Uncertainties in inverse dynamics solutions: a comprehensive analysis and an application to gait

Details

• Personal Author:
  Hsiao-Wecksler ET ; Riemer R ; Zhang X
• Description:
  This paper presents a comprehensive analysis of the uncertainties in joint torque estimates derived through inverse dynamics. The analysis considered most of the quantifiable sources of inaccuracy in the input variables for inverse dynamics solutions (i.e., errors in body segment parameter estimates, joint center of rotation locations, force plate measurements, motion capture system measurements, and segment angle calculations due to skin movement artifacts). Estimates of inaccuracies were synthesized from existing literature and from a complementary set of experimental data. The analysis was illustrated and tested via an inverse dynamic analysis of gait, in which kinematic and force plate data from 10 adult subjects were recorded and used to calculate the planar (flexion/extension) torques at the ankle, knee, hip, elbow, shoulder, and bottom of torso. The results suggested that the uncertainties in torque estimates derived through inverse dynamics can be substantial (6-232% of the estimated torque magnitude); the time-varying uncertainty patterns do not resemble the torque profiles, and the magnitudes are smaller for more distal joints; the main contributors to these uncertainties were identified to be the inaccuracies in estimated segment angles and body segment parameters. The empirical test also showed that the uncertainty predicted by a more conservative (smaller) set of inaccuracy estimates was comparable to the statistical (3s) bound of the error. Implications in terms of how inverse dynamics solutions should be interpreted and improved, along with the limitations of the current work, are discussed. [Description provided by NIOSH]
• Subjects:
  Electricity Mining Occupational Health Safety
• Keywords:
  Author Keywords: Error Analysis Biodynamics Biomechanics Ergonomics Inverse Dynamics Muscle-physiology Musculoskeletal-system Physical-capacity Physical-stress Physiological-factors Uncertainty

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• ISSN:
  0966-6362
• Document Type:
  Text
• Funding:
  Grant
• Genre:
  Journal Article
• Place as Subject:
  Illinois ; OSHA Region 5
• CIO:
  National Institute for Occupational Safety and Health (NIOSH)
• Topic:
  Workplace Safety & Health
• Location:
  North America
• Volume:
  27
• Issue:
  4
• NIOSHTIC Number:
  nn:20038381
• Citation:
  Gait Posture 2008 May; 27(4):578-588
• Contact Point Address:
  Xudong Zhang, Department of Mechanical and Industrial Engineering, University of Illinois at Urbana-Champaign, Urbana, IL 61801
• Email:
  xuz9@pitt.edu
• Federal Fiscal Year:
  2008
• NORA Priority Area:
  Disease and Injury: Musculoskeletal Disorders of the Upper Extremities
• Performing Organization:
  University of Illinois Urbana-Champaign
• Peer Reviewed:
  True
• Start Date:
  20030901
• Source Full Name:
  Gait and Posture
• End Date:
  20070831
• Collection(s):
  National Institute for Occupational Safety and Health
• Main Document Checksum:
  urn:sha-512:e6f5af680f5fbdf1c7b18bfa7b2729d964280788037688dc60d947e7deb8bb815455b5318f461a33e0f40b76399e71083a85add5bfeef4ffeea95e6aaa1196db
• Download URL:
  https://stacks.cdc.gov/view/cdc/192106/cdc_192106_DS1.pdf
• File Type:
  [PDF - 791.95 KB ]