Plantar Pressure Detection with Fiber Bragg Gratings Sensing System

Abstract

In this paper, a novel fiber-optic sensing system based on fiber Bragg gratings (FBGs) to measure foot plantar pressure is proposed. This study first explores the Pedar-X insole foot pressure types of the adult-size chart and then defines six measurement areas to effectively identify four foot types: neutral foot, cavus foot, supinated foot and flat foot. The plantar pressure signals are detected by only six FBGs, which are embedded in silicone rubber. The performance of the fiber optic sensing is examined and compared with a digital pressure plate of i-Step P1000 with 1024 barometric sensors. In the experiment, there are 11 participants with different foot types to participate in the test. The Pearson correlation coefficient, which is determined from the measured results of the homemade fiber-optic plantar pressure system and i-Step P1000 plantar pressure plate, reaches up to 0.671 (p < 0.01). According to the measured results from the plantar pressure data, the proposed fiber optic sensing system can successfully identify the four different foot types. Measurements of this study have demonstrated the feasibility of the proposed system so that it can be an alternative for plantar pressure detection systems.

Design and Testing of a 2D Optical Fiber Sensor for Building Tilt Monitoring Based on Fiber Bragg Gratings

“…Not only silica optical fiber sensors but also polymer optical fibers (POF) sensors are widely used in different sensing applications. Several fiber sensor designs based on FBG have been reported for various applications, such as liquid level monitoring [13], transverse force sensing [14], concentration measurement [15], biomedical measurement [16,17], pressure [18][19][20], displacement [21,22], temperature [23,24], and ground vibration [25]. An FBG is a type of distributed Bragg reflector constructed in a short segment of optical fiber that reflects particular wavelengths of light and transmits all others.…”

Design, Fabrication and Calibration of Compliant, Multi-Axis, Fiber-Optic Force/Torque Sensors for Biomechanical Measurements

“…The prototype is depicted in Figure 2.15. In an eort to increase sensor exibility, six Bragg gratings were inscribed along an optical ber and were embedded inside a silicon rubber as shown in Figure 2.16 [17]. However, only a static performance was demonstrated and only the normal (vertical) ground reaction force was measured but no shear forces were measured.…”

“…Wavelength-modulation-based sensors such as ber Bragg Gratings (FBGs) are another desirable option due to their high sensitivity, small size, and multiplexing sensing capabilities. The most recent work presented the feasibility of developing exible sensors where the bers were embedded into a silicon rubber [17,22,146,147].…”

“…16: A exible insole force sensor composed of six FBG sensing elements for distributive plantar normal pressure measurements[17].…”

“…17 andFigure 6.18 shows the performance of the shear force sensing element compared to the ATI 6-axis force and torque sensor.The coecient of determination is found to be 98% when the proposed LR-NARX model is applied, which is an improvement compared to the NARX model alone with 97.5% and the linear least squares regression alone with 92%.Table 6.2 summarizes the results obtained from the fabricated shear force sening elementFigure 6.16: A comparison between the performance of the novel LR-NARX and the performance of the static quadratic model.…”