Sensitivity-Tunable Oscillator-Accelerometer Based on Optical Fiber Bragg Grating

Abstract

We demonstrate a fiber Bragg grating (FBG)-based oscillator-accelerometer in which the acceleration sensitivity can be tuned by controlling the location of the mass oscillator. We theoretically and experimentally investigated the performance of the proposed accelerometer. Theoretical analysis showed that both the mass and location of the oscillator affect the sensitivity and resonant frequency of the accelerometer. To simplify the analysis, a nondimensional parameter, P, was introduced to tune the sensitivity of the FBG-based oscillator-accelerometer, which is related to the location of the mass oscillator. Numerical analysis showed that the accelerometer sensitivity is linearly proportional to the P parameter. In the experiment, six FBG-based oscillator-accelerometers with different P parameters (0.125, 0.25, 0.375, 0.5, 0.625, 0.75) were fabricated and tested. The experimental results agree very well with the numerical analysis, in which the sensitivity of the proposed accelerometer linearly increased with the increase in parameter P (7.6 pm/g, 15.8 pm/g, 19.3 pm/g, 25.4 pm/g, 30.6 pm/g, 35.7 pm/g). The resonance frequency is quadratically proportional to parameter P, and the resonance frequency reaches the minimum of 440 Hz when P is equal to 0.5. The proposed oscillator-accelerometer showed very good orthogonal vibration isolation.

A Low-Frequency Fiber Bragg Grating Acceleration Sensor Based on Spring Support and Symmetric Compensation Structure with Flexible Hinges

“…The sensor and the experimental platform are constructed from 304 stainless steel, while the preliminarily selected sensor dimensions, along with the test grating FBG1 parameters, are presented in Table 1. When the thickness of the mass block w = 30 mm, the height of the mass block h = 28 mm, and the radius and width of the hinge vary in a range from 1 mm to 10 mm and 0.5 mm to 2 mm, respectively, the variation curves of the resonant frequency and sensitivity of the sensor obtained according to Equations ( 4) and (7) are shown in Figure 3a,b. The sensitivity of the sensor increases with the increase in the flexure hinge radius r and decreases with the increase in the hinge width t. The natural frequency is vice versa, and the size of the sensor is limited, so r = 5.5 mm is selected.…”

“…It is necessary to meet the measurement requirements of the sensor body but also consider the overall size of the sensor body and the difficulty of installation, so w = 30 mm and h = 28 mm are selected. When the hinge radius r = 5.5 mm, the hinge width t = 1 mm, and the height and thickness of the mass block vary in a range from 20 to 50 mm, the resonant frequency and sensitivity of the sensor are obtained according to Equations ( 4) and (7). Figure 4a,b shows that the sensitivity of the sensor increases with the increase in the mass block width W and the mass block height H. The resonant frequency decreases as W and h increase.…”

“…One of the key pieces of equipment for acquiring vibration signals is the acceleration sensor, which is widely used in the monitoring of large structures and for ensuring environmental safety. Compared to traditional electrical acceleration sensors, as an advanced optical fiber-sensing technology, fiber Bragg grating technology offers high sensitivity, a wide frequency response range, low noise, and strong resistance to electromagnetic interference, making it a research hotspot in the field of acceleration sensors [5][6][7][8].…”

Special Issue on “Advancements in Fiber Bragg Grating Research”

“…A uniform FBG has been used in a spring-mass structure to constitute an accelerometer for the measurement of gravity and vibration. A nondimensional parameter is introduced to tune the sensitivity of an FBG-based oscillator-accelerometer [5]. An FBG can also be written in polymer optical fibers, showing distinct features of negative thermo-optic coefficients and an affinity for water.…”