Calibration device and calibration method, device, equipment and medium for optical fiber sensor

Abstract

The embodiment of the application discloses a kind of calibration device and calibration method, device, equipment, medium of optical fiber sensor, calibration device includes: the temperature strain control box being provided with observation window, with the target optical fiber of optical fiber sensor, inside being provided with the first temperature detection device close to the sensing part of optical fiber sensor;With the temperature control execution device being connected with control box;With the strain applying device being detachably connected with target optical fiber;Photosensitive surface is towards the image sensor of observation window;With the optical fiber demodulator being connected with the tail fiber of target optical fiber;With the control device being communicatively connected with temperature control execution device, first temperature detection device, image sensor and optical fiber demodulator.The optical fiber of the embodiment is loaded in temperature strain control box and strain loading, and reliable temperature sensitivity coefficient and strain sensitivity coefficient are calculated simultaneously based on the data collected by image sensor, optical fiber demodulator etc., compared with prior art, the calibration precision of optical fiber sensor is improved.

Description

Technical Field

[0001] This application relates to, but is not limited to, the field of fiber optic sensing technology, and in particular to a calibration device, calibration method, equipment, and medium for a fiber optic sensor. Background Technology

[0002] Fiber optic sensors (such as FBG sensors) inherently exhibit cross-sensitivity to strain and temperature, making it impossible to distinguish whether a measured single center wavelength shift is caused by mechanical strain or temperature change. Therefore, accurately calibrating the strain sensitivity coefficient and temperature sensitivity coefficient of fiber optic sensors is a crucial prerequisite for ensuring their measurement accuracy under complex real-world operating conditions.

[0003] The existing calibration method for fiber optic sensors is a serial discrete calibration method, which involves first calibrating the temperature sensitivity coefficient separately in a constant temperature water bath, and then calibrating the strain sensitivity coefficient separately on a universal testing machine. However, this ignores the cross-coupling effect of the strain field and temperature field on the FBG response, which causes the calibrated coefficients to have a non-negligible deviation under actual "temperature-strain" coexistence conditions, resulting in poor reliability of the calibration coefficients. Summary of the Invention

[0004] This application provides a calibration device, method, equipment, and medium for fiber optic sensors, which can effectively improve the reliability of the calibration coefficients of fiber optic sensors, thereby improving the measurement accuracy of fiber optic sensors.

[0005] In a first aspect, embodiments of this application provide a calibration device for an optical fiber sensor, comprising:

[0006] A temperature strain control box, in which a target optical fiber carrying an optical fiber sensor is inserted, is provided with an observation window, and both the target optical fiber and the sensing part of the optical fiber sensor are located within the field of view of the observation window.

[0007] A temperature control actuator, which is connected to the temperature strain control box, is used to adjust the temperature of the environment in which the target optical fiber is located;

[0008] The first temperature detection device is installed inside the temperature strain control box and close to the sensing unit;

[0009] The strain application device is detachably connected to the target optical fiber;

[0010] An image sensor, with its photosensitive surface facing the observation window, is used to acquire optical feature images of the target optical fiber surface. The optical feature images are processed to obtain the actual strain value of the target optical fiber.

[0011] An optical fiber demodulator, wherein the optical fiber demodulator is connected to the pigtail of the target optical fiber;

[0012] The control device is communicatively connected to the temperature control actuator, the first temperature detection device, the image sensor, and the fiber optic demodulator, respectively.

[0013] The control device sends a temperature control command to the temperature control execution device. After the strain application device applies strain to the target optical fiber, when a preset condition is reached, the control device receives the target temperature sent by the first temperature detection device, the optical feature image of the target optical fiber surface sent by the image sensor, and the center wavelength value of the optical fiber sensor sent by the optical fiber demodulator. Based on the target temperature, the optical feature image, and the center wavelength value, the control device calculates the target temperature sensitivity coefficient and the target strain sensitivity coefficient of the optical fiber sensor.

[0014] In some embodiments, the temperature strain control box is provided with a heat-conducting plate, the temperature control actuator includes a TEC module and a water-cooling circulation module, the TEC module is connected to the water-cooling circulation module, the TEC module is fixed on the heat-conducting plate, the TEC module is connected to a second temperature detection device, and the control device is electrically connected to the second temperature detection device and the TEC module respectively.

[0015] In some embodiments, the strain application device includes a first axial displacement adjustment device and a second axial displacement adjustment device. The first axial displacement adjustment device is provided with a first clamping structure, and the second axial displacement adjustment device is provided with a second clamping structure. The first clamping structure is detachably connected to one end of the target optical fiber, and the second clamping structure is detachably connected to the other end of the target optical fiber. The pigtail of the target optical fiber passing through one end of the second clamping structure is connected to the optical fiber demodulator.

[0016] In some embodiments, the temperature strain control box has a first through hole and a second through hole on its opposite side walls, and the target optical fiber passes through the first through hole and the second through hole. Both the first clamping structure and the second clamping structure include a base and a cover plate. The upper surface of the base is provided with a mounting groove that matches the target optical fiber. The cover plate is detachably connected to the base through a connector. The mounting groove is coaxially arranged with the first through hole and the second through hole. When the cover plate is locked with the base, both ends of the target optical fiber can be clamped in the corresponding mounting groove.

[0017] Secondly, embodiments of this application provide a calibration method for an optical fiber sensor, applied to a control device of a calibration apparatus for an optical fiber sensor according to a first aspect embodiment. The temperature control actuator includes a TEC module, the TEC module is connected to a second temperature detection device, and the control device is electrically connected to both the second temperature detection device and the TEC module. The calibration method includes:

[0018] Acquire target combination data, wherein the target combination data includes m×n sets of observation data, and any set of observation data corresponds to a stable temperature-strain state. The observation data includes the actual strain value of the target optical fiber obtained by processing the optical feature image acquired by the image sensor, the first temperature acquired by the first temperature detection device, and the center wavelength value of the optical fiber sensor output by the optical fiber demodulator. The stable temperature-strain state indicates that the second temperature acquired by the second temperature detection device reaches the preset i-th level target temperature, the actual strain value of the target optical fiber reaches the preset j-th level target strain, and the first temperature and the actual strain value both satisfy the preset stability conditions, 1≤i≤m, 1≤j≤n, where n and m are positive integers greater than 1.

[0019] Determine the offset data between the reference data and each group of observation data, and associate the offset data with the observation data of the corresponding group. The reference data includes the initial strain value of the target optical fiber, the initial temperature collected by the first temperature detection device, and the initial center wavelength value of the optical fiber sensor under the condition of no temperature control operation and strain loading operation. The offset data includes temperature offset, strain offset, and center wavelength offset.

[0020] First target data is determined from all the offset data, and a temperature sensitivity coefficient is calculated based on the first temperature offset and the first center wavelength offset in the first target data, wherein the first strain offset in the first target data is less than a first threshold.

[0021] The second target data is determined from all the offset data, and the strain sensitivity coefficient is calculated based on the second strain offset and the second center wavelength offset in the second target data, wherein the second temperature offset in the second target data is less than the second threshold.

[0022] For any set of observation data corresponding to the offset data, the reference center wavelength offset is calculated based on the temperature sensitivity coefficient, the strain sensitivity coefficient, the temperature offset, and the strain offset.

[0023] The validity index is calculated based on the reference center wavelength offset and the measured center wavelength offset in the offset data of the corresponding group. When the validity index meets the preset conditions, the temperature sensitivity coefficient is determined as the target temperature sensitivity coefficient, and the strain sensitivity coefficient is determined as the target strain sensitivity coefficient. The validity index is used to judge the validity of the temperature sensitivity coefficient and the strain sensitivity coefficient.

[0024] In some embodiments, the control device corresponds to a temperature step sequence and a strain loading level sequence, wherein the temperature step sequence includes i target temperature levels, and the strain loading level sequence includes j target strain levels. The acquisition of target combination data includes:

[0025] Based on the temperature ladder sequence, each target temperature level is traversed sequentially, and the currently traversed target temperature level is used as the target temperature to generate a temperature control command, which is then sent to the TEC module.

[0026] When the second temperature reaches the corresponding target temperature level, and the fluctuation range of the first temperature within a first preset time period is less than the first fluctuation threshold, it is determined that the first temperature meets the stability condition. Based on the strain loading level sequence, each target strain level is traversed sequentially, and the target optical fiber is subjected to strain loading operation through the strain application device so that the actual strain value of the target optical fiber reaches the target strain level currently traversed. The actual strain value is calculated based on a preset image processing algorithm, the current optical feature image, and a reference image. The optical feature image is acquired by the image sensor, and the reference image is the optical feature image of the target optical fiber in the state before strain loading operation.

[0027] When the fluctuation amplitude of the actual strain value of the target optical fiber within a second preset time period is less than the second fluctuation threshold, it is determined that the actual strain value meets the stability condition, triggering the optical fiber demodulator to calculate the center wavelength value of the optical fiber sensor, the first temperature detection device to re-acquire a new first temperature, and the image sensor to re-acquire a new optical feature image of the target optical fiber surface, and calculate a new actual strain value based on the image processing algorithm, the new optical feature image and the reference image;

[0028] The center wavelength value, the new first temperature, and the new actual strain value are determined as a set of observation data, and all the observation data obtained by traversing the temperature step sequence and the strain loading series sequence are determined as the target combination data.

[0029] In some embodiments, the effectiveness index includes goodness of fit, which characterizes the degree of fit between the measured center wavelength offset and the reference center wavelength offset in any set of offset data. The effectiveness index is calculated based on the reference center wavelength offset and the measured center wavelength offset in the corresponding set of offset data. When the effectiveness index meets preset conditions, the temperature sensitivity coefficient is determined as the target temperature sensitivity coefficient, and the strain sensitivity coefficient is determined as the target strain sensitivity coefficient, including:

[0030] Calculate the average of the center wavelength offset in the observation data for all groups;

[0031] For any set of offset data, the goodness of fit is calculated based on the measured center wavelength offset, the average value, and the reference center wavelength offset.

[0032] When the goodness of fit is greater than or equal to the third threshold, the temperature sensitivity coefficient is determined as the target temperature sensitivity coefficient, and the strain sensitivity coefficient is determined as the target strain sensitivity coefficient.

[0033] Thirdly, embodiments of this application provide a control device, including at least one control processor and a memory for communicatively connecting to the at least one control processor; the memory stores instructions executable by the at least one control processor, which, when executed by the at least one control processor, enable the at least one control processor to perform the calibration method for the fiber optic sensor as described in the first aspect.

[0034] Fourthly, embodiments of this application also provide an electronic device, including the control device of the second aspect.

[0035] Fifthly, embodiments of this application also provide a computer-readable storage medium storing computer-executable instructions for performing the calibration method for the fiber optic sensor as described in the first aspect.

[0036] This application provides a calibration device, method, apparatus, equipment, and medium for an optical fiber sensor. The calibration device includes: a temperature strain control box, in which a target optical fiber carrying the optical fiber sensor is inserted; the temperature strain control box has an observation window, and both the target optical fiber and the sensing part of the optical fiber sensor are located within the field of view of the observation window; a temperature control actuator connected to the temperature strain control box for adjusting the temperature of the environment in which the target optical fiber is located; a first temperature detection device disposed inside the temperature strain control box and close to the sensing part; a strain application device detachably connected to the target optical fiber; and an image sensor with its photosensitive surface facing the observation window, used to acquire optical feature images of the surface of the target optical fiber. The image is processed to obtain the actual strain value of the target optical fiber; an optical fiber demodulator is connected to the pigtail of the target optical fiber; a control device is communicatively connected to the temperature control actuator, the first temperature detection device, the image sensor, and the optical fiber demodulator; wherein, the control device sends a temperature control command to the temperature control actuator, and after the strain application device performs a strain loading operation on the target optical fiber, when a preset condition is reached, the control device receives the target temperature sent by the first temperature detection device, the optical feature image of the target optical fiber surface sent by the image sensor, and the center wavelength value of the optical fiber sensor sent by the optical fiber demodulator, and calculates the target temperature sensitivity coefficient and the target strain sensitivity coefficient of the optical fiber sensor based on the target temperature, the optical feature image, and the center wavelength value. According to the solution provided in the embodiments of this application, the optical fiber can realize temperature loading and strain loading in the temperature and strain control box based on the temperature control actuator and the strain application device, and simultaneously calculate reliable temperature sensitivity coefficient and strain sensitivity coefficient based on the data collected by the image sensor, the optical fiber demodulator and the first temperature detection device. Compared with the existing serial discrete calibration scheme, it can effectively improve the reliability of the calibration coefficient of the optical fiber sensor. Attached Figure Description

[0037] To more clearly illustrate the technical solutions of the embodiments of this application, the drawings used in the description of the embodiments of this application will be briefly introduced below. Obviously, the drawings described below are only some embodiments of this application. For those skilled in the art, other drawings can be obtained based on these drawings without creative effort.

[0038] Figure 1 This is a schematic diagram of the structure of a calibration device for an optical fiber sensor provided in one embodiment of this application;

[0039] Figure 2A flowchart illustrating the steps of a calibration method for an optical fiber sensor, provided in another embodiment of this application;

[0040] Figure 3 This is a schematic diagram of a control device provided in another embodiment of this application.

[0041] Explanation of reference numerals in the attached figures:

[0042] Temperature strain control box 110; temperature control actuator 120; first temperature detection device 130; first axial displacement adjustment device 141; first base 142; first cover plate 143; second axial displacement adjustment device 151; second base 152; second cover plate 153; image sensor 160; fiber optic demodulator 170; temperature control unit 181; computer 182; optical vibration isolation platform 190; target optical fiber 200. Detailed Implementation

[0043] To make the objectives, technical solutions, and advantages of this application clearer, the following detailed description is provided in conjunction with the accompanying drawings and embodiments. It should be understood that the specific embodiments described herein are for illustrative purposes only and are not intended to limit the scope of this application. All other embodiments obtained by those skilled in the art based on the embodiments in this application without inventive effort are within the scope of protection of this application.

[0044] It is understandable that although functional modules are divided in the device schematic diagram and a logical order is shown in the flowchart, in some cases, the steps shown or described may be performed in a different order than the module division in the device or the order in the flowchart. The terms "first," "second," etc., in the specification, claims, or the aforementioned drawings are used to distinguish similar objects and are not necessarily used to describe a specific order or sequence.

[0045] Fiber optic sensors (such as FBG sensors) inherently exhibit cross-sensitivity to strain and temperature, making it impossible to distinguish whether a measured single center wavelength shift is caused by mechanical strain or temperature change. Therefore, accurately calibrating the strain sensitivity coefficient and temperature sensitivity coefficient of fiber optic sensors is a crucial prerequisite for ensuring their measurement accuracy under complex real-world operating conditions.

[0046] The existing calibration method for fiber optic sensors is a serial discrete calibration method, which involves first calibrating the temperature sensitivity coefficient separately in a constant temperature water bath, and then calibrating the strain sensitivity coefficient separately on a universal testing machine. However, this ignores the cross-coupling effect of the strain field and temperature field on the FBG response, which causes the calibrated coefficients to have a non-negligible deviation under actual "temperature-strain" coexistence conditions, resulting in poor reliability of the calibration coefficients.

[0047] To address the aforementioned problems, this application provides a calibration device, method, apparatus, equipment, and medium for an optical fiber sensor. The calibration device includes: a temperature strain control box, in which a target optical fiber carrying the optical fiber sensor is inserted; the temperature strain control box has an observation window, and both the target optical fiber and the sensing part of the optical fiber sensor are located within the field of view of the observation window; a temperature control actuator connected to the temperature strain control box for adjusting the temperature of the environment in which the target optical fiber is located; a first temperature detection device disposed inside the temperature strain control box and close to the sensing part; a strain application device detachably connected to the target optical fiber; and an image sensor with its photosensitive surface facing the observation window, used to acquire optical feature images of the surface of the target optical fiber. The optical feature image is processed to obtain the actual strain value of the target optical fiber; an optical fiber demodulator is connected to the pigtail of the target optical fiber; a control device is communicatively connected to the temperature control actuator, the first temperature detection device, the image sensor, and the optical fiber demodulator; wherein, the control device sends a temperature control command to the temperature control actuator, and after the strain application device performs a strain loading operation on the target optical fiber, when a preset condition is reached, the control device receives the target temperature sent by the first temperature detection device, the optical feature image of the target optical fiber surface sent by the image sensor, and the center wavelength value of the optical fiber sensor sent by the optical fiber demodulator, and calculates the target temperature sensitivity coefficient and the target strain sensitivity coefficient of the optical fiber sensor based on the target temperature, the optical feature image, and the center wavelength value. According to the solution provided in the embodiments of this application, the optical fiber can realize temperature loading and strain loading in the temperature and strain control box based on the temperature control actuator and the strain application device, and simultaneously calculate reliable temperature sensitivity coefficient and strain sensitivity coefficient based on the data collected by the image sensor, the optical fiber demodulator and the first temperature detection device. Compared with the existing serial discrete calibration scheme, it can effectively improve the reliability of the calibration coefficient of the optical fiber sensor.

[0048] The embodiments of this application will be further described below with reference to the accompanying drawings.

[0049] refer to Figure 1 , Figure 1 This is a schematic diagram of the structure of a calibration device for an optical fiber sensor according to an embodiment of this application. The calibration device includes:

[0050] Temperature strain control box 110, target optical fiber 200 carrying optical fiber sensor is inserted through temperature strain control box 110, temperature strain control box 110 is provided with observation window 111, target optical fiber 200 and sensing part of optical fiber sensor are both located within the field of view of observation window.

[0051] Temperature control actuator 120 is connected to temperature strain control box 110 and is used to adjust the temperature of the environment where the target optical fiber 200 is located.

[0052] The first temperature detection device 130 is installed inside the temperature strain control box 110 and is close to the sensing unit;

[0053] The strain application device is detachably connected to the target optical fiber 200;

[0054] Image sensor 160, with its photosensitive surface facing the observation window, is used to acquire optical feature images of the surface of the target optical fiber 200. The optical feature images are processed to obtain the actual strain value of the target optical fiber 200.

[0055] Fiber optic demodulator 170 is connected to the pigtail of the target fiber optic cable 200.

[0056] The control device is communicatively connected to the temperature control actuator 120, the first temperature detection device 130, the image sensor 160, and the fiber optic demodulator 170, respectively.

[0057] The control device sends a temperature control command to the temperature control execution device 120. After the strain application device applies strain to the target optical fiber 200, when the preset conditions are met, the control device receives the target temperature sent by the first temperature detection device 130, the optical feature image of the surface of the target optical fiber 200 sent by the image sensor 160, and the center wavelength value of the optical fiber sensor sent by the optical fiber demodulator 170. Based on the target temperature, the optical feature image, and the center wavelength value, the control device calculates the target temperature sensitivity coefficient and the target strain sensitivity coefficient of the optical fiber sensor.

[0058] It is understood that this embodiment provides, as follows: Figure 1 The calibration device for the fiber optic sensor shown can apply temperature and strain loading to the target fiber optic cable 200 within the temperature and strain control box 110 using a temperature control actuator 120 and a strain application device. After the loading operation is completed and the cable is determined to be in a stable temperature and strain state, reliable temperature sensitivity coefficients and strain sensitivity coefficients are simultaneously calculated based on data collected by the image sensor 160, the fiber optic demodulator 170, and the first temperature detection device 130. Compared with the existing serial and discrete calibration schemes, this effectively avoids coupling errors caused by spatiotemporal misalignment of the temperature sensitivity coefficient and the strain sensitivity coefficient, thereby improving the reliability of the calibration coefficients of the fiber optic sensor.

[0059] It should be noted that this embodiment does not limit the specific fiber optic sensor. It can be an FBG sensor, and the sensing part corresponds to the grid region position of the FBG sensor. The fiber optic sensor in this embodiment can also be an LPFG sensor. Those skilled in the art can choose according to the actual situation.

[0060] It should be noted that this embodiment does not limit the specific number of fiber optic sensors carried by the target fiber optic cable 200. It can be one, two, three or more, and those skilled in the art can determine it according to actual needs.

[0061] It should be noted that the embodiments of this application do not limit the specific type of the first temperature detection device 130, and it can be as follows: Figure 1 As shown, the first temperature detection device 130 uses a type K thermocouple, which is introduced through the lead hole of the top cover of the temperature strain control box 110. The temperature measuring end of the type K thermocouple is close to the sensing part of the fiber optic sensor. Alternatively, it can be an infrared thermometer, etc., which can be selected by those skilled in the art according to actual needs.

[0062] It should be noted that this embodiment does not limit the specific image sensor 160. It can be a CMOS camera, a CCD camera, etc., and those skilled in the art can choose according to actual needs.

[0063] It should be noted that the surface of the target optical fiber 200 in this embodiment is provided with random speckle or marker points. When strain loading is applied to the target optical fiber 200 using a strain loading device, the random speckle or marker points on the surface of the target optical fiber 200 will differ from those before strain loading. Since the photosensitive surface of the image sensor 160 faces the observation window, such as... Figure 1 As shown, this embodiment can acquire optical feature images of the target optical fiber 200 after strain loading through the image sensor 160, compare them with the reference image before strain loading, and calculate the actual strain value of the target optical fiber 200 by combining the preset image processing algorithm, thereby providing an effective data basis for subsequent calculation of the strain sensitivity coefficient.

[0064] It is understandable that during the calibration of the target optical fiber 200, it will inevitably be affected by vibrations such as ground vibration, vibrations caused by human activities, and sound interference. In order to reduce or avoid the impact of vibration on the optical fiber calibration process, this embodiment integrates the core components of the optical fiber sensor calibration device, such as the temperature strain control box 110, temperature control execution device 120, first temperature detection device 130, strain application device, and image sensor 160, onto the optical vibration isolation platform 190.

[0065] In some embodiments, the temperature strain control box 110 is provided with a heat-conducting plate, the temperature control actuator 120 includes a TEC module and a water-cooling circulation module, the TEC module is connected to the water-cooling circulation module, the TEC module is fixed on the heat-conducting plate, the TEC module is connected to a second temperature detection device, and the control device is electrically connected to the second temperature detection device and the TEC module respectively.

[0066] It should be noted that this embodiment does not limit the specific temperature control actuator 120. It can be a TEC module alone, or it can be an integrated TEC module and a water cooling circulation module. The inlet and outlet of the water cooling circulation module are connected to an external cold water tank to circulate cold water. This can work with the control device to control the internal temperature of the temperature strain control box 110, and can achieve bidirectional temperature control for both cooling and heating.

[0067] It should be noted that this embodiment does not limit the specific number of TEC modules and heat-conducting plates, or the arrangement of them on the temperature strain control box 110. It is possible that two heat-conducting plates are arranged from top to bottom on the side wall of the temperature strain control box 110, and each heat-conducting plate is fixed with a TEC module, so as to ensure the uniformity of the temperature field during temperature control. Alternatively, only one heat-conducting plate and the corresponding TEC module can be arranged on the side wall of the temperature strain control box 110. Those skilled in the art can choose according to actual needs.

[0068] It should be noted that this embodiment does not limit the specific second temperature detection device. It can be an NTC thermistor or a PTC thermistor. Those skilled in the art can choose according to actual needs.

[0069] In some embodiments, the strain application device includes a first axial displacement adjustment device 141 and a second axial displacement adjustment device 151. The first axial displacement adjustment device 141 is provided with a first clamping structure, and the second axial displacement adjustment device 151 is provided with a second clamping structure. The first clamping structure is detachably connected to one end of the target optical fiber 200, and the second clamping structure is detachably connected to the other end of the target optical fiber 200. The pigtail of the target optical fiber 200 passing through one end of the second clamping structure is connected to the optical fiber demodulator 170.

[0070] It should be noted that this embodiment does not limit the specific strain application device, and it can be, for example, Figure 1As shown, a first axial displacement adjustment device 141 and a second axial displacement adjustment device 151 are respectively arranged on opposite sides of the temperature strain control box 110. Since the first clamping structure on the first axial displacement adjustment device 141 is detachably connected to one end of the target optical fiber 200, and the second clamping structure on the second axial displacement adjustment device 151 is detachably connected to the other end of the target optical fiber 200, when both clamping structures clamp the target optical fiber 200 on the corresponding axial displacement adjustment device, the target optical fiber 200 is pulled by manually fine-tuning the first axial displacement adjustment device 141 and the second axial displacement adjustment device 151 to apply a small, quantitative tensile strain to the target optical fiber 200. Alternatively, an axial displacement adjustment device can be arranged on one side of the temperature strain control box 110, and a clamping device for fixing the target optical fiber 200 can be arranged on the opposite side. Strain loading of the target optical fiber 200 can be achieved by manually fine-tuning the axial displacement adjustment device on one side. Alternatively, the axial displacement adjustment device in the above two strain application device schemes can be an electrically powered displacement adjustment device. Those skilled in the art can choose according to the actual situation.

[0071] In some embodiments, reference Figure 1 The temperature strain control box 110 has a first through hole and a second through hole on its opposite side walls. The target optical fiber 200 passes through the first through hole and the second through hole. The first clamping structure and the second clamping structure both include a base (first base 142, second base 152) and a cover plate (first cover plate 143, second cover plate 153). The upper surface of the base is provided with an installation groove that matches the target optical fiber 200. The cover plate is detachably connected to the base through a connector. The installation groove is coaxially arranged with the first through hole and the second through hole. When the cover plate is locked with the base, both ends of the target optical fiber 200 can be clamped in the corresponding installation groove.

[0072] It should be noted that this embodiment does not limit the specific clamping structure, except that it can be as follows: Figure 1 As shown, the target optical fiber 200 can be locked by a cover plate and a base that are detachably connected by a connector. Alternatively, the target optical fiber 200 can be locked by a magnetically coupled cover plate and base (i.e., the cover plate and base are magnetically coupled by a built-in strong magnet). Those skilled in the art can choose according to actual needs.

[0073] It should be noted that this embodiment does not limit the specific shape of the mounting groove. It can be a V-shaped groove or a U-shaped groove. Those skilled in the art can choose according to actual needs.

[0074] It should be noted that this embodiment does not limit the specific connecting parts. They can be threaded connecting parts or snap-fit ​​connecting parts. Those skilled in the art can choose according to actual needs, as long as they can realize the connection between the cover plate and the base.

[0075] It is understandable that by locking both ends of the target optical fiber 200 onto the strain loading device through the first clamping structure and the second clamping structure, the accurate transmission and application of strain can be ensured.

[0076] It should be noted that the embodiments of this application do not limit the specific control device, and can be such as Figure 1 As shown, the control device includes a computer 182 and a temperature control unit 181. The second temperature detection device and the temperature control execution device 120 are electrically connected to the temperature control unit 181. The computer 182 is electrically connected to the first temperature detection device 130, the image sensor 160, the fiber optic demodulator 170, and the temperature control unit 181, respectively. Alternatively, the control device may only include the computer 182, which is electrically connected to the second temperature detection device, the temperature control execution device 120, the first temperature detection device 130, the image sensor 160, the fiber optic demodulator 170, and the temperature control unit 181. Those skilled in the art can choose according to the actual situation.

[0077] Specifically, the preset conditions of this embodiment include: (1) after the temperature loading operation, the first temperature of the first temperature detection device 130 meets the stability condition; (2) after the strain loading operation, the actual strain value of the target optical fiber 200 meets the stability condition.

[0078] It is understood that, referring to the description of the above embodiments, when the control device as Figure 1 The diagram includes a computer 182 and a temperature control unit 181. The computer 182 can send temperature control commands to the TEC module through the temperature control unit 181. The temperature control unit 181 uses the reading of the second temperature detection device (selected as an NTC thermistor) as a feedback signal and implements temperature control using a PID algorithm. The computer 182 then uses the reading of the first temperature detection device 130 as a feedback signal to determine whether the first temperature meets the stability condition (i.e., whether the temperature field is stable). When the first temperature meets the stability condition, the operator manually adjusts the strain loading device to apply strain to the target optical fiber 200. At the same time, the computer 182 calculates the current actual strain value of the target optical fiber 200 based on the optical feature image detected by the image sensor 160 and displays it on the computer 182 interface until the actual strain value reaches the strain value corresponding to the target strain level in the strain loading level sequence, and the creep of the axial displacement adjustment device of the strain loading device approaches zero. At this point, it is determined that the preset condition is met. Then, based on the data collected by the image sensor 160, the fiber demodulator 170, and the first temperature detection device 130, a reliable temperature sensitivity coefficient and a strain sensitivity coefficient are calculated simultaneously.

[0079] refer to Figure 2 , Figure 2This is a flowchart illustrating the steps of a calibration method for an optical fiber sensor according to an embodiment of this application. This embodiment provides a calibration method for an optical fiber sensor, which is applied to the control device of the calibration apparatus for the optical fiber sensor provided in the above embodiment. The temperature control actuator includes a TEC module, which is connected to a second temperature detection device. The control device is electrically connected to both the second temperature detection device and the TEC module. The method includes, but is not limited to, the following steps:

[0080] Step S10: Obtain target combination data, wherein the target combination data includes m×n sets of observation data, and any set of observation data corresponds to a stable temperature-strain state. The observation data includes the actual strain value of the target optical fiber obtained by processing the optical feature image acquired by the image sensor, the first temperature acquired by the first temperature detection device, and the center wavelength value of the optical fiber sensor output by the optical fiber demodulator. The stable temperature-strain state indicates that the second temperature acquired by the second temperature detection device reaches the preset i-th level target temperature, the actual strain value of the target optical fiber reaches the preset j-th level target strain, and both the first temperature and the actual strain value satisfy the preset stability conditions, 1≤i≤m, 1≤j≤n, where n and m are positive integers greater than 1.

[0081] Specifically, the target combination data in this embodiment is used to indicate the actual strain value, temperature value, and center wavelength value of a fiber optic sensor under m×n different temperature-strain states. It is understood that acquiring observation data under different temperature-strain states provides an effective data foundation for subsequent calculations of accurate temperature sensitivity coefficients and strain sensitivity coefficients.

[0082] Understandably, before acquiring the target combination data, this embodiment first performs system initialization and specimen clamping to form a system as follows: Figure 1 The calibration device for the fiber optic sensor shown specifically involves setting the first axial displacement adjustment device and the second axial displacement adjustment device on both sides of the temperature strain control box. Then, the moving axes of the two axial displacement adjustment devices are aligned to be coaxial. The two ends of the target fiber are respectively inserted into the V-grooves of the bases corresponding to the first clamping structure and the second clamping structure, and locked by the cover plate. The pigtail of the target fiber is connected to the fiber optic demodulator, and the temperature control unit, the circulating water cooling interface, the image sensor and the computer are connected. After checking the connection status, the temperature strain control box is closed.

[0083] Specifically, in some embodiments, the control device corresponds to a temperature step sequence and a strain loading level sequence, wherein the temperature step sequence includes i target temperature levels and the strain loading level sequence includes j target strain levels. Figure 2 Step S10 includes, but is not limited to, the following steps:

[0084] Step S11: Based on the temperature ladder sequence, traverse each target temperature level in sequence, and use the currently traversed target temperature level as the target temperature to generate a temperature control command and send it to the TEC module;

[0085] Step S12: When the second temperature reaches the current target temperature level and the fluctuation range of the first temperature within the first preset time period is less than the first fluctuation threshold, it is determined that the first temperature meets the stability condition. Based on the strain loading level sequence, each target strain level is traversed sequentially, and the target optical fiber is subjected to strain loading operation through the strain application device so that the actual strain value of the target optical fiber reaches the target strain level currently traversed. The actual strain value is calculated based on the preset image processing algorithm, the current optical feature image and the reference image. The optical feature image is acquired by the image sensor, and the reference image is the optical feature image of the target optical fiber in the state where no strain loading operation has been performed.

[0086] Step S13: When the fluctuation amplitude of the actual strain value of the target optical fiber within the second preset time period is less than the second fluctuation threshold, it is determined that the actual strain value meets the stability condition. The fiber demodulator is triggered to calculate the center wavelength value of the fiber sensor, the first temperature detection device re-acquires the new first temperature, and the image sensor re-acquires the new optical feature image of the target optical fiber surface. The new actual strain value is calculated based on the image processing algorithm, the new optical feature image and the reference image.

[0087] Step S14: The center wavelength value, the new first temperature, and the new actual strain value are determined as a set of observation data, and all the observation data obtained by traversing the temperature step sequence and the strain loading level sequence are determined as the target combination data.

[0088] Specifically, the temperature step sequence and strain loading series sequence in this embodiment can be preset, or the operator can input a custom temperature step sequence and strain loading series sequence through the analysis software interface running on the computer. No further restrictions are imposed here.

[0089] It is understood that the temperature step sequence in this embodiment includes , , …, Strain loading series , , …, Before acquiring the target combination data, the control device automatically initializes the dual cyclic index based on the temperature step sequence and the strain loading level sequence, setting the temperature step index i=1 and the strain level index j=1, thereby establishing an m×n data matrix that stores the observation data of the target optical fiber under m×n temperature-strain states. Each observation data includes the center wavelength, the actual strain value, and the first temperature.

[0090] It should be noted that the observation data in this embodiment may also include timestamps, which represent the acquisition time of each data point in the observation data.

[0091] It should be noted that this embodiment does not limit the specific first preset time period and the first fluctuation threshold. The first preset time period can be 3 minutes and the first fluctuation threshold can be 0.2 °C. Those skilled in the art can determine these according to actual needs.

[0092] It is understood that the method for obtaining the target combination data in this embodiment is as follows: based on the temperature ladder sequence, sequentially traverse each target temperature level (corresponding to the temperature ladder sequence in...) , , …, The system then generates a temperature control command for the target temperature level it has traversed, and sends it to the TEC module so that the TEC module, in conjunction with the water cooling circulation module, performs temperature control according to the current target temperature level. After that, it enters the temperature stability judgment. When the second temperature reaches the current target temperature level and the fluctuation range of the first temperature within the first preset time period is less than the first fluctuation threshold, it is determined that the first temperature meets the stability condition. Next, based on the strain loading sequence, each target strain level is traversed sequentially, and strain loading is applied to the target optical fiber using a strain application device to bring the actual strain value of the target optical fiber to the currently traversed target strain level. When the fluctuation amplitude of the actual strain value of the target optical fiber within a second preset time period is less than a second fluctuation threshold (the specific value of the second fluctuation threshold can be determined by those skilled in the art based on actual conditions, and is not limited here), it is determined that the actual strain value meets the stability condition (i.e., the current target optical fiber strain field is stable). Subsequently, multi-source parameter synchronous acquisition is triggered. Specifically, the optical fiber demodulator is triggered to calculate the center wavelength value of the optical fiber sensor using a peak-finding algorithm, the first temperature detection device re-acquires a new first temperature, and the image sensor re-acquires a new optical feature image of the target optical fiber surface. Based on the image processing algorithm, the new optical feature image, and the reference image, a new actual strain value is calculated. The center wavelength value, the new first temperature, and the new actual strain value are determined as a set of observation data, and all the observation data obtained after traversing the temperature step sequence and the strain loading sequence are determined as the target combination data. This provides an effective data foundation for the subsequent calculation of the temperature sensitivity coefficient and the strain sensitivity coefficient.

[0093] Additionally, it should be noted that during the temperature stability judgment process, when the fluctuation range of the first temperature within the first preset time period is greater than or equal to the first fluctuation threshold, the current temperature control operation is maintained and the cycle waits until the fluctuation range of the first temperature within the first preset time period is less than the first fluctuation threshold before step S12 is triggered to perform the strain loading operation.

[0094] It is understandable that after obtaining the center wavelength value, the new first temperature, and the new actual strain value of the target optical fiber under the same temperature-strain state, these values ​​are simultaneously written into the corresponding (i, j) position of the data matrix to form a complete set of observation data. , , ).

[0095] Furthermore, it is understandable that in this embodiment, during the process of traversing the temperature step sequence and strain loading series to obtain observation data under m×n temperature-strain states, the current strain level index is determined. Has the preset maximum value been reached? .like Then let Return to step S12 to execute the next stage of strain loading and data acquisition; if This indicates all temperatures under the current temperature level. The strain level data has been collected, and the current temperature level index has been determined. Has the maximum number of levels been reached? .like Then let And reset the strain order index to Return to step S11 to execute the loading and traversal acquisition of the next temperature level; if This indicates all All observation data have been collected.

[0096] Step S20: Determine the offset data between the reference data and each group of observation data, and associate the offset data with the observation data of the corresponding group. The reference data includes the initial strain value of the target optical fiber, the initial temperature collected by the first temperature detection device, and the initial center wavelength value of the optical fiber sensor under the conditions of no temperature control operation and strain loading operation. The offset data includes temperature offset, strain offset, and center wavelength offset.

[0097] It is understood that this embodiment is based on the initial strain value, initial temperature, and initial center wavelength value in the reference data, i.e. ( , , ), calculate the fiber optic sensor in the first Offset data under group operating conditions (temperature offset) Strain offset Center wavelength offset ),in, , , = - This provides a solid data foundation for subsequent calculations of the temperature sensitivity coefficient and the strain sensitivity coefficient.

[0098] Step S30: Determine the first target data from all the offset data, and calculate the temperature sensitivity coefficient based on the first temperature offset and the first center wavelength offset in the first target data, wherein the first strain offset in the first target data is less than the first threshold.

[0099] It should be noted that this embodiment does not limit the specific first threshold. Those skilled in the art can determine it according to the actual situation, as long as it can constrain the first strain offset in the first target data to approach 0.

[0100] It should be noted that in this embodiment, the temperature sensitivity coefficient is calculated based on the first temperature offset and the first center wavelength offset in the first target data, and is obtained according to the following single-parameter linear model:

[0101] ;

[0102] in, This is the first center wavelength offset. This is the temperature sensitivity coefficient. This represents the first temperature offset. It can be understood that the temperature sensitivity coefficient of the fiber optic sensor is calculated by performing a linear fit on the single-parameter linear model related to the temperature sensitivity coefficient described above. .

[0103] Step S40: Determine the second target data from all the offset data, and calculate the strain sensitivity coefficient based on the second strain offset and the second center wavelength offset in the second target data, wherein the second temperature offset in the second target data is less than the second threshold.

[0104] It should be noted that this embodiment does not limit the specific second threshold. Those skilled in the art can determine it according to the actual situation, as long as it can constrain the second temperature offset in the second target data to approach 0.

[0105] It should be noted that in this embodiment, the strain sensitivity coefficient is calculated based on the second strain offset and the second center wavelength offset in the second target data, and is obtained according to the following single-parameter linear model:

[0106] ;

[0107] in, This is the second center wavelength offset. The strain sensitivity coefficient, This represents the second strain offset. It can be understood that the strain sensitivity coefficient of the fiber optic sensor is obtained by performing a linear fit on the single-parameter linear model associated with the strain sensitivity coefficient described above. .

[0108] Step S50: For any set of observation data, calculate the reference center wavelength offset based on the temperature sensitivity coefficient, strain sensitivity coefficient, temperature offset, and strain offset.

[0109] Step S60: Calculate the effectiveness index based on the reference center wavelength offset and the measured center wavelength offset in the offset data of the corresponding group. When the effectiveness index meets the preset conditions, determine the temperature sensitivity coefficient as the target temperature sensitivity coefficient and the strain sensitivity coefficient as the target strain sensitivity coefficient. The effectiveness index is used to judge the effectiveness of the temperature sensitivity coefficient and the strain sensitivity coefficient.

[0110] Understandably, after calculating the temperature sensitivity coefficient and strain sensitivity coefficient, it is necessary to verify the validity of these two coefficients to ensure the measurement accuracy of the subsequent fiber optic sensor. In this embodiment, for any set of observation data corresponding to the offset data, a reference center wavelength offset is calculated based on the temperature sensitivity coefficient, strain sensitivity coefficient, and the temperature and strain offsets in the offset data. Furthermore, a validity index is calculated using the reference center wavelength offset and the measured center wavelength offset in the corresponding set of offset data. This validity index is used to determine the validity of the temperature sensitivity coefficient and strain sensitivity coefficient, thereby ensuring calibration accuracy.

[0111] It should be noted that in this embodiment, the reference center wavelength offset is calculated based on the temperature sensitivity coefficient, strain sensitivity coefficient, temperature offset, and strain offset, and is obtained according to the following formula:

[0112] ;

[0113] in, This is the reference center wavelength offset.

[0114] It should be noted that this embodiment does not limit the specific type of effectiveness index. It can be goodness of fit, which characterizes the degree of fit between the measured center wavelength offset and the reference center wavelength offset in any set of offset data; it can also be repeatability error, which is the arithmetic mean of the measured center wavelength offset under the same temperature-strain condition, and the maximum value of the absolute value of the difference between each measured value and the average value, etc. Those skilled in the art can determine it according to actual needs.

[0115] It should be noted that this embodiment does not limit or restrict the number of effectiveness indicators. It may include only one effectiveness indicator, and when the preset conditions are met, the calculated temperature sensitivity coefficient and strain sensitivity coefficient are determined as the final target calibration coefficients; or it may include multiple effectiveness indicators, and when all effectiveness indicators meet the preset conditions, the calculated temperature sensitivity coefficient and strain sensitivity coefficient are determined as the final target calibration coefficients.

[0116] In addition, after calibration, this embodiment also includes archiving a calibration report file containing the temperature sensitivity coefficient, strain sensitivity coefficient, effectiveness index, target combination data, and offset data associated with each group of observation data in the target combination data, so as to provide an effective data foundation for subsequent troubleshooting and review.

[0117] Specifically, in some embodiments, the effectiveness metric includes goodness of fit, which characterizes the degree of fit between the measured center wavelength offset and the reference center wavelength offset in any set of offset data. Figure 3 Step S60 includes, but is not limited to, the following steps:

[0118] Step S61: Calculate the average value of the center wavelength offset in the observation data of all groups;

[0119] Step S62: For any set of offset data, calculate the goodness of fit based on the measured center wavelength offset, the average value, and the reference center wavelength offset;

[0120] Step S63: When the goodness of fit is greater than or equal to the third threshold, the temperature sensitivity coefficient is determined as the target temperature sensitivity coefficient, and the strain sensitivity coefficient is determined as the target strain sensitivity coefficient.

[0121] It should be noted that in this embodiment, the goodness of fit is calculated based on the measured center wavelength offset, the average value, and the reference center wavelength offset, and is obtained according to the following formula:

[0122] ;

[0123] in, For goodness of fit, The average value is given. It is understandable that calculating the goodness of fit provides a valid basis for judging whether the calculated temperature sensitivity coefficient and strain sensitivity coefficient are effective.

[0124] It should be noted that this embodiment does not limit the specific value of the third threshold; it can be 0.99, and those skilled in the art can determine it according to actual needs.

[0125] like Figure 3 As shown, Figure 3This is a structural diagram of a control device provided in one embodiment of this application. The present invention also provides a control device 200, including: a processor 210, which can be implemented using a general-purpose central processing unit (CPU), microprocessor, application-specific integrated circuit (ASIC), or one or more integrated circuits, for executing relevant programs to implement the technical solutions provided in the embodiments of this application; and a memory 220, which can be implemented using a read-only memory (ROM), static storage device, dynamic storage device, or random access memory (RAM), etc. The memory 220 can store the operating system and other applications. When the technical solutions provided in the embodiments of this specification are implemented by software or firmware, the relevant program code is stored in the memory 220 and is called and executed by the processor 210 to execute the calibration method of the fiber optic sensor in the embodiments of this application. The input / output interface 230 is used to realize information input and output. The communication interface 240 is used to realize communication interaction between this device and other devices. Communication can be realized by wired means (e.g., USB, network cable, etc.) or by wireless means (e.g., mobile network, WIFI, Bluetooth, etc.). The bus 250 transmits information between the various components of the device (e.g., processor 210, memory 220, input / output interface 230 and communication interface 240). The processor 210, memory 220, input / output interface 230 and communication interface 240 realize communication connection between each other within the device through the bus 250.

[0126] In addition, this application also provides an electronic device, including the control device 200 described in the above embodiments.

[0127] In addition, this application embodiment also provides a storage medium, which is a computer-readable storage medium, storing a computer program that, when executed by a processor, implements the above-described calibration method for the fiber optic sensor.

[0128] Memory, as a non-transitory computer-readable storage medium, can be used to store non-transitory software programs and non-transitory computer-executable programs. Furthermore, memory may include high-speed random access memory, and may also include non-transitory memory, such as at least one disk storage device, flash memory device, or other non-transitory solid-state storage device. In some embodiments, memory may optionally include memory remotely located relative to the processor, and these remote memories can be connected to the processor via a network. Examples of such networks include, but are not limited to, the Internet, intranets, local area networks, mobile communication networks, and combinations thereof. The device embodiments described above are merely illustrative, and the units described as separate components may or may not be physically separate, and may be located in one place or distributed across multiple network units. Some or all of the modules can be selected to achieve the purpose of this embodiment according to actual needs.

[0129] It will be understood by those skilled in the art that all or some of the steps and systems in the methods disclosed above can be implemented as software, firmware, hardware, and suitable combinations thereof. Some or all of the physical components can be implemented as software executed by a processor, such as a central processing unit, digital signal processor, or microprocessor, or as hardware, or as an integrated circuit, such as an application-specific integrated circuit. Such software can be distributed on a computer-readable medium, which can include computer storage media (or non-transitory media) and communication media (or transient media). As is known to those skilled in the art, the term computer storage media includes volatile and non-volatile, removable and non-removable media implemented in any method or technology for storing information (such as computer-readable instructions, data structures, program modules, or other data). Computer storage media includes, but is not limited to, RAM, ROM, EEPROM, flash memory or other memory technologies, CD-ROM, digital versatile disc (DVD) or other optical disc storage, magnetic cartridges, magnetic tape, disk storage or other magnetic storage devices, or any other medium that can be used to store desired information and is accessible to a computer. Furthermore, as is known to those skilled in the art, communication media typically include computer-readable instructions, data structures, program modules, or other data in modulated data signals such as carrier waves or other transmission mechanisms, and may include any information delivery medium.

[0130] The above provides a detailed description of the preferred embodiments of the present invention. However, the present invention is not limited to the above embodiments. Those skilled in the art can make various equivalent modifications or substitutions without departing from the spirit of the present invention. All such equivalent modifications or substitutions are included within the scope defined by the claims of the present invention.

Claims

1. A calibration device for an optical fiber sensor, characterized in that, include: A temperature strain control box, in which a target optical fiber carrying an optical fiber sensor is inserted, is provided with an observation window, and both the target optical fiber and the sensing part of the optical fiber sensor are located within the field of view of the observation window. A temperature control actuator, which is connected to the temperature strain control box, is used to adjust the temperature of the environment in which the target optical fiber is located; The first temperature detection device is installed inside the temperature strain control box and close to the sensing unit; The strain application device is detachably connected to the target optical fiber; An image sensor, with its photosensitive surface facing the observation window, is used to acquire optical feature images of the target optical fiber surface. The optical feature images are processed to obtain the actual strain value of the target optical fiber. An optical fiber demodulator, wherein the optical fiber demodulator is connected to the pigtail of the target optical fiber; The control device is communicatively connected to the temperature control actuator, the first temperature detection device, the image sensor, and the fiber optic demodulator, respectively. The control device sends a temperature control command to the temperature control execution device. After the strain application device applies strain to the target optical fiber, when a preset condition is reached, the control device receives the target temperature sent by the first temperature detection device, the optical feature image of the target optical fiber surface sent by the image sensor, and the center wavelength value of the optical fiber sensor sent by the optical fiber demodulator. Based on the target temperature, the optical feature image, and the center wavelength value, the control device calculates the target temperature sensitivity coefficient and the target strain sensitivity coefficient of the optical fiber sensor.

2. The calibration device according to claim 1, characterized in that, The temperature strain control box is equipped with a heat-conducting plate. The temperature control actuator includes a TEC module and a water-cooling circulation module. The TEC module is connected to the water-cooling circulation module and is fixed on the heat-conducting plate. The TEC module is connected to a second temperature detection device. The control device is electrically connected to the second temperature detection device and the TEC module respectively.

3. The calibration device according to claim 1, characterized in that, The strain application device includes a first axial displacement adjustment device and a second axial displacement adjustment device. The first axial displacement adjustment device is provided with a first clamping structure, and the second axial displacement adjustment device is provided with a second clamping structure. The first clamping structure is detachably connected to one end of the target optical fiber, and the second clamping structure is detachably connected to the other end of the target optical fiber. The pigtail of the target optical fiber passing through one end of the second clamping structure is connected to the optical fiber demodulator.

4. The calibration device according to claim 3, characterized in that, The temperature strain control box has a first through hole and a second through hole on its opposite side walls. The target optical fiber passes through the first through hole and the second through hole. Both the first clamping structure and the second clamping structure include a base and a cover plate. The upper surface of the base is provided with a mounting groove that matches the target optical fiber. The cover plate is detachably connected to the base through a connector. The mounting groove is coaxially arranged with the first through hole and the second through hole. When the cover plate is locked with the base, both ends of the target optical fiber can be clamped in the corresponding mounting groove.

5. A calibration method for an optical fiber sensor, characterized in that, A control device for a calibration apparatus of a fiber optic sensor according to any one of claims 1 to 4, wherein the temperature control actuator includes a TEC module, the TEC module is connected to a second temperature detection device, the control device is electrically connected to the second temperature detection device and the TEC module respectively, and the calibration method includes: Acquire target combination data, wherein the target combination data includes m×n sets of observation data, and any set of observation data corresponds to a stable temperature-strain state. The observation data includes the actual strain value of the target optical fiber obtained by processing the optical feature image acquired by the image sensor, the first temperature acquired by the first temperature detection device, and the center wavelength value of the optical fiber sensor output by the optical fiber demodulator. The stable temperature-strain state indicates that the second temperature acquired by the second temperature detection device reaches the preset i-th level target temperature, the actual strain value of the target optical fiber reaches the preset j-th level target strain, and the first temperature and the actual strain value both satisfy the preset stability conditions, 1≤i≤m, 1≤j≤n, where n and m are positive integers greater than 1. Determine the offset data between the reference data and each group of observation data, and associate the offset data with the observation data of the corresponding group. The reference data includes the initial strain value of the target optical fiber, the initial temperature collected by the first temperature detection device, and the initial center wavelength value of the optical fiber sensor under the condition of no temperature control operation and strain loading operation. The offset data includes temperature offset, strain offset, and center wavelength offset. First target data is determined from all the offset data, and a temperature sensitivity coefficient is calculated based on the first temperature offset and the first center wavelength offset in the first target data, wherein the first strain offset in the first target data is less than a first threshold. The second target data is determined from all the offset data, and the strain sensitivity coefficient is calculated based on the second strain offset and the second center wavelength offset in the second target data, wherein the second temperature offset in the second target data is less than the second threshold. For any set of observation data corresponding to the offset data, the reference center wavelength offset is calculated based on the temperature sensitivity coefficient, the strain sensitivity coefficient, the temperature offset, and the strain offset. The validity index is calculated based on the reference center wavelength offset and the measured center wavelength offset in the offset data of the corresponding group. When the validity index meets the preset conditions, the temperature sensitivity coefficient is determined as the target temperature sensitivity coefficient, and the strain sensitivity coefficient is determined as the target strain sensitivity coefficient. The validity index is used to judge the validity of the temperature sensitivity coefficient and the strain sensitivity coefficient.

6. The calibration method according to claim 5, characterized in that, The control device corresponds to a temperature step sequence and a strain loading level sequence. The temperature step sequence includes i target temperature levels, and the strain loading level sequence includes j target strain levels. Acquiring the target combination data includes: Based on the temperature ladder sequence, each target temperature level is traversed sequentially, and the currently traversed target temperature level is used as the target temperature to generate a temperature control command, which is then sent to the TEC module. When the second temperature reaches the corresponding target temperature level, and the fluctuation range of the first temperature within a first preset time period is less than the first fluctuation threshold, it is determined that the first temperature meets the stability condition. Based on the strain loading level sequence, each target strain level is traversed sequentially, and the target optical fiber is subjected to strain loading operation through the strain application device so that the actual strain value of the target optical fiber reaches the target strain level currently traversed. The actual strain value is calculated based on a preset image processing algorithm, the current optical feature image, and a reference image. The optical feature image is acquired by the image sensor, and the reference image is the optical feature image of the target optical fiber in the state before strain loading operation. When the fluctuation amplitude of the actual strain value of the target optical fiber within a second preset time period is less than the second fluctuation threshold, it is determined that the actual strain value meets the stability condition, triggering the optical fiber demodulator to calculate the center wavelength value of the optical fiber sensor, the first temperature detection device to re-acquire a new first temperature, and the image sensor to re-acquire a new optical feature image of the target optical fiber surface, and calculate a new actual strain value based on the image processing algorithm, the new optical feature image and the reference image; The center wavelength value, the new first temperature, and the new actual strain value are determined as a set of observation data, and all the observation data obtained by traversing the temperature step sequence and the strain loading series sequence are determined as the target combination data.

7. The calibration method according to claim 5, characterized in that, The effectiveness index includes goodness of fit, which characterizes the degree of fit between the measured center wavelength offset and the reference center wavelength offset in any set of offset data. The effectiveness index is calculated based on the reference center wavelength offset and the measured center wavelength offset in the corresponding set of offset data. When the effectiveness index meets preset conditions, the temperature sensitivity coefficient is determined as the target temperature sensitivity coefficient, and the strain sensitivity coefficient is determined as the target strain sensitivity coefficient, including: Calculate the average of the center wavelength offset in the observation data for all groups; For any set of offset data, the goodness of fit is calculated based on the measured center wavelength offset, the average value, and the reference center wavelength offset. When the goodness of fit is greater than or equal to the third threshold, the temperature sensitivity coefficient is determined as the target temperature sensitivity coefficient, and the strain sensitivity coefficient is determined as the target strain sensitivity coefficient.

8. A control device, characterized in that, It includes at least one control processor and a memory for communicatively connecting to the at least one control processor; the memory stores instructions executable by the at least one control processor to enable the at least one control processor to perform the calibration method for the fiber optic sensor as described in any one of claims 5 to 7.

9. An electronic device, characterized in that, Includes the control device as described in claim 8.

10. A computer-readable storage medium, characterized in that, The computer-readable storage medium stores computer-executable instructions for causing a computer to perform the calibration method for the fiber optic sensor as described in any one of claims 5 to 7.

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