Strain gauge based on optical fiber MEMS technology

Abstract

The utility model relates to a strain gauge based on optical fiber MEMS technology, which comprises a first extrusion fixing column, a second extrusion fixing column, a first deformation beam and a support connecting plate, the first deformation beam and the support connecting plate are arranged between the first extrusion fixing column and the second extrusion fixing column, the first deformation beam comprises a first vertical plate, a second vertical plate and a first transverse plate, and a semi-arc notch on the second vertical plate is concentric with a 1 / 4 arc on the support connecting plate and is connected with the 1 / 4 arc on the support connecting plate. A collimator with an optical fiber is arranged on the supporting connecting plate, and the light emitting side of the collimator is aligned with the MEMS chip forming an included angle with the second vertical plate. Based on the advantages of high resolution and high precision of the optical fiber MEMS, the strain gauge basically has no deformation lag, can monitor infinitesimal displacement so as to provide reliable data support, is not interfered by electromagnetic radiation and temperature change, and can stably work for a long time in an environment with strong electromagnetic radiation and large temperature difference change.

Description

Technical Field

[0001] This utility model relates to the field of optical sensing technology, and in particular to a strain gauge based on fiber optic MEMS technology. Background Technology

[0002] Currently, the main types of strain gauges built into anchor bolt sensors are vibrating wire strain gauges, resistance strain gauges, and fiber optic strain gauges. However, vibrating wire strain gauges and resistance strain gauges have weak electromagnetic interference resistance and relatively low accuracy, while fiber optic strain gauges exhibit significant signal variation with temperature, severe zero drift during long-term monitoring, and significant lag in the rebound process, requiring periodic calibration and making them unsuitable for long-term observation.

[0003] Chinese patent application CN115560682B discloses a displacement measuring device and its manufacturing method. The device includes a left fixed support and a right fixed support, which are mounted on the surface of the target object. A support beam is positioned between the left and right fixed supports. The support beam comprises a left support beam, a right support beam, and a top support beam positioned between the left and right support beams. A cantilever beam is mounted on the left support beam, with a blazed grating chip at the end of the cantilever beam furthest from the left support beam. A collimation unit is positioned below the top support beam. The collimation unit receives the light source signal on its incident side and outputs the collimated light source signal to the blazed grating chip on its emitting side. This solution can capture minute displacements of the measured object, achieving displacement changes from nanometer to millimeter level. It exhibits high sensitivity and high precision, and is applicable to a wide range of scenarios. The blazed grating chip involved is a MEMS chip, which is an integrated chip using microelectromechanical processing technology. It utilizes the Fabry-Perot interferometry (FP) principle to convert pressure changes into changes in the length of the FP sensitive cavity inside the sensor. This makes it suitable for high-voltage, strong electromagnetic interference, highly corrosive, flammable, explosive, and highly disturbed environments. However, this type of strain gauge is mainly used to measure deformation by fixing it to the surface of the object being measured. In contrast, the strain gauge built into a typical anchor bolt sensor primarily uses the compression deformation along the length of the anchor bolt to provide feedback. This type of strain gauge clearly cannot meet practical requirements. Utility Model Content

[0004] Therefore, the technical problem to be solved by this utility model is to overcome the lack of a strain gauge in the prior art that is suitable for anchor cable sensors and has strong anti-electromagnetic interference capability, high accuracy, and strong environmental adaptability.

[0005] To solve the above-mentioned technical problems, this utility model provides a strain gauge based on fiber optic MEMS technology, comprising:

[0006] First compression fixing column;

[0007] The first deformable beam includes a first horizontal plate, a first vertical plate, and a second vertical plate. The bottom end of the first vertical plate is connected to the first extrusion fixing column. One end of the first horizontal plate is connected to the top end of the first vertical plate. The top end of the second vertical plate is connected to the end of the first horizontal plate away from the first vertical plate. A MEMS chip is disposed on the middle part of the second vertical plate away from the first vertical plate. The MEMS chip and the second vertical plate are at an angle. A semi-circular arc notch is disposed at the bottom end of the second vertical plate. The semi-circular arc notch is disposed on the same side as the MEMS chip.

[0008] A supporting connecting plate, one end of which is connected to the bottom end of the second vertical plate, and the end of the supporting connecting plate connected to the second vertical plate is provided with a 1 / 4 circular arc notch, the center of the 1 / 4 circular arc notch being concentric with the center of the semi-circular arc notch;

[0009] A collimator is disposed in the middle of the support connecting plate. The collimator is cylindrical and has a first through hole at its axis. An optical fiber is inserted at one end of the first through hole, and the other end of the first through hole is aligned with the MEMS chip.

[0010] The second compression fixing column is connected to the end of the support connecting plate away from the second vertical plate, and the second compression fixing column is concentrically arranged with the first compression fixing column.

[0011] In one embodiment of the present invention, a chip holder is provided in the middle of the second vertical plate, and an inclined surface is provided at the end of the chip holder away from the second vertical plate, and the MEMS chip is attached to the inclined surface.

[0012] In one embodiment of the present invention, a collimator mounting base is provided in the middle of the supporting connecting plate, and the collimator passes through the collimator mounting base.

[0013] In one embodiment of the present invention, a waist-shaped connecting block is provided at the bottom of the collimator mounting base, and a waist-shaped hole is provided on the support connecting plate, and the waist-shaped connecting block is engaged in the waist-shaped hole.

[0014] In one embodiment of this utility model, the cross-section of the collimator mounting base is horseshoe-shaped, and the collimator mounting base is provided with a second through hole along the length direction, the diameter of the second through hole being the same as the outer diameter of the collimator.

[0015] In one embodiment of the present invention, the collimator is further provided with a plurality of welding holes along its length, and the plurality of welding holes are all connected to the second through hole.

[0016] In one embodiment of the present invention, a third vertical plate is provided at the end of the supporting connecting plate away from the second vertical plate, and the third vertical plate is connected to the second compression fixing column.

[0017] In one embodiment of the present invention, the first compression fixing column is provided with a first limiting installation notch at the end away from the first vertical plate, and the second compression fixing column is provided with a second limiting installation notch at the end away from the supporting connecting plate.

[0018] In one embodiment of this utility model, both the first deformable beam and the supporting connecting plate are made of 40CrNiMo material.

[0019] The above-mentioned technical solution of this utility model has the following advantages compared with the prior art:

[0020] This strain gauge based on fiber optic MEMS technology uses a first and second compression fixing post to connect the pressure point inside the anchor sensor. Initially, the angle between the MEMS chip and the beam emitted from the optical fiber on the collimator is calibrated to 0°. When the strain gauge is deformed by compression, the semi-circular arc segment on the first vertical plate and the quarter-circular arc segment on the supporting connecting plate, together with the MEMS chip fixed on the first deformation beam, act as the second deformation beam. The collimator is fixed on the supporting connecting plate, causing a linear change in the angle between the MEMS chip and the beam emitted from the optical fiber. The light source, through the optical fiber and collimator, is directed to the reflective surface of the fiber optic MEMS chip, generating a reflected beam that returns along its original path. Calibration is performed by the demodulator at the back end of the optical fiber, and the deformation and force of the external structure can be calculated using the reflected light wavelength. This strain gauge leverages the high resolution and high precision advantages of fiber optic MEMS, exhibits virtually no deformation hysteresis, can monitor minute displacements to provide reliable data support, and is unaffected by electromagnetic radiation and temperature changes, allowing for long-term stable operation in environments with strong electromagnetic radiation and large temperature variations. Attached Figure Description

[0021] To make the content of this utility model easier to understand, the present utility model will be further described in detail below with reference to specific embodiments and accompanying drawings.

[0022] Figure 1 This is a schematic diagram of the overall structure of the strain gauge based on fiber optic MEMS technology of this utility model;

[0023] Figure 2 for Figure 1 The image shows a top view of a strain gauge based on fiber optic MEMS technology.

[0024] Figure 3 for Figure 1The diagram shows the overall structure of a strain gauge based on fiber optic MEMS technology, excluding the collimator and MEMS chip.

[0025] Figure 4 for Figure 1 The diagram shows the overall structure of the collimator mounting base in a strain gauge based on fiber optic MEMS technology.

[0026] Explanation of reference numerals in the accompanying drawings: 1. First extrusion fixing post; 110. First limiting installation notch; 2. First deformation beam; 210. First horizontal plate; 220. First vertical plate; 230. Second vertical plate; 231. Semi-circular arc notch; 240. MEMS chip; 3. Support connecting plate; 310. 1 / 4 arc notch; 320. Waist-shaped hole; 330. Second through hole; 340. Welding hole; 4. Collimator; 410. First through hole; 5. Optical fiber; 6. Second extrusion fixing post; 610. Second limiting installation notch; 7. Chip fixing seat; 710. Inclined surface; 8. Collimator mounting seat; 810. Waist-shaped connecting block; 9. Third vertical plate. Detailed Implementation

[0027] The present invention will be further described below with reference to the accompanying drawings and specific embodiments, so that those skilled in the art can better understand and implement the present invention. However, the embodiments are not intended to limit the present invention.

[0028] Reference Figures 1 to 4 As shown, this utility model provides a strain gauge based on fiber optic 5MEMS technology, comprising:

[0029] First compression fixing column 1;

[0030] The first deformable beam 2 includes a first horizontal plate 210, a first vertical plate 220, and a second vertical plate 230. The bottom end of the first vertical plate 220 is connected to the first compression fixing column 1. One end of the first horizontal plate 210 is connected to the top end of the first vertical plate 220. The top end of the second vertical plate 230 is connected to the end of the first horizontal plate 210 away from the first vertical plate 220. A MEMS chip 240 is provided on the middle part of the second vertical plate 230 away from the first vertical plate 220. The MEMS chip 240 and the second vertical plate 230 are at an angle. A semi-circular arc notch 231 is provided at the bottom end of the second vertical plate 230. The semi-circular arc notch 231 is provided on the same side as the MEMS chip 240.

[0031] Support connecting plate 3, one end of support connecting plate 3 is connected to the bottom end of second vertical plate 230, and the end of support connecting plate 3 connected to second vertical plate 230 is provided with 1 / 4 arc notch 310, the arc center of 1 / 4 arc notch 310 is concentric with the arc center of semi-circular notch 231;

[0032] The collimator 4 is located in the middle of the support connecting plate 3. The collimator 4 is cylindrical and has a first through hole 410 at its axis. One end of the first through hole 410 is fitted with an optical fiber 5, and the other end of the first through hole 410 is aligned with the MEMS chip 240.

[0033] The second compression fixing column 6 is connected to the end of the support connecting plate 3 away from the second vertical plate 230, and the second compression fixing column 6 is concentrically arranged with the first compression fixing column 1.

[0034] This strain gauge based on fiber optic MEMS technology uses a first compression fixing post 1 and a second compression fixing post 6 to connect the stress compression point inside the anchor sensor. In the initial stage, the angle between the MEMS chip 240 and the beam emitted by the fiber optic 5 on the collimator 4 is calibrated to 0. When the strain gauge is deformed by compression, since the MEMS chip 240 is fixed on the first deformation beam 2, the semi-circular arc segment on the first vertical plate and the 1 / 4 arc segment on the support connecting plate 3 together act as the second deformation beam, and the collimator 4 is fixed on the support connecting plate 3, so that the angle between the MEMS chip 240 and the beam emitted by the fiber optic 5 changes linearly. The light source is directed to the reflective surface of the fiber optic MEMS chip 240 through the fiber optic 5 and the collimator 4, and the reflected beam returns along the original path. After being calibrated by the demodulator at the back end of the fiber optic 5, the deformation of the external structure and the magnitude of the force can be calculated by the wavelength of the reflected light. This strain gauge leverages the high resolution and precision of fiber optic 5MEMS, exhibits virtually no deformation hysteresis, and can monitor minute displacements to provide reliable data support. Furthermore, it is unaffected by electromagnetic radiation and temperature changes, allowing it to operate stably for extended periods in environments with strong electromagnetic radiation and large temperature variations.

[0035] Specifically, the first compression fixing column 1 and the second compression fixing column 6 are made of high-strength metal materials and welded to the first vertical plate 220 of the first deformation beam 2. They are used to fix the entire strain gauge body and to transmit force to the strain gauge body. The first deformation beam 2 is generally U-shaped with a small gap in the middle. The first vertical plate 220 mainly serves to connect the first compression fixing column 1. The second vertical plate 230 and the first horizontal plate 210 serve to amplify the deformation. Therefore, the second vertical plate 230 and the first horizontal plate 210 are relatively thin. The second vertical plate 230 is integrally formed with the support connecting plate 3. The semi-circular arc notch 231 on the second vertical plate 230 and the 1 / 4 arc segment on the support connecting plate 3 form the second deformation beam and are used to further amplify the deformation. As described below, to maintain a certain angle between the MEMS chip 240 and the collimator 4, a protrusion extends from the second vertical plate 230, and the MEMS chip 240 is fixed on the protrusion. The relative position of the MEMS chip 240 and the collimator 4 needs to be determined with the assistance of a gimbal. First, the entire strain gauge is placed under a microscope, and the MEMS chip 240 is glued to the corresponding installation position on the strain gauge body with special adhesive. Then, the strain gauge body and the collimator 4 are fixed to the gimbal, the collimator 4 is connected to the demodulation equipment, and the distance and angle between the collimator 4 and the chip are adjusted until the wavelength and intensity of the reflected light are within the required range. Then, the collimator 4 is fixed. The optical fiber 5 is used to emit the light beam and receive the emitted light column to transmit it to the back-end demodulation equipment.

[0036] Furthermore, a chip holder 7 is provided in the middle of the second vertical plate 230, and an inclined surface 710 is provided at the end of the chip holder 7 away from the second vertical plate 230, on which the MEMS chip 240 is attached.

[0037] Specifically, the main body of the chip holder 7 can be square or cylindrical. The chip holder 7 and the second vertical plate 230 are welded together, and a bevel 710 is machined at the end of the chip holder 7 for attaching the MEMS chip 240.

[0038] Furthermore, a collimator mounting base 8 is provided in the middle of the supporting connecting plate 3, and the collimator 4 passes through the collimator mounting base 8.

[0039] Specifically, the collimator 4 is used for fixed installation of the collimator 4. The collimator 4 is inserted through the collimator mounting base 8 and then fixed with solder.

[0040] Furthermore, the bottom of the collimator mounting base 8 is provided with a waist-shaped connecting block 810, and the support connecting plate 3 is provided with a waist-shaped hole 320, with the waist-shaped connecting block 810 being engaged in the waist-shaped hole 320.

[0041] Specifically, when calibrating the position of the collimator 4 and the MEMS chip, the collimator 4 is first soldered to the collimator 4, and then the waist-shaped connecting block 810 on the collimator mounting base 8 is placed in the waist-shaped hole 320 on the support connecting plate 3. After the position of the collimator 4 and the MEMS chip is calibrated, the collimator mounting base 8 is fixed to the support connecting plate 3 by soldering.

[0042] Furthermore, the collimator mounting base 8 has a horseshoe-shaped cross-section, and the collimator mounting base 8 is provided with a second through hole 330 along its length. The diameter of the second through hole 330 is the same as the outer diameter of the collimator 4.

[0043] Specifically, the second through hole 330 is used to fix the collimator 4.

[0044] Furthermore, multiple sets of welding holes 340 are provided on the side of the collimator 4 along the length direction, and all sets of welding holes 340 are connected to the second through hole 330.

[0045] Specifically, the design of the welding hole 340 facilitates the welding of the collimator 4 onto the collimator mounting base 8.

[0046] Furthermore, a third vertical plate 9 is provided at the end of the supporting connecting plate 3 away from the second vertical plate 230, and the third vertical plate 9 is connected to the second compression fixing column 6.

[0047] Specifically, the third vertical plate 9 is used to install the second extrusion fixing column 6 and ensure that the second extrusion fixing column 6 and the first extrusion fixing column 1 are concentrically positioned.

[0048] Furthermore, the first compression fixing column 1 is provided with a first limiting installation notch 110 at the end away from the first vertical plate 220, and the second compression fixing column 6 is provided with a second limiting installation notch 610 at the end away from the supporting connecting plate 3.

[0049] Specifically, the first limiting installation notch 110 and the second limiting installation notch 610 can ensure the anti-rotation of the entire strain gauge in the anchor sensor.

[0050] Furthermore, both the first deformable beam 2 and the supporting connecting plate 3 are made of 40CrNiMo material.

[0051] Specifically, the first deformation beam 2, the support connecting plate 3, and the third vertical plate 9 are all made of 40CrNiMo material. This material has very small deformation hysteresis under stress, which can be almost ignored. Internal stress is eliminated through heat treatment to avoid the influence of microstructure differences on sensor measurement.

[0052] Obviously, the above embodiments are merely illustrative examples for clear explanation and are not intended to limit the implementation. Those skilled in the art will recognize that other variations or modifications can be made based on the above description. It is neither necessary nor possible to exhaustively list all possible implementations here. However, obvious variations or modifications derived therefrom are still within the protection scope of this invention.

Claims

1. A strain gauge based on fiber optic MEMS technology, characterized in that, include: First compression fixing column; The first deformable beam includes a first horizontal plate, a first vertical plate, and a second vertical plate. The bottom end of the first vertical plate is connected to the first extrusion fixing column. One end of the first horizontal plate is connected to the top end of the first vertical plate. The top end of the second vertical plate is connected to the end of the first horizontal plate away from the first vertical plate. A MEMS chip is disposed on the middle part of the second vertical plate away from the first vertical plate. The MEMS chip and the second vertical plate are at an angle. A semi-circular arc notch is disposed at the bottom end of the second vertical plate. The semi-circular arc notch is disposed on the same side as the MEMS chip. A supporting connecting plate, one end of which is connected to the bottom end of the second vertical plate, and the end of the supporting connecting plate connected to the second vertical plate is provided with a 1 / 4 circular arc notch, the center of the 1 / 4 circular arc notch being concentric with the center of the semi-circular arc notch; A collimator is disposed in the middle of the support connecting plate. The collimator is cylindrical and has a first through hole at its axis. An optical fiber is inserted at one end of the first through hole, and the other end of the first through hole is aligned with the MEMS chip. The second compression fixing column is connected to the end of the support connecting plate away from the second vertical plate, and the second compression fixing column is concentrically arranged with the first compression fixing column.

2. The strain gauge based on fiber optic MEMS technology according to claim 1, characterized in that: A chip holder is provided in the middle of the second vertical plate, and an inclined surface is provided at the end of the chip holder away from the second vertical plate, on which the MEMS chip is attached.

3. The strain gauge based on fiber optic MEMS technology according to claim 1, characterized in that: A collimator mounting base is provided in the middle of the support connecting plate, and the collimator passes through the collimator mounting base.

4. The strain gauge based on fiber optic MEMS technology according to claim 3, characterized in that: The bottom of the collimator mounting base is provided with a waist-shaped connecting block, and the support connecting plate is provided with a waist-shaped hole, and the waist-shaped connecting block is engaged in the waist-shaped hole.

5. The strain gauge based on fiber optic MEMS technology according to claim 4, characterized in that: The collimator mounting base has a horseshoe-shaped cross-section, and a second through hole is provided along the length direction of the collimator mounting base. The diameter of the second through hole is the same as the outer diameter of the collimator.

6. The strain gauge based on fiber optic MEMS technology according to claim 5, characterized in that: The collimator is also provided with multiple sets of welding holes along its length, and all of the welding holes are connected to the second through hole.

7. The strain gauge based on fiber optic MEMS technology according to claim 1, characterized in that: A third vertical plate is also provided at the end of the support connecting plate away from the second vertical plate, and the third vertical plate is connected to the second compression fixing column.

8. The strain gauge based on fiber optic MEMS technology according to claim 1, characterized in that: The first compression fixing column has a first limiting installation notch at the end away from the first vertical plate, and the second compression fixing column has a second limiting installation notch at the end away from the supporting connecting plate.

9. The strain gauge based on fiber optic MEMS technology according to claim 1, characterized in that: Both the first deformable beam and the supporting connecting plate are made of 40CrNiMo material.

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