High linearity large range fiber optic displacement sensor with sensitivity compensation and method of use

Abstract

The application provides a high-linearity large-range optical fiber displacement sensor with sensitivity compensation and a use method thereof, and belongs to the technical field of displacement sensors. The sensor comprises an optical fiber connected with a light source at one end and connected with an optical power meter at the other end in sequence through a guiding unit two and a guiding unit one. The guiding unit two and the guiding unit one are rotationally connected with a support. The guiding unit one is connected with a slope through a driving unit. The guiding unit two is synchronously rotated with the guiding unit one through a transmission unit. The guiding unit two comprises a lead screw structure. The optical fiber moves axially with a moving nut in the lead screw structure and is wound on a sensing bobbin of the guiding unit one. The application realizes macro-bending loss sensitivity attenuation compensation and response linearization regulation and control, finally obtains displacement sensing performance with large range, high linearity output, stable sensitivity and strong environmental adaptability, and adapts to the requirement of slope cross-scale displacement precise monitoring.

Description

Technical Field

[0001] This invention belongs to the technical field of displacement sensors, specifically a high linearity, large range fiber optic displacement sensor with sensitivity compensation and its usage method. Background Technology

[0002] Slope and landslide geological disasters occur frequently and pose significant risks in my country. Continuous monitoring of deep displacement is a core technical means to achieve early warning of disaster precursors and instability. Traditional inductive and potentiometer-based displacement monitoring equipment is susceptible to electromagnetic interference and humid environments in the field, and suffers from limitations such as large signal drift, poor long-term stability, and difficulty in distributed deployment. Fiber optic sensing technology, with its advantages of resistance to electromagnetic interference, passive adaptation, and flexible structure, has gradually become an important development direction for displacement monitoring in geotechnical engineering. Among them, strength-type fiber optic sensors based on macro-bending loss have good application potential in slope field monitoring due to their low cost, simple demodulation, and easy large-scale deployment.

[0003] However, due to the physical mechanism of optical fiber macro-bending loss, its loss response changes exponentially nonlinearly with the bending radius. This directly leads to an inherent bottleneck in the sensor, where sensitivity, measurement range, and output linearity are mutually constrained. When monitoring a large range, problems such as sharp decrease in sensitivity and deterioration of linear response are likely to occur. At the same time, the optical fiber is prone to suspension and deviation on the bending frame, which further aggravates signal fluctuations and makes it difficult to meet the high-precision and high-stability monitoring requirements of the entire process of slope from micro-creep to large-scale slippage.

[0004] Therefore, it is urgent to solve the inherent defects of existing technologies, such as the exponential nonlinearity of macro-bending loss response, the mutual constraints between sensitivity, range and linearity, and the significant attenuation of sensitivity under large-range monitoring, while also addressing the insufficient reliability of fiber optic signals.

[0005] It should be noted that the above technical information is intended only to enhance the understanding of the overall background technology of the present invention, and should not be regarded as an admission or in any way implying that the above technical information constitutes prior art known to those skilled in the art. Summary of the Invention

[0006] To address the shortcomings in the aforementioned background technology, this invention proposes a high-linearity, large-range fiber optic displacement sensor with sensitivity compensation and its usage method. This solves the inherent defects of existing fiber optic macrobending displacement sensors, such as exponential nonlinearity in macrobending loss response, mutual constraints between sensitivity, range, and linearity, and significant sensitivity attenuation under large-range monitoring. It also addresses the problem of insufficient reliability of fiber optic signals.

[0007] The technical solution of this application is as follows: A high linearity, large range fiber optic displacement sensor with sensitivity compensation includes an optical fiber with one end connected to a light source and the other end connected to an optical power meter via a second guide unit and a first guide unit. Both the second guide unit and the first guide unit are rotatably connected to a support. The first guide unit is connected to a slope via a drive unit. The second guide unit rotates synchronously with the first guide unit via a transmission unit. The second guide unit includes a lead screw structure. The optical fiber moves axially with the moving nut in the lead screw structure and is wound around the sensing winding shaft of the first guide unit.

[0008] Furthermore, both the sensing winding shaft and the wiring shaft are truncated cones, and the outer walls of the sensing winding shaft and the wiring shaft are provided with a non-uniform variable pitch helical structure.

[0009] Furthermore, the pitch near the end with the smaller diameter of the sensing winding shaft and the cable tray is greater than the pitch near the end with the larger diameter. This invention achieves structural compensation through the synergistic design of a gradient radius and a non-uniform pitch. The gradient radius allows the curvature to change continuously with displacement, while the non-uniform pitch adjusts the arc length of the optical fiber in different curvature regions, making the loss change caused by unit displacement tend to be constant across the entire range. The coupling of these two elements actively matches the loss sensitivity and the rate of curvature change, effectively overcoming sensitivity attenuation under large deformation and achieving high linearity and wide-range sensing.

[0010] Furthermore, the spiral structure includes a spiral groove 1 disposed on the outer wall of the sensing winding shaft. The optical fiber is wound in the spiral groove 1. When the optical fiber enters the spiral groove 1, its bending radius changes, resulting in a corresponding macro-bending loss. By recording the relationship between macro-bending loss and displacement, the fitting curve is calibrated, thereby realizing the measurement of displacement. The spiral groove 1 is filled with optical grease for the optical fiber to fit the groove body throughout its entire length, ensuring that the optical fiber fits the groove body throughout its entire length without any suspension or offset, thereby improving the stability of the sensing signal and environmental robustness.

[0011] Furthermore, the spiral structure includes a spiral groove two disposed on the outer wall of the ribbon cable shaft, a ribbon cable slider slidably connected to the limiting groove of the bracket, and a guide rod inserted into the spiral groove two disposed on the side of the ribbon cable slider. The guide rod moves linearly along the spiral groove two as the ribbon cable shaft rotates.

[0012] Furthermore, the guide hole is located directly above the sensing winding shaft, and the pitch variation ranges of the first spiral groove and the second spiral groove are matched.

[0013] Furthermore, the drive unit includes a drive disc fixed to the sensing winding shaft, with steel wire wound around the drive disc. The other end of the steel wire is connected to the slope. The drive disc adopts a passive mechanical drive method, with steel wire pre-tightly wound in the groove on its outer edge. The distal end of the steel wire is rigidly connected to the structure being measured for displacement. When the slope slips, a pulling force is generated, and the steel wire is pulled accordingly, thereby driving the drive disc to rotate. This accurately converts the measured linear displacement into mechanical rotational motion, completing the displacement transmission.

[0014] Furthermore, the transmission unit includes a first synchronous pulley fixed to the sensing winding shaft and a second synchronous pulley fixed to the winding shaft, with a synchronous belt connecting the first and second synchronous pulleys. The steel belt drives the drive disc to rotate, which in turn drives the sensing winding shaft, the winding reel, and the first synchronous pulley to rotate. The optical fiber winds along the sensing winding shaft, and the first synchronous pulley drives the second synchronous pulley to rotate synchronously. The second synchronous pulley drives the second synchronous pulley to rotate synchronously, achieving a 1:1 backlash-free transmission between the first and second synchronous pulleys.

[0015] Furthermore, the drive disc, the sensing winding shaft, and the synchronous pulley are coaxially arranged, and a synchronously rotating winding spool is also coaxially arranged between the sensing winding shaft and the synchronous pulley.

[0016] A method for using a high linearity, large range fiber optic displacement sensor with sensitivity compensation includes the following installation steps: S1: Select the monitoring section, and the installation hole vertically passes through the slope sliding layer and the slope stationary layer in sequence and is fixed to the slope stationary layer. The end of the steel wire in the drive unit is anchored to the installation hole. S2: Fix the fiber optic displacement sensor to a stable platform above the slope sliding layer, install one or more guide wheels, and wrap the steel wire around the guide wheels; S3: Adjust the number of turns of the steel wire wound around the drive disc in the drive unit, and apply a preload to keep the steel wire slightly tensioned. When the slope slips, a pulling force is generated, which drives the drive disc to rotate. The optical fiber is wound along the spiral groove from the small diameter end to the large diameter end, while gradually transitioning from a large pitch to a small pitch. This accurately converts the measured linear displacement into mechanical rotary motion, completing the displacement transfer. By adjusting the unit optical loss and spiral length through a spiral curve with varying pitch and radius, the optical loss and displacement output by the sensor exhibit a linear relationship. S4: Connect the light source and the optical power meter to the two ends of the optical fiber respectively to form a complete optical signal transmission loop; S5: When the monitored section is displaced, the steel wire is pulled, and the drive disc drives the sensing winding shaft, winding reel, synchronous pulley one, synchronous pulley two, and wire guide shaft to rotate synchronously. S6: The ribbon cable shaft drives the meshing ribbon cable slider to slide along the support axis. The optical fiber passes through the ribbon cable slider and is wound around the spiral groove below as the ribbon cable slider moves.

[0017] The specific beneficial effects of this invention include: 1. In this invention, both guide unit one and guide unit two are provided with a frustum-shaped shaft, and the shaft is provided with a non-uniform spiral groove, which provides the core geometric constraint for macro-bending loss control, so that the optical fiber forms a macro-bend with curvature that changes continuously and controllably with linear displacement in a single plane, thereby realizing a stable, monotonic, and calibrable correspondence between optical transmission loss and the measured displacement, and completing passive optical fiber sensing of linear displacement. The drive unit synchronously drives guide unit one and guide unit two to ensure strict matching of the cable laying and fiber winding movements, and realizes the precise guidance of the optical fiber into the groove. The three work together to make the bending radius and winding length of the optical fiber change synergistically with the displacement according to the optimized law, thereby ensuring that the total macro-bending loss has a strict linear relationship with the displacement, and effectively avoiding problems such as optical fiber loosening, overlapping, and slot skipping. 2. This invention constructs a precise displacement-curvature mapping relationship through the synergistic geometric design of non-uniform variable pitch spiral grooves and gradually changing radii. It also achieves precise synchronous fiber arrangement with synchronous wheel trains and cable sliders, and improves fiber bonding stability by combining optical silicone grease. It realizes macro-bending loss sensitivity attenuation compensation and response linearization control from the structural level, and finally obtains displacement sensing performance with a large range, high linear output, stable sensitivity and strong environmental adaptability, which is suitable for the needs of precise monitoring of cross-scale displacement of slopes. 3. The macro-bending loss of optical fiber decreases exponentially with increasing bending radius, which is the fundamental reason for the sharp drop in sensitivity of traditional sensors under large bending ranges. In this invention, the radius of the frustum gradually increases with axial displacement, which would normally lead to a sharp decrease in loss; however, at the same time, the non-uniform variable pitch helical groove causes a controllable change in the winding arc length of the optical fiber within a unit axial displacement. By optimizing the pitch distribution, this arc length increment can be increased synchronously with the increase of radius, thereby compensating for the attenuation of macro-bending loss. 4. This invention is a purely mechanical passive structure that converts exponential macro-bending loss into an output signal that is highly linearly correlated with axial displacement, thereby enabling large-range, highly linear slope displacement monitoring to meet the needs of precise monitoring of cross-scale displacement in slope engineering, from micro-creep to large-scale accelerated sliding. Attached Figure Description

[0018] To more clearly illustrate the embodiments of the present invention, the accompanying drawings used in the description of the embodiments will be briefly introduced below. Obviously, the accompanying 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.

[0019] Figure 1 This is a schematic diagram of the present invention. Figure 1 ; Figure 2 This is a schematic diagram of the present invention. Figure 2 ; Figure 3 This is a schematic diagram of a sensor winding shaft; Figure 4 This is a schematic diagram of the ribbon cable reel; Figure 5 This is a schematic diagram of the ribbon cable slider; Figure 6 This is a schematic diagram of a cable reel; Figure 7 This is a schematic diagram showing the connection relationship between the sensor and the slope in this invention; Figure 8 A calibration curve for the sensor.

[0020] Explanation of icon numbers: 2. Optical fiber; 3. Guiding Unit 1; 4. Guiding Unit 2; 5. Transmission unit; 6. Support frame; 7. Mounting holes; 8. Guide wheels; 11. Drive disc; 12. Steel wire; 14. Winding reel; 15. Tableting; 21. Sensor winding shaft; 22. Spiral groove one; 31. Synchronous pulley one; 32. Synchronous pulley two; 33. Synchronous belt; 40. Limiting groove; 41. Cable guide shaft; 42. Spiral groove two; 43. Cable slider; 44. Guide rod; 45. Guide hole. Detailed Implementation

[0021] The technical solutions of the embodiments of the present invention will be clearly and completely described below with reference to the accompanying drawings. Obviously, the described embodiments are only some embodiments of the present invention, and not all embodiments. Based on the core concept of the present invention and the following embodiments, all other embodiments obtained by those skilled in the art without creative effort are within the scope of protection of the present invention.

[0022] These embodiments are provided to make the application thorough and complete, and to fully express the scope of the application to those skilled in the art. It should be noted that, unless otherwise specifically stated, the relative arrangement of components and steps, material composition, numerical expressions, and values ​​illustrated in these embodiments should be interpreted as merely exemplary and not as limiting.

[0023] All terms used in this application have the same meaning as understood by one of ordinary skill in the art to which this application pertains, unless otherwise specifically defined. It should also be understood that terms defined in general dictionaries should be interpreted as having meanings consistent with their meanings in the context of the relevant art, and not as idealized or highly formalized, unless expressly defined herein.

[0024] Techniques, methods, and equipment known to those skilled in the art may not be discussed in detail, but where appropriate, such techniques, methods, and equipment should be considered part of the specification.

[0025] A high linearity, large range fiber optic displacement sensor with sensitivity compensation, such as Figure 1 , Figure 2 As shown, an optical fiber 2 is included, with one end connected to a light source and the other end sequentially passing through guide unit 2 4 and guide unit 1 3 and connected to an optical power meter. Guide unit 2 4 and guide unit 1 3 are both rotatably connected to a support 6. Guide unit 1 3 is connected to a slope via a drive unit. Guide unit 2 4 rotates synchronously with guide unit 1 3 via a transmission unit 5. Guide unit 2 4 includes a lead screw structure. The optical fiber 2 moves axially with the moving nut in the lead screw structure and is wound around the sensing winding shaft 21 of guide unit 1 3. Geometric constraints are applied to the optical fiber to form a macrobend in a single plane whose curvature changes continuously and controllably with linear displacement. This achieves a stable, monotonic, and calibrable correspondence between optical transmission loss and the measured displacement, completing passive optical fiber sensing of linear displacement.

[0026] Based on the above embodiments, as a preferred embodiment, the lead screw structure includes a cable guide shaft 41 rotatably connected to the bracket and a cable guide slider 43 that slides along the limiting groove 40 of the bracket 6. The cable guide slider 43 is provided with a guide hole 45 for the optical fiber 2 to pass through.

[0027] Based on the above embodiments, as a preferred embodiment, such as... Figure 3 , Figure 4 As shown, the sensing winding shaft 21 and the wiring shaft 41 are both truncated cones. The outer walls of the sensing winding shaft 21 and the wiring shaft 41 are provided with a non-uniform variable pitch helical structure. The pitch near the end of the sensing winding shaft 21 and the wiring shaft 41 with a smaller diameter is greater than the pitch near the end of the sensing winding shaft 21 and the wiring shaft 41 with a larger diameter.

[0028] Specifically, this invention employs a non-uniform variable pitch helical structure, which reduces macrobending loss attenuation compared to uniform pitch or fixed radius structures. The nonlinearity of macrobending loss in uniform pitch or fixed radius structures (which is exponentially related to the radius of curvature) and the decrease in the rate of curvature change per unit displacement under large deformation jointly lead to sensitivity attenuation. However, this invention achieves structural compensation through the synergistic design of a gradient radius and a non-uniform pitch. The gradient radius allows the curvature to change continuously with displacement, while the non-uniform pitch adjusts the arc length of the optical fiber in different curvature regions, making the loss change caused by unit displacement tend to be constant across the entire range. The two are coupled to actively match the loss sensitivity and the rate of curvature change, effectively overcoming the sensitivity attenuation under large deformation and achieving high linearity and wide range sensing.

[0029] Based on the above embodiments, as a preferred embodiment, the spiral structure includes a spiral groove 22 disposed on the outer wall of the sensing winding shaft 21. The optical fiber 2 is wound in the spiral groove 22. When the optical fiber 2 enters the spiral groove 22, its bending radius changes, resulting in a corresponding macro-bending loss. By recording the relationship between macro-bending loss and displacement, the fitting curve is calibrated, thereby realizing the measurement of displacement. The spiral groove 22 is filled with optical grease for the optical fiber 2 to fit the groove body throughout its entire length, ensuring that the optical fiber 2 fits the groove body throughout its entire length without any suspension or offset, thereby improving the stability of the sensing signal and environmental robustness.

[0030] Specifically, fiber 2 is wound along helical groove 22. As the axial displacement increases, the local bending radius r of fiber 2 changes synchronously with the winding arc length. By optimizing the radius gradient and pitch distribution, the increase in winding length actively offsets the exponential attenuation of macrobending loss caused by the increase in radius. This geometrically complementary design makes the rate of increase of total loss with displacement tend to be constant, thereby achieving high linearity signal output across the entire range.

[0031] Based on the above embodiments, as a preferred embodiment, the spiral structure includes a spiral groove 42 disposed on the outer wall of the cable shaft 41, a cable slider 43 slidably connected to the limiting groove 40 of the bracket 6, and a guide rod 44 inserted into the spiral groove 42 on the side of the cable slider 43. The guide rod 44 moves linearly along the spiral groove 42 as the cable shaft 41 rotates. Figure 5 As shown, when the ribbon cable shaft 41 rotates one revolution, the ribbon cable slider 43 moves axially by exactly one lead. The lead matches the pitch of the spiral groove 42. The ribbon cable slider 43 is provided with a guide hole 45. The optical fiber 2 passes through the guide hole 45 and is precisely guided into the spiral groove 22 of the sensing winding shaft 21.

[0032] Based on the above embodiments, as a preferred embodiment, the guide hole 45 is positioned directly above the sensing winding shaft 21, allowing the optical fiber 2 to be precisely wound within the spiral groove 22. The spiral groove 22 and the spiral groove 42 correspond vertically, with the same number of turns and matching pitch variations from beginning to end. For every rotation of the sensing winding shaft 21, the cable tray 41 also rotates precisely one revolution.

[0033] Based on the above embodiments, as a preferred embodiment, the driving unit includes a driving disk 11 fixed to the sensing winding shaft 21. A steel wire 12 is wound around the driving disk 11, with the other end of the steel wire 12 connected to the slope. The driving disk 11 employs a passive mechanical drive method, with the steel wire 12 pre-tightly wound in its outer edge groove. The distal end of the steel wire 12 is rigidly connected to the structure being measured for displacement. When the slope slips, a pulling force is generated, causing the steel wire 12 to be pulled, thereby driving the driving disk 11 to rotate. This accurately converts the measured linear displacement into mechanical rotational motion, completing the displacement transmission.

[0034] Based on the above embodiments, as a preferred embodiment, the transmission unit 5 includes a first synchronous pulley 31 fixed to the sensing winding shaft 21 and a second synchronous pulley 32 fixed to the winding shaft 41. A synchronous belt 33 connects the first synchronous pulley 31 and the second synchronous pulley 32. The steel wire 12 drives the drive disc 11 to rotate, and the drive disc 11 drives the sensing winding shaft 21, the winding reel 14, and the first synchronous pulley 31 to rotate. The optical fiber 2 is wound along the sensing winding shaft 21. The first synchronous pulley 31 drives the second synchronous pulley 32 to rotate synchronously through the belt 33. The second synchronous pulley 32 drives the 41 to rotate synchronously. The first synchronous pulley 31 and the second synchronous pulley 32 achieve a 1:1 backlash-free transmission.

[0035] Based on the above embodiments, as a preferred embodiment, the drive disk 11, the sensing winding shaft 21, and the synchronous pulley 31 are coaxially arranged, and a synchronously rotating winding reel 14 is also coaxially arranged between the sensing winding shaft 21 and the synchronous pulley 31. Figure 6 As shown, the winding reel 14 is provided with a clamping plate 15 for fixing the end of the optical fiber 2, and baffles are provided on both sides of the winding reel 14 to prevent the optical fiber 2 from falling off. The starting end of the optical fiber 2 wound on the winding reel 14 is rigidly pressed and fixed to the core shaft of the winding reel 14 by the miniature optical fiber clamping plate 15. The optical fiber 2 is wound in an orderly multi-layer manner on the core shaft of the winding reel 14 with constant micro-tension, without looseness or stacking; the clamping plate 15 and the winding reel 14 are fixedly connected by screws to prevent the starting end of the optical fiber from being pulled out.

[0036] A method for using a high linearity, large range fiber optic displacement sensor with sensitivity compensation includes the following installation steps: S1: Select a monitoring section on the slip surface between the slope sliding layer and the stationary layer. The installation hole 7 vertically passes through the slope sliding layer and the slope stationary layer in sequence and is fixed to the slope stationary layer. The end of the steel wire 12 in the drive unit is anchored to the installation hole 7. S2: Fix the fiber optic displacement sensor to a stable platform above the slope sliding layer, install one or more guide wheels 8 and adjust their angle, and wrap the steel wire 12 around the guide wheel 8 to ensure that the steel wire can pass through smoothly. S3: Adjust the number of turns of the steel wire 12 wound around the drive disk 11 in the drive unit, and apply a preload to keep the steel wire 12 slightly tensioned to ensure error-free displacement transmission; when the slope slips, a pulling force is generated, which drives the drive disk 11 to rotate. The optical fiber 2 starts to wind along the spiral groove 22 from the small diameter end and gradually winds to the large diameter end. At the same time, it gradually transitions from a large pitch to a small pitch, accurately converting the measured linear displacement into mechanical rotary motion and completing the displacement transmission; by adjusting the unit optical loss and spiral length through a spiral curve with variable pitch and variable radius, the optical loss and displacement output by the sensor show a linear relationship; S4: Connect the light source and the optical power meter to the two ends of optical fiber 2 respectively to form a complete optical signal transmission loop; S5: When the monitored section is displaced, the steel wire 12 is pulled, and the drive disc 11 drives the sensing winding shaft 21, the winding disc 14, the synchronous pulley 31, the synchronous pulley 32, and the wire guide shaft 41 to rotate synchronously; the number of rotations of the sensing winding shaft 21 corresponds one-to-one with the displacement of the steel wire 12. S6: The cable shaft 41 drives the meshing cable slider 43 to slide axially along the limiting groove 40 of the bracket 6. The optical fiber 2 passes through the guide hole 45 on the cable slider 43 and is wound in the spiral groove 22 below as the cable slider 43 moves.

[0037] Specifically, the stable light signal emitted by the light source is transmitted through the optical fiber 2 and enters the spiral groove 22 of the sensing winding shaft 21. The spiral groove 22 is a gradually changing radius and non-uniform pitch coupling structure. The optical fiber forms a continuous and controlled bend in the groove, generating a stable and adjustable macro-bending loss. When the cable slider 43 drives the optical fiber 2 to move axially, the winding length and bending radius of the optical fiber 2 in the spiral groove 22 of the sensing winding shaft 21 change in tandem with the measured displacement: the smaller the bending radius and the longer the winding length, the greater the macro-bending loss, realizing a linear correspondence between the measured displacement and the macro-bending loss.

[0038] Specifically, the optical signal attenuated in the bending region is detected in real time by an optical power meter, and the change in optical power is positively correlated with the macro-bending loss. Through the pre-calibrated optical power-displacement calibration curve, the real-time displacement of the measured structure can be accurately calculated, realizing continuous, highly linear, and high-resolution displacement monitoring.

[0039] This invention converts the elongation displacement of the steel wire into the rotation angle of the main shaft, thereby driving the optical fiber to move along a spiral groove with a gradually changing radius and non-uniform pitch, so that the macrobending loss of the optical fiber changes monotonically with the displacement.

[0040] Experiments show that: Within a measurement range of 0–120 mm, the sensor in this application exhibits a displacement-loss fitting determination coefficient R² = 0.9987, a nonlinearity error < ±0.8% FS (full scale), and a sensitivity of 0.085 dB / mm. Compared to the traditional cylindrical helical structure (measurement range only 40 mm, nonlinearity error ±4.2%), the linearity and measurement range are significantly improved, achieving high linearity (R² > 0.998) and a large measurement range (≥ 100 mm) passive monitoring of slope displacement. This invention utilizes a fiber optic displacement sensor with large range coverage, high linearity output across the entire range, and stable sensitivity to meet the precise monitoring needs of cross-scale displacement in slope engineering, ranging from minute creep to large-scale accelerated slip.

[0041] All aspects not detailed in this invention are conventional technical means known to those skilled in the art.

[0042] The above content shows and describes the basic principles, main features, and beneficial effects of the present invention. The above description is merely a preferred embodiment of the present invention and is not intended to limit the invention. Any modifications, equivalent substitutions, or improvements made within the spirit and principles of the present invention should be included within the scope of protection of the present invention.

Claims

1. A high linearity, large-range fiber optic displacement sensor with sensitivity compensation, characterized in that: The optical fiber (2) is connected to the light source at one end and passes through the second guide unit (4) and the first guide unit (3) in sequence and is connected to the optical power meter at the other end. The second guide unit (4) and the first guide unit (3) are rotatably connected to the bracket (6). The first guide unit (3) is connected to the slope through the drive unit. The second guide unit (4) rotates synchronously with the first guide unit (3) through the transmission unit (5). The second guide unit (4) includes a screw structure. The optical fiber (2) moves axially with the moving nut in the screw structure and is wound on the sensing winding shaft (21) of the first guide unit (3).

2. The high linearity, large range fiber optic displacement sensor with sensitivity compensation according to claim 1, characterized in that: The lead screw structure includes a cable shaft (41) rotatably connected to the bracket and a cable slider (43) sliding along the limiting groove (40) of the bracket (6). The cable slider (43) is provided with a guide hole (45) for the optical fiber (2) to pass through.

3. The high linearity, large range fiber optic displacement sensor with sensitivity compensation according to claim 2, characterized in that: The sensing winding shaft (21) and the wiring shaft (41) are both truncated cones. The outer walls of the sensing winding shaft (21) and the wiring shaft (41) are provided with a non-uniform variable pitch spiral structure. The pitch near the end with the smaller diameter of the sensing winding shaft (21) and the wiring shaft (41) is greater than the pitch near the end with the larger diameter of the sensing winding shaft (21) and the wiring shaft (41).

4. The high linearity, large range fiber optic displacement sensor with sensitivity compensation according to claim 3, characterized in that: The spiral structure includes a spiral groove (22) disposed on the outer wall of the sensing winding shaft (21), the optical fiber (2) is wound in the spiral groove (22), and the spiral groove (22) is filled with optical grease for the optical fiber (2) to fit the groove body throughout.

5. The high linearity, large range fiber optic displacement sensor with sensitivity compensation according to claim 3, characterized in that: The spiral structure includes a spiral groove 2 (42) disposed on the outer wall of the cable shaft (41), and a guide rod (44) inserted into the spiral groove 2 (42) is disposed on the side of the cable slider (43).

6. The high linearity, large range fiber optic displacement sensor with sensitivity compensation according to claim 5, characterized in that: The guide hole (45) is located directly above the sensing winding shaft (21), and the pitch variation range of the spiral groove one (22) and the spiral groove two (42) are matched.

7. The high linearity, large range fiber optic displacement sensor with sensitivity compensation according to any one of claims 1-7, characterized in that: The drive unit includes a drive disk (11) fixed to the sensing winding shaft (21), the drive disk (11) is wound with a steel wire (12), and the other end of the steel wire (12) is connected to the slope.

8. The high linearity, large range fiber optic displacement sensor with sensitivity compensation according to any one of claims 1-7, characterized in that: The transmission unit (5) includes a first synchronous pulley (31) fixed to the sensing winding shaft (21) and a second synchronous pulley (32) fixed to the winding shaft (41). A synchronous belt (33) connects the first synchronous pulley (31) and the second synchronous pulley (32).

9. The high linearity, large range fiber optic displacement sensor with sensitivity compensation according to claim 8, characterized in that: The drive disk (11), the sensing winding shaft (21), and the first synchronous pulley (31) are coaxially arranged, and a synchronously rotating winding spool (14) is also coaxially arranged between the sensing winding shaft (21) and the first synchronous pulley (31).

10. A method of using a high linearity large-range fiber optic displacement sensor with sensitivity compensation, comprising the high linearity large-range fiber optic displacement sensor with sensitivity compensation as described in any one of claims 2-9, characterized in that: The installation process includes the following steps: S1: Select the monitoring section, install the hole (7) vertically through the slope sliding layer and the slope stationary layer in sequence and fix it to the slope stationary layer, and anchor the end of the steel wire (12) in the drive unit to the installation hole (7); S2: Fix the fiber optic displacement sensor to a stable platform above the slope sliding layer, install one or more guide wheels (8), and wrap the steel wire (12) around the guide wheels (8); S3: Adjust the number of turns of the steel wire (12) on the drive disc (11) in the drive unit, and apply a preload to make the steel wire (12) slightly taut; S4: Connect the light source and the optical power meter to the two ends of the optical fiber (2) respectively; S5: When the monitored section is displaced, the steel wire (12) is pulled, and the drive disc (11) drives the sensing winding shaft (21), winding disc (14), synchronous wheel one (31), synchronous wheel two (32), and winding shaft (41) to rotate synchronously; S6: The ribbon cable shaft (41) drives the meshing ribbon cable slider (43) to slide axially along the limiting groove (40) of the bracket (6). The optical fiber (2) passes through the guide hole (45) on the ribbon cable slider (43) and is wound in the spiral groove (22) below as the ribbon cable slider (43) moves.

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