IMU-based joint axis identification method for arbitrary joints in OpenSim - a simulation study

IMU-based joint axis identification method for arbitrary joints in OpenSim - a simulation study | Research Square window.SnipcartSettings = { analytics: { enabled: false } }; (function() { var accessVector = localStorage.getItem('access_vector') || ''; window.dataLayer = window.dataLayer || []; if (accessVector) { window.dataLayer.push({ user: { profile: { profileInfo: { snid: accessVector } } } }); } })(); (function(w,d,s,l,i){w[l]=w[l]||[];w[l].push({'gtm.start':new Date().getTime(),event:'gtm.js'});var f=d.getElementsByTagName(s)[0],j=d.createElement(s),dl=l!='dataLayer'?'&l='+l:'';j.async=true;j.src='https://www.googletagmanager.com/gtm.js?id='+i+dl;f.parentNode.insertBefore(j,f);})(window,document,'script','dataLayer','GTM-K279D39R'); Browse Preprints In Review Journals COVID-19 Preprints AJE Video Bytes Research Tools Research Promotion AJE Professional Editing AJE Rubriq About Preprint Platform In Review Editorial Policies Our Team Advisory Board Help Center Sign In Submit a Preprint Cite Share Download PDF Research Article IMU-based joint axis identification method for arbitrary joints in OpenSim - a simulation study Iris Wechsler, Julian Shanbhag, Sandro Wartzack, Anne D. Koelewijn, and 1 more This is a preprint; it has not been peer reviewed by a journal. https://doi.org/ 10.21203/rs.3.rs-4325016/v1 This work is licensed under a CC BY 4.0 License Status: Published Journal Publication published 21 Nov, 2025 Read the published version in BMC Biomedical Engineering → Version 1 posted 4 You are reading this latest preprint version Abstract In musculoskeletal simulation, individualized joint axes enhance the accuracy and reliability of kinematic and kinetic simulation results. We investigated the correctness and performance of an analytical method for identifying the instantaneous axis of rotation between two bodies based on motion data in OpenSim. The instantaneous center of rotation is the point at which two bodies have the same velocity. The relative linear and angular velocity between the two bodies, as well as their relative position to each another, are required as inputs to calculate it. Using the instantaneous center of rotation, fixed or moving joint centers of rotation can be identified. To prove the general applicability of the method, the instantaneous centers of rotation of a revolute joint of a simple double pendulum model and the hip and knee joint of a more complex musculoskeletal model were investigated. The hip joint is defined as a ball joint. The knee joint is defined as an OpenSim custom joint which describes the motion of the child segment in relation to the parent segment as a function of generalized coordinates. To verify the correctness of the approach in OpenSim, the moving centers of rotation were calculated using synthetic noisefree data. The results were compared to the implementation of the respective joints in the model which act as the ground truth. White Gaussian noise was added to the synthetic data to analyze its effect on the quality of the calculated centers of rotation. We were able to correctly identify the center of rotation of each joint using noisefree data. In the case of noisy data, joint centers of rotation can be determined by applying additional filtering or optimization methods to the calculated instantaneous centers of rotation. Consequently, we are able to determine the center of rotation for arbitrary joints based on noisy synthetic data. This approach is applicable for both fixed and moving centers of rotation which distinguishes it from commonly used methods in the field of biomechanical simulation. biomechanical modeling and simulation joint axis identification model individualization instantaneous axis of rotation measurement noise Full Text Additional Declarations No competing interests reported. Cite Share Download PDF Status: Published Journal Publication published 21 Nov, 2025 Read the published version in BMC Biomedical Engineering → Version 1 posted Editorial decision: Revision requested 08 May, 2024 Editor assigned by journal 08 May, 2024 Submission checks completed at journal 06 May, 2024 First submitted to journal 25 Apr, 2024 You are reading this latest preprint version Research Square lets you share your work early, gain feedback from the community, and start making changes to your manuscript prior to peer review in a journal. As a division of Research Square Company, we’re committed to making research communication faster, fairer, and more useful. We do this by developing innovative software and high quality services for the global research community. Our growing team is made up of researchers and industry professionals working together to solve the most critical problems facing scientific publishing. Also discoverable on Platform About Our Team In Review Editorial Policies Advisory Board Help Center Resources Author Services Accessibility API Access RSS feed Manage Cookie Preferences © Research Square 2026 | ISSN 2693-5015 (online) Privacy Policy Terms of Service Do Not Sell My Personal Information {"props":{"pageProps":{"initialData":{"identity":"rs-4325016","acceptedTermsAndConditions":true,"allowDirectSubmit":false,"archivedVersions":[],"articleType":"Research Article","associatedPublications":[],"authors":[{"id":300346714,"identity":"4bbcc0ce-21cd-41f6-9dba-25e75b8f7c90","order_by":0,"name":"Iris Wechsler","email":"data:image/png;base64,iVBORw0KGgoAAAANSUhEUgAAAZAAAAAyAQMAAABI0h/eAAAABlBMVEX///8AAABVwtN+AAAACXBIWXMAAA7EAAAOxAGVKw4bAAAA4UlEQVRIie2RsWrDMBRFbxA4iyCrjck/XBC4FEL6K88IPAWcsdAhhkI69gP6H50FgmbJXAoZ2hLw1CGjt8bJlkVJ6NJBZ3xwOFcIiET+JwkwB0YYbIHJ4SCXKASyRhmgukahu1Th6rH97jipzbtXhEzLZmhdWFm/3RjN6vZ1Y5VAbNnoNpwpPmZJDnoWm9q7QafKJp0xrHz+JFnHX5oXqxxk0Sv17kxFJ6mmI/PjMH+oBA3crasi17RM+7dQZGWWug0Py558m3X3U476YelOHsbPQ/sVzpwgOH5TJBKJRP7KHgwlQP9XGaLpAAAAAElFTkSuQmCC","orcid":"","institution":"1Engineering Design, Department of Mechanical Engineering, Friedrich-Alexander-Universität Erlangen-Nürnberg","correspondingAuthor":true,"prefix":"","firstName":"Iris","middleName":"","lastName":"Wechsler","suffix":""},{"id":300346716,"identity":"af51e039-bbe6-4181-b36e-a1dfaa664c3e","order_by":1,"name":"Julian Shanbhag","email":"","orcid":"","institution":"1Engineering Design, Department of Mechanical Engineering, Friedrich-Alexander-Universität Erlangen-Nürnberg","correspondingAuthor":false,"prefix":"","firstName":"Julian","middleName":"","lastName":"Shanbhag","suffix":""},{"id":300346717,"identity":"9c93596e-b28a-41ae-b649-b91ec469df5c","order_by":2,"name":"Sandro Wartzack","email":"","orcid":"","institution":"1Engineering Design, Department of Mechanical Engineering, Friedrich-Alexander-Universität Erlangen-Nürnberg","correspondingAuthor":false,"prefix":"","firstName":"Sandro","middleName":"","lastName":"Wartzack","suffix":""},{"id":300346718,"identity":"179a1097-51bd-44e7-bcdb-e40ad7768aeb","order_by":3,"name":"Anne D. 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To verify the correctness of the approach in OpenSim, the moving centers of rotation were calculated using synthetic noisefree data. The results were compared to the implementation of the respective joints in the model which act as the ground truth. White Gaussian noise was added to the synthetic data to analyze its effect on the quality of the calculated centers of rotation. We were able to correctly identify the center of rotation of each joint using noisefree data. In the case of noisy data, joint centers of rotation can be determined by applying additional filtering or optimization methods to the calculated instantaneous centers of rotation. Consequently, we are able to determine the center of rotation for arbitrary joints based on noisy synthetic data. 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