Investigation of High-Resolution Distributed Fiber Sensing System Embedded in Flexible Silicone Carpet for 2D Pressure Mapping

Abstract

Fiber-optic sensors are a powerful tool to investigate physical properties like temperature, strain, and pressure. Such properties make these sensors interesting for many applications including biomedical applications. Fiber sensors are also a great platform for distributed sensing by using the principles of optical frequency domain reflectometry. Distributed sensing is becoming more and more used to achieve high-resolution measurements and to map physical properties of biomaterials at small scale, thus obtaining 2D and 3D mapping of a particular area of interest. This work aims at building and investigating a 2D sensing carpet based on a distributed fiber sensing technique, to map local pressure applied to the carpet. The two-dimensional mapping is obtained by embedding a single-mode optical fiber inside a soft silicone carpet. The fiber has been bent and arranged in a specific configuration characterized by several parallel lines. Different fiber fixation methods have been investigated by means of a comparative analysis to perform better characterization and to achieve a more precise response of the carpet. The best pressure sensitivity coefficient (0.373 pm/kPa or considering our setup 1.165 nm/kg) was detected when the fiber was fully embedded inside the silicone carpet. This paper demonstrates the possibility of mapping a 2D distributed pressure over a surface with a resolution of 2 mm by 2 mm. The surface of investigation is 2 cm by 6 cm, containing 310 sensing points. The sensing carpet has been validated selecting several preferential positions, by testing the consistency of the results over different portions of the carpet.

Bite Force Mapping Based on Distributed Fiber Sensing Network Approach

“…The experimental configuration utilized to reconstruct the two-dimensional representation of pressure distribution consisted of the following elements: a rack structure employed to apply local force; the upper part of the dental jaw; silicone bites featuring two different fiber configurations (one of which was parallel with a 1 × 8 splitter); and an OBR equipped with data processing software to analyze the fiber spectra. The rack structure for point sensing, which is not shown in the actual setup, was described in our previous work [ 31 ]. The pressing part of the rack system had a tip diameter of 2 mm.…”

“…In this work, we exploited a 2D strain mapping technique [ 31 ] to assess and measure bite force in order to prove the concept of the high-density distributed fiber sensing technique for future development in dentistry applications. We introduced two silicone bites that exploited distributed sensing technology.…”

The role of optical fiber sensors in the new generation of healthcare devices: a review

“…They can be employed in different healthcare applications, such as upper limb mechanical perturbation detection, 18 liver tissue temperature distribution measurement, 113 and shape-sensing guiding system. 114 Table 1 summarizes the key information about the optical fiber sensors employed in healthcare settings discussed in this chapter.…”

Optical Frequency Domain Reflectometry Based on Multilayer Perceptron

“…Since Wc Eickhoff et al proposed the optical frequency domain reflectometry (OFDR) sensing system in 1981 [ 1 ], due to its advantage of high spatial resolution, it is now widely used in distributed measurement fields such as temperature measurement [ 2 , 3 , 4 , 5 ], strain measured [ 6 , 7 , 8 , 9 ], and shape sensing [ 10 , 11 , 12 , 13 , 14 , 15 ]. The cross-correlation algorithm (CCA) is a common data processing algorithm for OFDR systems, which calculates the wavelength shift value by comparing spectrum fingerprint peaks between the reference signal and the measured signal.…”