{"status":"ok","message-type":"work","message-version":"1.0.0","message":{"indexed":{"date-parts":[[2026,2,4]],"date-time":"2026-02-04T23:17:57Z","timestamp":1770247077601,"version":"3.49.0"},"reference-count":38,"publisher":"MDPI AG","issue":"2","license":[{"start":{"date-parts":[[2026,2,4]],"date-time":"2026-02-04T00:00:00Z","timestamp":1770163200000},"content-version":"vor","delay-in-days":0,"URL":"https:\/\/creativecommons.org\/licenses\/by\/4.0\/"}],"funder":[{"name":"Special Project of Basic Research on Frontier Leading Technology in Jiangsu Province","award":["BK20232008"],"award-info":[{"award-number":["BK20232008"]}]},{"name":"Jiangsu Provincial Frontier Technology R&D Program Project","award":["BF2025057"],"award-info":[{"award-number":["BF2025057"]}]},{"name":"Project of the Strategy Priority Research Program (Category B) of Chinese Academy of Sciences","award":["XDB1150102"],"award-info":[{"award-number":["XDB1150102"]}]}],"content-domain":{"domain":[],"crossmark-restriction":false},"short-container-title":["Biomimetics"],"abstract":"<jats:p>Continuum robots (CRs) exhibit high compliance and environmental adaptability in confined, tortuous spaces, yet their inherent low stiffness and load capacity limit performance in precise positioning and stable support tasks. To solve the \u201csoft-rigid\u201d paradox, this study proposes and implements a three-segment tendon-driven variable-stiffness CR. Structurally, a segmented constant-curvature model directs the optimization of grid skeletons and notch parameters, enhancing bending consistency and motion predictability. Elongated flat airbag actuators, arranged in annular arrays, enable segment-level stiffness switching through the enhancement of surface properties like axial constraints and friction amplification. A time-sharing drive strategy decouples multi-segment coupling into sequential single-segment subproblems, reducing drivers and kinematic complexity while maintaining dexterity. Experimental results demonstrate that flexible-mode joints maintain near-constant curvature with stable motion (average end-effector trajectory error &lt; 0.9 mm), and in rigid mode, stiffness increases by a factor of 5.77 (rated load: 4.0 N). Shape-locking disturbances during transitions are confined to millimeter levels (remote offset &lt; 1.32 mm), with successful traversal of J\/U\/S-shaped and irregular paths confirmed in pipeline tests. This work introduces a practical, scalable system for designing variable-stiffness structures and enabling low-complexity multi-segment control, offering valuable insights for minimally invasive devices and industrial endoscopy in confined spaces.<\/jats:p>","DOI":"10.3390\/biomimetics11020113","type":"journal-article","created":{"date-parts":[[2026,2,4]],"date-time":"2026-02-04T10:02:57Z","timestamp":1770199377000},"page":"113","update-policy":"https:\/\/doi.org\/10.3390\/mdpi_crossmark_policy","source":"Crossref","is-referenced-by-count":0,"title":["Design and Implementation of a Three-Segment Tendon-Driven Continuum Robot with Variable Stiffness for Manipulation in Confined Spaces"],"prefix":"10.3390","volume":"11","author":[{"given":"Zhixuan","family":"Weng","sequence":"first","affiliation":[{"name":"School of Biomedical Engineering (Suzhou), Division of Life Sciences and Medicine, University of Science and Technology of China, Hefei 230000, China"},{"name":"Suzhou Institute of Biomedical Engineering and Technology, Chinese Academy of Sciences, Suzhou 215000, China"}],"role":[{"role":"author","vocabulary":"crossref"}]},{"ORCID":"https:\/\/orcid.org\/0000-0002-5002-759X","authenticated-orcid":false,"given":"Liansen","family":"Sha","sequence":"additional","affiliation":[{"name":"School of Biomedical Engineering (Suzhou), Division of Life Sciences and Medicine, University of Science and Technology of China, Hefei 230000, China"},{"name":"Suzhou Institute of Biomedical Engineering and Technology, Chinese Academy of Sciences, Suzhou 215000, China"}],"role":[{"role":"author","vocabulary":"crossref"}]},{"given":"Yufei","family":"Chen","sequence":"additional","affiliation":[{"name":"School of Biomedical Engineering (Suzhou), Division of Life Sciences and Medicine, University of Science and Technology of China, Hefei 230000, China"},{"name":"Suzhou Institute of Biomedical Engineering and Technology, Chinese Academy of Sciences, Suzhou 215000, China"}],"role":[{"role":"author","vocabulary":"crossref"}]},{"given":"Bingyu","family":"Fan","sequence":"additional","affiliation":[{"name":"School of Biomedical Engineering (Suzhou), Division of Life Sciences and Medicine, University of Science and Technology of China, Hefei 230000, China"},{"name":"Suzhou Institute of Biomedical Engineering and Technology, Chinese Academy of Sciences, Suzhou 215000, China"}],"role":[{"role":"author","vocabulary":"crossref"}]},{"given":"Lan","family":"Li","sequence":"additional","affiliation":[{"name":"School of Biomedical Engineering (Suzhou), Division of Life Sciences and Medicine, University of Science and Technology of China, Hefei 230000, China"},{"name":"Suzhou Institute of Biomedical Engineering and Technology, Chinese Academy of Sciences, Suzhou 215000, China"}],"role":[{"role":"author","vocabulary":"crossref"}]},{"given":"Bin","family":"Liu","sequence":"additional","affiliation":[{"name":"School of Biomedical Engineering (Suzhou), Division of Life Sciences and Medicine, University of Science and Technology of China, Hefei 230000, China"},{"name":"Suzhou Institute of Biomedical Engineering and Technology, Chinese Academy of Sciences, Suzhou 215000, China"}],"role":[{"role":"author","vocabulary":"crossref"}]}],"member":"1968","published-online":{"date-parts":[[2026,2,4]]},"reference":[{"key":"ref_1","doi-asserted-by":"crossref","first-page":"1261","DOI":"10.1109\/TRO.2015.2489500","article-title":"Continuum Robots for Medical Applications: A Survey","volume":"31","author":"Rucker","year":"2015","journal-title":"IEEE Trans. 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