{"status":"ok","message-type":"work","message-version":"1.0.0","message":{"indexed":{"date-parts":[[2026,7,7]],"date-time":"2026-07-07T18:43:12Z","timestamp":1783449792682,"version":"3.55.0"},"reference-count":48,"publisher":"MDPI AG","issue":"13","license":[{"start":{"date-parts":[[2021,6,24]],"date-time":"2021-06-24T00:00:00Z","timestamp":1624492800000},"content-version":"vor","delay-in-days":0,"URL":"https:\/\/creativecommons.org\/licenses\/by\/4.0\/"}],"funder":[{"DOI":"10.13039\/100000002","name":"National Institutes of Health","doi-asserted-by":"publisher","award":["R01EB025819"],"award-info":[{"award-number":["R01EB025819"]}],"id":[{"id":"10.13039\/100000002","id-type":"DOI","asserted-by":"publisher"}]},{"DOI":"10.13039\/100000001","name":"National Science Foundation","doi-asserted-by":"publisher","award":["#1317952, #1536136, and #1659484"],"award-info":[{"award-number":["#1317952, #1536136, and #1659484"]}],"id":[{"id":"10.13039\/100000001","id-type":"DOI","asserted-by":"publisher"}]},{"name":"National Institute of Aging","award":["3R01EB025819-04S1"],"award-info":[{"award-number":["3R01EB025819-04S1"]}]},{"DOI":"10.13039\/100000015","name":"Department of Energy","doi-asserted-by":"publisher","award":["contract TOA#0000403076"],"award-info":[{"award-number":["contract TOA#0000403076"]}],"id":[{"id":"10.13039\/100000015","id-type":"DOI","asserted-by":"publisher"}]}],"content-domain":{"domain":[],"crossmark-restriction":false},"short-container-title":["Sensors"],"abstract":"<jats:p>Multifunctional flexible tactile sensors could be useful to improve the control of prosthetic hands. To that end, highly stretchable liquid metal tactile sensors (LMS) were designed, manufactured via photolithography, and incorporated into the fingertips of a prosthetic hand. Three novel contributions were made with the LMS. First, individual fingertips were used to distinguish between different speeds of sliding contact with different surfaces. Second, differences in surface textures were reliably detected during sliding contact. Third, the capacity for hierarchical tactile sensor integration was demonstrated by using four LMS signals simultaneously to distinguish between ten complex multi-textured surfaces. Four different machine learning algorithms were compared for their successful classification capabilities: K-nearest neighbor (KNN), support vector machine (SVM), random forest (RF), and neural network (NN). The time-frequency features of the LMSs were extracted to train and test the machine learning algorithms. The NN generally performed the best at the speed and texture detection with a single finger and had a 99.2 \u00b1 0.8% accuracy to distinguish between ten different multi-textured surfaces using four LMSs from four fingers simultaneously. The capability for hierarchical multi-finger tactile sensation integration could be useful to provide a higher level of intelligence for artificial hands.<\/jats:p>","DOI":"10.3390\/s21134324","type":"journal-article","created":{"date-parts":[[2021,6,24]],"date-time":"2021-06-24T23:22:14Z","timestamp":1624576934000},"page":"4324","update-policy":"https:\/\/doi.org\/10.3390\/mdpi_crossmark_policy","source":"Crossref","is-referenced-by-count":28,"title":["Hierarchical Tactile Sensation Integration from Prosthetic Fingertips Enables Multi-Texture Surface Recognition"],"prefix":"10.3390","volume":"21","author":[{"ORCID":"https:\/\/orcid.org\/0000-0002-8495-4244","authenticated-orcid":false,"given":"Moaed A.","family":"Abd","sequence":"first","affiliation":[{"name":"Ocean and Mechanical Engineering Department, Florida Atlantic University, Boca Raton, FL 33431, USA"}],"role":[{"vocabulary":"crossref","role":"author"}]},{"given":"Rudy","family":"Paul","sequence":"additional","affiliation":[{"name":"Ocean and Mechanical Engineering Department, Florida Atlantic University, Boca Raton, FL 33431, USA"}],"role":[{"vocabulary":"crossref","role":"author"}]},{"given":"Aparna","family":"Aravelli","sequence":"additional","affiliation":[{"name":"Applied Research Center, Florida International University, Miami, FL 33174, USA"}],"role":[{"vocabulary":"crossref","role":"author"}]},{"given":"Ou","family":"Bai","sequence":"additional","affiliation":[{"name":"Electrical and Computer Engineering, Florida International University, Miami, FL 33174, USA"}],"role":[{"vocabulary":"crossref","role":"author"}]},{"given":"Leonel","family":"Lagos","sequence":"additional","affiliation":[{"name":"Applied Research Center, Florida International University, Miami, FL 33174, USA"}],"role":[{"vocabulary":"crossref","role":"author"}]},{"ORCID":"https:\/\/orcid.org\/0000-0002-9460-2111","authenticated-orcid":false,"given":"Maohua","family":"Lin","sequence":"additional","affiliation":[{"name":"Ocean and Mechanical Engineering Department, Florida Atlantic University, Boca Raton, FL 33431, USA"}],"role":[{"vocabulary":"crossref","role":"author"}]},{"given":"Erik D.","family":"Engeberg","sequence":"additional","affiliation":[{"name":"Ocean and Mechanical Engineering Department, Florida Atlantic University, Boca Raton, FL 33431, USA"},{"name":"The Center for Complex Systems & Brain Sciences, Florida Atlantic University, Boca Raton, FL 33431, USA"}],"role":[{"vocabulary":"crossref","role":"author"}]}],"member":"1968","published-online":{"date-parts":[[2021,6,24]]},"reference":[{"key":"ref_1","doi-asserted-by":"crossref","first-page":"422","DOI":"10.1016\/j.apmr.2007.11.005","article-title":"Estimating the prevalence of limb loss in the United States: 2005 to 2050","volume":"89","author":"MacKenzie","year":"2008","journal-title":"Arch. 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