{"status":"ok","message-type":"work","message-version":"1.0.0","message":{"indexed":{"date-parts":[[2026,10,31]],"date-time":"2026-10-31T10:13:18Z","timestamp":1793441598846,"version":"4.5.0"},"reference-count":52,"publisher":"Frontiers Media SA","license":[{"start":{"date-parts":[[2021,4,27]],"date-time":"2021-04-27T00:00:00Z","timestamp":1619481600000},"content-version":"vor","delay-in-days":0,"URL":"https:\/\/creativecommons.org\/licenses\/by\/4.0\/"}],"content-domain":{"domain":["frontiersin.org"],"crossmark-restriction":true},"short-container-title":["Front. Mater."],"abstract":"<jats:p>Fibre strain sensors commonly use three major modalities to transduce strain\u2014piezoresistance, capacitance, and inductance. The electrical signal in response to strain differs between these sensing technologies, having varying sensitivity, maximum measurable loading rate, and susceptibility to deleterious effects like hysteresis and drift. The wide variety of sensor materials and strain tracking applications makes it difficult to choose the best sensor modality for a wearable device when considering signal quality, cost, and difficulty of manufacture. Fibre strain sensor samples employing the three sensing mechanisms are fabricated and subjected to strain using a tensile tester. Their mechanical and electrical properties are measured in response to strain profiles designed to exhibit particular shortcomings of sensor behaviour. Using these data, the sensors are compared to identify materials and sensing technologies well suited for different textile motion tracking applications. Several regression models are trained and validated on random strain pattern data, providing guidance for pairing each sensor with a model architecture that compensates for non-ideal effects. A thermoplastic elastomer-core piezoresistive sensor had the highest sensitivity (average gauge factor: 12.6) and a piezoresistive sensor of similar construction with a polyether urethane-urea core had the largest bandwidth, capable of resolving strain rates above 300% <jats:inline-formula><mml:math xmlns:mml=\"http:\/\/www.w3.org\/1998\/Math\/MathML\" id=\"minf1\"><mml:mrow><mml:msup><mml:mtext>s<\/mml:mtext><mml:mrow><mml:mo>\u2212<\/mml:mo><mml:mn>1<\/mml:mn><\/mml:mrow><\/mml:msup><\/mml:mrow><\/mml:math><\/jats:inline-formula> with 36% signal amplitude attenuation. However, both piezoresistve sensors suffered from larger hysteresis and drift than a coaxial polymer sensor using the capacitive strain sensing mechanism. Machine learning improved the piezoresistive sensors\u2019 root-mean-squared error when tracking a random strain signal by up to 58% while maintaining their high sensitivity, bandwidth, and ease of interfacing electronically.<\/jats:p>","DOI":"10.3389\/fmats.2021.639823","type":"journal-article","created":{"date-parts":[[2021,4,27]],"date-time":"2021-04-27T15:20:17Z","timestamp":1619536817000},"update-policy":"https:\/\/doi.org\/10.3389\/crossmark-policy","source":"Crossref","is-referenced-by-count":21,"title":["Understanding the Impact of Machine Learning Models on the Performance of Different Flexible Strain Sensor Modalities"],"prefix":"10.3389","volume":"8","author":[{"given":"Brett C.","family":"Hannigan","sequence":"first","affiliation":[],"role":[{"vocabulary":"crossref","role":"author"}]},{"given":"Tyler J.","family":"Cuthbert","sequence":"additional","affiliation":[],"role":[{"vocabulary":"crossref","role":"author"}]},{"given":"Wanhaoyi","family":"Geng","sequence":"additional","affiliation":[],"role":[{"vocabulary":"crossref","role":"author"}]},{"given":"Mohammad","family":"Tavassolian","sequence":"additional","affiliation":[],"role":[{"vocabulary":"crossref","role":"author"}]},{"given":"Carlo","family":"Menon","sequence":"additional","affiliation":[],"role":[{"vocabulary":"crossref","role":"author"}]}],"member":"1965","published-online":{"date-parts":[[2021,4,27]]},"reference":[{"key":"B1","doi-asserted-by":"publisher","first-page":"8819","DOI":"10.1021\/nn503454h","article-title":"Sensitive, high-strain, high-rate bodily motion sensors based on graphene-rubber composites","volume":"8","author":"Boland","year":"2014","journal-title":"ACS Nano"},{"key":"B2","doi-asserted-by":"publisher","first-page":"2079","DOI":"10.1002\/polb.20085","article-title":"Electrical and mechanical behavior of filled elastomers. I: The effect of strain","volume":"41","author":"Busfield","year":"2003","journal-title":"J. Polym. Sci. Part B Polym. Phys."},{"key":"B3","doi-asserted-by":"publisher","first-page":"4305","DOI":"10.1021\/acsami.7b17790","article-title":"Transparent and waterproof ionic liquid-based fibers for highly durable multifunctional sensors and strain-insensitive stretchable conductors","volume":"10","author":"Chen","year":"2018","journal-title":"ACS Appl. Mater. Interfaces"},{"key":"B4","doi-asserted-by":"publisher","first-page":"1770","DOI":"10.1021\/acsami.6b12415","article-title":"Highly stretchable, hysteresis-free ionic liquid-based strain sensor for precise human motion monitoring","volume":"9","author":"Choi","year":"2017","journal-title":"ACS Appl. Mater. Interfaces"},{"key":"B5","doi-asserted-by":"publisher","first-page":"7","DOI":"10.4028\/www.scientific.net\/ast.80.7","article-title":"Development of piezoresistive fiber sensors, based on carbon black filled thermoplastic elastomer compounds, for textile application","volume":"80","author":"Clemens","year":"2012","journal-title":"Adv. Sci. Technol."},{"key":"B6","doi-asserted-by":"publisher","first-page":"1605630","DOI":"10.1002\/adfm.201605630","article-title":"Stretchable capacitive sensors of torsion, strain, and touch using double helix liquid metal fibers","volume":"27","author":"Cooper","year":"2017","journal-title":"Adv. Funct. Mater."},{"key":"B7","doi-asserted-by":"publisher","first-page":"1","DOI":"10.1016\/j.compscitech.2015.01.006","article-title":"Mechanical vs. electrical hysteresis of carbon nanotube\/styrene-butadiene-styrene composites and their influence in the electromechanical response","volume":"109","author":"Costa","year":"2015","journal-title":"Compos. Sci. Technol."},{"key":"B8","doi-asserted-by":"publisher","first-page":"301","DOI":"10.1179\/1743289812Y.0000000022","article-title":"Roles of prestrain and hysteresis on piezoresistance in conductive elastomers for strain sensor applications","volume":"41","author":"De Focatiis","year":"2012","journal-title":"Plast. Rubber Compos."},{"key":"B9","doi-asserted-by":"publisher","first-page":"601","DOI":"10.1016\/j.eurpolymj.2008.11.017","article-title":"A review on the Mullins effect","volume":"45","author":"Diani","year":"2009","journal-title":"Eur. Polym. J."},{"key":"B10","doi-asserted-by":"publisher","first-page":"116","DOI":"10.1016\/j.mechmat.2013.09.019","article-title":"Unusual mechanical response of carbon black-filled thermoplastic elastomers","volume":"69","author":"Drozdov","year":"2014","journal-title":"Mech. Mater."},{"key":"B11","doi-asserted-by":"publisher","first-page":"173","DOI":"10.3390\/electronics4010173","article-title":"E-textiles in clinical rehabilitation: a scoping review","volume":"4","author":"Fleury","year":"2015","journal-title":"Electronics"},{"key":"B12","doi-asserted-by":"publisher","first-page":"2440","DOI":"10.1002\/adma.201500072","article-title":"Capacitive soft strain sensors via multicore-shell fiber printing","volume":"27","author":"Frutiger","year":"2015","journal-title":"Adv. Mater."},{"key":"B13","doi-asserted-by":"publisher","first-page":"122","DOI":"10.1021\/acsapm.0c00708","article-title":"Conductive thermoplastic elastomer composite capacitive strain sensors and their application in a wearable device for quantitative joint angle prediction","volume":"3","author":"Geng","year":"2020","journal-title":"ACS Appl. Polym. Mater."},{"key":"B14","doi-asserted-by":"publisher","first-page":"5884","DOI":"10.1039\/C9NR01005J","article-title":"Highly stretchable multi-walled carbon nanotube\/thermoplastic polyurethane composite fibers for ultrasensitive, wearable strain sensors","volume":"11","author":"He","year":"2019","journal-title":"Nanoscale"},{"key":"B15","first-page":"4555","article-title":"Study of performance of knitted conductive sleeves as wearable textile strain sensors for joint motion tracking","author":"Isaia","year":"2020"},{"key":"B16","doi-asserted-by":"publisher","first-page":"1","DOI":"10.1186\/s40486-019-0097-2","article-title":"Wearable piezoresistive strain sensor based on graphene-coated three-dimensional micro-porous PDMS sponge","volume":"7","author":"Jung","year":"2019","journal-title":"Micro Nano Syst. Lett."},{"key":"B17","doi-asserted-by":"publisher","first-page":"572","DOI":"10.1109\/TMECH.2011.2108664","article-title":"A new approach for modeling piezoresistive force sensors based on semiconductive polymer composites","volume":"17","author":"Kalantari","year":"2012","journal-title":"IEEE\/ASME Trans. Mechatron."},{"key":"B18","doi-asserted-by":"publisher","first-page":"1123","DOI":"10.1007\/s10544-016-0141-4","article-title":"An ionic liquid based strain sensor for large displacement measurement","volume":"19","author":"Keulemans","year":"2017","journal-title":"Biomed. Microdevices"},{"key":"B19","doi-asserted-by":"publisher","first-page":"229","DOI":"10.3390\/s17020229","article-title":"Hysteresis compensation of piezoresistive carbon nanotube\/polydimethylsiloxane composite-based force sensors","volume":"17","author":"Kim","year":"2017","journal-title":"Sensors"},{"key":"B20","doi-asserted-by":"publisher","first-page":"26407","DOI":"10.1021\/acsami.7b06474","article-title":"Wearable and transparent capacitive strain sensor with high sensitivity based on patterned Ag nanowire networks","volume":"9","author":"Kim","year":"2017","journal-title":"ACS Appl. Mater. Interfaces"},{"key":"B21","first-page":"227","article-title":"Development of a telemetric goniometer","author":"Laskoski","year":"2009"},{"key":"B22","doi-asserted-by":"publisher","first-page":"2433","DOI":"10.1002\/adma.201500009","article-title":"Conductive fiber-based ultrasensitive textile pressure sensor for wearable electronics","volume":"27","author":"Lee","year":"2015","journal-title":"Adv. Mater."},{"key":"B23","doi-asserted-by":"publisher","first-page":"18962","DOI":"10.1039\/c1jm14491j","article-title":"Electrospun PEDOT:PSS-PVA nanofiber based ultrahigh-strain sensors with controllable electrical conductivity","volume":"21","author":"Liu","year":"2011","journal-title":"J. Mater. Chem."},{"key":"B24","doi-asserted-by":"publisher","first-page":"400","DOI":"10.1126\/science.aaa7952","article-title":"Hierarchically buckled sheath-core fibers for superelastic electronics, sensors, and muscles","volume":"349","author":"Liu","year":"2015","journal-title":"Science"},{"key":"B25","doi-asserted-by":"publisher","first-page":"645","DOI":"10.3390\/s18020645","article-title":"Flexible, stretchable sensors for wearable health monitoring: sensing mechanisms, materials, fabrication strategies and features","volume":"18","author":"Liu","year":"","journal-title":"Sensors"},{"key":"B26","doi-asserted-by":"publisher","first-page":"1800353","DOI":"10.1002\/aelm.201800353","article-title":"On the evaluation of the sensitivity coefficient of strain sensors","volume":"4","author":"Liu","year":"","journal-title":"Adv. Electron. Mater."},{"key":"B27","doi-asserted-by":"publisher","first-page":"1748","DOI":"10.1177\/0278364914543793","article-title":"Wearable soft sensing suit for human gait measurement","volume":"33","author":"Meng\u00fc\u00e7","year":"2014","journal-title":"Int. J. Rob. Res."},{"key":"B28","doi-asserted-by":"publisher","first-page":"20736","DOI":"10.1039\/c2jm32228e","article-title":"Self-healing electrodes for dielectric elastomer actuators","volume":"22","author":"Michel","year":"2012","journal-title":"J. Mater. Chem."},{"key":"B29","doi-asserted-by":"publisher","first-page":"27","DOI":"10.3389\/frobt.2019.00027","article-title":"A deep learning approach to non-linearity in wearable stretch sensors","volume":"6","author":"Miodownik","year":"2019","journal-title":"Front. Robot. AI"},{"key":"B30","doi-asserted-by":"publisher","first-page":"8205","DOI":"10.1109\/TIE.2018.2884204","article-title":"Model-based compensation of rate-dependent hysteresis in a piezoresistive strain sensor","volume":"66","author":"Oliveri","year":"2019","journal-title":"IEEE Trans. Ind. Electron."},{"key":"B31","doi-asserted-by":"publisher","first-page":"905","DOI":"10.3390\/s20030905","article-title":"Wearable device to monitor back movements using an inductive textile sensor","volume":"20","author":"Pati\u00f1o","year":"2020","journal-title":"Sensors"},{"key":"B32","doi-asserted-by":"publisher","first-page":"1047","DOI":"10.1109\/TBCAS.2016.2518871","article-title":"On the use of knitted antennas and inductively coupled RFID tags for wearable applications","volume":"10","author":"Patron","year":"2016","journal-title":"IEEE Trans. Biomed. Circuits Syst."},{"key":"B33","doi-asserted-by":"publisher","first-page":"1825","DOI":"10.1016\/S1388-2457(00)00384-9","article-title":"Determinants of physiologic tremor in a large normal population","volume":"111","author":"Raethjen","year":"2000","journal-title":"Clin. Neurophysiol."},{"key":"B34","doi-asserted-by":"publisher","first-page":"337","DOI":"10.1007\/s12221-019-8778-2","article-title":"Electrospun spandex nanofiber webs with ionic liquid for highly sensitive, low hysteresis piezocapacitive sensor","volume":"20","author":"Reza","year":"2019","journal-title":"Fibers Polym."},{"key":"B35","doi-asserted-by":"publisher","first-page":"4288","DOI":"10.3390\/s19194288","article-title":"Application-based production and testing of a core-sheath fiber strain sensor for wearable electronics: feasibility study of using the sensors in measuring tri-axial trunk motion angles","volume":"19","author":"Rezaei","year":"2019","journal-title":"Sensors"},{"key":"B36","first-page":"161","article-title":"Smart vest for posture monitoring in rehabilitation exercises","author":"Sardini","year":"2012"},{"key":"B37","doi-asserted-by":"publisher","first-page":"21150","DOI":"10.1021\/acsami.5b04892","article-title":"Knitted strain sensor textiles of highly conductive all-polymeric fibers","volume":"7","author":"Seyedin","year":"2015","journal-title":"ACS Appl. Mater. Interfaces"},{"key":"B38","doi-asserted-by":"publisher","first-page":"2663","DOI":"10.1002\/adma.200904270","article-title":"Elastomeric conductive composites based on carbon nanotube forests","volume":"22","author":"Shin","year":"2010","journal-title":"Adv. Mater."},{"key":"B39","doi-asserted-by":"publisher","first-page":"1700284","DOI":"10.1002\/admt.201700284","article-title":"Ultrastretchable strain sensors using carbon black-filled elastomer composites and comparison of capacitive versus resistive sensors","volume":"3","author":"Shintake","year":"2018","journal-title":"Adv. Mater. Technol."},{"key":"B40","doi-asserted-by":"publisher","first-page":"1206","DOI":"10.1002\/pen.21888","article-title":"Mechanical and electrical analysis of carbon black networking in elastomers under strain","volume":"51","author":"St\u00fcbler","year":"2011","journal-title":"Polym. Eng. Sci."},{"key":"B41","doi-asserted-by":"publisher","first-page":"1900165","DOI":"10.1002\/aisy.201900165","article-title":"Textile\u2010based inductive soft strain sensors for fast frequency movement and their application in wearable devices measuring multiaxial hip joint angles during running","volume":"2","author":"Tavassolian","year":"2020","journal-title":"Adv. Intell. Syst."},{"key":"B42","doi-asserted-by":"publisher","first-page":"3109","DOI":"10.3390\/s18093109","article-title":"Human motion recognition by textile sensors based on machine learning algorithms","volume":"18","author":"Vu","year":"2018","journal-title":"Sensors"},{"key":"B43","doi-asserted-by":"publisher","first-page":"4998","DOI":"10.1002\/adma.201600405","article-title":"Downsized sheath-core conducting fibers for weavable superelastic wires, biosensors, supercapacitors, and strain sensors","volume":"28","author":"Wang","year":"2016","journal-title":"Adv. Mater."},{"key":"B44","doi-asserted-by":"publisher","first-page":"571","DOI":"10.1109\/JSEN.2006.874488","article-title":"Inductive fiber-meshed strain and displacement transducers for respiratory measuring systems and motion capturing systems","volume":"6","author":"Wijesiriwardana","year":"2006","journal-title":"IEEE Sens. J."},{"key":"B45","doi-asserted-by":"publisher","first-page":"288","DOI":"10.1016\/0021-9290(89)90511-3","article-title":"Spectral analysis of impact shock during running","volume":"8","author":"Winslow","year":"1989","journal-title":"J. Appl. Biomech."},{"key":"B46","doi-asserted-by":"publisher","first-page":"9936","DOI":"10.1021\/acsami.6b01174","article-title":"Highly sensitive, stretchable, and wash-durable strain sensor based on ultrathin conductive Layer@Polyurethane yarn for tiny motion monitoring","volume":"8","author":"Wu","year":"2016","journal-title":"ACS Appl. Mater. Interfaces"},{"key":"B47","doi-asserted-by":"publisher","first-page":"1","DOI":"10.1016\/j.mser.2017.02.001","article-title":"Recent advances in wearable tactile sensors: materials, sensing mechanisms, and device performance","volume":"115","author":"Yang","year":"2017","journal-title":"Mater. Sci. Eng. R Rep."},{"key":"B48","doi-asserted-by":"publisher","first-page":"32054","DOI":"10.1021\/acsami.7b09652","article-title":"Highly stretchable, ultrasensitive, and wearable strain sensors based on facilely prepared reduced graphene oxide woven fabrics in an ethanol flame","volume":"9","author":"Yin","year":"2017","journal-title":"ACS Appl. Mater. Interfaces"},{"key":"B49","doi-asserted-by":"publisher","first-page":"179","DOI":"10.1016\/j.snb.2019.01.063","article-title":"A highly sensitive, multifunctional, and wearable mechanical sensor based on RGO\/synergetic fiber bundles for monitoring human actions and physiological signals","volume":"285","author":"Jia","year":"2019","journal-title":"Sens. Actuators B"},{"key":"B50","doi-asserted-by":"publisher","first-page":"213","DOI":"10.1016\/j.matdes.2017.09.026","article-title":"Strain-responsive mercerized conductive cotton fabrics based on PEDOT:PSS\/graphene","volume":"135","author":"Zahid","year":"2017","journal-title":"Mater. Des."},{"key":"B51","doi-asserted-by":"publisher","first-page":"13167","DOI":"10.3390\/s121013167","article-title":"Development of a respiratory inductive plethysmography module supporting multiple sensors for wearable systems","volume":"12","author":"Zhang","year":"2012","journal-title":"Sensors"},{"key":"B52","doi-asserted-by":"publisher","first-page":"510","DOI":"10.1016\/j.compositesa.2019.04.014","article-title":"Highly sensitive and multifunctional piezoresistive sensor based on polyaniline foam for wearable Human-Activity monitoring","volume":"121","author":"Zheng","year":"2019","journal-title":"Composites Part A"}],"container-title":["Frontiers in Materials"],"original-title":[],"link":[{"URL":"https:\/\/www.frontiersin.org\/articles\/10.3389\/fmats.2021.639823\/full","content-type":"unspecified","content-version":"vor","intended-application":"similarity-checking"}],"deposited":{"date-parts":[[2021,4,27]],"date-time":"2021-04-27T15:20:19Z","timestamp":1619536819000},"score":1,"resource":{"primary":{"URL":"https:\/\/www.frontiersin.org\/articles\/10.3389\/fmats.2021.639823\/full"}},"subtitle":[],"short-title":[],"issued":{"date-parts":[[2021,4,27]]},"references-count":52,"alternative-id":["10.3389\/fmats.2021.639823"],"URL":"https:\/\/doi.org\/10.3389\/fmats.2021.639823","relation":{},"ISSN":["2296-8016"],"issn-type":[{"value":"2296-8016","type":"electronic"}],"subject":[],"published":{"date-parts":[[2021,4,27]]},"article-number":"639823"}}