Article

This study quantified the accuracy of inertial sensors in 3D anatomical joint
angle measurement with respect to an instrumented gimbal.
The gimbal rotated
about three axes and directly measured the angles in the ISB recommended knee
joint coordinate system. Through the use of sensor attachment devices physically
fixed to the gimbal, the joint angle estimation error due to sensor attachment
(the inaccuracy of the sensor attachment matrix) was essentially eliminated,
leaving only error due to the inertial sensors. The angle estimation error (RMSE)
corresponding to the sensor was found to be 3.20 degrees in flexion/extension,
3.42 degrees in abduction/adduction and 2.88 degrees in internal/external
rotation. Bland-Altman means of maximum absolute value were -1.63 degrees
inflexion/extension, 3.22 degrees in abduction/adduction and -2.61 degrees in
internal/external rotation.
The magnitude of the errors reported in this study
imply that even under ideal conditions irreproducible in human gait studies,
inertial angle measurement will be subject to errors of a few degrees.
Conversely, the reported errors are smaller than those reported previously in
human gait studies, which suggest that the sensor attachment is also significant
source of error in inertial gait measurement. The proposed apparatus and
methodology could be used to quantify the performance of different sensor systems
and orientation estimation algorithms, and to verify experimental protocols
before human experimentation.
CI - Crown Copyright (c) 2011. Published by Elsevier B.V. All rights reserved.

Langue : ANGLAIS