{"status":"ok","message-type":"work","message-version":"1.0.0","message":{"indexed":{"date-parts":[[2025,12,30]],"date-time":"2025-12-30T08:52:34Z","timestamp":1767084754049,"version":"build-2065373602"},"reference-count":17,"publisher":"MDPI AG","issue":"12","license":[{"start":{"date-parts":[[2024,6,18]],"date-time":"2024-06-18T00:00:00Z","timestamp":1718668800000},"content-version":"vor","delay-in-days":0,"URL":"https:\/\/creativecommons.org\/licenses\/by\/4.0\/"}],"funder":[{"name":"National Key Research and Development Program of China","award":["2022YFB4701500","2023BAB090"],"award-info":[{"award-number":["2022YFB4701500","2023BAB090"]}]},{"name":"Hubei Provincial Key Research and Development Program","award":["2022YFB4701500","2023BAB090"],"award-info":[{"award-number":["2022YFB4701500","2023BAB090"]}]}],"content-domain":{"domain":[],"crossmark-restriction":false},"short-container-title":["Sensors"],"abstract":"<jats:p>The accurate perception of external environment information through the robot foot is crucial for the mobile robot to evaluate its ability to traverse terrain. Adequate foot-end contact signals can provide robust support for robot motion control and decision-making processes. The shape and uncertain rotation of the wheel-legged robot foot end represent a significant challenge to sensing the robot foot-end contact state, which current foot-end sensing schemes cannot solve. This paper presents a sensing method for the tire stress field of wheel-legged robots. A finite element analysis was conducted to study the deformation characteristics of the foot-end tire under force. Based on this analysis, a heuristic contact position estimator was designed that utilizes symmetrical deformation characteristics. Strain sensors, arranged in an array, extract the deformation information on the inner surface of the tire at a frequency of 200 Hz. The contact position estimator reduces the dimensionality of the data and fits the eigenvalues to the estimated contact position. Using support vector regression, the force estimator utilizes the estimated contact position and sensor signal to estimate the normal reaction force, designated as FZ. The sensing system is capable of detecting the contact position on the wheel circumference (with a root mean square error of 1.150\u00b0), as well as the normal force of 160 N on the Z axis (with a root mean square error of 6.04%). To validate the efficacy of the sensor detection method, a series of randomized and repeated experiments were conducted on a self-constructed test platform. This novel approach offers a promising avenue for perceiving contact states in wheel-legged robots.<\/jats:p>","DOI":"10.3390\/s24123956","type":"journal-article","created":{"date-parts":[[2024,6,19]],"date-time":"2024-06-19T08:06:06Z","timestamp":1718784366000},"page":"3956","update-policy":"https:\/\/doi.org\/10.3390\/mdpi_crossmark_policy","source":"Crossref","is-referenced-by-count":8,"title":["Research on Foot Contact State Detection Technology of Wheel-Legged Robot"],"prefix":"10.3390","volume":"24","author":[{"ORCID":"https:\/\/orcid.org\/0009-0003-6862-7686","authenticated-orcid":false,"given":"Yaodong","family":"Wang","sequence":"first","affiliation":[{"name":"School of Mechanical and Electronic Engineering, Wuhan University of Technology, Wuhan 430070, China"}]},{"given":"Meng","family":"Hong","sequence":"additional","affiliation":[{"name":"School of Mechanical and Electronic Engineering, Wuhan University of Technology, Wuhan 430070, China"}]},{"given":"Hui","family":"Chai","sequence":"additional","affiliation":[{"name":"School of Control Science and Engineering, Shandong University, Jinan 250061, China"}]},{"given":"Yinglong","family":"Zhang","sequence":"additional","affiliation":[{"name":"School of Mechanical and Electronic Engineering, Wuhan University of Technology, Wuhan 430070, China"}]},{"given":"Guan","family":"Wang","sequence":"additional","affiliation":[{"name":"School of Mechanical and Electronic Engineering, Wuhan University of Technology, Wuhan 430070, China"}]},{"given":"Chaoqun","family":"Wu","sequence":"additional","affiliation":[{"name":"School of Mechanical and Electronic Engineering, Wuhan University of Technology, Wuhan 430070, China"}]},{"ORCID":"https:\/\/orcid.org\/0000-0001-7962-610X","authenticated-orcid":false,"given":"Min","family":"Guo","sequence":"additional","affiliation":[{"name":"School of Mechanical and Electronic Engineering, Wuhan University of Technology, Wuhan 430070, China"}]}],"member":"1968","published-online":{"date-parts":[[2024,6,18]]},"reference":[{"key":"ref_1","first-page":"334","article-title":"Research overview on touchdown detection methods for footed robots","volume":"58","author":"Jiang","year":"2024","journal-title":"J. Zhejiang Univ. (Eng. Sci.)"},{"key":"ref_2","doi-asserted-by":"crossref","unstructured":"Chuah, M.Y.M., Epstein, L., Kim, D., Romero, J., and Kim, S. (2019, January 3\u20138). Bi-Modal Hemispherical Sensor: A Unifying Solution for Three Axis Force and Contact Angle Measurement. Proceedings of the 2019 IEEE\/RSJ International Conference on Intelligent Robots and Systems (IROS), Macau, China.","DOI":"10.1109\/IROS40897.2019.8967878"},{"key":"ref_3","doi-asserted-by":"crossref","unstructured":"Ruppert, F., and Badri-Sprowitz, A. (August, January 31). FootTile: A Rugged Foot Sensor for Force and Center of Pressure Sensing in Soft Terrain. Proceedings of the 2020 IEEE International Conference on Robotics and Automation (ICRA), Paris, France.","DOI":"10.1109\/ICRA40945.2020.9197466"},{"key":"ref_4","unstructured":"Mason, W., Brenken, D., Dai, F.Z., Castillo, R.G.C., Cormier, O.S.-M., and Sedal, A. (2024). Acoustic Tactile Sensing for Mobile Robot Wheels. arXiv."},{"key":"ref_5","doi-asserted-by":"crossref","first-page":"15","DOI":"10.1109\/TRO.2019.2935336","article-title":"Tactile Sensing and Terrain-Based Gait Control for Small Legged Robots","volume":"36","author":"Wu","year":"2020","journal-title":"IEEE Trans. Robot."},{"key":"ref_6","doi-asserted-by":"crossref","unstructured":"Garcia-Pozuelo, D., Olatunbosun, O., Yunta, J., Yang, X., and Diaz, V. (2017). A Novel Strain-Based Method to Estimate Tire Conditions Using Fuzzy Logic for Intelligent Tires. Sensors, 17.","DOI":"10.3390\/s17020350"},{"key":"ref_7","doi-asserted-by":"crossref","first-page":"55","DOI":"10.1177\/0954407018771253","article-title":"A Novel Approach to Tire Parameter Identification","volume":"233","author":"Lee","year":"2019","journal-title":"Proc. Inst. Mech. Eng. Part D J. Automob. Eng."},{"key":"ref_8","doi-asserted-by":"crossref","first-page":"114007","DOI":"10.1016\/j.sna.2022.114007","article-title":"Tire-Road Friction Coefficient Estimation Method Design for Intelligent Tires Equipped with PVDF Piezoelectric Film Sensors","volume":"349","author":"Quan","year":"2023","journal-title":"Sens. Actuators A Phys."},{"key":"ref_9","doi-asserted-by":"crossref","first-page":"1756","DOI":"10.1109\/JSEN.2013.2241051","article-title":"Embedded Flexible Force Sensor for In-Situ Tire\u2013Road Interaction Measurements","volume":"13","author":"Zhang","year":"2013","journal-title":"IEEE Sens. J."},{"key":"ref_10","doi-asserted-by":"crossref","unstructured":"Emon, M., and Choi, J.-W. (2017). Flexible Piezoresistive Sensors Embedded in 3D Printed Tires. Sensors, 17.","DOI":"10.3390\/s17030656"},{"key":"ref_11","doi-asserted-by":"crossref","first-page":"75","DOI":"10.1016\/j.jterra.2015.07.003","article-title":"Investigation into Use of Piezoelectric Sensors in a Wheeled Robot Tire for Surface Characterization","volume":"62","author":"Armstrong","year":"2015","journal-title":"J. Terramech."},{"key":"ref_12","doi-asserted-by":"crossref","first-page":"44","DOI":"10.4271\/2011-01-0095","article-title":"Tire Sensors for the Measurement of Slip Angle and Friction Coefficient and Their Use in Stability Control Systems","volume":"4","author":"Erdogan","year":"2011","journal-title":"SAE Int. J. Passeng. Cars Mech. Syst."},{"key":"ref_13","doi-asserted-by":"crossref","first-page":"1013","DOI":"10.1080\/00423110701790731","article-title":"Experimental Investigation of Tyre Dynamics by Means of MEMS Accelerometers Fixed on the Liner","volume":"46","author":"Brusarosco","year":"2008","journal-title":"Veh. Syst. Dyn."},{"key":"ref_14","doi-asserted-by":"crossref","unstructured":"Matsuzaki, R., and Todoroki, A. (2009, January 9\u201312). Intelligent Tires for Improved Tire Safety Based on Strain Measurements. Proceedings of the Health Monitoring of Structural and Biological Systems 2009, San Diego, CA, USA.","DOI":"10.1117\/12.815403"},{"key":"ref_15","doi-asserted-by":"crossref","first-page":"793","DOI":"10.1016\/j.ymssp.2015.06.019","article-title":"OPTYRE\u2014A New Technology for Tire Monitoring: Evidence of Contact Patch Phenomena","volume":"66\u201367","author":"Roveri","year":"2016","journal-title":"Mech. Syst. Signal Process."},{"key":"ref_16","doi-asserted-by":"crossref","unstructured":"Bernabei, F., Lo Preti, M., and Beccai, L. (2024). The T-Blep: A Soft Optical Sensor for Stiffness and Contact Force Measurement. Micromachines, 15.","DOI":"10.3390\/mi15020233"},{"key":"ref_17","doi-asserted-by":"crossref","first-page":"637","DOI":"10.1016\/S0893-6080(98)00032-X","article-title":"The Connection between Regularization Operators and Support Vector Kernels","volume":"11","author":"Smola","year":"1998","journal-title":"Neural Netw."}],"container-title":["Sensors"],"original-title":[],"language":"en","link":[{"URL":"https:\/\/www.mdpi.com\/1424-8220\/24\/12\/3956\/pdf","content-type":"unspecified","content-version":"vor","intended-application":"similarity-checking"}],"deposited":{"date-parts":[[2025,10,10]],"date-time":"2025-10-10T15:00:46Z","timestamp":1760108446000},"score":1,"resource":{"primary":{"URL":"https:\/\/www.mdpi.com\/1424-8220\/24\/12\/3956"}},"subtitle":[],"short-title":[],"issued":{"date-parts":[[2024,6,18]]},"references-count":17,"journal-issue":{"issue":"12","published-online":{"date-parts":[[2024,6]]}},"alternative-id":["s24123956"],"URL":"https:\/\/doi.org\/10.3390\/s24123956","relation":{},"ISSN":["1424-8220"],"issn-type":[{"type":"electronic","value":"1424-8220"}],"subject":[],"published":{"date-parts":[[2024,6,18]]}}}