A MEMS fiber optic pressure sensing probe with environmental compensation function

Abstract

The present invention relates to the technical field of using optical means for detection, and specifically to a MEMS optical fiber pressure sensing probe with an environmental compensation function, comprising a light emitting component, an optical fiber grating sensor body, a photodetector and a compensation component, wherein the compensation component comprises an environmental parameter detection module and a data processor, wherein the environmental parameter detection module obtains environmental parameters in a target time period, and the data processor obtains interference effects of the environmental parameters on detection results; according to an actual Bragg wavelength and an original Bragg wavelength of the optical fiber grating sensor body, curve characteristics before and after the actual Bragg wavelength in an optical spectrum curve, and interference effects, the interference degree of the optical fiber grating sensor body to the environmental parameters is obtained; according to the interference effects and the interference degree, a compensation parameter is obtained, thereby compensating the optical spectrum curve, completing the influence of environmental factors in a pressure detection process, and effectively improving the accuracy and credibility of the pressure detection results.

Description

Technical Field

[0001] The invention relates to the technical field of detection using optical means, and in particular to a MEMS optical fiber pressure sensing probe with an environmental compensation function. Background Art

[0002] With the advancement of science and technology and the continuous development of industrial automation, pressure sensors are playing an increasingly important role in many fields such as petroleum, chemical industry, medical treatment, aerospace, etc. The development of MEMS (micro-electromechanical system) technology has made sensors more miniaturized and integrated, and their performance has also been greatly improved. The introduction of optical fiber technology provides MEMS pressure sensors with higher sensitivity and anti-interference ability. Combining optical fiber with MEMS can achieve high-precision pressure monitoring.

[0003] The existing MEMS optical fiber pressure sensing probe comprises a light emitting component 100, an optical fiber grating sensor body 200 and a photoelectric detector 300 which are arranged in sequence. Figure 1 A specific structure of an existing MEMS fiber optic pressure sensing probe is given, wherein a light emitting component 100 includes a laser source 101, an optical fiber 102, a collimating lens 103, a polarizer 104 and a quarter wave plate 105, and a fiber grating sensor body 200 includes an electro-optic crystal 201 and an analyzer 203, and the electro-optic crystal 201 is provided with a sensitive element 202 (such as a MEMS diaphragm). In the process of pressure detection by the MEMS fiber optic pressure sensor probe, first, the laser source 101 emits monochromatic light, which is transmitted to the collimating lens 103 through the optical fiber 102. The collimating lens 103 focuses and collimates the light beam; after the light beam passes through the polarizer 104, the polarization state of the light wave is modulated; after passing through the 1 / 4 wave plate 105, the polarization state of the polarized light wave is further adjusted to become circularly polarized light; when pressure is applied to the electro-optical crystal 201, the sensitive element 202 (such as the MEMS diaphragm) will be deformed, and the refractive index of the electro-optical crystal 201 will change due to the applied pressure; the light signal modulated by the electro-optical crystal 201 reaches the analyzer 203. The function of the analyzer 203 is to selectively filter light of a specific polarization state for subsequent signal detection; the light signal passing through the analyzer 203 finally reaches the photodetector 300; the photodetector 300 converts the light signal into an electrical signal for subsequent analysis.

[0004] However, environmental factors (such as temperature, humidity, etc.) will affect the accuracy and stability of pressure measurement of MEMS fiber optic pressure sensing probes, so it is particularly important to perform environmental compensation on MEMS fiber optic pressure sensing probes. Summary of the invention

[0005] In view of this, in order to solve the above technical problems, the present invention provides a MEMS optical fiber pressure sensing probe with an environmental compensation function.

[0006] The technical solutions adopted are as follows:

[0007] A MEMS optical fiber pressure sensing probe with an environmental compensation function, comprising a light emitting component, an optical fiber grating sensor body and a photoelectric detector arranged in sequence, and also comprising a compensation component, wherein the output end of the photoelectric detector is connected to the compensation component, and the compensation component comprises an environmental parameter detection module and a data processor;

[0008] The environmental parameter detection module is used to detect the environmental parameters of the target time period, and the environmental parameters include at least one of temperature and humidity;

[0009] The data processor obtains the spectral curve detected by the fiber grating sensor body in the target time period and the environmental parameters, and obtains the interference effect of the compensation environmental parameters on the detection result of the fiber grating sensor body; obtains the interference degree of the fiber grating sensor body to the environmental parameters according to the actual Bragg wavelength and the original Bragg wavelength of the fiber grating sensor body, the curve characteristics before and after the actual Bragg wavelength in the spectral curve, and the interference effect; obtains the compensation parameter according to the interference effect and the interference degree, and compensates the spectral curve according to the compensation parameter.

[0010] In one embodiment, the process of obtaining the interference impact includes:

[0011] Acquire each extreme value point in the environmental parameter data sequence corresponding to the environmental parameter of the target time period, and obtain the environmental parameter fluctuation characteristics according to the difference of the environmental parameters between two adjacent extreme value points;

[0012] According to the environmental parameter data sequence, a change trend feature of the environmental parameter is obtained, wherein the change trend feature is used to characterize the degree of the trend of the environmental parameter being an increase or decrease;

[0013] The interference influence is obtained according to the fluctuation characteristics and the change trend characteristics of the environmental parameters, and the interference influence is positively correlated with both the fluctuation characteristics and the change trend characteristics of the environmental parameters.

[0014] In one embodiment, the process of acquiring the curve characteristics before and after the actual Bragg wavelength in the spectrum curve includes:

[0015] According to the actual Bragg wavelength, the spectrum curve is divided into a first curve segment and a second curve segment, wherein the first curve segment is a curve segment before the actual Bragg wavelength in the spectrum curve, and the second curve segment is a curve segment after the actual Bragg wavelength in the spectrum curve;

[0016] The areas of the regions where the first curve segment and the second curve segment are located are obtained, and the area difference between the regions where the first curve segment and the second curve segment are located is obtained.

[0017] In one embodiment, the process of obtaining the interference degree includes:

[0018] Obtaining a wavelength difference according to the actual Bragg wavelength and the original Bragg wavelength;

[0019] The interference degree is obtained according to the area difference, the wavelength difference and the interference influence, and the interference degree is positively correlated with the area difference, the wavelength difference and the interference influence.

[0020] In one embodiment, the process of obtaining the actual Bragg wavelength includes: obtaining the maximum peak point in the spectrum curve, and taking the wavelength at the position of the maximum peak point as the actual Bragg wavelength;

[0021] The original Bragg wavelength is calculated from the effective refractive index and grating period of the fiber grating sensor body.

[0022] In one embodiment, obtaining a compensation parameter according to the interference impact and the interference degree includes:

[0023] Obtain the interference impact and interference degree of multiple historical time periods to form an interference impact data series and an interference degree data series respectively;

[0024] Obtaining the correlation between the interference impact data sequence and the interference degree data sequence;

[0025] The compensation parameter is obtained according to the correlation degree, and the compensation parameter is positively correlated with the correlation degree.

[0026] In one embodiment, compensating the spectral curve according to the compensation parameter includes: using the compensation parameter as an error parameter of a Kalman filter to smooth the spectral curve.

[0027] In one embodiment, the environmental parameters include temperature and humidity;

[0028] The compensation parameters include temperature compensation parameters and humidity compensation parameters;

[0029] A comprehensive compensation parameter is obtained according to the temperature compensation parameter and the humidity compensation parameter, and the spectrum curve is compensated according to the comprehensive compensation parameter.

[0030] In one embodiment, the comprehensive compensation parameter is obtained according to the temperature compensation parameter and the humidity compensation parameter, including:

[0031] The temperature compensation parameter and the humidity compensation parameter are subjected to Euclidean norm calculation, and the result obtained is the comprehensive compensation parameter.

[0032] In one embodiment, the compensation component further includes a shell, a vent is provided on the shell, the vent is provided with a baffle for blocking light, and the environmental parameter detection module and the data processor are arranged in the shell.

[0033] The present invention has at least the following beneficial effects: according to the environmental parameters of the MEMS optical fiber pressure sensing probe and the influence on the actual detection result of the MEMS optical fiber pressure sensing probe, that is, the spectrum curve, and then combined with the characteristics of the spectrum curve itself: the actual Bragg wavelength, the original Bragg wavelength, and the curve characteristics, the interference degree of the environmental parameters is obtained, and finally based on the interference degree, the compensation parameters are obtained to compensate the spectrum curve, which can effectively compensate for the errors caused by environmental factors in the optical fiber detection process, make the detection results more accurate, and ensure that accurate measurement results can still be obtained under complex environmental conditions. BRIEF DESCRIPTION OF THE DRAWINGS

[0034] Figure 1 It is a schematic diagram of the hardware structure of an existing MEMS optical fiber pressure sensing probe;

[0035] Figure 2 Schematic diagram of the hardware structure of a MEMS optical fiber pressure sensing probe with environmental compensation function provided in this embodiment;

[0036] Figure 3 is the appearance structure intention of the compensation component 400;

[0037] Figure 4 is an exploded view of the appearance structure of the compensation component 400;

[0038] Figure 5 is a schematic diagram of the internal structure of the compensation component 400;

[0039] Figure 6 It is the overall flow chart of environmental compensation;

[0040] Figure 7 It is a flow chart for obtaining interference effects;

[0041] Figure 8 It is a temperature graph;

[0042] Fig. 9 It is an example of a spectrum curve.

[0043] Fig.10 It is a flow chart for obtaining curve features;

[0044] Fig.11 It is a flow chart for obtaining the degree of interference;

[0045] Fig.12 is a flow chart for obtaining compensation parameters;

[0046] In the figure, 100 is the light emitting component, 200 is the fiber grating sensor body, 300 is the photodetector, 400 is the compensation component, 101 is the laser source, 102 is the optical fiber, 103 is the collimating lens, 104 is the polarizer, 105 is the 1 / 4 wave plate, 201 is the electro-optical crystal, 202 is the sensitive element, 203 is the analyzer, 1 is the shell, 2 is the fixing part, 3 is the vent, 4 is the baffle, 5 is the outer cylindrical body, 6 is the environmental parameter detection module, and 7 is the data processor. DETAILED DESCRIPTION

[0047] This embodiment provides a MEMS optical fiber pressure sensing probe with an environmental compensation function. Figure 2 As shown, it includes a light emitting component 100, a fiber Bragg grating sensor body 200, a photodetector 300 and a compensation component 400. Among them, the specific structures and working principles of the light emitting component 100, the fiber Bragg grating sensor body 200 and the photodetector 300 are all prior art and will not be repeated here. It should be understood that the specific composition of the light emitting component 100 and the fiber Bragg grating sensor body 200 in the MEMS fiber pressure sensing probe with environmental compensation function provided in this embodiment is not limited to Figure 1 and Figure 2 The structure shown in the figure can be selected by the implementer according to actual needs.

[0048] The output end of the photodetector 300 is connected to the compensation component 400. The compensation component 400 is used to detect environmental parameters and obtain the spectrum curve obtained by the fiber grating sensor body 200 detecting the pressure. The spectrum curve is output to the compensation component 400 by the photodetector 300. By analyzing the environmental parameters and the spectrum curve, the compensation parameter is obtained, the spectrum curve is compensated according to the compensation parameter, and finally the spectrum curve after environmental compensation is output.

[0049] In the actual pressure measurement process of the existing MEMS fiber optic pressure sensor probe, due to the particularity of fiber optic measurement, the measurement process is easily affected by environmental factors, such as temperature, humidity, etc. Environmental parameters will cause errors in the pressure measurement process, which will lead to inaccurate measurement results. Therefore, the compensation component 400 is used to perform environmental compensation on the MEMS fiber optic pressure sensor probe during the pressure measurement process to improve the accuracy of pressure measurement.

[0050] The compensation component 400 includes an environmental parameter detection module 6 and a data processor 7. The environmental parameter detection module 6 is used to detect the environmental parameters of the target time period. Among them, the target time period is the time period for environmental compensation, and the target time period can be the current time period, that is, the end time of the current time period is the current time, and the length of the current time period is set according to actual needs. The environmental parameters include at least one of temperature and humidity, then there are three cases, namely: the environmental parameter is only temperature, the environmental parameter is only humidity, and the environmental parameter includes both temperature and humidity. If the environmental parameter is only temperature, the environmental parameter detection module 6 is specifically a temperature sensor, if the environmental parameter is only humidity, then the environmental parameter detection module 6 is specifically a humidity sensor, if the environmental parameter includes both temperature and humidity, then the environmental parameter detection module 6 includes a temperature sensor and a humidity sensor, or the environmental parameter detection module 6 is a temperature and humidity integrated sensor. As a specific embodiment, if it is in a humidity environment with a low humidity value and stable humidity, the influence of humidity on the detection can be ignored, then the environmental parameter detection module 6 takes the temperature sensor as an example, that is, the detected environmental parameter is the ambient temperature. In this embodiment, the electro-optical crystal 201 in the fiber Bragg grating sensor body 200 is specifically a fiber Bragg grating (FBG). Changes in ambient temperature during the measurement process will cause thermal expansion or contraction of the optical fiber material and changes in the refractive index, thereby causing the Bragg wavelength of the fiber Bragg grating in the fiber Bragg grating sensor body 200 to drift, causing the actual measurement result to deviate from the measurement result under the ideal state.

[0051] The environmental parameter detection module 6 is connected to the data processor 7 by signal. The data processor 7 receives the environmental parameters detected by the environmental parameter detection module 6 and performs data processing on the spectrum curve obtained by the pressure detection by the fiber grating sensor body 200. The data processor 7 can be a conventional controller chip, such as a single-chip microcomputer, a PLC, a CPU, etc. The environmental parameter detection module 6 and the data processor 7 can be connected by wired signals (such as through a signal line or a copper busbar), or wirelessly, and the two can also be integrated.

[0052] Since the data processor 7 also receives the spectrum curve obtained by the fiber grating sensor body 200 detecting the pressure, the output end of the photodetector 300 is specifically connected to the data processor 7. The data processor 7 outputs the spectrum curve after environmental compensation.

[0053] like Figure 3 , Figure 4 and Figure 5As shown, a specific mechanical structure of the compensation component 400 is given. The compensation component 400 includes a housing 1, and the environmental parameter detection module 6 and the data processor 7 are arranged in the housing 1. The material of the housing 1 is set according to actual needs. In order to reliably conduct heat, the housing 1 is made of a material with strong thermal conductivity, such as stainless steel. The housing 1 is fixedly connected to the fixing part 2, and the fixing part 2 is used to fix the compensation component 400 to a desired position.

[0054] The housing 1 is provided with a vent hole 3, and the shape and size of the vent hole 3 are set according to actual conditions. In this embodiment, the shape of the vent hole 3 is rectangular. The main purpose of the vent hole 3 is to assist in dissipating the accumulated heat in the housing 1 to prevent the high temperature or high humidity in the housing 1 from affecting the compensation accuracy. The vent hole 3 is provided with a baffle 4, which is used to block light and prevent ambient light from directly entering the housing 1. Multiple baffles 4 are arranged obliquely in the vent hole.

[0055] In this embodiment, the shell 1 is a cylindrical shell, and an outer cylindrical body 5 is coaxially arranged on the outer side of the shell 1, that is, the shell 1 is coaxially sleeved in the outer cylindrical body 5, and the outer cylindrical body 5 and the shell 1 can rotate relative to each other along the central axis. The outer cylindrical body 5 can also be made of a material with strong thermal conductivity. Moreover, the side of the outer cylindrical body 5 is a semi-side surface, so that when the outer cylindrical body 5 rotates relative to the shell 1, by rotating at different angles, the semi-side surface of the outer cylindrical body 5 can block the vent 3, or the semi-side surface of the outer cylindrical body 5 does not block the vent 3. Not only can the collection of environmental parameters be achieved, but also when the outer cylindrical body 5 blocks the vent 3, it can further prevent ambient light from entering the shell 1 through the vent 3.

[0056] It should be understood that Figure 3-Figure 5 is only a specific mechanical structure of the compensation component 400, and the compensation component 400 is not limited to Figure 3-Figure 5 The core components of the compensation component 400 are the environmental parameter detection module 6 and the data processor 7. On the basis of the environmental parameter detection module 6 and the data processor 7, other related components are flexibly set by the implementer according to actual needs.

[0057] The data processor 7 obtains the spectrum curve detected by the fiber grating sensor body 200 in the target time period and the environmental parameters detected by the environmental parameter detection module 6, and corrects the spectrum curve detected by the fiber grating sensor body 200 according to these data information to achieve environmental compensation for the sensor detection results. Figure 6 As shown, the details are as follows:

[0058] Step S1: Obtain the interference effect of the environmental parameters on the detection result of the fiber grating sensor body.

[0059] Environmental parameters will have a certain interference effect on the detection results of the fiber Bragg grating sensor body 200, and the more abnormal the environmental parameters are, the more serious the interference effect on the detection results. Therefore, based on the acquired environmental parameters, the interference effect on the detection results of the fiber Bragg grating sensor body 200 is obtained.

[0060] As a specific implementation, a specific process for obtaining interference influence is given as follows: Figure 7 As shown, including:

[0061] Step S1-1: Acquire each extreme value point in the environmental parameter data sequence corresponding to the environmental parameter of the target time period, and obtain the environmental parameter fluctuation characteristics according to the difference of the environmental parameters between two adjacent extreme value points.

[0062] According to the preset sampling period, various environmental parameters are obtained, so multiple environmental parameters can be obtained in the target time period. The multiple environmental parameters obtained in the target time period are combined in time sequence to form an environmental parameter data sequence, such as Figure 8 As shown, it is a data curve corresponding to the environmental parameter data sequence, specifically a temperature curve, where the horizontal axis is time and the vertical axis is temperature.

[0063] Each extreme point in the environmental parameter data sequence is obtained, and the extreme points include maximum points and minimum points. The difference in environmental parameters between any two adjacent extreme points is obtained, and the difference here is specifically the absolute value of the difference. Then, according to the difference in environmental parameters between any two adjacent extreme points obtained, the environmental parameter fluctuation characteristic is obtained. As a specific implementation method, the absolute value of the difference in temperature between every two adjacent extreme points is obtained, and then the average value of the absolute value of the difference in temperature is calculated, and the average value is normalized, and the normalized average value is used as the environmental parameter fluctuation characteristic. The larger the environmental parameter fluctuation characteristic is, the more drastic the temperature fluctuation in the environmental parameter data sequence is, and the stronger the interference effect on the detection result is.

[0064] It should be understood that the normalization method in this embodiment may be: , where y is the normalized value and x is the input value. It is an exponential function with the natural constant e as its base.

[0065] Step S1-2: According to the environmental parameter data sequence, a change trend characteristic of the environmental parameter is obtained, where the change trend characteristic is used to characterize the degree of the upward or downward trend of the environmental parameter.

[0066] According to the environmental parameter data sequence, the change trend characteristics of the environmental parameters are obtained. The change trend is divided into an upward trend and a downward trend. The change trend characteristics are used to characterize the degree of the upward or downward trend of the environmental parameters, that is, the more the change trend of the environmental parameters is an upward trend or a downward trend, the higher the value of the change trend characteristics.

[0067] As a specific implementation, the sampling point sequence of each sampling point in the target time period is obtained, and the sampling point sequence includes the time of each sampling point. The later the time is, the larger the value corresponding to the time is. Then, the sampling point sequence of the target time period is a data sequence with gradually increasing values, and the change is monotonic.

[0068] The Pearson correlation coefficient between the environmental parameter data sequence and the sampling point sequence is obtained. Then, the more the environmental parameter data sequence has an upward trend or a downward trend, the more relevant the change of the environmental parameter data sequence and the sampling point sequence is, and the larger the absolute value of the Pearson correlation coefficient between the environmental parameter data sequence and the sampling point sequence is, the closer it is to 1. Therefore, the absolute value of the Pearson correlation coefficient is used as the change trend feature of the environmental parameter. The larger the Pearson correlation coefficient is, the more the ambient temperature shows a trend of gradually rising or falling during the measurement process, and the stronger the interference effect of the temperature change trend on the detection result.

[0069] Step S1 - 3 : obtaining the interference influence according to the fluctuation characteristics and the change trend characteristics of the environmental parameters, wherein the interference influence is positively correlated with the fluctuation characteristics and the change trend characteristics of the environmental parameters.

[0070] According to the environmental parameter fluctuation characteristics and change trend characteristics, the interference effect is obtained. The larger the environmental parameter fluctuation characteristics, the more the temperature shows a certain volatility. Moreover, the larger the change trend characteristics, the more the temperature shows a trend of gradually rising or gradually falling during the measurement process, and the greater the interference effect on the pressure measurement result. Therefore, the interference effect is positively correlated with the environmental parameter fluctuation characteristics and the change trend characteristics. As a specific implementation method, the quantification method of the interference effect is given as follows: the product of the environmental parameter fluctuation characteristics and the change trend characteristics is taken as the interference effect.

[0071] It should be understood that in the actual pressure measurement process, changes in ambient temperature will affect the measurement accuracy in the optical fiber measurement process. It is necessary to combine the actual optical fiber measurement results to verify the authenticity of the impact of temperature changes, so that the potential relationship between temperature changes and measurement results can be obtained later, and to provide better data support for subsequent environmental compensation.

[0072] Step S2: Obtain the interference degree of the fiber Bragg grating sensor body to the environmental parameters according to the actual Bragg wavelength and the original Bragg wavelength of the fiber Bragg grating sensor body, the curve characteristics before and after the actual Bragg wavelength in the spectrum curve, and the interference influence.

[0073] It should be understood that temperature changes will cause thermal expansion or contraction of the optical fiber material in the fiber Bragg grating sensor body 200, which in turn causes the fiber Bragg wavelength of the fiber Bragg grating to drift. As the temperature rises, the Bragg wavelength usually moves toward the long-wave direction; as the temperature decreases, the Bragg wavelength usually moves toward the short-wave direction. Under ideal conditions, that is, without the influence of external environmental changes (temperature, humidity, etc.), the Bragg wavelength of the fiber Bragg grating should remain stable, and the central wavelength of the reflection spectrum is fixed at the Bragg wavelength position.

[0074] Therefore, the original Bragg wavelength of the fiber Bragg grating is obtained. The original Bragg wavelength is an intrinsic parameter of the fiber Bragg grating. In this embodiment, the original Bragg wavelength of the fiber Bragg grating is The calculation formula is: Get the actual Bragg wavelength of the fiber Bragg grating as follows: Get the maximum peak point in the spectrum curve, that is, the maximum value of all peak points (the peak point can be obtained by the peak point detection algorithm), and take the wavelength at the location of the maximum peak point as the actual Bragg wavelength ,like Fig. 9 As shown, the horizontal axis is wavelength and the vertical axis is light intensity.

[0075] Get the actual Bragg wavelength in the spectrum curve The curve features before and after, such as Fig.10 As shown, the details are as follows:

[0076] Step S2-1: dividing the spectrum curve into a first curve segment and a second curve segment according to the actual Bragg wavelength, wherein the first curve segment is the curve segment before the actual Bragg wavelength in the spectrum curve, and the second curve segment is the curve segment after the actual Bragg wavelength in the spectrum curve.

[0077] like Fig. 9 As shown, according to the actual Bragg wavelength , the spectrum curve is divided into the first curve segment and the second curve segment, the first curve segment is the actual Bragg wavelength in the spectrum curve The previous curve segment, that is, the wavelength is smaller than the actual Bragg wavelength The second curve segment is the actual Bragg wavelength in the spectrum curve. The following curve segment has a wavelength greater than the actual Bragg wavelength curve segment.

[0078] Step S2-2: Obtain the areas of the regions where the first curve segment and the second curve segment are located, and obtain the area difference between the regions where the first curve segment and the second curve segment are located.

[0079] Get the area of ​​the region where the first curve segment and the second curve segment are located. Specifically: through integral operation, get the area of ​​the region where the first curve segment and the second curve segment are located, which are respectively recorded as and Then get and In this embodiment, the area difference is .

[0080] According to the original Bragg wavelength obtained above and the actual Bragg wavelength , curve characteristics, and interference effects, to obtain the interference degree of the fiber grating sensor body 200 to the environmental parameters. As a specific implementation, Fig.11 As shown in FIG. 1 , the process of obtaining the interference degree includes:

[0081] Step S2-3: Obtaining a wavelength difference according to the actual Bragg wavelength and the original Bragg wavelength.

[0082] In this embodiment, the original Bragg wavelength and the actual Bragg wavelength The absolute value of the difference as the wavelength difference.

[0083] Step S2-4: Obtain the interference degree according to the area difference, the wavelength difference and the interference influence, wherein the interference degree is positively correlated with the area difference, the wavelength difference and the interference influence.

[0084] Under normal circumstances, the spectrum curve has a high degree of symmetry. Therefore, the greater the area difference, the more asymmetric the spectrum curve is. The greater the temperature interference during the pressure detection process, the higher the degree of interference. Under normal circumstances, the original Bragg wavelength and the actual Bragg wavelength The smaller the difference, the greater the wavelength difference, the greater the temperature interference during the pressure detection process, and the higher the degree of interference. The greater the interference effect, the higher the degree of interference. Therefore, the degree of interference is positively correlated with the area difference, wavelength difference and interference effect. As a specific implementation method, a quantification method of the degree of interference is given as follows: Among them, Y represents the degree of interference, F represents the interference impact, Represents the normalization function.

[0085] The larger Y is, the higher the temperature change trend is during the measurement process, the Bragg wavelength has drifted, and the spectrum curve is no longer symmetrical; that is, the pressure detection process is subject to greater temperature interference, and the degree of interference with the ambient temperature is greater.

[0086] Step S3: obtaining compensation parameters according to the interference influence and the interference degree, and compensating the spectrum curve according to the compensation parameters.

[0087] Due to different interference effects and interference levels, the degree of environmental compensation for the detection results is different. Therefore, according to the interference effect F and interference level Y obtained above, the compensation parameter is obtained for environmental compensation. Fig.12 As shown in FIG. 1 , the process of obtaining the compensation parameters includes:

[0088] Step S3-1: Obtain the interference impact and interference degree of multiple historical time periods to form an interference impact data series and an interference degree data series respectively.

[0089] Get multiple historical time periods. The number of historical time periods is set according to actual needs. In order to improve the accuracy and reliability of compensation, the length of each historical time period can be the same as the length of the target time period. Each historical time period is earlier than the target time period. The selection of each historical time period is set according to actual needs. As an optimized implementation method, each historical time period and the target time period can be the same time period on different days, such as: the time period from 10:00 to 10:30 am on each day of a month.

[0090] The interference impact and interference degree of each historical time period are obtained by using the acquisition process of the interference impact and interference degree of the target time period in the above text.

[0091] Then, according to the time sequence, that is, according to the time sequence of each historical time period and the target time period, the interference impact data series and the interference degree data series are obtained respectively. Among them, the interference impact data series consists of the interference impact of each historical time period and the interference impact of the target time period. The interference degree data series consists of the interference degree of each historical time period and the interference degree of the target time period.

[0092] Step S3-2: Obtain the correlation between the interference impact data sequence and the interference degree data sequence.

[0093] As a specific implementation, curve fitting may be performed on the interference influence data sequence and the interference degree data sequence respectively to obtain an interference influence curve corresponding to the interference influence data sequence and an interference degree curve corresponding to the interference degree data sequence.

[0094] Then, the correlation between the interference impact data sequence and the interference degree data sequence is obtained. As a specific implementation, a specific calculation process of the correlation is given as follows: Among them, Q is the correlation between the interference impact data sequence and the interference degree data sequence, R is the interference impact data sequence, G is the interference degree data sequence, It represents the cosine similarity between the interference impact data sequence R and the interference degree data sequence G.

[0095] The larger the value is, the more correlated the interference impact data sequence R is with the interference degree data sequence G, and the higher the correlation degree Q is.

[0096] Through Normalization is performed to limit the value of the correlation degree Q to the range of 0-1.

[0097] As another implementation, the correlation degree may also be calculated by using other existing correlation coefficient calculation methods, such as: in, It represents the mean square error between the interference impact data sequence R and the interference degree data sequence G, Express Perform negative correlation normalization. It should be understood that the negative correlation normalization method in this embodiment can be: .

[0098] Step S3-3: Obtain the compensation parameter according to the correlation degree, wherein the compensation parameter is positively correlated with the correlation degree.

[0099] The higher the correlation degree Q, the more compensation is needed to ensure that the compensated detection results can better eliminate the influence of temperature on optical fiber detection, making the pressure monitoring results more accurate, that is, the higher the compensation parameter. Then, the compensation parameter is obtained according to the correlation degree Q, and the compensation parameter is positively correlated with the correlation degree Q. As a specific implementation method, the obtained correlation degree Q is directly used as the compensation parameter.

[0100] Finally, the spectral curve is compensated according to the compensation parameter. In this embodiment, the compensation parameter is used as the error parameter of the Kalman filter to smooth the spectral curve in the actual detection result, that is, to compensate for the influence of environmental factors in the measurement process, output the compensated spectral curve, obtain the measurement result after environmental compensation, and complete a more accurate pressure measurement. Specifically: in the state transfer equation of the Kalman filter, the compensation parameter is used as a control input to affect the state variable; in the observation equation of the Kalman filter, the compensation parameter is introduced to correct the observation value, adjust the observation equation, and then use the adjusted observation equation and state equation to calculate the Kalman gain, and use the Kalman gain as the parameter of the Kalman filter, and then smooth the spectral curve. That is, the influence of environmental factors in the pressure detection process is completed, and the accuracy and credibility of the pressure detection result are effectively improved. Since the process of smoothing the spectral curve based on the Kalman filter belongs to the prior art, it will not be described in detail.

[0101] The above embodiment is described by taking the environmental parameter as temperature as an example. As other implementation methods, humidity will also affect the accuracy of the pressure detection results. Therefore, the environmental parameters include temperature and humidity. Then, this embodiment also uses the above-mentioned temperature compensation parameter calculation process based on the acquired humidity data to obtain the humidity compensation parameter, that is, the compensation parameter finally obtained includes the temperature compensation parameter and the humidity compensation parameter. Then, a comprehensive compensation parameter is obtained based on the temperature compensation parameter and the humidity compensation parameter. This embodiment performs Euclidean norm calculation on the temperature compensation parameter and the humidity compensation parameter, and the result obtained is the comprehensive compensation parameter. Finally, the spectral curve is compensated according to the comprehensive compensation parameter. The compensation process is also: the comprehensive compensation parameter is used as the error parameter of the Kalman filter, the spectral curve in the actual detection result is smoothed, and the compensated spectral curve is output to obtain the measurement result after environmental compensation, and a more accurate pressure measurement is completed. Specifically: in the state transfer equation of the Kalman filter, the comprehensive compensation parameter is used as the control input to affect the state variable; in the observation equation of the Kalman filter, the comprehensive compensation parameter is introduced to correct the observation value, adjust the observation equation, and then use the adjusted observation equation and state equation to calculate the Kalman gain, use the Kalman gain as the parameter of the Kalman filter, and then smooth the spectral curve.

[0102] The embodiments described above are only used to illustrate the technical solutions of the present application, rather than to limit them. Although the present application has been described in detail with reference to the aforementioned embodiments, a person skilled in the art should understand that the technical solutions described in the aforementioned embodiments may still be modified, or some of the technical features may be replaced by equivalents. Such modifications or replacements do not deviate the essence of the corresponding technical solutions from the scope of the technical solutions of the embodiments of the present application, and should all be included in the protection scope of the present application.

Claims

1. A MEMS fiber optic pressure sensing probe with environmental compensation function, comprising a light emitting component, a fiber grating sensor body and a photoelectric detector arranged in sequence, characterized in that: It also includes a compensation component, the output end of the photoelectric detector is connected to the compensation component, and the compensation component includes an environmental parameter detection module and a data processor; The environmental parameter detection module is used to detect the environmental parameters of the target time period, and the environmental parameters include at least one of temperature and humidity; The data processor obtains the spectrum curve detected by the fiber Bragg grating sensor body in the target time period and the environmental parameters, and obtains the interference effect of the environmental parameters on the detection result of the fiber Bragg grating sensor body; obtains the interference degree of the fiber Bragg grating sensor body to the environmental parameters according to the actual Bragg wavelength and the original Bragg wavelength of the fiber Bragg grating sensor body, the curve characteristics before and after the actual Bragg wavelength in the spectrum curve, and the interference effect; obtains the compensation parameter according to the interference effect and the interference degree, and compensates the spectrum curve according to the compensation parameter; The process of obtaining the interference influence includes: Acquire each extreme value point in the environmental parameter data sequence corresponding to the environmental parameter of the target time period, and obtain the environmental parameter fluctuation characteristics according to the difference of the environmental parameters between two adjacent extreme value points; According to the environmental parameter data sequence, a change trend feature of the environmental parameter is obtained, wherein the change trend feature is used to characterize the degree of the trend of the environmental parameter being an increase or decrease; The interference influence is obtained according to the fluctuation characteristics and the change trend characteristics of the environmental parameters, and the interference influence is positively correlated with the fluctuation characteristics and the change trend characteristics of the environmental parameters; The process of acquiring the curve characteristics before and after the actual Bragg wavelength in the spectrum curve includes: According to the actual Bragg wavelength, the spectrum curve is divided into a first curve segment and a second curve segment, wherein the first curve segment is a curve segment before the actual Bragg wavelength in the spectrum curve, and the second curve segment is a curve segment after the actual Bragg wavelength in the spectrum curve; The areas of the regions where the first curve segment and the second curve segment are located are obtained, and the area difference between the regions where the first curve segment and the second curve segment are located is obtained.

2. The MEMS optical fiber pressure sensing probe with environmental compensation function according to claim 1, characterized in that: The process of obtaining the interference degree includes: Obtaining a wavelength difference according to the actual Bragg wavelength and the original Bragg wavelength; The interference degree is obtained according to the area difference, the wavelength difference and the interference influence, and the interference degree is positively correlated with the area difference, the wavelength difference and the interference influence.

3. The MEMS optical fiber pressure sensing probe with environmental compensation function according to claim 1, characterized in that: The process of obtaining the actual Bragg wavelength includes: obtaining the maximum peak point in the spectrum curve, and taking the wavelength at the position of the maximum peak point as the actual Bragg wavelength; The original Bragg wavelength is calculated from the effective refractive index and grating period of the fiber grating sensor body.

4. The MEMS optical fiber pressure sensing probe with environmental compensation function according to claim 1, characterized in that: According to the interference impact and the interference degree, a compensation parameter is obtained, including: Obtain the interference impact and interference degree of multiple historical time periods to form an interference impact data series and an interference degree data series respectively; Obtaining the correlation between the interference impact data sequence and the interference degree data sequence; The compensation parameter is obtained according to the correlation degree, and the compensation parameter is positively correlated with the correlation degree.

5. The MEMS optical fiber pressure sensing probe with environmental compensation function according to claim 1, characterized in that: The spectral curve is compensated according to the compensation parameter, including: using the compensation parameter as an error parameter of a Kalman filter to smooth the spectral curve.

6. The MEMS optical fiber pressure sensing probe with environmental compensation function according to claim 1, characterized in that: The environmental parameters include temperature and humidity; The compensation parameters include temperature compensation parameters and humidity compensation parameters; A comprehensive compensation parameter is obtained according to the temperature compensation parameter and the humidity compensation parameter, and the spectrum curve is compensated according to the comprehensive compensation parameter.

7. The MEMS optical fiber pressure sensing probe with environmental compensation function according to claim 6, characterized in that: The comprehensive compensation parameters are obtained according to the temperature compensation parameters and the humidity compensation parameters, including: The temperature compensation parameter and the humidity compensation parameter are subjected to Euclidean norm calculation, and the result obtained is the comprehensive compensation parameter.

8. The MEMS optical fiber pressure sensing probe with environmental compensation function according to claim 1, characterized in that: The compensation component further comprises a shell, a vent is provided on the shell, a baffle for shielding light is provided on the vent, and the environmental parameter detection module and the data processor are arranged in the shell.

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