{"status":"ok","message-type":"work","message-version":"1.0.0","message":{"indexed":{"date-parts":[[2026,4,11]],"date-time":"2026-04-11T22:41:45Z","timestamp":1775947305291,"version":"3.50.1"},"reference-count":34,"publisher":"MDPI AG","issue":"14","license":[{"start":{"date-parts":[[2022,7,19]],"date-time":"2022-07-19T00:00:00Z","timestamp":1658188800000},"content-version":"vor","delay-in-days":0,"URL":"https:\/\/creativecommons.org\/licenses\/by\/4.0\/"}],"funder":[{"name":"Regional Joint Fund Project of the Basic and Applied Research Fund of Guangdong Province, Hong Kong Research Grants Council (RGC) Collaborative Research Fund","award":["(CRF C4026-21GF) 2300075"],"award-info":[{"award-number":["(CRF C4026-21GF) 2300075"]}]},{"name":"Regional Joint Fund Project of the Basic and Applied Research Fund of Guangdong Province, Hong Kong Research Grants Council (RGC) Collaborative Research Fund","award":["(GRS)#3110167"],"award-info":[{"award-number":["(GRS)#3110167"]}]}],"content-domain":{"domain":[],"crossmark-restriction":false},"short-container-title":["Sensors"],"abstract":"<jats:p>With the emerging need for human\u2013machine interactions, multi-modal sensory interaction is gradually pursued rather than satisfying common perception forms (visual or auditory), so developing flexible, adaptive, and stiffness-variable force-sensing devices is the key to further promoting human\u2013machine fusion. However, current sensor sensitivity is fixed and nonadjustable after fabrication, limiting further development. To solve this problem, we propose an origami-inspired structure to achieve multiple degrees of freedom (DoFs) motions with variable stiffness for force-sensing, which combines the ductility and flexibility of origami structures. In combination with the pneumatic actuation, the structure can achieve and adapt the compression, pitch, roll, diagonal, and array motions (five motion modes), which significantly increase the force adaptability and sensing diversity. To achieve closed-loop control and avoid excessive gas injection, the ultra-flexible microfiber sensor is designed and seamlessly embedded with an approximately linear sensitivity of \u223c0.35 \u03a9\/kPa at a relative pressure of 0\u2013100 kPa, and an exponential sensitivity at a relative pressure of 100\u2013350 kPa, which can render this device capable of working under various conditions. The final calibration experiment demonstrates that the pre-pressure value can affect the sensor\u2019s sensitivity. With the increasing pre-pressure of 65\u201395 kPa, the average sensitivity curve shifts rightwards around 9 N intervals, which highly increases the force-sensing capability towards the range of 0\u20132 N. When the pre-pressure is at the relatively extreme air pressure of 100 kPa, the force sensitivity value is around 11.6 \u03a9\/N. Therefore, our proposed design (which has a low fabrication cost, high integration level, and a suitable sensing range) shows great potential for applications in flexible force-sensing development.<\/jats:p>","DOI":"10.3390\/s22145370","type":"journal-article","created":{"date-parts":[[2022,7,19]],"date-time":"2022-07-19T05:37:53Z","timestamp":1658209073000},"page":"5370","update-policy":"https:\/\/doi.org\/10.3390\/mdpi_crossmark_policy","source":"Crossref","is-referenced-by-count":21,"title":["Origami-Inspired Structure with Pneumatic-Induced Variable Stiffness for Multi-DOF Force-Sensing"],"prefix":"10.3390","volume":"22","author":[{"ORCID":"https:\/\/orcid.org\/0000-0002-9788-3705","authenticated-orcid":false,"given":"Wenchao","family":"Yue","sequence":"first","affiliation":[{"name":"Department of Electronic Engineering, The Chinese University of Hong Kong, Hong Kong, China"},{"name":"Department of Biomedical Engineering, National University of Singapore, Singapore 119077, Singapore"},{"name":"Shenzhen Research Institute, The Chinese University of Hong Kong, Shenzhen 518172, China"}],"role":[{"role":"author","vocabulary":"crossref"}]},{"given":"Jiaming","family":"Qi","sequence":"additional","affiliation":[{"name":"Department of Biomedical Engineering, National University of Singapore, Singapore 119077, Singapore"}],"role":[{"role":"author","vocabulary":"crossref"}]},{"given":"Xiao","family":"Song","sequence":"additional","affiliation":[{"name":"Department of Biomedical Engineering, National University of Singapore, Singapore 119077, Singapore"}],"role":[{"role":"author","vocabulary":"crossref"}]},{"given":"Shicheng","family":"Fan","sequence":"additional","affiliation":[{"name":"Department of Biomedical Engineering, National University of Singapore, Singapore 119077, Singapore"}],"role":[{"role":"author","vocabulary":"crossref"}]},{"ORCID":"https:\/\/orcid.org\/0000-0002-4039-891X","authenticated-orcid":false,"given":"Giancarlo","family":"Fortino","sequence":"additional","affiliation":[{"name":"Department of Computer Science, University of Calabria, 87036 Rende, Italy"}],"role":[{"role":"author","vocabulary":"crossref"}]},{"given":"Chia-Hung","family":"Chen","sequence":"additional","affiliation":[{"name":"Department of Biomedical Engineering, City University of Hong Kong, Kowloon, Hong Kong, China"}],"role":[{"role":"author","vocabulary":"crossref"}]},{"given":"Chenjie","family":"Xu","sequence":"additional","affiliation":[{"name":"Department of Biomedical Engineering, City University of Hong Kong, Kowloon, Hong Kong, China"}],"role":[{"role":"author","vocabulary":"crossref"}]},{"ORCID":"https:\/\/orcid.org\/0000-0002-6488-1551","authenticated-orcid":false,"given":"Hongliang","family":"Ren","sequence":"additional","affiliation":[{"name":"Department of Electronic Engineering, The Chinese University of Hong Kong, Hong Kong, China"},{"name":"Department of Biomedical Engineering, National University of Singapore, Singapore 119077, Singapore"},{"name":"Shenzhen Research Institute, The Chinese University of Hong Kong, Shenzhen 518172, China"},{"name":"Shun Hing Institute of Advanced Engineering, The Chinese University of Hong Kong, Hong Kong, China"}],"role":[{"role":"author","vocabulary":"crossref"}]}],"member":"1968","published-online":{"date-parts":[[2022,7,19]]},"reference":[{"key":"ref_1","doi-asserted-by":"crossref","unstructured":"Villalba-Diez, J., and Ordieres-Mer\u00e9, J. 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