Pull rope type displacement sensor based on optical fiber MEMS technology

Abstract

The utility model relates to a pull rope type displacement sensor based on an optical fiber MEMS technology, which comprises an installation box body, a reset assembly, a wire wheel assembly, a displacement reduction assembly and an MEMS displacement meter, the reset assembly adopts a vortex spring structure, the wire wheel assembly is a pull rope for pulling and driving a wire roller and sequentially transmitting rotation motion to a lead screw and a vortex spring shaft in the displacement reduction assembly, and the MEMS displacement meter is arranged in the installation box body. And the connecting seat which moves along with rotation on the screw rod drives the MEMS chip and the collimator in the displacement meter to generate displacement change so as to transmit an optical signal to external demodulation equipment, so that the readability of the pull rope is realized. An optical fiber MEMS technology is adopted, so that interference of electromagnetic radiation and temperature change is avoided; a vortex spring reset mode is used, the reset precision is high, repeated use can be achieved, mounting and dismounting are convenient, and the measuring speed is increased; a theoretical algorithm and high-precision calibration combined mode is used, accurate and stable data support is provided in the engineering detection field of coal mines, tunnels, bridges and the like, and tiny changes of an observed object can be found in engineering monitoring so as to achieve an early warning effect.

Description

Technical Field

[0001] This utility model relates to the field of optical sensing technology, and in particular to a pull-string displacement sensor based on fiber optic MEMS technology. Background Technology

[0002] Traditional electronic draw-wire displacement sensors first involve winding a stretchable traction rope around a threaded hub, which is then connected to a precision rotary sensor. This sensor can be an incremental encoder, an absolute (independent) encoder, a hybrid or conductive plastic rotary potentiometer, a synchronizer, or a resolver, etc. The end of the traction rope is then fixed to the moving object, aligning the linear motion of the rope with the axis of motion of the object. Because this type of electronic draw-wire displacement sensor uses an electrical strain gauge as its core sensing element, it inevitably suffers from susceptibility to environmental electromagnetic radiation interference and poor long-term stability, failing to meet the requirement of long-term stable operation in electromagnetic radiation environments.

[0003] Although some displacement sensors use fiber optic grating sensors, which can be used in electromagnetic radiation environments, they still suffer from significant signal fluctuations with temperature and time, making them unsuitable for long-term stable use in environments with large temperature variations. Furthermore, in electronic pull-wire displacement sensors, the diameter of the pull wire coil increases with the number of turns as the pull wire winds around the hub, resulting in inconsistent wire extension and retraction lengths per revolution of the hub in the early and later stages of measurement, further affecting measurement accuracy. If a rotation sensor is used to measure the wire displacement, the sensor's resolution and accuracy will also limit the overall accuracy of the pull-wire displacement sensor. Currently, most sensors in the industry use manual or electric wire winding, which cannot accurately reset the wire to its initial position, leading to large errors in multiple measurements and requiring periodic calibration. Utility Model Content

[0004] Therefore, the technical problem to be solved by this utility model is to overcome the problem that existing displacement sensors cannot simultaneously achieve the advantages of strong anti-electromagnetic interference capability, strong environmental adaptability and high accuracy.

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

[0006] The mounting box includes a fixed base plate and a removable top cover;

[0007] A reset assembly is disposed within the mounting box. The reset assembly includes a spiral spring, a spiral spring mounting base, and a spiral spring shaft. The spiral spring mounting base is disposed at one end of the fixed base plate. The main body of the spiral spring mounting base is a circular groove facing the inner wall of the mounting box. One end of the spiral spring shaft passes through the center of the circular groove towards the inner wall of the mounting box. The spiral spring is engaged within the circular groove, and the outer end of the spiral spring is connected to the groove wall of the circular groove, while the inner end of the spiral spring is connected to the spiral spring shaft.

[0008] A reel assembly is disposed on the fixed base plate at one end away from the reset assembly. The reel assembly includes a reel roller and a pull rope. The pull rope is tightly wound around the reel roller. The reel roller includes a roller shaft and a winding groove. One end of the pull rope is connected to the bottom of the winding groove, and the other end of the pull rope extends horizontally out of the mounting box.

[0009] The displacement reduction assembly includes a fixed bearing and a lead screw. The fixed bearing is disposed on the fixed base plate near the reset assembly. One end of the lead screw passes through the inner ring of the fixed bearing and is connected to the spiral spring shaft. The other end of the lead screw is connected to the roller shaft. A connecting seat is sleeved on the lead screw and is threadedly connected to the lead screw. The connecting seat is disposed between the reel assembly and the fixed bearing and can move freely in the horizontal direction as the lead screw rotates.

[0010] A MEMS displacement meter is disposed on one side of the displacement reduction assembly. The MEMS displacement meter includes a cylinder, a piston, a MEMS chip, and a collimator. The cylinder is connected to the fixed base plate. The head of the piston passes through the cylinder. The MEMS chip is vertically attached to the head of the piston. The collimator is engaged at the end of the cylinder away from the piston. The collimator includes a light-emitting side and a light-receiving side. The light-emitting side is aligned with the MEMS chip in a horizontal direction. An optical fiber is disposed on the light-receiving side. The optical fiber extends horizontally out of the mounting box. The end of the piston away from the collimator is connected to the connecting seat. The axis of the piston and the axis of the lead screw are in the same plane.

[0011] In one embodiment of this utility model, the reel assembly further includes a guide wheel mounting base and a plurality of auxiliary guide wheels. The plurality of auxiliary guide wheels are all connected to the guide wheel mounting base, the guide wheel mounting base is connected to the fixed base plate, and the pull rope is sequentially wound around the plurality of auxiliary guide wheels and finally led out from the mounting box.

[0012] In one embodiment of the present invention, an auxiliary sliding component is further included. The auxiliary sliding component includes a sliding shaft and a slider. The sliding shaft is connected to the fixed base plate, the slider is engaged with the sliding shaft, and the slider is connected to the bottom surface of the connecting seat.

[0013] In one embodiment of the present invention, limiting grooves are provided on both sides of the sliding shaft, a sliding groove is provided on the lower surface of the slider, a limiting strip is provided on the groove wall of the sliding groove, the limiting strip is engaged in the limiting groove, and the bottom of the sliding groove is in close contact with the upper surface of the sliding shaft.

[0014] In one embodiment of this utility model, two limiting blocks are provided on the fixed base plate, and the two limiting blocks are respectively provided at the front and rear ends of the connecting seat in the moving direction.

[0015] In one embodiment of this utility model, a connecting plate is provided at the end of the lead screw away from the reset assembly. One side of the connecting plate is fastened to the connecting seat, and the other side of the connecting plate is connected to the roller shaft. A connecting post is provided at the end of the lead screw away from the reel assembly. The spiral spring shaft is T-shaped and includes a large end and a small end. The small end is provided with a slot, and the inner end of the spiral spring is engaged in the slot. The large end is provided with a first insertion groove and a limiting hole. The limiting hole communicates with the first insertion groove. The first insertion groove is sleeved on the connecting post. A set screw is provided in the limiting hole, and the set screw abuts against the connecting post.

[0016] In one embodiment of this utility model, the cylinder body is provided with a limiting waist-shaped hole, and the piston is provided with a limiting pin. The limiting pin always moves horizontally within the limiting waist-shaped hole, and the movement distance of the limiting pin is the same as the movement distance of the connecting seat between the two limiting blocks.

[0017] In one embodiment of this utility model, the piston head is provided with a second insertion groove, and a chip mounting post is engaged in the second insertion groove. The MEMS chip is attached to the end of the chip mounting post. The cylinder body includes a first connecting tube, a second connecting tube, and a third connecting tube. The first connecting tube and the second connecting tube are connected through the third connecting tube. The MEMS displacement meter also includes a collimator mounting base and an optical fiber lead-out connector. The collimator is engaged in the collimator mounting base. One end of the collimator mounting base passes through one end of the third connecting tube, and the chip mounting base passes through the other end of the third connecting tube. The optical fiber lead-out connector is connected to the end of the second connecting tube.

[0018] In one embodiment of this utility model, the fixed base plate has the same structure as the detachable top cover, and the mounting box also includes a surrounding side plate. The bottom and top of the surrounding side plate are provided with rectangular grooves, and a sealing ring is provided in the rectangular grooves. The surrounding side plate is provided with fiber optic connector fixing holes and pull rope lead-out holes.

[0019] In one embodiment of this utility model, the displacement reduction assembly further includes a bearing mounting base, the bearing mounting base being connected to the fixed base plate, and the fixed bearing being connected to the bearing mounting base.

[0020] The above-mentioned technical solution of this utility model has the following advantages compared with the prior art:

[0021] When using this fiber optic MEMS-based pull-string displacement sensor, the free end of the pull string is first fixed to the object to be measured. When the object pulls the pull string outward, the pull string drives the lead screw to rotate. The connecting seat on the lead screw is displaced along the length of the lead screw, which in turn drives the piston to move in the cylinder. The MEMS displacement meter converts the displacement change into a change in light wavelength, and then connects to an external optical signal demodulation device through an optical fiber to further demodulate the optical signal into readable information.

[0022] The advantages of this utility model include the following:

[0023] 1. This utility model adopts fiber optic MEMS technology to solve the problem of signal reception and transmission of existing displacement sensors in harsh working environments with electromagnetic interference and large temperature differences.

[0024] 2. This utility model can combine theoretical algorithms with precise calibration. Through modeling simulation and precise algorithms, the theoretical relationship between the movement of the pull rope and the change in the displacement meter signal is calculated. The relationship is verified and improved during the calibration process to obtain the real relationship between the movement of the pull rope and the change in the displacement meter. The change of the pull rope is cleverly transformed into the change in the relative position of the chip and the collimator inside the MEMS displacement meter, thereby improving the measurement accuracy of the sensor. It provides accurate and stable data support in engineering detection fields such as coal mines, tunnels, and bridges. In engineering monitoring, it can detect minute changes in the observed object and provide disaster early warning information for the engineering site at an earlier time.

[0025] 3. Since the range of the MEMS displacement meter is small, this utility model adopts a displacement reduction component to convert the displacement. The long range of the pull rope is converted into the small range of the MEMS displacement meter through the rotational displacement of the lead screw and connecting seat, thereby realizing high-precision measurement with a large range.

[0026] 4. This utility model uses a reset assembly to connect the lead screw. When the end of the pull rope is detached from the object being measured, the spiral spring mechanism can drive the lead screw and pull rope to return to their initial positions, thereby achieving repeatability of multiple measurements. Attached Figure Description

[0027] 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.

[0028] Figure 1This is a schematic diagram of the overall structure of the pull-string displacement sensor based on fiber optic MEMS technology of this utility model;

[0029] Figure 2 for Figure 1 The image shows a top view of the internal structure of the mounting box in a draw-wire displacement sensor based on fiber optic MEMS technology.

[0030] Figure 3 for Figure 1 The image shows a front view of the internal structure of the mounting box in a pull-wire displacement sensor based on fiber optic MEMS technology.

[0031] Figure 4 for Figure 1 The image shows a left view of the internal structure of the mounting box in a draw-wire displacement sensor based on fiber optic MEMS technology.

[0032] Figure 5 for Figure 1 The image shows a right view of the internal structure of the mounting box in a pull-wire displacement sensor based on fiber optic MEMS technology.

[0033] Figure 6 for Figure 1 The diagram shows the overall structure of the MEMS displacement gauge in a draw-wire displacement sensor based on fiber optic MEMS technology.

[0034] Figure 7 for Figure 1 The figure shows a cross-sectional view of the MEMS displacement gauge in a drawstring displacement sensor based on fiber optic MEMS technology.

[0035] Explanation of reference numerals in the accompanying drawings: 1. Mounting housing; 110. Fixed base plate; 120. Removable top cover; 130. Surrounding side plate; 131. Pull cord outlet hole; 132. Fiber optic connector fixing hole; 2. Reset assembly; 210. Vortex spring mounting base; 220. Vortex spring shaft; 3. Wire wheel assembly; 310. Wire roller; 320. Pull cord; 330. Guide wheel mounting base; 340. Auxiliary guide wheel; 4. Displacement reduction assembly; 410. Fixed bearing; 420. Lead screw; 430. Connecting seat; 440. Bearing mounting base; 5. MEMS displacement gauge; 510. Cylinder body; 511. First connecting pipe; 512. Second connecting pipe; 513. Third connecting pipe; 520. Piston; 521. Second insertion slot; 522. Chip mounting post; 530. MEMS chip; 540. Collimator; 550. Optical fiber; 560. Collimator mounting base; 570. Optical fiber lead-out connector; 6. Auxiliary sliding assembly; 610. Sliding shaft; 611. Limiting groove; 620. Slider; 622. Limiting strip; 7. Limiting block; 8. Connecting plate; 9. Limiting hole; 10. Limiting waist-shaped hole; 11. Limiting pin. Detailed Implementation

[0036] 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.

[0037] Reference Figures 1 to 7 As shown, this utility model provides a 320-type displacement sensor based on MEMS technology, comprising:

[0038] The mounting box 1 includes a fixed base plate 110 and a removable top cover 120;

[0039] The reset assembly 2 is disposed inside the mounting box 1. The reset assembly 2 includes a spiral spring, a spiral spring mounting base 210, and a spiral spring shaft 220. The spiral spring mounting base 210 is disposed at one end of the fixed base plate 110. The main body of the spiral spring mounting base 210 is a circular groove facing the inner wall of the mounting box 1. One end of the spiral spring shaft 220 passes through the center of the circular groove towards the inner wall of the mounting box 1. The spiral spring is engaged in the circular groove, and the outer end of the spiral spring is connected to the groove wall of the circular groove, while the inner end of the spiral spring is connected to the spiral spring shaft 220.

[0040] The reel assembly 3 is disposed on the fixed base plate 110 at one end away from the reset assembly 2. The reel assembly 3 includes a reel 310 and a pull rope 320. The pull rope 320 is tightly wound on the reel 310. The reel 310 includes a roller shaft and a winding groove. One end of the pull rope 320 is connected to the bottom of the winding groove, and the other end of the pull rope 320 extends out of the mounting box 1 in the horizontal direction.

[0041] The displacement reduction assembly 4 includes a fixed bearing 410 and a lead screw 420. The fixed bearing 410 is disposed on the fixed base plate 110 near the reset assembly 2. One end of the lead screw 420 passes through the inner ring of the fixed bearing 410 and is connected to the spiral spring shaft 220. The other end of the lead screw 420 is connected to the roller shaft. A connecting seat 430 is sleeved on the lead screw 420. The connecting seat 430 is threadedly connected to the lead screw 420. The connecting seat 430 is disposed between the threaded wheel assembly 3 and the fixed bearing 410 and can move freely in the horizontal direction as the lead screw 420 rotates.

[0042] MEMS displacement meter 5 is disposed on one side of displacement reduction component 4. MEMS displacement meter 5 includes: cylinder 510, piston 520, MEMS chip 530 and collimator 540. Cylinder 510 is connected to fixed base plate 110. The head of piston 520 is inserted into cylinder 510. MEMS chip 530 is vertically attached to head of piston 520. Collimator 540 is locked at the end of cylinder 510 away from piston 520. Collimator 540 includes light-emitting side and light-incoming side. Light-emitting side is aligned with MEMS chip 530 in the horizontal direction. Light-incoming side is provided with optical fiber 550. Optical fiber 550 extends out of mounting box 1 in the horizontal direction. The end of piston 520 away from collimator 540 is connected to connector 430. The axis of piston 520 and axis of lead screw 420 are in the same plane.

[0043] When using this MEMS-based draw-wire 320 displacement sensor, the free end of the draw-wire 320 is first fixed to the object to be measured. When the object to be measured pulls the draw-wire 320 outward, the draw-wire 320 drives the lead screw to rotate. The connecting seat 430 sleeved on the lead screw generates a corresponding displacement along the length of the lead screw 420, which in turn drives the piston 520 to move within the cylinder 510. The MEMS displacement gauge 5 converts the displacement change into a change in optical wavelength, and connects to an external optical signal demodulation device through an optical fiber 550 to further demodulate the optical signal into readable information.

[0044] The advantages of this utility model include the following:

[0045] 1. This utility model adopts fiber optic MEMS technology to solve the problem of signal reception and transmission of existing displacement sensors in harsh working environments with electromagnetic interference and large temperature differences.

[0046] 2. This utility model can adopt a combination of theoretical algorithms and precise calibration. Through modeling simulation and precise algorithms, the theoretical relationship between the movement of the pull rope 320 and the change in the displacement meter signal is calculated. The relationship is verified and improved during the calibration process to obtain the real relationship between the movement of the pull rope 320 and the change in the displacement meter. The change of the pull rope 320 is cleverly transformed into the relative position change between the chip inside the MEMS displacement meter 5 and the collimator 540, thereby improving the measurement accuracy of the sensor. It provides accurate and stable data support in engineering detection fields such as coal mines, tunnels, and bridges. In engineering monitoring, it can detect small changes in the observed object and provide disaster early warning information for the engineering site earlier.

[0047] 3. Since the range of MEMS displacement meter 5 is small, this utility model adopts displacement reduction component 4 to convert the displacement. The long range of the pull rope 320 is converted into the small range of MEMS displacement meter 5 through the rotational displacement of the lead screw and connecting seat 430, thereby realizing high-precision measurement with a large range.

[0048] 4. This utility model uses a reset component 2 to connect the lead screw. When the end of the pull rope 320 is detached from the object being measured, the spiral spring mechanism can drive the lead screw and pull rope 320 to return to their initial positions, thereby achieving repeatability of multiple measurements.

[0049] Specifically, the number of turns of the pull rope 320 wound on the wire roller 310 is proportional to the length of each turn of the pull rope 320. During use, as the pull rope 320 is pulled, the number of turns of the pull rope 320 on the wire roller 310 decreases, the winding radius of the coil decreases, and the length of a single turn of the pull rope 320 also changes accordingly. In order to obtain a more accurate amount of change in the length of the pull rope 320, the length of each turn of the pull rope 320 (Ln), the number of turns (n), the wire diameter d of the pull rope 320, and the diameter (R) of the wire roller 310 are calculated. The relationship is: Ln = π * {(n * d + R}. This relationship is introduced into the system of lead screw 420 and connecting seat 430, specifically the relationship between the length of each turn of the pull rope 320 and the displacement of the MEMS displacement gauge 5. Software algorithms are used to repeatedly fit the length of the pull rope 320 with the displacement of the MEMS displacement gauge 5, thereby obtaining accurate data on the displacement of the pull rope 320. The fitted coefficients and calibration fixtures are then used for verification. Experiments show that the accuracy of the MEMS displacement gauge 5 can reach 0.05%.

[0050] Specifically, the mounting box 1 is made of high-strength metal, possessing corrosion resistance and damage resistance, effectively protecting all internal components. The dimensions of the vortex spring, vortex spring mounting base 210, and vortex spring shaft 220 in the reset assembly 2 must be appropriate, and the vortex spring should have high fatigue resistance to ensure repeated reset of the lead screw 420 and pull rope 320. In this embodiment, the pull rope 320 is a high-strength steel wire rope, and the material of the roller 310 is also a high-strength wear-resistant material, ensuring that the calibrated displacement data of the pull rope 320 remains applicable during long-term repeated use of the sensor. The roller shaft of the roller 310 is suspended and fixed by the lead screw 420, and the rotation of the roller 310 is synchronized with the lead screw 420. The connecting seat 430 in the displacement reduction assembly 4 is generally L-shaped, and its connection to the lead screw 420 is "mountain" shaped, as described below, with one end of the lead screw 420 passing through... The connecting plate 8 is used to fix the connecting seat 430 to the connecting seat 430. One side of the connecting seat 430 is used to fix the piston 520 on the MEMS displacement gauge 5. It can be seen that the connection between the connecting seat 430 and the piston 520 is fixed by a set screw. A corresponding pin hole can be set on the piston 520 to facilitate the insertion of the set screw to further limit the piston 520. The lead screw 420 and the roller also rotate synchronously. More importantly, the lead screw 420 is a high-precision lead screw 420. Together with the connecting seat 430, it forms a common high-precision lead screw 420 nut system, which ensures the accuracy of displacement transmission. The MEMS displacement gauge 5 adopts fiber optic MEMS technology, which is not affected by electromagnetic radiation and temperature changes. It can work stably for a long time in environments with strong electromagnetic radiation and large temperature differences, solving the problem of signal reception and transmission of existing displacement sensors in harsh working environments with electromagnetic interference and large temperature differences.

[0051] Furthermore, the reel assembly 3 also includes a guide wheel mounting base 330 and multiple auxiliary guide wheels 340. The multiple auxiliary guide wheels 340 are all connected to the guide wheel mounting base 330. The guide wheel mounting base 330 is connected to the fixed base plate 110. The pull rope 320 is sequentially wound around the multiple auxiliary guide wheels 340 and finally led out from the mounting box 1.

[0052] Specifically, in this embodiment, the auxiliary guide wheels 340 are designed as two and connected to the guide wheel mounting base 330 in the vertical direction. The bottom of the guide wheel mounting base 330 is fastened to the fixed base plate 110 by bolts. The pull rope 320 is led out from the wire roller 310 and then wrapped around the auxiliary guide wheel 340 in an S-shape and led out from the outside of the mounting box 1. The auxiliary guide wheels 340 can play a role in organizing the pull rope 320 and preventing the pull rope 320 from getting tangled inside the mounting box 1. More auxiliary guide wheels 340 can be provided.

[0053] Furthermore, it also includes an auxiliary sliding component 6, which includes a sliding shaft 610 and a slider 620. The sliding shaft 610 is connected to the fixed base plate 110, and the slider 620 is locked onto the sliding shaft 610 and connected to the bottom surface of the connecting seat 430.

[0054] Specifically, the auxiliary sliding assembly 6 provides support for the movement of the connecting seat 430 along the direction of the lead screw 420.

[0055] Furthermore, both sides of the sliding shaft 610 are provided with limiting grooves 611, the lower surface of the slider 620 is provided with a sliding groove, the groove wall of the sliding groove is provided with a limiting strip 622, the limiting strip 622 is locked in the limiting groove 611, and the bottom of the sliding groove is in close contact with the upper surface of the sliding shaft 610.

[0056] Specifically, the setting of the limiting groove 611 and the limiting bar 622 ensures the movement stability of the connecting seat 430.

[0057] Furthermore, two limiting blocks 7 are provided on the fixed base plate 110, and the two limiting blocks 7 are respectively located at the front and rear ends of the connecting seat 430 in the moving direction.

[0058] Specifically, since the range of the MEMS displacement meter 5 is small, adding limit blocks 7 at the front and rear ends of the connector 430 can prevent the piston 520 from moving beyond the readable range of the MEMS displacement meter 5 within the cylinder 510.

[0059] Furthermore, a connecting plate 8 is provided at the end of the lead screw 420 away from the reset assembly 2. One side of the connecting plate 8 is fastened to the connecting seat 430, and the other side of the connecting plate 8 is connected to the roller shaft. A connecting post is provided at the end of the lead screw 420 away from the reel assembly 3. The vortex spring shaft 220 is T-shaped and includes a large end and a small end. The small end is provided with a slot, and the inner end of the vortex spring is locked in the slot. The large end is provided with a first insertion groove and a limiting hole 9. The limiting hole 9 communicates with the first insertion groove. The first insertion groove is sleeved on the connecting post. A set screw is provided in the limiting hole 9, and the set screw abuts against the connecting post.

[0060] Specifically, as described above, the connecting plate 8 is used to fix the lead screw 420, the roller shaft, and the connecting seat 430, while ensuring that the lead screw 420, the roller shaft, and the spiral spring shaft 220 are concentrically arranged. The connection method between the spiral spring shaft 220 and the lead screw 420 is plug-in limiting fixation, which is convenient for assembly. Furthermore, a pin hole can be provided on the connecting column. After the set screw passes through the limiting hole 9, it falls into the pin hole of the connecting column, which can strengthen the connection between the lead screw 420 and the spiral spring shaft 220.

[0061] Furthermore, the cylinder body 510 is provided with a limiting waist-shaped hole 10, and the piston 520 is provided with a limiting pin 11. The limiting pin 11 always moves horizontally within the limiting waist-shaped hole 10, and the movement distance of the limiting pin 11 is the same as the movement distance of the connecting seat 430 between the two limiting blocks 7.

[0062] Specifically, the limiting waist-shaped hole 10 and the limiting pin 11 on the MEMS displacement gauge 5 have the adjustment range of the piston 520 within the cylinder 510, and the relative position of the limiting block 7 and the connecting seat 430 can be determined by this range of movement.

[0063] Furthermore, the piston 520 has a second insertion groove 521 at its head, and a chip mounting post 522 is inserted in the second insertion groove 521. The MEMS chip 530 is attached to the end of the chip mounting post 522. The cylinder 510 includes a first connecting tube 511, a second connecting tube 512, and a third connecting tube 513. The first connecting tube 511 and the second connecting tube 512 are connected through the third connecting tube 513. The MEMS displacement meter 5 also includes a collimator mounting base 560 and an optical fiber lead-out connector 570. The collimator 540 is inserted in the collimator mounting base 560. One end of the collimator mounting base 560 passes through one end of the third connecting tube 513, and the chip mounting base passes through the other end of the third connecting tube 513. The optical fiber lead-out connector 570 is connected to the end of the second connecting tube 512.

[0064] Specifically, the cylinder body 510 has an overall plug-in structure, which facilitates the assembly of the entire MEMS displacement gauge 5. The collimator 540 is fixed to the collimator mounting base 560 by welding. The chip mounting post 522 and the piston 520 are interference fit, as shown in the figure. The cylinder body 510 is connected to the fixed base plate 110 through the cylinder body 510 mounting base. The cylinder body 510 mounting base is fastened to the fixed base plate 110 by bolts, ensuring that the cylinder body 510 and the internal collimator 540 remain fixed relative to the fixed base plate 110. The piston 520 drives the change of distance between the MEMS chip 530 and the collimator 540, thereby changing the wavelength of the reflected wave. It is connected to the external demodulation equipment through the optical fiber 550 and the optical fiber lead-out connector 570, so as to realize the readability of the displacement of the pull rope 320.

[0065] Furthermore, the fixed base plate 110 has the same structure as the detachable top cover 120. The mounting box 1 also includes a surrounding side plate 130. The bottom and top of the surrounding side plate 130 are provided with rectangular grooves, and a sealing ring is provided in the rectangular grooves. The surrounding side plate 130 is provided with a fiber optic 550 connector fixing hole 132 and a pull rope 320 lead-out hole 131.

[0066] Specifically, the sealing ring design ensures the airtightness of the mounting box 1, preventing internal components from being contaminated by moisture and further guaranteeing the measurement accuracy of the sensor.

[0067] Furthermore, the displacement reduction assembly 4 also includes a bearing mounting base 440, which is connected to the fixed base plate 110, and the fixed bearing 410 is connected to the bearing mounting base 440.

[0068] Specifically, the bearing mounting base 440 is connected to the fixed base plate 110 by set screws and is used to install the fixed bearing 410. In this embodiment, the fixed bearing 410 is a ball bearing.

[0069] 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 drawstring displacement sensor based on fiber optic MEMS technology, characterized in that, include: The mounting box includes a fixed base plate and a removable top cover; A reset assembly is disposed within the mounting box. The reset assembly includes a spiral spring, a spiral spring mounting base, and a spiral spring shaft. The spiral spring mounting base is disposed at one end of the fixed base plate. The main body of the spiral spring mounting base is a circular groove facing the inner wall of the mounting box. One end of the spiral spring shaft passes through the center of the circular groove towards the inner wall of the mounting box. The spiral spring is engaged within the circular groove, and the outer end of the spiral spring is connected to the groove wall of the circular groove, while the inner end of the spiral spring is connected to the spiral spring shaft. A reel assembly is disposed on the fixed base plate at one end away from the reset assembly. The reel assembly includes a reel roller and a pull rope. The pull rope is tightly wound around the reel roller. The reel roller includes a roller shaft and a winding groove. One end of the pull rope is connected to the bottom of the winding groove, and the other end of the pull rope extends horizontally out of the mounting box. The displacement reduction assembly includes a fixed bearing and a lead screw. The fixed bearing is disposed on the fixed base plate near the reset assembly. One end of the lead screw passes through the inner ring of the fixed bearing and is connected to the spiral spring shaft. The other end of the lead screw is connected to the roller shaft. A connecting seat is sleeved on the lead screw and is threadedly connected to the lead screw. The connecting seat is disposed between the reel assembly and the fixed bearing and can move freely in the horizontal direction as the lead screw rotates. A MEMS displacement meter is disposed on one side of the displacement reduction assembly. The MEMS displacement meter includes a cylinder, a piston, a MEMS chip, and a collimator. The cylinder is connected to the fixed base plate. The head of the piston passes through the cylinder. The MEMS chip is vertically attached to the head of the piston. The collimator is engaged at the end of the cylinder away from the piston. The collimator includes a light-emitting side and a light-receiving side. The light-emitting side is aligned with the MEMS chip in a horizontal direction. An optical fiber is disposed on the light-receiving side. The optical fiber extends horizontally out of the mounting box. The end of the piston away from the collimator is connected to the connecting seat. The axis of the piston and the axis of the lead screw are in the same plane.

2. The drawstring displacement sensor based on fiber optic MEMS technology according to claim 1, characterized in that: The reel assembly also includes a guide wheel mounting base and multiple auxiliary guide wheels. The multiple auxiliary guide wheels are all connected to the guide wheel mounting base, and the guide wheel mounting base is connected to the fixed base plate. The pull rope is sequentially wound around the multiple auxiliary guide wheels and finally led out from the mounting box.

3. The drawstring displacement sensor based on fiber optic MEMS technology according to claim 1, characterized in that: It also includes an auxiliary sliding assembly, which includes a sliding shaft and a slider. The sliding shaft is connected to the fixed base plate, the slider is engaged with the sliding shaft, and the slider is connected to the bottom surface of the connecting seat.

4. The drawstring displacement sensor based on fiber optic MEMS technology according to claim 3, characterized in that: Limiting grooves are provided on both sides of the sliding shaft, and a sliding groove is provided on the lower surface of the slider. A limiting strip is provided on the groove wall of the sliding groove, and the limiting strip is locked in the limiting groove. The bottom of the sliding groove is in close contact with the upper surface of the sliding shaft.

5. The draw-wire displacement sensor based on fiber optic MEMS technology according to claim 1, characterized in that: Two limiting blocks are provided on the fixed base plate, and the two limiting blocks are respectively located at the front and rear ends of the connecting seat in the moving direction.

6. The drawstring displacement sensor based on fiber optic MEMS technology according to claim 1, characterized in that: A connecting plate is provided at the end of the lead screw away from the reset assembly. One side of the connecting plate is fastened to the connecting seat, and the other side of the connecting plate is connected to the roller shaft. A connecting post is provided at the end of the lead screw away from the reel assembly. The spiral spring shaft is T-shaped and includes a large end and a small end. The small end is provided with a slot, and the inner end of the spiral spring is engaged in the slot. The large end is provided with a first insertion groove and a limiting hole. The limiting hole communicates with the first insertion groove. The first insertion groove is sleeved on the connecting post. A set screw is provided in the limiting hole, and the set screw abuts against the connecting post.

7. The drawstring displacement sensor based on fiber optic MEMS technology according to claim 5, characterized in that: The cylinder body is provided with a limiting waist-shaped hole, and the piston is provided with a limiting pin. The limiting pin always moves horizontally within the limiting waist-shaped hole, and the movement distance of the limiting pin is the same as the movement distance of the connecting seat between the two limiting blocks.

8. The drawstring displacement sensor based on fiber optic MEMS technology according to claim 1, characterized in that: The piston head is provided with a second insertion groove, and a chip mounting post is inserted into the second insertion groove. The MEMS chip is attached to the end of the chip mounting post. The cylinder body includes a first connecting tube, a second connecting tube, and a third connecting tube. The first connecting tube and the second connecting tube are connected through the third connecting tube. The MEMS displacement meter also includes a collimator mounting base and an optical fiber lead-out connector. The collimator is inserted into the collimator mounting base. One end of the collimator mounting base passes through one end of the third connecting tube. The chip mounting base passes through the other end of the third connecting tube. The optical fiber lead-out connector is connected to the end of the second connecting tube.

9. The drawstring displacement sensor based on fiber optic MEMS technology according to claim 1, characterized in that: The fixed base plate has the same structure as the detachable top cover. The mounting box also includes a surrounding side plate. The bottom and top of the surrounding side plate are provided with rectangular grooves. A sealing ring is provided in the rectangular groove. The surrounding side plate is provided with fiber optic connector fixing holes and pull rope lead-out holes.

10. The drawstring displacement sensor based on fiber optic MEMS technology according to claim 1, characterized in that: The displacement reduction assembly also includes a bearing mounting base, which is connected to the fixed base plate, and the fixed bearing is connected to the bearing mounting base.

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