Mechanics of Torque-Free Rolling in Soft Actuated Tubes: Experiments, Simulations, and Models

Mechanics of Torque-Free Rolling in Soft Actuated Tubes: Experiments, Simulations, and Models | 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 Mechanics of Torque-Free Rolling in Soft Actuated Tubes: Experiments, Simulations, and Models Yutang Zhou, Junqi Jiang, Zheng Zhong, Xudong Liang This is a preprint; it has not been peer reviewed by a journal. https://doi.org/ 10.21203/rs.3.rs-8830703/v1 This work is licensed under a CC BY 4.0 License Status: Posted Version 1 posted You are reading this latest preprint version Abstract Rolling locomotion in soft, deformable bodies can arise from internal shape change without relying on rigid wheels or externally applied torques. However, the mechanics underlying such motion remain unclear due to the combined effects of large deformation, distributed friction, and time-dependent actuation. In this work, we study torque-free rolling in a soft, pneumatically actuated tubular structure through experiments, finite-element simulations, and theoretical modeling. A reduced-order dynamic model is formulated within an extended Lagrangian framework, treating the system as a continuously bending body subject to time-varying actuation moments and spatially inhomogeneous friction with stick-slip transitions. Experimental measurements of rolling kinematics, curvature evolution, and ground reaction forces, together with finite-element simulations that resolve large deformations and contact migration, show quantitative agreement with model predictions. The analysis shows that rolling dynamics are governed by phase locking between the internal actuation cycle and mechanical responses. At low actuation frequencies, a stable phase-locked state exists with nearly constant curvature and uniform rolling. Increasing the frequency leads to phase unlocking due to the inertial effect and dissipation, resulting in oscillatory velocity and reduced net translation. A lock-unlock phase diagram is constructed in the space of actuation frequency, peak pressure, and actuator number, identifying a bounded operating window for stable rolling. These results provide a mechanics-based framework for understanding and designing shape-driven locomotion in next-generation soft robotic systems. soft robotic locomotion bending-induced rolling large deformation dynamics distributed frictional contact phase locking Full Text Additional Declarations No competing interests reported. Supplementary Files Movie1.mp4 Movie2.mp4 Movie3.mp4 Cite Share Download PDF Status: Posted Version 1 posted 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-8830703","acceptedTermsAndConditions":true,"allowDirectSubmit":true,"archivedVersions":[],"articleType":"Research Article","associatedPublications":[],"authors":[{"id":589551665,"identity":"56680a61-70e1-44b3-b9bf-4a01ce0ab0dd","order_by":0,"name":"Yutang Zhou","email":"","orcid":"","institution":"Harbin Institute of Technology","correspondingAuthor":false,"prefix":"","firstName":"Yutang","middleName":"","lastName":"Zhou","suffix":""},{"id":589551666,"identity":"657bbef9-9acd-4e45-9504-695038bd49d9","order_by":1,"name":"Junqi Jiang","email":"","orcid":"","institution":"Harbin Institute of 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