Optical fiber tilt angle sensor

Abstract

The invention discloses an optical fiber tilt angle sensor, which comprises a mounting cylinder provided with an accommodating cavity with an upper opening; the cylinder cover detachably covers the upper end of the accommodating cavity; the mounting seat is detachably mounted on the barrel cover, and a vertically-penetrating wire passing hole is formed in the center of the mounting seat; the upper end of the elastic metal sheet is fixedly connected with the bottom of the mounting base, the bottom of the elastic metal sheet is connected with a balancing weight, and the elastic metal sheet is provided with a wire passing notch with an upper opening and aligned with the wire passing hole; the bottom of the wire passing gap is provided with two slots, and the two slots respectively form embedding ports on the two side surfaces of the elastic metal sheet. Positioning grooves are formed in the peripheral walls of the two ends of the insertion groove; the two optical fibers are provided with extension sections and Bragg grating sections; bragg grating sections of the two optical fibers are fixedly installed in the two slots respectively, and radial protrusions embedded into the positioning grooves are arranged on the peripheral walls of the two ends of the Bragg grating sections. According to the invention, the Bragg grating section can better follow the deformation of the elastic metal sheet, so that the measurement precision and reliability of the sensor are improved.

Description

Technical Field

[0001] The invention relates to the technical field of tilt angle measurement, and in particular to an optical fiber tilt angle sensor. Background Art

[0002] Tilt sensing is an important technology widely used in industries such as industry, construction, and transportation. It is mainly used to measure the tilt angle or change of an object relative to the ground. With the development of modern science and technology, the demand for tilt sensing technology continues to grow, and it plays an important role in scenarios such as structural health monitoring, equipment attitude control, and navigation. Early tilt measurements relied on bubble levels, which were simple and reliable, but limited in sensitivity and accuracy.

[0003] Fiber optic tilt sensors are gaining more and more attention due to their high sensitivity, resistance to electromagnetic interference, and ability to adapt to harsh environments. This type of sensor uses refraction, reflection, or grating effect inside the optical fiber to detect changes in tilt angles, and is suitable for long-distance monitoring and high-precision applications. Usually, the grating segment of the optical fiber is connected to the deformable part so that it can follow the deformation of the deformable part to achieve measurement. However, the connection between the grating segment and the deformable part is not tight and stable enough, which can easily cause the grating segment to not follow the deformation of the deformable part well, affecting the measurement results. Summary of the invention

[0004] The present invention aims to solve at least one of the technical problems existing in the prior art. To this end, the present invention provides an optical fiber tilt sensor.

[0005] To achieve the above purpose, the technical solution adopted by the present invention is as follows: A fiber optic inclination sensor comprises: a mounting tube having an accommodating cavity with an upper opening; a tube cover, which is a detachable cover arranged at the upper end of the accommodating cavity; a mounting seat, which is detachably mounted on the tube cover and has a wire-passing hole running vertically through the center; an elastic metal sheet, whose upper end is fixedly connected to the bottom of the mounting seat and whose bottom is connected to a counterweight block, and the elastic metal sheet is provided with a wire-passing notch with an upper opening and aligned with the wire-passing hole; two slots are arranged at the bottom of the wire-passing notch, and the two slots are respectively provided with embedding openings formed on two side surfaces of the elastic metal sheet; positioning slots are arranged on the peripheral walls at both ends of the slots; two optical fibers have an extension section and a Bragg grating section, and the extension sections are both passed through the wire-passing hole and the wire-passing notch; the Bragg grating sections of the two optical fibers are respectively fixedly mounted on the two slots, and the outer peripheral walls at both ends of the Bragg grating sections are provided with radial protrusions embedded in the positioning slots.

[0006] Furthermore, the counterweight block is hinged to the bottom of the elastic metal sheet, and the hinge axis of the counterweight block is perpendicular to the thickness direction of the elastic metal sheet.

[0007] Furthermore, a raised limit block is provided at the bottom of the cylinder cover, and a limit hole is provided on the limit block; a mounting block is provided on the peripheral wall of the accommodating cavity, and the mounting block is provided with a through hole, in which a movable column is movably inserted, one end of the movable column is provided with a plug, and the other end is detachably connected to a dial ring, and a resist ring is provided at the inner end of the plug, and a spring is sleeved on the movable column; one end of the spring abuts against the resist ring, and the other end abuts against the mounting block; the movable column has a limited state and a disassembly state; in the limited state, the dial ring abuts against the mounting block, and the plug is inserted into the limited hole; the plug in the disassembly state is separated from the limited hole; a movable cylinder is provided with a movable sleeve on the outer periphery of the mounting cylinder, and the movable cylinder is provided with a lever that passes through the cylinder wall of the mounting cylinder and is inserted into the accommodating cavity, and the rotation of the movable cylinder can drive the lever to move the dial ring, thereby making the movable column move from the limited state to the disassembly state.

[0008] Furthermore, the upper end of the shifting ring protrudes from the mounting block, the shifting rod is in contact with the upper end of the shifting ring, and the shifting rod is higher than the mounting block.

[0009] Furthermore, a cylinder wall of the installation cylinder is provided with a movable notch with an upper opening, and the shifting rod is passed through the movable notch.

[0010] Furthermore, the movable notch has two end walls, and when the shift rod abuts against the two end walls respectively, the movable column is in a limited state and a disassembled state respectively.

[0011] Furthermore, the mounting seat includes a top plate and a column, the column is connected to the bottom of the top plate, a socket for inserting the column is provided in the center of the tube cover, a clamping block is provided on the peripheral wall of the bottom of the column, a through groove for the clamping block to pass through is provided on the peripheral wall of the socket, the clamping block can rotate to be staggered with the through groove after passing through the through groove, a sink groove for the top plate to be embedded is provided on the upper end of the socket, an elastic clamping column with elastic lifting and lowering movement is installed on the bottom wall of the sink groove, and a positioning hole is provided on the bottom surface of the top plate; when the elastic clamping column is inserted into the positioning hole, the clamping block is staggered with the through groove, the bottom surface of the top plate is in contact with the bottom wall of the sink groove, and the clamping block is in contact with the bottom surface of the tube cover.

[0012] Furthermore, a positioning stopper is provided on the bottom surface of the cylinder cover. When the clamping block abuts against the positioning stopper, the clamping block is staggered with the through groove, and the elastic clamping column is aligned with the positioning hole; an unlocking hole extending to the top surface of the top plate is provided on the top of the positioning hole.

[0013] Furthermore, it also includes a fixing piece connected to the elastic metal sheet and used for limiting the Bragg grating segment in the slot.

[0014] Furthermore, the fixing member is a connecting plate, and embedded parts are provided at both ends of the connecting plate. The radial protrusions are provided in two groups and the two groups of radial protrusions are respectively provided at both ends of the Bragg grating segment. The two radial protrusions in the same group are formed with annular grooves, and the embedded parts are embedded in the corresponding annular grooves.

[0015] The present invention has the following beneficial effects: By fixing the Bragg grating segment of the optical fiber in the slot of the elastic metal sheet, and using the cooperation of the radial protrusion and the positioning groove, the tight connection between the optical fiber Bragg grating segment and the elastic metal sheet is ensured, so that the Bragg grating segment can stably follow the deformation of the elastic metal sheet, thereby accurately reflecting the change of the tilt angle, avoiding the measurement error caused by the loose connection between the grating segment and the deformed parts in the traditional optical fiber tilt sensor, and significantly improving the measurement accuracy and stability of the sensor. The detachable installation barrel, barrel cover and mounting seat design make the installation and replacement of the optical fiber more convenient. When tilting occurs, the counterweight block will drive the elastic metal sheet to deform, the Bragg grating segment on one side will be pulled, and the Bragg grating segment on the other side will be compressed, which can accurately sense the deformation caused by the tilt. And through the detachable connection between the barrel cover and the mounting seat, the installation and maintenance of the optical fiber are convenient, further improving the practicality and economy of the sensor.

[0016] In addition to the above-described purposes, features and advantages, the present invention has other purposes, features and advantages. The present invention will be further described in detail with reference to the accompanying drawings. BRIEF DESCRIPTION OF THE DRAWINGS

[0017] The drawings constituting a part of this application are used to provide a further understanding of the present invention. The exemplary embodiments of the present invention and their descriptions are used to explain the present invention and do not constitute an improper limitation of the present invention. In the drawings: Figure 1 is a schematic diagram of the overall structure of an embodiment of the present invention; Figure 2 is an internal cross-sectional view of an embodiment of the present invention; Figure 3 yes Figure 1 Schematic diagram of the decomposed state structure; Figure 4 It is a schematic diagram of the local structure in the limit state; Figure 5 It is a schematic diagram of the local structure in a disassembled state; Figure 6 It is a schematic diagram of the local structural decomposition at the movable column; Figure 7 It is a schematic diagram of the connection structure of the cylinder cover, the mounting seat and the elastic metal sheet; Figure 8 yes Figure 7 A magnified view of point A; Fig. 9 It is a schematic diagram of the decomposed state structure at the Bragg grating segment; Fig.10 yes Figure 7 A partial view of the exploded state; Fig.11 It is a schematic diagram of the structure of the mounting base and the cylinder cover in an exploded state; Fig.12 It is a partial cross-sectional view of the elastic clamping column; Fig.13 It is a schematic diagram of the connection between the optical fiber tilt sensor of the present invention and an optical fiber splitter, a broadband light source, and an optical spectrum analyzer; Fig.14 is a spectrum diagram of the detection output of an embodiment of the present invention; Fig.15 It is the fitting diagram of the central wavelength difference and the tilt angle.

[0018] Legend: The mounting cylinder 100, the accommodating cavity 110, the mounting block 120, the through hole 121, the movable column 130, the plug 131, the pull ring 132, the resisting ring 133, the spring 134, the movable notch 140, and the end wall 141; The cylinder cover 200, the limiting block 210, the limiting hole 211, the insertion hole 220, the through slot 221, the sinking slot 230, the installation slot 231, the elastic clamping column 240, the positioning block 250, and the positioning protrusion 260; Mounting seat 300, wire hole 301, top plate 310, positioning hole 311, unlocking hole 312, plug post 320, and block 321; The elastic metal sheet 400, the counterweight block 410, the wire notch 420, the slot 421, and the positioning slot 422; Optical fiber 500, extension section 510, Bragg grating section 520, radial protrusion 521, annular groove 522; A connecting plate 600 and an embedding portion 610; A movable cylinder 700 and a lever 710; Fiber optic splitter 800 , broadband light source 801 , and spectrum analyzer 802 . DETAILED DESCRIPTION

[0019] It should be understood that the specific embodiments described herein are only used to explain the present invention, and are not used to limit the present invention.

[0020] The following will be combined with the drawings in the embodiments of the present invention to clearly and completely describe the technical solutions in the embodiments of the present invention. Obviously, the described embodiments are only part of the embodiments of the present invention, not all of the embodiments. Based on the embodiments of the present invention, all other embodiments obtained by ordinary technicians in this field without creative work are within the scope of protection of the present invention.

[0021] It should be noted that all directional indications (such as up, down, left, right, front, back, etc.) in the embodiments of the present invention are only used to explain the relative position relationship, movement status, etc. between the components under a certain specific posture (as shown in the accompanying drawings). If the specific posture changes, the directional indication will also change accordingly.

[0022] In addition, the descriptions of "first", "second", etc. in the present invention are only used for descriptive purposes and cannot be understood as indicating or implying their relative importance or implicitly indicating the number of the indicated technical features. Therefore, the features defined as "first" and "second" may explicitly or implicitly include at least one of the features. In addition, the technical solutions between the various embodiments can be combined with each other, but they must be based on the ability of ordinary technicians in the field to implement them. When the combination of technical solutions is contradictory or cannot be implemented, it should be deemed that such a combination of technical solutions does not exist and is not within the scope of protection required by the present invention.

[0023] Please refer to Figure 1 and Figure 2 A fiber optic tilt sensor in a preferred embodiment of the present invention includes a mounting tube 100, a tube cover 200, a mounting seat 300, an elastic metal sheet 400, and an optical fiber 500.

[0024] The mounting tube 100 has a receiving chamber 110 with an upper opening. The tube cover 200 is detachably disposed on the upper end of the receiving chamber 110, thereby forming a sealed space to protect the elastic metal sheet 400 and the optical fiber 500.

[0025] The mounting seat 300 can be detachably mounted on the barrel cover 200, and a wire hole 301 is vertically penetrated in the center of the mounting seat 300. The upper end of the elastic metal sheet 400 is fixedly connected to the bottom of the mounting seat 300. Specifically, the upper end of the elastic metal sheet 400 can be connected to the mounting seat 300 through a fastener, or the upper end of the elastic metal sheet 400 is inserted into the mounting seat 300 and connected through a fastener. Of course, the elastic metal sheet 400 and the mounting seat 300 can also be integrally formed. A counterweight block 410 is connected to the bottom of the elastic metal sheet 400, and the elastic metal sheet 400 is provided with a wire notch 420 with an upper opening aligned with the wire hole 301, so that the wire harness can extend out. Refer to Fig. 9Two slots 421 are provided at the bottom of the wire notch 420. The two slots 421 are respectively provided with embedded openings on the two sides of the elastic metal sheet 400, that is, the two slots 421 are arranged at intervals along the thickness direction of the elastic metal sheet 400. The upper ends of the slots 421 are connected to the wire notch 420. The slots 421 are provided with embedded openings on the sides of the elastic metal sheet 400 close to the wire notch 420, so as to facilitate embedding from the embedded openings during installation. For example, if the thickness direction of the elastic metal sheet 400 is the left-right direction, the two slots 421 are arranged at intervals on the left-right direction, and the slot 421 on the left side forms an embedded opening on the left side of the elastic metal sheet 400, and the slot 421 on the right side forms an embedded opening on the right side of the elastic metal sheet 400. Positioning grooves 422 are provided on the peripheral walls at both ends of the slots 421.

[0026] Two optical fibers 500 are provided, and the optical fibers 500 have an extension section 510 and a Bragg grating section 520. The extension section 510 is passed through the wire hole 301 and the wire notch 420. The Bragg grating sections 520 of the two optical fibers 500 are fixedly installed in the two slots 421 respectively. The Bragg grating sections 520 can be fixed in the slots 421 by additional connectors, or by filling the slots 421 with glue, such as casting glue and welding glue. Of course, a metal layer can also be coated on the outside of the Bragg grating section 520, and the metal layer is welded to the elastic metal sheet 400 to fix the Bragg grating section 520. The outer peripheral walls at both ends of the Bragg grating section 520 are provided with radial protrusions 521 embedded in the positioning grooves 422.

[0027] The optical fiber tilt sensor provided by the present invention ensures the tight connection between the optical fiber Bragg grating segment 520 and the elastic metal sheet 400 by fixing the Bragg grating segment 520 of the optical fiber 500 in the slot 421 of the elastic metal sheet 400, and uses the cooperation between the radial protrusion 521 and the positioning groove 422, so that the Bragg grating segment 520 can stably follow the deformation of the elastic metal sheet, thereby accurately reflecting the change of the tilt angle, avoiding the measurement error caused by the loose connection between the grating segment and the deformed parts in the traditional optical fiber tilt sensor, and significantly improving the measurement accuracy and stability of the sensor. The detachable installation cylinder, cylinder cover and mounting seat design are adopted to make the installation and replacement of the optical fiber more convenient. When tilting occurs, the counterweight block 410 will drive the elastic metal sheet 400 to deform, the Bragg grating segment 520 on one side is pulled, and the Bragg grating segment 520 on one side is compressed, so that the deformation caused by the tilt can be accurately sensed. And through the detachable connection between the cylinder cover 200 and the mounting seat 300, the installation and maintenance of the optical fiber 500 are convenient, and the practicality and economy of the sensor are further improved.

[0028] Reference Figure 2In some embodiments of the present invention, the counterweight 410 is hinged to the bottom of the elastic metal sheet 400, and the hinge axis of the counterweight 410 is perpendicular to the thickness direction of the elastic metal sheet 400. Thus, the counterweight 410 is movably connected to the bottom of the elastic metal sheet 400, so that the counterweight 410 can change its posture according to the tilt angle, avoiding the rigid connection between the counterweight 410 and the bottom of the elastic metal sheet 400, which causes stress concentration at the connection.

[0029] Reference Figure 3 , Figure 4 , Figure 5 and Figure 6 In a further embodiment of the present invention, a raised stopper block 210 is provided at the bottom of the barrel cover 200, and a stopper hole 211 is provided on the stopper block 210; a mounting block 120 is provided on the peripheral wall of the accommodating cavity 110, and a through hole 121 is provided on the mounting block 120, and a movable column 130 is movably inserted in the through hole 121, and the through hole 121 is adapted to the cross section of the movable column 130 to play a role in movable guiding and positioning. A plug 131 is provided at one end of the movable column 130, and a dial ring 132 is detachably connected to the other end. Specifically, a stud is provided at the other end of the movable column 130, and a threaded hole is provided in the center of the dial ring 132 to be threadedly connected to the stud, so as to facilitate installation and disassembly. A retaining ring 133 is provided at the inner end of the plug 131, and a spring 134 is sleeved on the movable column 130; one end of the spring 134 abuts against the retaining ring 133, and the other end abuts against the mounting block 120, thereby applying elastic force to the plug 131, so that when it is aligned with the limiting hole 211, it can automatically insert into the limiting hole 211 to realize the vertical limiting of the cylinder cover 200; the movable column 130 has a limiting state and a disassembled state. Figure 2 and Figure 4 As shown, in the limited position, the pull ring 132 abuts against the mounting block 120, and the plug 131 is inserted into the limited hole 211. In order to facilitate the insertion, the end of the plug 131 is provided with a chamfer, and at this time, the cylinder cover 200 fits with the upper end surface of the mounting cylinder 100 to seal the upper end of the accommodating cavity 110. Figure 5 As shown, the plug 131 in the disassembled state is separated from the limiting hole 211, and the limiting block 210 is released at this time, and the cylinder cover 200 can be directly pulled upward to realize the disassembly of the cylinder cover 200 and the installation cylinder 100. The outer circumference of the installation cylinder 100 is provided with a movable cylinder 700, and the movable cylinder 700 is provided with a lever 710 that passes through the cylinder wall of the installation cylinder 100 and is inserted into the accommodating cavity 110. The rotation of the movable cylinder 700 can drive the lever 710 to move the dial ring 132, so that the movable column 130 moves from the limiting state to the disassembled state. When there is no external force, if the plug 131 is aligned with the limiting hole 211, it can automatically return to the limiting state under the action of the spring 134. The spring 134 can be specifically a compression spring.

[0030] Therefore, the state of the movable column 130 can be switched by rotating the movable cylinder 700 outside the accommodating cavity 110, thereby realizing the installation and removal of the cylinder cover 200, and the operation is simple and convenient.

[0031] Reference Figure 4 , Figure 5 and Figure 6 In a further embodiment of the present invention, the upper end of the dial ring 132 protrudes from the mounting block 120, the dial rod 710 contacts the upper end of the dial ring 132, and the dial rod 710 is higher than the mounting block 120, so that the dial rod 710 can rotate to avoid the mounting block 120 to dial the dial ring 132, thereby avoiding structural interference. Moreover, the fact that the dial rod 710 is higher than the mounting block 120 also means that during installation, the dial rod 710 does not need to pass over the mounting block 120 and the movable column 130, thereby avoiding structural interference during installation.

[0032] Reference Figure 4 , Figure 5 and Figure 6 In a further embodiment of the present invention, the wall of the mounting tube 100 is provided with a movable notch 140 with an upper opening, and the lever 710 is passed through the movable notch 140 and can rotate and swing in the movable notch 140 to drive the lever ring 132 and the movable column 130 to move. During installation, first install the movable column 130 on the mounting block 120, and then install the movable cylinder 700. The lever 710 is inserted into the movable notch 140 from the upper end of the movable notch 140, and then the movable cylinder 700 is rotated so that the lever 710 moves the dial ring 132 and the movable column 130 to the disassembly state. Then the cylinder cover 200 is installed. After the cylinder cover 200 is in place, the movable cylinder 700 is released. Under the action of the spring 134, the plug 131 of the movable column 130 is inserted into the limiting hole 211, and the installation is completed. For disassembly, the movable cylinder 700 is rotated so that the lever 710 moves the dial ring 132 and the movable column 130 to the disassembly state. After the plug 131 is out of the limiting hole 211, the cylinder cover 200 can be directly removed upwards. It can be understood that in order for the cylinder cover 200 to be installed in the specified position during installation so that the plug 131 is aligned with the limiting hole 211, there is no need to repeatedly rotate and adjust the position of the cylinder cover 200. Refer to Figure 7 A positioning protrusion 260 is provided on the surface of the tube cover 200 that fits with the upper end surface of the installation tube 100. The positioning protrusion 260 is embedded in the upper end of the movable notch 140 to achieve circumferential positioning. Therefore, during installation, it is only necessary to embed the positioning protrusion 260 into the movable notch 140 to ensure that the limiting hole 211 can be accurately aligned with the plug 131.

[0033] Reference Figure 4 , Figure 5In a further embodiment of the present invention, the movable notch 140 has two end walls 141. When the lever 710 respectively abuts against the two end walls 141, the movable column 130 is respectively in a limited state and a disassembled state. That is, when the lever 710 needs to switch the state of the movable column 130, it only needs to be rotated until it abuts against the other end wall 141 to indicate that the switching is completed, which is convenient for judgment during operation.

[0034] Reference Figure 8 , Fig.10 , Fig.11 and Fig.12 In some embodiments of the present invention, the mounting base 300 includes a top plate 310 and a plug post 320, the plug post 320 is connected to the bottom of the top plate 310, a plug hole 220 for the plug post 320 to be inserted is provided in the center of the cylinder cover 200, a block 321 is provided on the peripheral wall of the bottom of the plug post 320, a through groove 221 for the block 321 to pass through is provided on the peripheral wall of the plug hole 220, the block 321 can pass through the through groove 221 and then rotate to be staggered with the through groove 221, a sink 230 for the top plate 310 to be embedded is provided on the upper end of the plug hole 220, an elastic plug post 240 with elastic lifting and lowering movement is installed on the bottom wall of the sink groove 230, and a positioning hole 311 is provided on the bottom surface of the top plate 310; when the elastic plug post 240 is inserted into the positioning hole 311, the block 321 is staggered with the through groove 221, the bottom surface of the top plate 310 is in contact with the bottom wall of the sink groove 230, and the block 321 is in contact with the bottom surface of the cylinder cover 200. The bottom surface of the top plate 310 is fitted with the bottom wall of the sink 230, and the block 321 is fitted with the bottom surface of the cylinder cover 200 to achieve the vertical positioning of the mounting seat 300. Then, the elastic clamping column 240 is clamped into the positioning hole 311 to achieve the circumferential positioning of the mounting seat 300, so that the block 321 and the through groove 221 are kept staggered, thereby achieving the stable positioning and installation of the mounting seat 300. No fasteners are required for installation and fixation, which is convenient for subsequent disassembly and maintenance. In order to facilitate disassembly, the cross-sectional profile of the elastic metal sheet 400 and the counterweight block 410 is smaller than the insertion hole 220, so that it can directly pass through the insertion hole 220 and thus be detached as a whole with the mounting seat 300.

[0035] Reference Figure 8 , Fig.10 , Fig.11 and Fig.12In a further embodiment of the present invention, a positioning block 250 is provided on the bottom surface of the cylinder cover 200. When the block 321 abuts against the positioning block 250, the block 321 is staggered with the through slot 221, and the elastic clamping column 240 is aligned with the positioning hole 311, so as to facilitate the alignment of the elastic clamping column 240 with the positioning hole 311; the top of the positioning hole 311 is provided with an unlocking hole 312 extending to the top surface of the top plate 310. During installation, the block 321 is aligned with the through slot 221 and inserted until the bottom surface of the top plate 310 fits with the bottom wall of the sink 230. At this time, the upper end surface of the block 321 is flush with the bottom surface of the cylinder cover 200, and then the mounting seat 300 is rotated until the block 321 abuts against the positioning block 250. At this time, the elastic clamping column 240 is aligned with the positioning hole 311 and the elastic clamping column 240 is clamped into the positioning hole 311 under the action of the elastic force to realize the circumferential positioning of the mounting seat 300. When unlocking is required, the cylinder cover 200 does not need to be removed. The ejector pin can be inserted from the unlocking hole 312, and the elastic clamping column 240 can be pushed out of the positioning hole 311, and then the mounting seat 300 can be rotated until the clamping block 321 is aligned with the through groove 221 and then the mounting seat 300 is pulled upward, so as to facilitate installation. It can be understood that in order to achieve stable installation of the elastic clamping column 240, a guide column is provided at the bottom of the elastic clamping column 240, a mounting groove 231 is provided at the bottom wall of the sink 230, a guide hole is provided at the bottom wall of the mounting groove 231, a nut is passed through the guide hole and connected to the bottom of the guide column, and a compression spring is sleeved on the guide column, so as to achieve elastic and movable installation of the elastic clamping column 240.

[0036] Reference Figures 7 to 9 In some embodiments of the present invention, a fixing member is further included, which is connected to the elastic metal sheet 400 and is used to limit the Bragg grating segment 520 in the slot 421, thereby playing a role in limiting and fixing the Bragg grating segment 520, and when it is necessary to fill glue in the slot 421, it can ensure that the position of the Bragg grating segment 520 is stable during the filling process.

[0037] In a specific embodiment of the present invention, the fixing member is a connecting plate 600, which is attached to the elastic metal sheet 400 and is provided with corresponding holes to be connected and fixed by fasteners. Embedding portions 610 are provided at both ends of the connecting plate 600, and two groups of radial protrusions 521 are provided, and the two groups of radial protrusions 521 are respectively provided at both ends of the Bragg grating segment 520, and the two radial protrusions 521 of the same group are formed with annular grooves 522, and the embedding portion 610 is embedded in the corresponding annular grooves 522. The embedding portion 610 is specifically a circular arc plate, and the semicircular arc plate is embedded in the annular groove 522 formed between the two radial protrusions 521, so as to position and fix the two ends of the Bragg grating segment 520.

[0038] Its working principle is: refer to Fig.13One side of the fiber optic splitter 800 is connected to two optical fibers 500, and the other side has two interfaces connected to a broadband light source 801 and a spectrum analyzer 802 respectively. The light emitted by the light source enters the two optical fibers 500 through a 2×2 splitter, and the light passing through two Bragg grating segments 520 is reflected back to the spectrometer for reception and demodulation. The optical fiber is a SMF-28 standard single-mode optical fiber, and the central wavelengths of the two optical fibers 500 are 1545.6nm and 1550.3nm respectively. The surface coating of the fiber grating is removed and replaced with a copper coating with a thickness of 25μm. The two copper-coated Bragg grating segments 520 are fixed on two symmetrical surfaces of the elastic metal sheet 400. The tilt sensitivity of the sensor can be adjusted by changing the length, thickness and weight of the elastic metal sheet 400.

[0039] When the sensor is tilted, the two Bragg grating segments 520 will be pulled or compressed respectively, causing the spectrum to redshift and blueshift respectively. The tilt angle can be determined based on the drift of the spectrum of the two Bragg grating segments 520. When the sensor tilt angle changes, the bending stress of the mass block on the two FBGs (Bragg grating segments 520) changes, causing the spectrum drift to change. Therefore, the sensor tilt angle can be obtained based on the drift of the FBG central wavelength.

[0040] In one embodiment, when performing tilt detection, the output spectrum is as follows: Fig.14 The fitting straight line of the difference between the central wavelengths of the two Bragg grating segments 520 and the tilt angle is shown in Fig.15 As shown. Since the temperature sensitivity of the two FBGs (Bragg grating segment 520) is the same, when the temperature changes, the difference in the central wavelengths of the two FBGs is not affected by the temperature, so the optical fiber tilt sensor is insensitive to temperature.

[0041] The above are only preferred embodiments of the present invention and are not intended to limit the present invention. For those skilled in the art, the present invention may have various modifications and variations. Any modification, equivalent replacement, improvement, etc. made within the spirit and principle of the present invention shall be included in the protection scope of the present invention.

Claims

1. A fiber optic tilt sensor, characterized in that: include: A mounting cylinder (100) having a receiving chamber (110) with an upper opening; A cylinder cover (200), which is a detachable cover disposed on the upper end of the accommodating chamber (110); A mounting seat (300) is detachably mounted on the cylinder cover (200) and has a wire hole (301) extending vertically through the center; An elastic metal sheet (400), the upper end of which is fixedly connected to the bottom of the mounting seat (300), and the bottom of which is connected to a counterweight block (410); the elastic metal sheet (400) is provided with a wire-passing notch (420) with an upper opening aligned with the wire-passing hole (301); the bottom of the wire-passing notch (420) is provided with two slots (421), and the two slots (421) are respectively provided with embedding openings on two side surfaces of the elastic metal sheet (400); and positioning slots (422) are provided on the peripheral walls at both ends of the slots (421); Two optical fibers (500) are provided with an extension section (510) and a Bragg grating section (520), wherein the extension section (510) is inserted through the wire-passing hole (301) and the wire-passing notch (420); the Bragg grating sections (520) of the two optical fibers (500) are respectively fixedly mounted in two slots (421), and the outer peripheral walls at both ends of the Bragg grating section (520) are provided with radial protrusions (521) embedded in the positioning grooves (422).

2. The optical fiber tilt sensor according to claim 1, characterized in that: The counterweight block (410) is hinged to the bottom of the elastic metal sheet (400), and the hinge axis of the counterweight block (410) is perpendicular to the thickness direction of the elastic metal sheet (400).

3. The optical fiber tilt sensor according to claim 1, characterized in that: A raised stop block (210) is provided at the bottom of the cylinder cover (200), and a stop hole (211) is provided on the stop block (210); a mounting block (120) is provided on the peripheral wall of the accommodating cavity (110), and the mounting block (120) is provided with a through hole (121), and a movable column (130) is movably inserted in the through hole (121); a plug (131) is provided at one end of the movable column (130), and a pull ring (132) is detachably connected to the other end; a stop ring (133) is provided at the inner end of the plug (131), and a spring (134) is sleeved on the movable column (130); one end of the spring (134) is against the stop ring (133), and the other end is against the mounting block (120). ) abut against each other; the movable column (130) has a limiting state and a disassembly state; in the limiting state, the shifting ring (132) abuts against the mounting block (120), and the plug (131) is inserted into the limiting hole (211); the plug (131) in the disassembly state is separated from the limiting hole (211); a movable cylinder (700) is provided on the outer circumference of the mounting cylinder (100) and the movable cylinder (700) is provided with a shifting rod (710) that passes through the cylinder wall of the mounting cylinder (100) and is inserted into the accommodating cavity (110); the rotation of the movable cylinder (700) can drive the shifting rod (710) to shift the shifting ring (132) to move, thereby allowing the movable column (130) to move from the limiting state to the disassembly state.

4. The optical fiber tilt sensor according to claim 3, characterized in that: The upper end of the shifting ring (132) protrudes from the mounting block (120), the shifting rod (710) contacts the upper end of the shifting ring (132), and the shifting rod (710) is higher than the mounting block (120).

5. The optical fiber tilt sensor according to claim 3, characterized in that: The wall of the installation cylinder (100) is provided with a movable notch (140) with an upper opening, and the shifting rod (710) is inserted into the movable notch (140).

6. The optical fiber tilt sensor according to claim 5, characterized in that: The movable notch (140) has two end walls (141), and when the lever (710) abuts against the two end walls (141) respectively, the movable column (130) is in a limited position state and a disassembled state respectively.

7. The optical fiber tilt sensor according to claim 1, characterized in that: The mounting seat (300) comprises a top plate (310) and a plug post (320), wherein the plug post (320) is connected to the bottom of the top plate (310), a plug hole (220) is provided at the center of the cylinder cover (200) for the plug post (320) to be inserted, a clamping block (321) is provided on the peripheral wall of the bottom of the plug post (320), and a through groove (221) is provided on the peripheral wall of the plug hole (220) for the clamping block (321) to pass through, and the clamping block (321) can pass through the through groove (221) and then rotate to be offset from the through groove (221), so that The upper end of the insertion hole (220) is provided with a sink groove (230) for the top plate (310) to be embedded, the bottom wall of the sink groove (230) is installed with an elastic clamping column (240) that can be lifted and lowered elastically, and the bottom surface of the top plate (310) is provided with a positioning hole (311); when the elastic clamping column (240) is inserted into the positioning hole (311), the clamping block (321) and the through groove (221) are offset, the bottom surface of the top plate (310) is in contact with the bottom wall of the sink groove (230), and the clamping block (321) is in contact with the bottom surface of the cylinder cover (200).

8. The optical fiber tilt sensor according to claim 7, characterized in that: A positioning stopper (250) is provided on the bottom surface of the cylinder cover (200); when the clamping block (321) abuts against the positioning stopper (250), the clamping block (321) and the through slot (221) are offset, and the elastic clamping column (240) is aligned with the positioning hole (311); and an unlocking hole (312) extending to the top surface of the top plate (310) is provided on the top of the positioning hole (311).

9. The optical fiber tilt sensor according to claim 1, characterized in that: It also includes a fixing piece connected to the elastic metal sheet (400) and used to limit the Bragg grating segment (520) in the slot (421).

10. The optical fiber tilt sensor according to claim 9, characterized in that: The fixing member is a connecting plate (600), and embedding portions (610) are provided at both ends of the connecting plate (600). Two groups of radial protrusions (521) are provided, and the two groups of radial protrusions (521) are respectively provided at both ends of the Bragg grating segment (520), and the two radial protrusions (521) in the same group are formed with annular grooves (522), and the embedding portions (610) are embedded in the corresponding annular grooves (522).

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