A sub-micron FBG strain sensor calibration device and method

Abstract

The present application relates to the technical field of strain sensor detection calibration, and particularly relates to a sub-micron FBG strain sensor calibration device and a calibration method. In terms of the calibration device, the first guiding clamping mechanism and the second guiding clamping mechanism realize synchronous displacement movement by relying on the guiding action of the first force bearing plate and the second force bearing plate respectively, the micro-displacement required for calibration operation is generated by changing the clamping interval of the first guiding clamping mechanism and the second guiding clamping mechanism, and combining the geometric constraint relationship of the first force bearing plate and the second force bearing plate fixed at a preset angle. During the calibration operation, the displacement detection mechanism collects real clamping interval change data of the first guiding clamping mechanism and the second guiding clamping mechanism in real time, the control mechanism dynamically corrects the output parameters of the micro-displacement driving part according to the real-time displacement feedback signal, realizes the sub-micron high-precision closed-loop control of the calibration displacement, and is beneficial to greatly improving the fitting accuracy of the wavelength parameters and the strain response parameters of the FBG strain sensor.

Description

Technical Field

[0001] This invention relates to the field of strain sensor testing and calibration technology, and in particular to a submicron-level FBG strain sensor calibration device and calibration method. Background Technology

[0002] According to industry testing standards and engineering application standards, FBG strain sensors must undergo systematic and precise strain calibration before leaving the factory and being put into use on-site to establish the correspondence between the change in the sensor's center wavelength and the actual strain. The accuracy of the sensor calibration parameters directly determines the accuracy and reliability of subsequent engineering monitoring data, and is a core prerequisite for ensuring the effectiveness of structural deformation monitoring and stress state assessment results.

[0003] Currently, mainstream FBG strain sensor calibration equipment in the industry generally adopts a theoretical deduction-based measurement method, which mainly uses the preset theoretical operating stroke of the drive component to indirectly calculate the tensile strain of the sensor. The strain values ​​of the entire calibration operation are derived entirely from programmed theoretical data such as motor operating parameters and the theoretical feed stroke of the lead screw.

[0004] Specifically, the FBG strain sensor calibration equipment is a precision mechanical system composed of multiple structures. During the assembly process, misalignment and cumulative assembly errors of parts inevitably occur in the lead screw drive, slide rail sliding, and various transmission connection structures. At the same time, during the long-term repetitive calibration operation, the various transmission and sliding structures will continuously generate wear and fit clearances, which cannot be completely eliminated by the initial static calibration method.

[0005] Due to the aforementioned inherent errors, the theoretical feed displacement set by the program always deviates from the actual tension displacement generated by the clamping mechanism. This ultimately leads to a significant deviation between the preset standard calibration strain value and the actual strain value applied to the FBG strain sensor body. Especially in high-precision calibration scenarios involving submicron-level micro-strain, minute mechanical deviations are significantly amplified, and the error superposition effect is further exacerbated, directly resulting in insufficient accuracy of core sensing parameters such as the sensor strain sensitivity coefficient and wavelength-strain fitting relationship obtained from the calibration.

[0006] Therefore, it is urgent for technical personnel to solve the above problems. Summary of the Invention

[0007] The purpose of this invention is to provide a submicron-level FBG strain sensor calibration device, which aims to solve the problem that existing calibration devices rely on the theoretical stroke of the drive to deduce strain values, and are prone to deviations between theoretical displacement and actual tension displacement due to inherent mechanical errors such as assembly deviations and structural wear.

[0008] This invention relates to a submicron-level FBG strain sensor calibration device, comprising a frame, a micro-displacement driving unit, a first guide clamping mechanism, a second guide clamping mechanism, a displacement detection mechanism, and a control mechanism; The frame includes a first load-bearing plate and a second load-bearing plate that are arranged at a preset angle to each other; The first guide clamping mechanism is slidably engaged with the first support plate, while the second guide clamping mechanism is slidably engaged with the second support plate; The first guide clamping mechanism and the second guide clamping mechanism work together to clamp the FBG strain sensor to be calibrated; The micro-displacement driving unit is used to drive the first guide clamping mechanism to perform synchronous displacement movement along the surface direction of the first support plate and the second guide clamping mechanism along the surface direction of the second support plate; The first guide clamping mechanism and the second guide clamping mechanism change the clamping distance through synchronous displacement movement, which, together with the preset angle between the first support plate and the second support plate, forms the calibration displacement required for the calibration of the FBG strain sensor. The displacement detection mechanism is used to detect the change in the horizontal clamping distance between the first guide clamping mechanism and the second guide clamping mechanism in real time; The control mechanism is electrically connected to the micro-displacement drive unit and the displacement detection unit respectively, and it uses the feedback signal from the displacement detection unit to perform closed-loop control of the micro-displacement drive unit, thereby achieving sub-micron level fine control of the calibration displacement of the FBG strain sensor.

[0009] As a further improvement to the technical solution disclosed in this invention, the submicron-level FBG strain sensor calibration device further includes a first guide assembly and a second guide assembly; the first guide assembly is assembled between the first support plate and the first guide clamping mechanism, and is used to guide and limit the displacement movement of the first guide clamping mechanism; the second guide assembly is assembled between the second support plate and the second guide clamping mechanism, and is used to guide and limit the displacement movement of the second guide clamping mechanism.

[0010] As a further improvement to the technical solution disclosed in this invention, the first guide assembly includes a first slide rail and a first slider; the first slide rail is fixedly mounted on a first support plate; the first slider is slidably mounted on the first slide rail and is fixedly connected to the first guide clamping mechanism; the second guide assembly includes a second slide rail and a second slider; the second slide rail is fixedly mounted on a second support plate; the second slider is slidably mounted on the second slide rail and is fixedly connected to the second guide clamping mechanism.

[0011] As a further improvement to the technical solution disclosed in this invention, the micro-displacement drive unit includes a mounting base, a geared motor, a synchronous belt transmission mechanism, a screw transmission lifting mechanism, and a force-applying beam; the mounting base is arranged directly above the frame and serves as the mounting foundation for the geared motor; the geared motor is connected to the synchronous belt transmission mechanism; the synchronous belt transmission mechanism is linked to the screw transmission mechanism; the output end of the screw transmission mechanism is connected to the force-applying beam; the force-applying beam is simultaneously connected to the first guide clamping mechanism and the second guide clamping mechanism to drive them to perform synchronous displacement motion.

[0012] As a further improvement to the technical solution disclosed in this invention, the micro-displacement driving unit also includes a third guide assembly for guiding and constraining the synchronous displacement motion of the first guide clamping mechanism and the second guide clamping mechanism; the third guide assembly includes a third slide rail, a left-positioned third slider and a right-positioned third slider; the third slide rail is fixedly mounted on the force-applying beam; the left-positioned third slider and the right-positioned third slider are slidably mounted on the third slide rail and are respectively fixedly connected to the first guide clamping mechanism and the second guide clamping mechanism in a one-to-one correspondence.

[0013] As a further improvement to the technical solution disclosed in this invention, the displacement detection mechanism includes a distance sensor; the detection end of the distance sensor is arranged facing the first guide clamping mechanism and the second guide clamping mechanism, and is used to collect data on the change of the horizontal clamping distance between the first guide clamping mechanism and the second guide clamping mechanism in real time at high frequency.

[0014] As a further improvement to the technical solution disclosed in this invention, the first guide clamping mechanism includes a first base and N sets of first clamps, and the second guide clamping mechanism includes a second base and N sets of second clamps, where N≥1; the first clamps are evenly distributed and assembled on the first base; the second clamps are evenly distributed and assembled on the second base; the first clamps and the second clamps are matched and matched one-to-one, and cooperate with each other to form a clamping position for clamping and fixing the FBG strain sensor.

[0015] As a further improvement to the technical solution disclosed in this invention, the first guide clamping mechanism further includes a first clamping force generating unit; the second guide clamping mechanism further includes a second clamping force generating unit; the first clamping force generating unit is assembled on the first base and is configured to cooperate with the corresponding first clamp; the second clamping force generating unit is assembled on the second base and is configured to cooperate with the corresponding second clamp; the first clamping force generating unit and the second clamping force generating unit respectively apply clamping external force to the corresponding first clamp and the second clamp to clamp and fix the FBG strain sensor in the corresponding clamping position.

[0016] As a further improvement to the technical solution disclosed in this invention, the frame also includes a first top-stop locking component and a second top-stop locking component; both the first top-stop locking component and the second top-stop locking component act between the first support plate and the second support plate to adjust and lock the included angle between the first support plate and the second support plate.

[0017] Furthermore, the present invention also discloses a calibration method for an FBG strain sensor, which is implemented by means of the aforementioned submicron-level FBG strain sensor calibration equipment; The calibration method for FBG strain sensors includes the following steps: S1. According to the calibration test requirements, adjust the first and second support plates of the frame to the preset calibration angle and complete the locking and positioning to construct the tilt calibration conditions required for this calibration. S2. Place both ends of the FBG strain sensor to be calibrated into the clamping positions of the first guide clamping mechanism and the second guide clamping mechanism, respectively, and clamp them with force. S3. The initial horizontal clamping distance between the first guide clamping mechanism and the second guide clamping mechanism is detected by the displacement detection mechanism, and the detection data is fed back to the control mechanism to complete the calibration and zeroing of the calibration reference parameters; S4. The control mechanism regulates the operation of the micro-displacement drive unit, drives the first guide clamping mechanism and the second guide clamping mechanism to move synchronously, so as to change the clamping distance between the first guide clamping mechanism and the second guide clamping mechanism, and apply tensile displacement to the FBG strain sensor to be calibrated. S5. The displacement detection mechanism continuously collects the dynamic change of the horizontal clamping distance between the first guide clamping mechanism and the second guide clamping mechanism, and feeds it back to the control mechanism; the control mechanism corrects the drive parameters and calculates the wavelength parameters and strain response parameters of the FBG strain sensor to be calibrated based on the displacement data. S6. Adjust the preset angle between the first and second load-bearing plates, and repeat steps S1-S5 to complete the calibration of the FBG strain sensor under multiple angle conditions.

[0018] Regarding the calibration equipment for submicron-level FBG strain sensors, it can achieve at least the following beneficial technical effects in practical applications, specifically: 1) A structural layout is adopted in which the first and second support plates are inclined at a preset angle. The first and second guide clamping mechanisms can perform synchronous displacement movements based on the guiding action of the first and second support plates, respectively. During the calibration operation, the synchronous displacement of the first and second guide clamping mechanisms changes the clamping distance. Based on the geometric constraint relationship of the fixed preset angle between the first and second support plates, the calibration displacement required for the submicron-level FBG strain sensor calibration operation is coupled to construct a stable deformation condition suitable for the tension calibration of the FBG strain sensor. 2) The displacement detection mechanism and the control mechanism constitute a closed-loop control system, using actual physical displacement data as the sole measurement benchmark to complete the strain parameter conversion of the FBG strain sensor. The displacement detection mechanism collects the real clamping distance change between the first and second guide clamping mechanisms in real time. The control mechanism dynamically corrects and compensates the output parameters of the micro-displacement drive unit based on the real-time displacement feedback signal, ensuring that the calibrated displacement value completely corresponds to the actual tension displacement value. This achieves sub-micron level fine control of the calibrated displacement, which helps improve the fitting accuracy between the wavelength parameters and strain response parameters of the FBG strain sensor.

[0019] Regarding the FBG strain sensor calibration method, by switching the preset angle between the first and second support plates and iteratively repeating the complete calibration process, calibration operations under various tilting stress conditions are completed in an orderly manner. This comprehensively covers the actual response characteristics of the FBG strain sensor under various actual stress angles and multiple tension states, closely matching the complex stress scenarios in actual FBG strain sensor applications. This facilitates the collection of strain response data from the FBG strain sensor under different working conditions. Furthermore, relying on multi-dimensional, multi-condition calibration data, the fitting accuracy between the wavelength parameters and strain response parameters of the FBG strain sensor is optimized and improved to restore the actual working response law of the FBG strain sensor, ultimately achieving sub-micron level high-precision, standardized calibration operations for FBG strain sensors. Attached Figure Description

[0020] To more clearly illustrate the technical solutions in the embodiments of the present invention or the prior art, the drawings used in the description of the embodiments or the prior art will be briefly introduced below. Obviously, the drawings described below are only some embodiments of the present invention. For those skilled in the art, other drawings can be obtained based on these drawings without creative effort.

[0021] Figure 1 This is a three-dimensional schematic diagram from one perspective of the submicron-level FBG strain sensor calibration device disclosed in this invention.

[0022] Figure 2 This is a three-dimensional schematic diagram from another perspective of the submicron-level FBG strain sensor calibration device disclosed in this invention.

[0023] Figure 3 This is a three-dimensional schematic diagram of the frame in the submicron-level FBG strain sensor calibration device disclosed in this invention, taken from one perspective.

[0024] Figure 4 This is a three-dimensional schematic diagram of the frame in the submicron-level FBG strain sensor calibration device disclosed in this invention from another perspective.

[0025] Figure 5 This is a three-dimensional schematic diagram of the micro-displacement drive unit in the submicron-level FBG strain sensor calibration device disclosed in this invention.

[0026] Figure 6 yes Figure 5 The front view.

[0027] Figure 7 This is a three-dimensional schematic diagram from one perspective of the first guide clamping mechanism in the submicron-level FBG strain sensor calibration device disclosed in this invention.

[0028] Figure 8 This is a three-dimensional schematic diagram from another perspective of the first guide clamping mechanism in the submicron-level FBG strain sensor calibration device disclosed in this invention.

[0029] Figure 9 This is a three-dimensional schematic diagram from one perspective of the second guide clamping mechanism in the submicron-level FBG strain sensor calibration device disclosed in this invention.

[0030] Figure 10 This is a three-dimensional schematic diagram from another perspective of the second guide clamping mechanism in the submicron-level FBG strain sensor calibration device disclosed in this invention.

[0031] Figure 11 This is a physical image of the submicron-level FBG strain sensor calibration device disclosed in this invention.

[0032] Figure 12 This is a calibration certificate generated after the calibration work is completed using the disclosed FBG strain sensor calibration method of this invention.

[0033] 1-Frame; 11-First support plate; 12-Second support plate; 13-First top-stop locking assembly; 131-First guide rod; 132-Left-positioned first top-stop sleeve; 133-Right-positioned first top-stop sleeve; 14-Second top-stop locking assembly; 141-Second guide rod; 142-Left-positioned second top-stop sleeve; 143-Right-positioned second top-stop sleeve; 15-First guide assembly; 151-First slide rail; 152-First slider; 16-Second guide assembly; 161-Second slide rail; 162-Second slider; 2-Micro-displacement drive unit; 21-Mounting base; 22-Gear motor; 23 - Synchronous belt drive mechanism; 24- Screw drive lifting mechanism; 25- Force application beam; 26- Third guide assembly; 261- Third slide rail; 262- Left-positioned third slider; 263- Right-positioned third slider; 3- First guide clamping mechanism; 31- First base; 32- First clamp; 33- First clamping force generating unit; 331- First cylinder; 332- First wedge expansion assembly; 4- Second guide clamping mechanism; 41- Second base; 42- Second clamp; 43- Second clamping force generating unit; 431- Second cylinder; 432- Second wedge expansion assembly. Detailed Implementation

[0034] The technical solution of the present invention will be further described in detail below with reference to specific embodiments and accompanying drawings. Figure 1 , Figure 2 Two perspective views of the submicron-level FBG strain sensor calibration device disclosed in this invention are shown. It is evident that the device mainly consists of a frame 1, a micro-displacement drive unit 2, a first guide clamping mechanism 3, a second guide clamping mechanism 4, a displacement detection mechanism (not shown), and a control mechanism (not shown). The frame 1 serves as the supporting structure for the entire device. The micro-displacement drive unit 2 is fixedly mounted on the top of the frame 1, positioned above the first guide clamping mechanism 3 and the second guide clamping mechanism 4. The first guide clamping mechanism 3 is slidably mounted on the left side of the frame 1, while the second guide clamping mechanism 4 is slidably mounted on the right side. The displacement detection mechanism is primarily a distance sensor, fixedly mounted on the first guide clamping mechanism 3, with its detection end facing the side detection reference surface of the second guide clamping mechanism 4. The control mechanism establishes electrical signal connections with the micro-displacement drive unit 2 and the distance sensor to achieve automated drive, real-time data acquisition, and closed-loop precise control of the device.

[0035] like Figure 3 , Figure 4 As shown, the frame 1 mainly consists of several parts, including a first support plate 11, a second support plate 12, a first top-stop locking assembly 13, a second top-stop locking assembly 14, a first guide assembly 15, and a second guide assembly 16. The first support plate 11 and the second support plate 12 form the main load-bearing structure of the frame 1, and are arranged at a preset angle relative to each other. The first top-stop locking assembly 13 and the second top-stop locking assembly 14 are assembled between the first support plate 11 and the second support plate 12 to adjust and lock the angle between them, thereby changing the displacement scaling factor. The first guide assembly 15 and the second guide assembly 16 are respectively assembled on the surface of the first support plate 11 and the second support plate 12, providing tilt guidance for the sliding movements of the first guide clamping mechanism 3 and the second guide clamping mechanism 4, respectively.

[0036] The first abutment locking assembly 13 consists of a first smooth rod 131, a left-positioned first abutment sleeve 132, and a right-positioned first abutment sleeve 133. Both the left-positioned first abutment sleeve 132 and the right-positioned first abutment sleeve 133 are fitted onto the first smooth rod 131; the left-positioned first abutment sleeve 132 is nested and fixed to the first support plate 11, and the right-positioned first abutment sleeve 133 is nested and fixed to the second support plate 12. The second abutment locking assembly 14 consists of a second smooth rod 141, a left-positioned second abutment sleeve 142, and a right-positioned second abutment sleeve 143. Both the left-positioned second abutment sleeve 142 and the right-positioned second abutment sleeve 143 are fitted onto the second smooth rod 141; the left-positioned second abutment sleeve 142 is nested and fixed to the first support plate 11, and the right-positioned second abutment sleeve 143 is nested and fixed to the second support plate 12.

[0037] During the specific debugging and angle adjustment process, the operator first loosens the locking screws on the left first top abutment sleeve 132, the right first top abutment sleeve 133, the left second top abutment sleeve 142, and the right second top abutment sleeve 143 (such as...). Figure 11 As shown in the diagram, the left first abutment sleeve 132 and the right first abutment sleeve 133 can slide freely along the first smooth rod 131, and the left second abutment sleeve 142 and the right second abutment sleeve 143 can slide freely along the second smooth rod 141. The operator adjusts the relative distance between the left first abutment sleeve 132 and the right first abutment sleeve 133 along the axis of the first smooth rod 131, and simultaneously adjusts the relative distance between the left second abutment sleeve 142 and the right second abutment sleeve 143 along the axis of the second smooth rod 141, thereby achieving precise control of the tilt angle between the first support plate 11 and the second support plate 12. After adjusting the angle parameters to the preset standard, tighten the locking screws on the left first top abutment sleeve 132, the right first top abutment sleeve 133, the left second top abutment sleeve 142 and the right second top abutment sleeve 143 to lock their respective assembly positions, fix the relative tilt angle between the first support plate 11 and the second support plate 12, and ensure the stability of the geometric working condition of the frame 1 during the calibration operation.

[0038] It should be noted that the operator only needs to fine-tune the axial assembly position of the left first top abutment sleeve 132, the right first top abutment sleeve 133, the left second top abutment sleeve 142 and the right second top abutment sleeve 143 to continuously and steplessly change the opening angle of the first support plate 11 and the second support plate 12. It has the characteristics of high angle adjustment accuracy, convenient operation and reliable and fast locking.

[0039] Similarly, Figure 3 , Figure 4As shown, the first guide assembly 15 consists of a first slide rail 151 and a first slider 152. The first slide rail 151 is fixedly installed on the first support plate 11; the first slider 152 is slidably engaged with the first slide rail 151 and is used to directly support the first guide clamping mechanism 3, providing inclined sliding guidance for the first guide clamping mechanism 3. The second guide assembly 16 consists of a second slide rail 161 and a second slider 162. The second slide rail 161 is fixedly installed on the second support plate 12; the second slider 162 is slidably engaged with the second slide rail 161 and is used to directly support the second guide clamping mechanism 4, providing inclined sliding guidance for the second guide clamping mechanism 4, ensuring that the sliding process of the first guide clamping mechanism 3 and the second guide clamping mechanism 4 is smooth, without jamming or swaying.

[0040] The inclined geometric relationship between the first support plate 11 and the second support plate 12 constitutes a displacement scaling mechanism. The first guide clamping mechanism 3 and the second guide clamping mechanism 4 perform synchronous sliding motion along the inclined guide trajectories of the first guide component 15 and the second guide component 16, respectively. Relying on the inclined geometric constraint of the first support plate 11 and the second support plate 12, the macroscopic step displacement output by the conventional drive mechanism is converted into the submicron-level micro-displacement required for the calibration of the FBG strain sensor, effectively solving the industry technical problem that micro-displacements cannot be directly and accurately applied.

[0041] After receiving the calibration command input by the operator, the control mechanism drives the micro-displacement drive unit 2 to output a vertical linear driving force, which is stably transmitted to the first guide clamping mechanism 3 and the second guide clamping mechanism 4. Under the limiting and guiding action of the first guide component 15 and the second guide component 16, the driving force is converted into a synchronous outward sliding motion of the first guide clamping mechanism 3 and the second guide clamping mechanism 4 along an inclined guide trajectory. During the calibration operation, the distance sensor collects the physical data of the change in the horizontal distance between the first guide clamping mechanism 3 and the second guide clamping mechanism 4 in real time and continuously feeds the real-time detection data back to the control mechanism. By comparing the difference between the preset target displacement and the measured displacement of the equipment, the control mechanism corrects the output parameters of the micro-displacement drive unit 2 in a closed loop, ultimately realizing the sub-micron level tensile calibration operation of the FBG strain sensor.

[0042] like Figure 5 , Figure 6 As shown, the micro-displacement drive unit 2 serves as a power output unit, specifically including a mounting base 21, a geared motor 22, a synchronous belt drive mechanism 23, a lead screw drive lifting mechanism 24, a force-applying beam 25, and a third guide assembly 26. The third guide assembly 26 comprises a third slide rail 261, a left-positioned third slider 262, and a right-positioned third slider 263.

[0043] Mounting base 21 is fixedly mounted on the top of frame 1, providing fixed support for each drive component. Gear motor 22 is fixedly mounted on mounting base 21, used to output stable and controllable rotational power. Synchronous belt drive mechanism 23 connects to the output end of gear motor 22, smoothly transmitting rotational power to screw drive lifting mechanism 24. Screw drive lifting mechanism 24 converts rotational motion into vertical linear motion with high precision, driving the force-applying beam 25 to descend smoothly in the vertical direction. The third guide assembly 26 constrains the movement trajectory of the force-applying beam 25 throughout its descent via the third slide rail 261, the left-positioned third slider 262, and the right-positioned third slider 263, preventing swaying and shaking during the descent and ensuring the coaxiality and stability of the power output. When the force-applying beam 25 descends, it synchronously pushes the first guide clamping mechanism 3 and the second guide clamping mechanism 4 to slide synchronously in opposite directions along the inclined guide trajectory of the first guide assembly 15 and the second guide assembly 16, completing the sensor stretching action.

[0044] like Figure 7 , Figure 8 As shown, the first guide clamping mechanism 3 includes a first base 31, four sets of first clamps 32, and a first clamping force generating unit 33. The first clamping force generating unit 33 includes a first cylinder 331 and a first wedge-shaped expansion assembly 332.

[0045] The first base 31 serves as the main load-bearing structure, with four sets of first clamps 32 symmetrically arranged on its front and rear sidewalls, forming a double-row, four-position synchronous clamping structure. Each set of first clamps 32 is equipped with a V-shaped positioning groove and an optical fiber clearance groove to match the shape of the FBG strain sensor and achieve centering and positioning. The first cylinder 331 is internally installed inside the first base 31 and achieves lever-linked synchronous clamping drive through the first wedge-shaped expansion assembly 332. During operation, the first cylinder 331 extends and retracts, driving the first wedge-shaped expansion assembly 332 to move. The first wedge-shaped expansion assembly 332 simultaneously pushes the movable grippers of the four sets of first clamps 32 to close synchronously, completing the uniform clamping and fixing of the four sensors in one operation.

[0046] like Figure 9 , Figure 10 As shown, the second guide clamping mechanism 4 is arranged in a completely symmetrical structure with the first guide clamping mechanism 3, including a second base 41, four sets of second clamps 42, and a second clamping force generating unit 43. The second clamping force generating unit 43 includes a second cylinder 431 and a second wedge-shaped expansion assembly 432.

[0047] Four sets of second clamps 42 correspond one-to-one with four sets of first clamps 32, forming four parallel and independent sensor calibration clamping stations. During calibration, the first cylinder 331 and the second cylinder 431 operate synchronously. The first cylinder 331 drives the first clamp 32 to clamp through the first wedge-shaped expansion assembly 332, and the second cylinder 431 drives the second clamp 42 to clamp through the second wedge-shaped expansion assembly 432. This ensures that the FBG strain sensor is horizontally tensioned and clamped between the corresponding first clamp 32 and second clamp 42. The sensor axis is strictly aligned with the direction of horizontal tensile displacement, ensuring that the tensile displacement is vertical and accurately transmitted without angular deviation or lateral stress interference.

[0048] During equipment calibration, the control mechanism employs a fully closed-loop PID control mode. Distance sensors continuously collect real-time data on the actual horizontal distance between the first guide clamping mechanism 3 and the second guide clamping mechanism 4, feeding this data back to the control mechanism. The control mechanism compares the measured displacement with the preset target displacement in real time, dynamically correcting the operating parameters of the reduction motor 22 using a PID algorithm. This process compensates for system errors such as lead screw backlash, cumulative assembly errors, and minor structural deformations, significantly improving displacement control accuracy and calibration repeatability.

[0049] This invention also discloses a calibration method for submicron-level FBG strain sensors. This method is implemented using the aforementioned calibration equipment and can achieve automated calibration with multiple stations, high precision, and multiple operating conditions. The specific steps are as follows: S1. According to the range and accuracy parameters of the FBG strain sensor to be calibrated, adjust the first top-stop locking assembly 13 and the second top-stop locking assembly 14, accurately set the preset tilt angle between the first support plate 11 and the second support plate 12, and after adjustment, tighten the locking screws of the left first top-stop sleeve 132, the right first top-stop sleeve 133, the left second top-stop sleeve 142 and the right second top-stop sleeve 143 to fix the tilt geometry parameters of the frame 1 and determine the displacement scaling factor.

[0050] S2. Place the four FBG strain sensors to be calibrated into the V-shaped positioning slots of the four clamping stations respectively, and arrange the fiber optic leads and place them in the fiber optic clearance slots. Activate the first clamping force generating unit 33 and the second clamping force generating unit 43 to complete the synchronous and uniform clamping and fixing of the four sensors.

[0051] S3. After the equipment is stationary and stable, the initial horizontal clamping distance between the first guide clamping mechanism 3 and the second guide clamping mechanism 4 is detected and collected by the distance sensor. This initial value is used as the calibration reference zero point and fed back to the control mechanism.

[0052] S4. By inputting the calibration tensile parameters through the control mechanism, the micro-displacement drive unit 2 is started. The reduction motor 22 drives the force-applying beam 25 downward through the synchronous belt transmission mechanism 23 and the screw transmission lifting mechanism 24. This drives the first guide clamping mechanism 3 and the second guide clamping mechanism 4 to slide synchronously in opposite directions along the inclined guide trajectory of the first guide component 15 and the second guide component 16, so as to accurately change the horizontal clamping distance and apply a preset gradient tensile load to the FBG strain sensor.

[0053] S5. During the stretching process, the distance sensor collects the changes in the horizontal clamping distance between the first guide clamping mechanism 3 and the second guide clamping mechanism 4 in real time throughout the process and transmits the data back to the control mechanism. The control mechanism dynamically closes the loop to correct the driving parameters of the micro-displacement drive unit 2 to ensure the accuracy of the displacement output. Simultaneously, the wavelength drift data of each FBG strain sensor is collected, the strain response parameters of the FBG strain sensor are calculated, and the strain-wavelength sensing characteristic equation of the FBG strain sensor under the current angle condition is obtained by fitting.

[0054] S6. Gradually adjust the angle between the first support plate 11 and the second support plate 12, changing the displacement scaling factor. Repeat steps S1 to S5 to complete the sensor calibration work under multiple scaling factors and multiple working conditions. Integrate all calibration data and generate a compliant and valid sensor calibration certificate (e.g., ...). Figure 12 (As shown in the figure) to complete the overall calibration process.

[0055] The above description of the disclosed embodiments enables those skilled in the art to make or use the invention. Various modifications to these embodiments will be readily apparent to those skilled in the art, and the general principles defined herein may be implemented in other embodiments without departing from the spirit or scope of the invention. Therefore, the invention is not to be limited to the embodiments shown herein, but is to be accorded the widest scope consistent with the principles and novel features disclosed herein.

Claims

1. A calibration device for a submicron-level FBG strain sensor, characterized in that, It includes a frame, a micro-displacement drive unit, a first guide clamping mechanism, a second guide clamping mechanism, a displacement detection mechanism, and a control mechanism; The frame includes a first load-bearing plate and a second load-bearing plate that are arranged at a preset angle relative to each other; The first guide clamping mechanism is slidably engaged with the first support plate, while the second guide clamping mechanism is slidably engaged with the second support plate; The first guide clamping mechanism and the second guide clamping mechanism work together to clamp the FBG strain sensor to be calibrated; The micro-displacement driving unit is used to drive the first guide clamping mechanism to perform synchronous displacement movement along the surface direction of the first support plate and the second guide clamping mechanism to perform synchronous displacement movement along the surface direction of the second support plate; The first guide clamping mechanism and the second guide clamping mechanism change the clamping distance through synchronous displacement movement, which, together with the preset angle between the first support plate and the second support plate, forms the calibration displacement required for the calibration of the FBG strain sensor; The displacement detection mechanism is used to detect the change in the horizontal clamping distance between the first guide clamping mechanism and the second guide clamping mechanism in real time; The control mechanism is electrically connected to the micro-displacement drive unit and the displacement detection mechanism respectively, and it controls the micro-displacement drive unit in a closed loop according to the feedback signal of the displacement detection mechanism to achieve sub-micron level fine control of the calibration displacement of the FBG strain sensor.

2. The submicron-level FBG strain sensor calibration device according to claim 1, characterized in that, It also includes a first guide component and a second guide component; the first guide component is assembled between the first support plate and the first guide clamping mechanism, and is used to guide and limit the displacement movement of the first guide clamping mechanism; the second guide component is assembled between the second support plate and the second guide clamping mechanism, and is used to guide and limit the displacement movement of the second guide clamping mechanism.

3. The submicron-level FBG strain sensor calibration device according to claim 2, characterized in that, The first guide assembly includes a first slide rail and a first slider; the first slide rail is fixedly mounted on the first support plate; the first slider is slidably mounted on the first slide rail and is fixedly connected to the first guide clamping mechanism; the second guide assembly includes a second slide rail and a second slider; the second slide rail is fixedly mounted on the second support plate; the second slider is slidably mounted on the second slide rail and is fixedly connected to the second guide clamping mechanism.

4. The submicron-level FBG strain sensor calibration device according to claim 1, characterized in that, The micro-displacement drive unit includes a mounting base, a geared motor, a synchronous belt drive mechanism, a lead screw drive lifting mechanism, and a force-applying beam. The mounting base is located directly above the frame and serves as the mounting foundation for the geared motor. The geared motor is connected to the synchronous belt drive mechanism. The synchronous belt drive mechanism is linked to the lead screw drive mechanism. The output end of the lead screw drive mechanism is connected to the force-applying beam. The force-applying beam is also connected to the first guide clamping mechanism and the second guide clamping mechanism to drive them to perform synchronous displacement movements.

5. The submicron-level FBG strain sensor calibration device according to claim 4, characterized in that, The micro-displacement driving unit further includes a third guide assembly for guiding and constraining the synchronous displacement motion of the first guide clamping mechanism and the second guide clamping mechanism; the third guide assembly includes a third slide rail, a left-positioned third slider, and a right-positioned third slider; the third slide rail is fixedly mounted on the force-applying beam; the left-positioned third slider and the right-positioned third slider are slidably mounted on the third slide rail, and are respectively fixedly connected to the first guide clamping mechanism and the second guide clamping mechanism in a one-to-one correspondence.

6. The submicron-level FBG strain sensor calibration device according to claim 1, characterized in that, The displacement detection mechanism includes a distance sensor; the detection end of the distance sensor is arranged facing the first guide clamping mechanism and the second guide clamping mechanism, and is used to collect data on the change of the horizontal clamping distance between the first guide clamping mechanism and the second guide clamping mechanism in real time at high frequency.

7. The submicron-level FBG strain sensor calibration device according to claim 1, characterized in that, The first guide clamping mechanism includes a first base and N sets of first clamps, and the second guide clamping mechanism includes a second base and N sets of second clamps, where N≥1; the first clamps are evenly distributed and assembled on the first base; the second clamps are evenly distributed and assembled on the second base; the first clamps and the second clamps are matched and matched one-to-one, and cooperate with each other to form a clamping position for clamping and fixing the FBG strain sensor.

8. The submicron-level FBG strain sensor calibration device according to claim 7, characterized in that, The first guide clamping mechanism further includes a first clamping force generating unit; the second guide clamping mechanism further includes a second clamping force generating unit; the first clamping force generating unit is assembled on the first base and is configured to cooperate with the corresponding first clamp; the second clamping force generating unit is assembled on the second base and is configured to cooperate with the corresponding second clamp; the first clamping force generating unit and the second clamping force generating unit respectively apply clamping external force to the corresponding first clamp and the second clamp to clamp and fix the FBG strain sensor in the corresponding clamping position.

9. The submicron-level FBG strain sensor calibration device according to claim 1, characterized in that, The frame also includes a first abutment locking component and a second abutment locking component; both the first abutment locking component and the second abutment locking component act between the first support plate and the second support plate to adjust and lock the included angle between the first support plate and the second support plate.

10. A calibration method for an FBG strain sensor, characterized in that, This is achieved using the submicron-level FBG strain sensor calibration device as described in any one of claims 1-9; The FBG strain sensor calibration method includes the following steps: S1. According to the calibration test requirements, adjust the first support plate and the second support plate of the frame to the preset calibration angle, and complete the locking and positioning to construct the tilt calibration condition required for this calibration. S2. Place both ends of the FBG strain sensor to be calibrated into the clamping positions of the first guide clamping mechanism and the second guide clamping mechanism, respectively, and clamp them with force. S3. The initial horizontal clamping distance between the first guide clamping mechanism and the second guide clamping mechanism is detected by the displacement detection mechanism, and the detection data is fed back to the control mechanism to complete the calibration and zeroing of the calibration reference parameters; S4. The control mechanism regulates the operation of the micro-displacement drive unit, drives the first guide clamping mechanism and the second guide clamping mechanism to move synchronously, so as to change the clamping distance between the first guide clamping mechanism and the second guide clamping mechanism, and apply tensile displacement to the FBG strain sensor to be calibrated. S5. The displacement detection mechanism continuously collects the dynamic change of the horizontal clamping distance between the first guide clamping mechanism and the second guide clamping mechanism, and feeds it back to the control mechanism; the control mechanism corrects the driving parameters and calculates the wavelength parameters and strain response parameters of the FBG strain sensor to be calibrated based on the displacement data. S6. Adjust the preset angle between the first load-bearing plate and the second load-bearing plate, and repeat steps S1-S5 to complete the calibration of the FBG strain sensor under multiple angle conditions.

Images