Abstract
The measurement of the mechanical energy expenditure of a subject in accomplishing
a given motor task has been reported as a valuable index to quantitatively assess
his/her motor ability or pathology stage [1-3]. In order to compute this parameter
applying inverse dynamics techniques [1], the subject’s joint kinematics during the
motor task and the inertial parameters (i.e. the mass, centre of mass and inertia
matrix) of his/her moving limbs must be known. While the joint kinematics can be measured
in-vivo using a motion analysis system (e.g. an optoelectronic system), the inertial
parameters of human limbs are usually retrieved from anthropometric tables [1]. When
the subject acquired is an amputee fitted with an artificial limb the problem of determining
the prosthesis inertial parameters therefore arises. Considering a trans-radial amputation
levels, a prosthesis is composed by standardized parts (hand, battery, lamination
ring and actuators), and the subject-specific inner and outer sockets: since the CAD
models of these parts are usually unavailable their single and cumulative inertia
parameters remain unknown. The aim of this work was therefore to propose two possible
simplified CAD models for trans-radial prostheses and to identify among them which
one leads to the best estimation of the mechanical energy expenditure during a flexion-extension
of the elbow in the sagittal and horizontal plane and during a shoulder internal-external
rotation. The models, of increasing complexity, take into account the sockets, battery
and lamination ring.
Citation
Proceedings of the MEC’05 conference, UNB; 2005.
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