Wearable and Fully-Portable Smart Garment for Mechanical Perturbation Detection With Nanoparticles Optical Fibers

This paper presents the development of a wearable smart textile for mechanical perturbation assessment during gait based on distributed optical fiber sensor system using the transmission-reflection analysis (TRA). In this case, magnesium and erbium co-doped optical fiber is employed as a high scattering medium, which results in high spatial resolution for the technique (in the order of a few millimeters). The optical fiber was embedded in a garment and controlled displacements at predefined locations on the garment were applied, where the simultaneous assessment of displacement amplitude and location was obtained using a slope-assisted technique. In the proposed technique, the slope inverses of the transmission-reflection curves are correlated with the displacement applied on the fiber, where a determination coefficient (R-2) of 0.996 was obtained. Then, the sloped-normalized reflection (or backscattered) response is used on the disturbance location estimation with relative errors as low as 3.7%. The on-body application tests show an inherent insensitivity of the proposed smart garment to body movement due to natural gait movements, indicating the feasibility of the proposed approach on detecting only the transverse induced mechanical perturbations. In the wearable tests, the sensor system shows high correlation (R-2 higher than 0.98) in the tests with different volunteers (subjected to similar displacements at predefined locations) and millimeter-accuracy on the disturbance location estimation.