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A Demodulation Method and System for Fiber Bragg Grating Temperature Sensing Based on Inversion Algorithm

A fiber grating and inversion algorithm technology, which is applied in the field of fiber grating temperature sensing demodulation based on inversion algorithm, can solve the problem of limited temperature resistance of sensing elements, inability to perform sensing measurement, and inability to exceed sensing elements. The highest temperature resistance and other issues, to achieve the effect of improving the response speed and high temperature resistance

Active Publication Date: 2022-07-12
XI AN JIAOTONG UNIV
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  • Abstract
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  • Application Information

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Problems solved by technology

[0004] At present, the time required for the commonly used FBG temperature sensing and demodulation method to obtain the external environment temperature depends on the response speed of the FBG sensor. However, the FBG temperature sensor needs to wait for its own temperature to reach thermal equilibrium with the external environment temperature to obtain the external temperature. And the time required for the sensor to reach the equilibrium temperature depends on the package of the sensor, which often cannot meet the needs of real-time measurement
[0005] In addition, the upper limit of measurable temperature of the fiber grating temperature sensor and other temperature sensors is limited by the temperature resistance of the sensing element itself, and it is impossible to realize the sensing that exceeds the maximum tolerance temperature of the sensing element itself.
For fiber gratings, its maximum applicable temperature is related to its own material limitations and the formation mechanism of fiber gratings. For example, the sapphire fiber grating with the best temperature resistance currently has a temperature measurement upper limit of about 1600 ° C. If the external temperature is above 1600 ° C , it is impossible to measure the sensor

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  • A Demodulation Method and System for Fiber Bragg Grating Temperature Sensing Based on Inversion Algorithm
  • A Demodulation Method and System for Fiber Bragg Grating Temperature Sensing Based on Inversion Algorithm
  • A Demodulation Method and System for Fiber Bragg Grating Temperature Sensing Based on Inversion Algorithm

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Embodiment 1

[0078] see Figure 1 to Figure 5 , the following takes the BP neural network optimized by genetic algorithm as an example to illustrate in detail, the input data combination method in the embodiment of the present invention adopts the wavelength value at a certain moment and the rate of change of the wavelength over time at the moment, and the rate of change of the wavelength over time is solved by gradient algorithm. The specific steps are as figure 1 shown, including:

[0079] Step 1, calibrate the response speed curve of the fiber grating temperature sensor and preprocess the original data, then divide the obtained sample data into a training set and a test set, and normalize the sample data;

[0080] Step 2. Establish a BP neural network regression model according to the sample data, respectively determine the number of nodes of the input layer, hidden layer and output layer of the BP neural network, and obtain the output of the BP neural network;

[0081] Step 3, using ...

Embodiment 2

[0097] see Figure 6 to Figure 8 , a fiber grating temperature sensing demodulation method based on an inversion algorithm according to an embodiment of the present invention specifically includes the following steps:

[0098] Step 1, calibrating the response speed curve of the fiber grating temperature sensor, and preprocessing the data to obtain sample data;

[0099] Step 2, calibrating the temperature-wavelength curve of the fiber grating temperature sensor;

[0100] Step 3. Use the sample data and the basic formula of the formula method to establish a fiber grating temperature inversion model, that is, to obtain K;

[0101] Step 4. Test the above-mentioned fiber grating temperature inversion model, and use the root mean square error as the evaluation standard. If the test passes, it means that the established model is valid; if the test fails, repeat the above step 3;

[0102] Step 5. Use the above model to predict the temperature.

[0103] In step 1 of this embodiment,...

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Abstract

The invention discloses a fiber grating temperature sensing demodulation method and system based on an inversion algorithm. The method includes the following steps: acquiring wavelengths at multiple preset moments of a fiber grating temperature sensor to be demodulated; According to the preset wavelengths at multiple times, the response speed curve of the fiber grating temperature sensor is obtained; based on the preset wavelengths at multiple times, the rate of change of the wavelength over time at each time is obtained; based on the inversion algorithm, the fiber grating temperature sensor is established The nonlinear relationship between the wavelength at each moment in the response speed curve and the rate of change of the wavelength corresponding to that moment with time and the outside temperature; based on the nonlinear relationship and the wavelengths at multiple moments, the outside temperature is obtained to achieve demodulation . The method of the invention can obviously improve the response speed of the fiber grating temperature sensor, and can realize temperature sensing with higher temperature resistance than the fiber grating sensor.

Description

technical field [0001] The invention belongs to the technical field of fiber grating sensing demodulation, in particular to a fiber grating temperature sensing demodulation method and system based on an inversion algorithm. Background technique [0002] Fiber Bragg Grating is one of the most widely used passive fiber devices at present, which is a fiber structure in which the refractive index of the core changes periodically. Fiber grating has many advantages, such as high sensitivity, low cost, small size, no interference from external electromagnetic radiation, good corrosion resistance, reusability, and adaptability to high temperature and high pressure environments. It has been widely used in national defense, aerospace, and industrial measurement. and other fields. [0003] The application in extreme environments is an important development direction of the current fiber grating sensing technology. With the development of advanced energy power systems such as aero-engi...

Claims

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Application Information

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Patent Type & Authority Patents(China)
IPC IPC(8): G01K11/3206G06N3/08G06F30/27
CPCG01K11/3206G06N3/08G06F30/27
Inventor 陈涛李颖捷司金海牛潇侯洵
Owner XI AN JIAOTONG UNIV