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Carnegie Mellon Robotics Institute

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Abstract

A simple method is developed for robustly estimating a fixed dominant axis of rotation (AoR) of anatomical joints from surface marker data. Previous approaches which assume a model of circular marker trajectories use plane-fitting to estimate the direction of the AoR. However, when there is limited joint range of motion and rotation due to a second degree of freedom, minimizing only the planar error can give poor estimates of the AoR direction. Optimizing a cost function which includes the error component within a plane, instead of only the component orthogonal to a plane, leads to improved estimates of the AoR direction for joints which exhibit additional rotational motion from a second degree of freedom. Results from synthetic data validation show the ranges of motion where the new method has lower estimation error compared to plane-fitting techniques. Estimates of the flexion-extension AoR from empirical motion capture data of the knee and index finger joints were also more anatomically plausible.

Keywords

Axis of rotation, Joint models, Optimization

Notes

Sponsor: NSF

Grant ID: CCF-0343161, IIS-0326322, ECS-0325383,and CNS-0423546

Associated Center(s) / Consortia: Center for the Foundations of Robotics

Number of pages: 9

Note: The PDF provided here is the revised preprint version. Please see the Journal of Biomechanics homepage (http://www.sciencedirect.com/science/journal/00219290) for the authoritative version of the article (http://dx.doi.org/10.1016/j.jbiomech.2007.01.010).

Text Reference

Lillian Y. Chang and Nancy Pollard, "Robust estimation of dominant axis of rotation," Journal of Biomechanics, Vol. 40, No. 12, 2007, pp. 2707 - 2715.

BibTeX Reference

@article{Chang_2007_5700,
   author = "Lillian Y. Chang and Nancy Pollard",
   title = "Robust estimation of dominant axis of rotation",
   journal = "Journal of Biomechanics",
   pages = "2707 - 2715",
   year = "2007",
   volume = "40",
   number = "12",
   Notes = "The PDF provided here is the revised preprint version. Please see the Journal of Biomechanics homepage (http://www.sciencedirect.com/science/journal/00219290) for the authoritative version of the article (http://dx.doi.org/10.1016/j.jbiomech.2007.01.010)."
}

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