CN-121977464-A - Temperature difference compensation method and system for edge filtering strain sensor

CN121977464ACN 121977464 ACN121977464 ACN 121977464ACN-121977464-A

Abstract

The invention discloses a temperature difference compensation method and a temperature difference compensation system of an edge filtering strain sensor, wherein the method comprises the steps of emitting light beams through an ASE light source, filtering the light beams through an intelligent filtering unit, and outputting linear dynamic adjustment light signals; the optical signals are divided into three equal optical signals through an optical fiber coupler and are respectively input into a three-grating sensing array to obtain three-grating reflected optical signals, the three-grating reflected optical signals are converted into electric signals through a three-grating photoelectric detection array, the electric signals of the three channels are synchronously collected through a collecting unit, the collected electric signals of the three channels are preprocessed to obtain three-channel calibrated signal increment, and accurate strain data are output through dynamic differential operation and multidimensional calibration. The temperature difference compensation method and the temperature difference compensation system for the edge filtering strain sensor realize the efficient separation of strain signals and temperature interference, and break through the application limitation of the traditional static compensation scheme.

Inventors

LI SONG
SU YUE
ZOU DEZHI
SHI LICHENG
JIANG FUCHUAN
YU JINFAN

Assignees

哈尔滨工程大学
哈尔滨工程大学三亚南海创新发展基地

Dates

Publication Date: 20260505
Application Date: 20260121

Claims (10)

1. The temperature difference compensation method of the edge filtering strain sensor is characterized by comprising the following steps of: s1, emitting a light beam through an ASE light source, and outputting a linear dynamic adjustment light signal after filtering by an intelligent filtering unit; S2, dividing the optical signals into three equal optical signals through an optical fiber coupler, and respectively inputting the three optical signals into a three-grating sensing array to obtain three-grating reflected optical signals, wherein the three-grating sensing array comprises a strain measurement grating, a temperature compensation grating and a reference calibration grating; S3, converting the three-grating reflected signals into corresponding electric signals through a three-channel photoelectric detection array, and synchronously collecting the three-channel electric signals through a collecting unit; S4, preprocessing the collected three-channel electric signals to obtain three-channel calibrated signal increment; S5, outputting accurate strain data through dynamic differential operation and multidimensional calibration.
2. The method for compensating the temperature difference of the edge filtering strain sensor according to claim 1, wherein the step S4 is to pre-process the collected three-channel electrical signal to obtain three-channel calibrated signal increment, and the specific contents are as follows: firstly, carrying out filtering treatment on the electric signals of three channels through Kalman filtering; then, removing abnormal values of the three-channel electric signals after filtering treatment by a sliding window method; and finally, correcting the electric signals corresponding to the strain measurement grating and the temperature compensation grating by taking the standard signal of the reference calibration grating as a standard, so as to obtain the signal increment after three-channel calibration.
3. The method of compensating for temperature differences of an edge filtered strain sensor of claim 2, wherein the three channel calibrated signal delta is as follows: ; Wherein, the 、、 The signal increment after three-channel calibration is respectively; 、、 original electrical signals acquired by the three-channel photoelectric detection array are respectively; 、、 Three channel zero reference values, respectively.
4. The method for compensating temperature difference of edge filter strain sensor according to claim 3, wherein in S5, accurate strain data is output by dynamic differential operation, and the specific contents are as follows: s51, establishing a linear model based on the signal increment after three-channel calibration, and obtaining initial strain data and real-time temperature through least square; s52, obtaining calibration strain data through dynamic differential operation; S53, a temperature-filtering slope calibration model is established, and errors of the calibration strain data output by the S52 are corrected in real time based on the real-time temperature obtained by the S51; S54, zero calibration is automatically carried out every 10 minutes, a known strain value is output through a built-in standard strain source, the strain sensitivity is corrected, and finally accurate strain data are obtained.
5. The method of compensating for temperature differences of an edge filtered strain sensor of claim 4, wherein the linear model in S51 is as follows: ; Wherein, the Is the initial strain sensitivity of the strain measurement grating; 、、 The temperature sensitivity of the three gratings respectively; Is strain data to be solved; is the real-time temperature.
6. The method for compensating for temperature difference of edge filter strain sensor according to claim 5, wherein the calibration strain data is obtained by dynamic differential operation in S52, specifically comprising the following steps: Firstly, calculating the difference between the calibrated signal increment of the strain measurement grating and the calibrated signal increment of the temperature compensation grating, and recording the difference as a first-stage difference; And secondly, calculating the difference between the calibrated signal increment of the temperature compensation grating and the calibrated signal increment of the reference calibration grating, recording the difference as a second-stage difference, judging that the temperature signals of the temperature compensation grating and the reference calibration grating are valid if the absolute value of the second-stage difference is smaller than or equal to a preset threshold value, otherwise triggering the temperature compensation grating to calibrate, and returning to S51 to continue execution after the calibration is completed.
7. The method of claim 6, wherein in S53, the temperature-filtering slope calibration model is as follows: ; Wherein, the A and b are fitting coefficients; is the least squares real-time temperature.
8. The method for compensating for temperature difference of an edge-filtered strain sensor as claimed in claim 7, the method is characterized by accurate strain data, as follows: ; Wherein, the Is accurate strain data; Is initial strain data obtained by least square; is the strain sensitivity after calibration; is the signal magnification; is the error correction value of the filtering slope; is zero offset correction value obtained by zero calibration.
9. The temperature difference compensation system of the edge filtering strain sensor is characterized by being used for executing the temperature difference compensation method of the edge filtering strain sensor according to any one of claims 1-8, and comprises an ASE light source, an intelligent filtering unit, an optical fiber coupler, a three-grating sensing array, a three-channel photoelectric detection array, a signal acquisition unit, an intelligent signal processing module and an output module.
10. The temperature difference compensation system of an edge filtered strain sensor of claim 9 wherein the ASE light source is configured to emit a broad spectrum light beam; The intelligent filtering unit comprises a long-period fiber grating LPFG, a temperature detection element and a temperature regulation element; the long period fiber grating LPFG is used for modulating the light beam into an optical signal with the optical power linearly changing along with the wavelength; The temperature detection element is used for acquiring the LPFG temperature in real time, triggering the temperature regulation element in real time according to the temperature data, and dynamically correcting the LPFG filter slope drift caused by the temperature to ensure the stability of the linear characteristic of an output optical signal; The optical fiber coupler is used for dividing the optical signal into three equal optical signals; the three-grating sensing array comprises a strain measurement grating, a temperature compensation grating and a reference calibration grating; the strain measurement grating is used for receiving the optical signals output by the intelligent filtering unit and synchronously sensing the strain and the temperature; The temperature compensation grating is used for receiving the optical signals output by the intelligent filtering unit and sensing the ambient temperature; A reference calibration grating for providing a standard reference signal; The three-channel photoelectric detection array corresponds to the three-grating sensing array one by one, and reflected light signals of the strain measurement grating, the temperature compensation grating and the reference calibration grating are respectively converted into electric signals; the signal acquisition unit is used for synchronously acquiring the electric signals output by the three-channel photoelectric detection array; The intelligent signal processing module comprises a preprocessing unit, a least square decoupling unit, a dynamic differential verification unit, a temperature correction unit and a calibration unit; the preprocessing unit is used for preprocessing the acquired three-channel electric signals to obtain three-channel calibrated signal increments; the least square decoupling unit is used for decoupling to obtain initial strain data and real-time temperature; The dynamic difference verification unit is used for calculating the difference value of the signal increment after three-channel calibration and verifying the signal validity of the temperature compensation grating and the reference calibration grating; The temperature correction unit is used for correcting errors of the calibration strain data based on the real-time temperature obtained by decoupling and combining with a temperature-filtering slope model; The calibration unit is used for periodically triggering the built-in standard strain source and correcting the strain sensitivity of the system; And the output module is used for outputting the accurate strain data obtained by the intelligent signal processing module to external equipment.

Description

Temperature difference compensation method and system for edge filtering strain sensor Technical Field The invention relates to the technical field of strain measurement, in particular to a temperature difference compensation method and a temperature difference compensation system for an edge filtering strain sensor. Background The edge filtering technology becomes a mainstream scheme of FBG spectrum demodulation due to the characteristics of simple equipment structure, wide measurement range, high response speed and the like, but key elements (such as long-period fiber gratings LPFG, sensing gratings and the like) in the sensor have obvious temperature sensitivity. The temperature change can cause the change of core parameters such as the geometric dimension, the refractive index and the like of the element, so that the problems of filter slope drift, optical signal baseline deviation and the like are caused, and effective signals generated by the temperature interference signals and the strain are mutually overlapped, so that the output result of the sensor has serious deviation. In the prior art, the temperature difference compensation method mostly adopts differential operation of a single temperature compensation grating and a measurement grating, and has the defects that firstly, the compensation dimension is single, non-uniform interference caused by temperature gradient change cannot be dealt with, and secondly, a calibration mechanism is static, so that the error drift under a dynamic temperature environment is difficult to adapt. Therefore, the invention provides a temperature difference compensation method and a temperature difference compensation system for an edge filter strain sensor. Disclosure of Invention The invention aims to provide a temperature difference compensation method and a temperature difference compensation system for an edge filtering strain sensor, which realize the efficient separation of strain signals and temperature interference through three-grating and dynamic differential operation, and effectively inhibit random noise and burst interference by adopting Kalman filtering and a sliding window to remove abnormal values. In order to achieve the above object, the present invention provides a temperature difference compensation method for an edge filter strain sensor, comprising the steps of: s1, emitting a light beam through an ASE light source, and outputting a linear dynamic adjustment light signal after filtering by an intelligent filtering unit; S2, dividing the optical signals into three equal optical signals through an optical fiber coupler, and respectively inputting the three optical signals into a three-grating sensing array to obtain three-grating reflected optical signals, wherein the three-grating sensing array comprises a strain measurement grating, a temperature compensation grating and a reference calibration grating; S3, converting the three-grating reflected signals into electric signals through a three-channel photoelectric detection array, and synchronously collecting the three-channel electric signals through a collecting unit; S4, preprocessing the collected three-channel electric signals to obtain three-channel calibrated signal increment; S5, outputting accurate strain data through dynamic differential operation and multidimensional calibration. Preferably, in S4, the collected three-channel electrical signal is preprocessed to obtain a three-channel calibrated signal increment, which specifically includes the following steps: firstly, carrying out filtering treatment on the electric signals of three channels through Kalman filtering; then, removing abnormal values of the three-channel electric signals after filtering treatment by a sliding window method; and finally, correcting the electric signals corresponding to the strain measurement grating and the temperature compensation grating by taking the standard signal of the reference calibration grating as a standard, so as to obtain the signal increment after three-channel calibration. Preferably, the three channel calibrated signal increment is as follows: ; Wherein, the 、、The signal increment after three-channel calibration is respectively;、、 original electrical signals acquired by the three-channel photoelectric detection array are respectively; 、、 Three channel zero reference values, respectively. Preferably, in S5, accurate strain data is output through dynamic differential operation, which specifically includes the following steps: s51, establishing a linear model based on the signal increment after three-channel calibration, and obtaining initial strain data and real-time temperature through least square; s52, obtaining calibration strain data through dynamic differential operation; S53, a temperature-filtering slope calibration model is established, and errors of the calibration strain data obtained in S52 are corrected in real time based on the real-time temperature obtained in S51; S54, zer