{"status":"ok","message-type":"work","message-version":"1.0.0","message":{"indexed":{"date-parts":[[2026,7,3]],"date-time":"2026-07-03T06:08:36Z","timestamp":1783058916596,"version":"3.54.6"},"reference-count":27,"publisher":"MDPI AG","issue":"12","license":[{"start":{"date-parts":[[2025,11,29]],"date-time":"2025-11-29T00:00:00Z","timestamp":1764374400000},"content-version":"vor","delay-in-days":0,"URL":"https:\/\/creativecommons.org\/licenses\/by\/4.0\/"}],"content-domain":{"domain":[],"crossmark-restriction":false},"short-container-title":["Micromachines"],"abstract":"<jats:p>Stroke rehabilitation exoskeletons require joint mechanisms capable of replicating physiological stiffness modulation to adapt to varying gait phases. This paper presents a novel compact variable-stiffness mechanism (VSM) for knee exoskeletons, based on a simplified three-bar linkage topology. The proposed design achieves a pre-configurable quasi-stiffness range of 0.15\u20132.0 NM\/deg. Static characterization under a 2 kg load demonstrated up to 23.0 N of collision force attenuation in softening regimes (\u03bb &lt; 2.3) through passive viscoelastic dissipation, whereas hardening behavior (\u03bb \u2265 2.3) preserved precise torque-angle characteristics scalable to physiological loading. A parametric analysis showed an 89% correlation between the theoretical and scaled experimental stiffness profiles for values from 0.5 to 2.5. The proposed architecture enables decoupled optimization of impact safety and positional precision, offering a clinically adaptable solution for hemiparetic gait assistance.<\/jats:p>","DOI":"10.3390\/mi16121365","type":"journal-article","created":{"date-parts":[[2025,12,1]],"date-time":"2025-12-01T09:34:37Z","timestamp":1764581677000},"page":"1365","update-policy":"https:\/\/doi.org\/10.3390\/mdpi_crossmark_policy","source":"Crossref","is-referenced-by-count":3,"title":["Design, Modeling, and Testing\u2014A Compact Variable-Stiffness Actuator for Knee Joint Dimensions"],"prefix":"10.3390","volume":"16","author":[{"ORCID":"https:\/\/orcid.org\/0000-0003-2034-1024","authenticated-orcid":false,"given":"Guoning","family":"Si","sequence":"first","affiliation":[{"name":"School of Health Science and Engineering, University of Shanghai for Science and Technology, Shanghai 200093, China"}],"role":[{"vocabulary":"crossref","role":"author"}]},{"given":"Zilong","family":"Guo","sequence":"additional","affiliation":[{"name":"School of Health Science and Engineering, University of Shanghai for Science and Technology, Shanghai 200093, China"}],"role":[{"vocabulary":"crossref","role":"author"}]},{"given":"Zhuo","family":"Zhang","sequence":"additional","affiliation":[{"name":"School of Modern Posts Industry, Xi\u2019an University of Posts and Telecommunications, Xi\u2019an 710121, China"}],"role":[{"vocabulary":"crossref","role":"author"}]}],"member":"1968","published-online":{"date-parts":[[2025,11,29]]},"reference":[{"key":"ref_1","doi-asserted-by":"crossref","first-page":"33","DOI":"10.1186\/s40779-023-00463-x","article-title":"China stroke surveillance report 2021","volume":"10","author":"Tu","year":"2023","journal-title":"Military Med. 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