@inproceedings{ca93ff9034d643dd8d8e21476e4e506d,
title = "Biaxial optical fiber sensor based in two multiplexed Bragg gratings for simultaneous shear stress and vertical pressure monitoring",
abstract = "This work consists on the design and implementation of a compact and accurate biaxial optical fiber sensor (OFS) based on two in-line fiber Bragg gratings (FBGs) for the simultaneous measurement of shear and vertical forces. The two FBGs were inscribed in the same optical fiber and placed individually in two adjacent cavities. In the calibration and performance tests, the response from the optical fiber cells was compared with the values given by a three-axial electronic force sensor. Sensitivity values obtained for the FBG1 are K1V= (14.15±0.10) pm/N (vertical force) and K1S= (-26.02±0.08) pm/N (shear force) and for the FBG2 are K2V= (7.35±0.02) pm/N and K2S= (-24.29±0.08) pm/N. The conversion of the Bragg wavelength shift, given by the optical fiber sensors, into the shear and vertical force values is also presented along with its comparison to the values retrieved by an electronic sensor, yielding to low RMSE values, which shows the high accuracy of the algorithm applied. This work stands out from the others with optical fiber by the simplicity of its structure. The proposed solution represents a compact and reliable device for simultaneous measurement of shear and vertical forces, useful in several areas, such as: Incorporation into insoles for plantar pressure and shear force measurement; electronic skin technologies; smart rehabilitation robotic exoskeletons; or even biomimetic prosthesis.",
keywords = "biaxial optical fiber sensor, fiber Bragg grating, shear force sensor, vertical force sensor",
author = "C. Tavares and M. Domingues and A. Frizera-Neto and C. Leita{\~o} and N. Alberto and C. Marques and A. Radwan and E. Rocon and P. Andr{\'e} and P. Antunes",
note = "Funding Information: C{\'a}tia Tavares acknowledges the financial support from WeHope project (ref. 818/2016). This work was also funded by FEDER funds through the COMPETE 2020 Programme, National Funds through FCT - Portuguese Foundation for Science and Technology under the projects UID/CTM/50025/2013, UID/EEA/50008/2013 and IT internal project WeHope. Carlos Marques and M. F{\'a}tima Domingues acknowledge the financial support from FCT through the fellowships SFRH/BPD/109458/2015 and SFRH/BPD/101372/2014, respectively. N{\'e}lia Alberto acknowledges the financial support received from the PREDICT project (FCT, IT-LA). Publisher Copyright: {\textcopyright} 2018 SPIE.; Optical Sensing and Detection V 2018 ; Conference date: 23-04-2018 Through 26-04-2018",
year = "2018",
doi = "10.1117/12.2306889",
language = "British English",
series = "Proceedings of SPIE - The International Society for Optical Engineering",
publisher = "SPIE",
editor = "Francis Berghmans and Mignani, {Anna G.}",
booktitle = "Optical Sensing and Detection V",
address = "United States",
}