric hand, via their quick-disconnected
wrist component, the electric wrist has been used in only a fraction of electric prostheses
because of four perceived problems: 1) the additional length required in he forearm,
which could eliminate mid-to-long transradial amputees as candidates, 2) the additional
weight of the component, although only about 100 gm, 3) the speculation of most prescribing
MD's and prosthetists that the function of electric writs rotation is unnecessary
and unused by amputees, and 4) the difficulty of using the tiaditional wrist control
methods.
The introduction in 1989 of a proportional controller, which allows a simple switching
method using muscles cocontraction, possibly makes an impact on problems #3 and #4
above. The control method is speculated to be easier to learn and to use, and also
allows proportional control of the wrist rotation Powered by a 9 volt battery, or
12 volt in above-elbow applications, greater speed of wrists rotation is also provided.
The purpose of this survey is to evaluate the actual usage of electiic wrist by the
wearers of proportional systems, and to document the functions in which electric wrist
rotation has proved valuable, if any. Also, the stuvey hopes to provide indications
of the present drawbacks which remain, and provide direction for future improvements.
The results to-date of the survey will be presented, and any conclusions which are
warranted by the data. Future developments which could impact upon electric prosthesis
usage will also be discussed.
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Citation
From "MEC 95," Proceedings of the 1995 MyoElectric Controls/Powered Prosthetics Symposium
Fredericton, New Brunswick, Canada: August, 1995. Copyright University of New Brunswick.