The Haptic Cycling Trainer (HaCT): a robotic device for lower-limb rehabilitation

The Haptic Cycling Trainer (HaCT): a robotic device for lower-limb rehabilitation | 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 The Haptic Cycling Trainer (HaCT): a robotic device for lower-limb rehabilitation Murat Sahin, Andrea Ortiz-Cuadros, Bahram Tarvirdizadeh, Giacomo Severini, and 1 more This is a preprint; it has not been peer reviewed by a journal. https://doi.org/ 10.21203/rs.3.rs-9105541/v2 This work is licensed under a CC BY 4.0 License Status: Posted Version 2 posted You are reading this latest preprint version Show more versions Abstract This article presents a robotic rehabilitation device comprising a cycle ergometer that can guide a user's feet through non-circular trajectories while dynamically assisting or resisting motion. The device possesses three degrees of freedom: a central motor governs crank rotation, while two additional motors independently control each crank's effective length; three rotational encoders provide position feedback. Each motor is regulated by nested position (outer), velocity, and current (inner) control loops. Controller gains for each cascade stage were optimized through simulations employing a model of the physical system. Inertial and dissipative parameters within this model were estimated via system identification, wherein a population-based search algorithm minimized the discrepancy between the model's predictions and the system's measured response. Validation of both the system model and its derived controller proceeded in two stages: first examining each degree of freedom in isolation, then considering them simultaneously. Evaluation entailed comparing the physical system's response to commanded trajectories and further assessing model fidelity by contrasting simulated predictions against experimentally observed response. Robotics Bees algorithm Cycle ergometer Haptic interface Rehabilitation engineering System identification Full Text Additional Declarations The authors declare no competing interests. Cite Share Download PDF Status: Posted Version 2 posted You are reading this latest preprint version Show more versions 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. 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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-9105541","acceptedTermsAndConditions":true,"allowDirectSubmit":true,"archivedVersions":[],"articleType":"Research Article","associatedPublications":[],"authors":[{"id":605396837,"identity":"4220d95d-1fad-4d1f-b090-c69fa646ff2d","order_by":0,"name":"Murat Sahin","email":"","orcid":"","institution":"University College Dublin","correspondingAuthor":false,"prefix":"","firstName":"Murat","middleName":"","lastName":"Sahin","suffix":""},{"id":605396838,"identity":"efa213d7-cbb4-42c6-b363-cdab547d44b2","order_by":1,"name":"Andrea Ortiz-Cuadros","email":"","orcid":"","institution":"University College Dublin","correspondingAuthor":false,"prefix":"","firstName":"Andrea","middleName":"","lastName":"Ortiz-Cuadros","suffix":""},{"id":605396839,"identity":"c0730a70-f640-437e-9112-65ccd40190c0","order_by":2,"name":"Bahram Tarvirdizadeh","email":"","orcid":"","institution":"University of Tehran","correspondingAuthor":false,"prefix":"","firstName":"Bahram","middleName":"","lastName":"Tarvirdizadeh","suffix":""},{"id":605396840,"identity":"067b9dcd-0dec-4d09-9afa-c38dc1d42e1c","order_by":3,"name":"Giacomo Severini","email":"data:image/png;base64,iVBORw0KGgoAAAANSUhEUgAAAZAAAAAyAQMAAABI0h/eAAAABlBMVEX///8AAABVwtN+AAAACXBIWXMAAA7EAAAOxAGVKw4bAAAA70lEQVRIiWNgGAWjYDACZhSeAQMPP5CSADJI0CLZQEgLBjA4ANKCB8i7Mz/88DHHhkG+vcfwcUXBHRnjG8kPbzAU2ODUYniYzVhy5rY0BoMzZ4wNzxg84zG7kWZswWCQhltLM4MZM++2wwwGEmlpkg0Gh4FactiAfjmMRwv7N7AW+fnP0n+CtBjPAGv5j9svzDwQWxhuMB9jBGkxkABrOYBTiwEzTzHILzwGZ5IPgx0mceaZsUWCQTJuW/qPb/zwcZuNnHz7wcaPDX8O2/O3A0Pswx873LZAHcCDKpyAUwPQlgY8kqNgFIyCUTAKwAAAJedLgx0FENEAAAAASUVORK5CYII=","orcid":"","institution":"University College Dublin","correspondingAuthor":true,"prefix":"","firstName":"Giacomo","middleName":"","lastName":"Severini","suffix":""},{"id":605396841,"identity":"8c986f1b-c782-4714-8e66-5e43ff0f1ca0","order_by":4,"name":"Donal Holland","email":"","orcid":"","institution":"University College Dublin","correspondingAuthor":false,"prefix":"","firstName":"Donal","middleName":"","lastName":"Holland","suffix":""}],"badges":[],"createdAt":"2026-03-12 13:50:34","currentVersionCode":2,"declarations":{"humanSubjects":false,"vertebrateSubjects":false,"conflictsOfInterestStatement":false,"humanSubjectEthicalGuidelines":false,"humanSubjectConsent":false,"humanSubjectClinicalTrial":false,"humanSubjectCaseReport":false,"vertebrateSubjectEthicalGuidelines":false},"doi":"10.21203/rs.3.rs-9105541/v2","doiUrl":"https://doi.org/10.21203/rs.3.rs-9105541/v2","draftVersion":[],"editorialEvents":[],"editorialNote":"","failedWorkflow":false,"files":[{"id":107481663,"identity":"efd6e0fb-e7b4-4f36-867f-70464768199d","added_by":"auto","created_at":"2026-04-22 02:19:32","extension":"pdf","order_by":1,"title":"","display":"","copyAsset":false,"role":"manuscript-pdf","size":1151053,"visible":true,"origin":"","legend":"","description":"","filename":"SahinetalHaCT.pdf","url":"https://assets-eu.researchsquare.com/files/rs-9105541/v2_covered_f11169f0-9d47-4ee3-aac6-05ac5740374d.pdf"}],"financialInterests":"The authors declare no competing interests.","formattedTitle":"The Haptic Cycling Trainer (HaCT): a robotic device for lower-limb rehabilitation","fulltext":[],"fulltextSource":"","fullText":"","funders":[],"hasAdminPriorityOnWorkflow":false,"hasManuscriptDocX":false,"hasOptedInToPreprint":true,"hasPassedJournalQc":"","hasAnyPriority":true,"hideJournal":true,"highlight":"","institution":"University College Dublin","isAcceptedByJournal":false,"isAuthorSuppliedPdf":true,"isDeskRejected":"","isHiddenFromSearch":false,"isInQc":false,"isInWorkflow":false,"isPdf":true,"isPdfUpToDate":true,"isWithdrawnOrRetracted":false,"journal":{"display":true,"email":"[email protected]","identity":"researchsquare","isNatureJournal":false,"hasQc":true,"allowDirectSubmit":true,"externalIdentity":"","sideBox":"","snPcode":"","submissionUrl":"/submission","title":"Research Square","twitterHandle":"researchsquare","acdcEnabled":true,"dfaEnabled":false,"editorialSystem":"","reportingPortfolio":"","inReviewEnabled":false,"inReviewRevisionsEnabled":true},"keywords":"Bees algorithm, Cycle ergometer, Haptic interface, Rehabilitation engineering, System identification","lastPublishedDoi":"10.21203/rs.3.rs-9105541/v2","lastPublishedDoiUrl":"https://doi.org/10.21203/rs.3.rs-9105541/v2","license":{"name":"CC BY 4.0","url":"https://creativecommons.org/licenses/by/4.0/"},"manuscriptAbstract":"\u003cp\u003eThis article presents a robotic rehabilitation device comprising a cycle ergometer that can guide a user's feet through non-circular trajectories while dynamically assisting or resisting motion. 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