{"status":"ok","message-type":"work","message-version":"1.0.0","message":{"indexed":{"date-parts":[[2026,10,5]],"date-time":"2026-10-05T11:53:09Z","timestamp":1791201189696,"version":"4.2.0"},"reference-count":37,"publisher":"MDPI AG","issue":"19","license":[{"start":{"date-parts":[[2026,10,3]],"date-time":"2026-10-03T00:00:00Z","timestamp":1790985600000},"content-version":"vor","delay-in-days":0,"URL":"https:\/\/creativecommons.org\/licenses\/by\/4.0\/"}],"funder":[{"DOI":"10.13039\/501100007504","name":"ISTANBUL TECHNICAL UNIVERSITY SCIENTIFIC RESEARCH PROJECTS COORDINATION UNIT","doi-asserted-by":"publisher","award":["MGA-2021-43003"],"award-info":[{"award-number":["MGA-2021-43003"]}],"id":[{"id":"10.13039\/501100007504","id-type":"DOI","asserted-by":"publisher"}]},{"award":["MGA-2021-43003"],"award-info":[{"award-number":["MGA-2021-43003"]}],"id":[{"id":"https:\/\/ror.org\/059636586","id-type":"ROR","asserted-by":"publisher"}]}],"content-domain":{"domain":[],"crossmark-restriction":false},"short-container-title":["Sensors"],"abstract":"<jats:p>Tire\u2013road interaction is increasingly important for situational awareness in autonomous vehicles and advanced driver-assistance systems, as tire deformation contains information that is related to both vehicle kinematics and tire forces. Optical sensing offers a direct means of observing this interaction with minimal influence on tire dynamics. In this study, an optical smart-wheel prototype was developed using a single high-speed camera rotating with the wheel and observing a circular-marker grid applied to the tire\u2019s inner liner. Camera calibration and distance-dependent imaging tests were used to support geometric correction and pixel-to-length conversion, after which the system was evaluated using static and on-road dynamic tests. Static drum calibration established a relationship between the diagonal-distance metric and vertical wheel load (R2 = 0.9992; RMSE = 33.37 N). Initial vehicle-level multi-point validation over 30 static conditions and loads up to approximately 3.92 kN yielded a prediction R2 of 0.9933 and an RMSE of 91.05 N. Dynamic tests revealed increasing longitudinal and lateral deformation with increasing maneuver speed and decreasing inflation pressure, together with direction-dependent lateral responses consistent with wheel-load transfer. Across the cases included in the cycle-variation analysis, the coefficients of variation ranged from 1.88% to 5.10% for longitudinal amplitude and from 6.08% to 19.98% for lateral peak deformation. These results demonstrate sensitivity to operating conditions and indicate a potential association between lateral deformation and slip angle, rather than constituting direct tire-force or slip-angle estimation. The proposed metric-based approach provides a promising lower-complexity alternative to full-field stereo-based deformation measurement for future real-time tire-state sensing and investigation of force-related deformation indicators.<\/jats:p>","DOI":"10.3390\/s26196284","type":"journal-article","created":{"date-parts":[[2026,10,5]],"date-time":"2026-10-05T10:57:46Z","timestamp":1791197866000},"page":"6284","update-policy":"https:\/\/doi.org\/10.3390\/mdpi_crossmark_policy","source":"Crossref","is-referenced-by-count":0,"title":["Optical Smart-Wheel Sensing of Tire Deformation for Tire State and Load Estimation"],"prefix":"10.3390","volume":"26","author":[{"ORCID":"https:\/\/orcid.org\/0000-0003-0126-4326","authenticated-orcid":false,"given":"Halil Yahya","family":"Ye\u015filyurt","sequence":"first","affiliation":[{"name":"Mechanical Engineering Department, Istanbul Technical University, Gumussuyu, \u0130stanbul 34437, T\u00fcrkiye"}],"role":[{"vocabulary":"crossref","role":"author"},{"role":"methodology","vocabulary":"credit"},{"role":"investigation","vocabulary":"credit"},{"role":"software","vocabulary":"credit"},{"role":"visualization","vocabulary":"credit"},{"role":"writing-original-draft","vocabulary":"credit"}]},{"ORCID":"https:\/\/orcid.org\/0000-0001-8136-214X","authenticated-orcid":false,"given":"\u00d6zgen","family":"Akal\u0131n","sequence":"additional","affiliation":[{"name":"Mechanical Engineering Department, Istanbul Technical University, Gumussuyu, \u0130stanbul 34437, T\u00fcrkiye"}],"role":[{"vocabulary":"crossref","role":"author"},{"role":"conceptualization","vocabulary":"credit"},{"role":"methodology","vocabulary":"credit"},{"role":"validation","vocabulary":"credit"},{"role":"writing-review-editing","vocabulary":"credit"},{"role":"supervision","vocabulary":"credit"},{"role":"project-administration","vocabulary":"credit"},{"role":"funding-acquisition","vocabulary":"credit"}]}],"member":"1968","published-online":{"date-parts":[[2026,10,3]]},"reference":[{"key":"ref_1","unstructured":"APOLLO Consortium (2005). 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