Tactile Sensor Array with Fiber Bragg Gratings in Quasi-Distributed Sensing

Abstract

This work describes the development of a quasi-distributed real-time tactile sensing system with a reduced number of fiber Bragg grating-based sensors and reports its use with a reconstruction method based on differential evolution. The sensing system is comprised of six fiber Bragg gratings encapsulated in silicone elastomer to form a tactile sensor array with total dimensions of 60 × 80 mm, divided into eight sensing cells with dimensions of 20 × 30 mm. Forces applied at the central position of the sensor array resulted in linear response curves for the gratings, highlighting their coupled responses and allowing the application of compressive sensing. The reduced number of sensors regarding the number of sensing cells results in an undetermined inverse problem, solved with a compressive sensing algorithm with the aid of differential evolution method. The system is capable of identifying and quantifying up to four different loads at four different cells with relative errors lower than 10.5% and signal-tonoise ratio better than 12 dB.

An Artificial Intelligence‐Motivated Skin‐Like Optical Fiber Tactile Sensor

“…Experimental results show that the force measurement error and positioning accuracy are less than 4.2% and up to 92.41%, respectively. These designs yield multiple breakthroughs with respect to previous FBG-based tactile sensors, [26][27][28]42] such as significantly ameliorating the stretchability of the sensor and effectively addressing the problem of signal crosstalk in FBG arrays.…”

“…[ 23–25 ] Some scholars have embedded distributed fiber Bragg gratings (FBGs) into the flexible substrate to realize arrayed tactile sensing. [ 26–28 ] However, FBG arrays suffer from the problem of signal crosstalk. [ 27 ] Moreover, due to the poor inherent tensile properties of silica fibers (tensile strain <1% [ 29 ] ), they are difficult to achieve skin‐like soft and stretchable compliant structures to cope with mechanical surface deformations such as robot joint bending.…”

“…[23][24][25] Some scholars have embedded distributed fiber Bragg gratings (FBGs) into the flexible substrate to realize arrayed tactile sensing. [26][27][28] However, FBG arrays suffer from the problem of signal crosstalk.…”

Tactile Sensing and Control of Robotic Manipulator Integrating Fiber Bragg Grating Strain-Sensor

“…State-of-art regarding applications adopting FBGs as transducers provide evidence of tactile sensors used in different scenarios. Compared to related works (i.e., soft tactile sensors embedding FBGs) (Heo et al, 2006; Saccomandi et al, 2015; Song et al, 2015; Jiang and Xiang, 2017; Negri et al, 2017; Li et al, 2018; Pedroso et al, 2018), the present sensor shares the concept of encapsulating the optical fiber in a soft matrix. Such cover not only protects the fiber from mechanical ruptures but also affects the transduction of the signal by mediating the transmission of pressure to the buried FBGs.…”