A robotic apparatus that dictates torque fields around joints without affecting inherent joint dynamics
Human Movement Science. 2010-10-01; 29(5): 701-712
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1. Hum Mov Sci. 2010 Oct;29(5):701-12. doi: 10.1016/j.humov.2010.06.004. Epub 2010
A robotic apparatus that dictates torque fields around joints without affecting
inherent joint dynamics.
Oytam Y(1), Lloyd D, Reid CS, de Rugy A, Carson RG.
(1)Perception and Motor Systems Laboratory, The University of Queensland,
This manuscript describes how motor behaviour researchers who are not at the same
time expert roboticists may implement an experimental apparatus, which has the
ability to dictate torque fields around a single joint on one limb or single
joints on multiple limbs without otherwise interfering with the inherent dynamics
of those joints. Such an apparatus expands the exploratory potential of the
researcher wherever experimental distinction of factors may necessitate
independent control of torque fields around multiple limbs, or the shaping of
torque fields of a given joint independently of its plane of motion, or its
directional phase within that plane. The apparatus utilizes torque motors. The
challenge with torque motors is that they impose added inertia on limbs and thus
attenuate joint dynamics. We eliminated this attenuation by establishing an
accurate mathematical model of the robotic device using the Box-Jenkins method,
and cancelling out its dynamics by employing the inverse of the model as a
compensating controller. A direct measure of the remnant inertial torque as
experienced by the hand during a 50 s period of wrist oscillations that increased
gradually in frequency from 1.0 to 3.8 Hz confirmed that the removal of the
inertial effect of the motor was effectively complete.
Copyright © 2010 Elsevier B.V. All rights reserved.
PMID: 20728232 [Indexed for MEDLINE]