Article

We developed a 2-degree-of-freedom (DOF) shoulder position transducer (sensing
shoulder protraction-retraction and elevation-depression) that can be used to
control two of a powered prosthetic humerus' DOFs.
We also developed an
evaluation protocol based on Fitts' law to assess the performance of our device.
The primary motivation for this work was to support development of powered
prosthetic shoulder joints of a new generation of prosthetic arms for people with
shoulder disarticulation and very high-level transhumeral amputation. We found
that transducers that provided resistance to shoulder movement performed better
than those providing no resistance. We also found that a position control scheme,
where effector position is proportional to shoulder position, performed better
than a velocity control scheme, where effector velocity is proportional to
shoulder position. More generally, our transducer can be used to control motion
along any two DOFs under a proportional control scheme. It can also be used in a
more general 4-DOF control scheme by sequentially controlling two DOFs at a time.
The evaluation protocol has general applicability for researchers and
practitioners. Researchers can employ it to compare different prosthesis designs
and control schemes, while practitioners may find the evaluation protocol useful
in evaluating and training people with amputation in the use of prostheses.

Langue : ANGLAIS