Device and method for determining horizontal displacement of vertical cycloid

Abstract

The invention provides a device and a method for determining the horizontal displacement of a vertical cycloid. The device is installed in a structural body with a vertical cave and comprises a first rectangular guide rail, a second rectangular guide rail and a sliding block. The short edge of the first rectangular guide rail is coupled to the inner wall of the vertical cave through the first elastic piece and the first fiber bragg grating. The short edge of the second rectangular guide rail is coupled to the inner wall of the vertical cave through a second elastic piece and a second fiber grating. And the first rectangular guide rail and the second rectangular guide rail are vertically crossed to form a vertically crossed space. And the sliding block is arranged in the vertical crossing space and is in contact with the first rectangular guide rail and the second rectangular guide rail.

Description

Technical field

[0001] This invention relates to a device and method for determining the horizontal displacement of a vertical cycloid, and more particularly, to a device and method for determining the horizontal displacement of a vertical cycloid relative to a surrounding structure by measuring the steering of intersecting rectangular guide rails. [Background Technology]

[0002] Cycloids are often used to monitor the displacement of a structure with a height relative to a reference vertical line (cycloid) under different load conditions. If the fixed end of the reference vertical line is set at the top of the structure, it is called a positive cycloid 10. Figure 1 If the fixed end is at the bottom of the structure, it is an inverse cycloid instrument 20, such as Figure 2 shown. Figure 1 and Figure 2 Schematic diagrams showing the installation and use of a positive cycloid 10 within a concrete dam body 11 and an inverse cycloid 20 within a foundation slab 21. These cycloids can measure the horizontal displacement of the concrete dam body 11 relative to the foundation slab 21 and the horizontal displacement of the foundation slab 21 relative to a deeper, presumably immovable, rock bed 22, respectively, as the water level of the concrete dam body 11 changes in the reservoir 12.

[0003] exist Figure 1 and Figure 2 In the cycloid, 101 and 201 are made of steel cables with a diameter of several millimeters (mm). In the sine cycloid 10, cycloid 101 has a fixed end 103 at the top, and a weight 102 of approximately 30 kg is used to straighten cycloid 101 from its bottom. In the inverse cycloid 20, cycloid 201 has a fixed end 203 at the bottom, and a buoyancy device 202 applies a tension of approximately 30 kg from its top to straighten cycloid 201 and provide damping. The weight 102 and buoyancy device 202 are immersed in an oil tank 13, which provides damping.

[0004] In practice, during the construction of the concrete dam body 11, a cavity 14 is reserved for the installation of the positive cycloid 10, and the fixed end 203 of the cycloid 201 is fixed to the bottom of the cavity 24 at the bottom of the negative cycloid 20 by grouting. The weight 102 at the tension end of the positive cycloid 10 is installed in the cavity 14. The positive cycloid 10 can install multiple displacement measurement points at different heights within the concrete dam body 11 to determine the distribution of the horizontal displacement of the concrete dam body 11. The humidity inside the concrete dam body 11, especially in the area below the water level, is usually very high. Traditional technology often uses lasers to measure the relative displacement of the cycloid at the displacement measurement point and the surrounding dam structure. Photoelectric equipment is easily damaged in a high humidity environment, and its maintenance costs are usually extremely high.

[0005] Optical fiber is a cylindrical, thin, long line. Commonly used single-mode optical fiber consists of a core made of silicon with an inner diameter of 125μm and an outer layer of acrylic coating. The overall outer diameter is 250μm. The following is a brief introduction to the commonly used fiber Bragg grating sensing methods.

[0006] Figure 3 This is a schematic diagram showing the reflection principle of optical fiber Bragg Grating (FBG). Figure 3 As shown, the manufacturing process of fiber Bragg grating is to expose a 1-20mm long optical fiber 300 (which includes a core 301 and an acrylic outer layer 302) to high-energy laser light, causing the refractive index of the optical fiber to change periodically and permanently. The portion of the refractive index change period A is called fiber Bragg grating 303. When a continuous broadband incident light 304 is coupled into the optical fiber core 301 including the fiber Bragg grating 303, in addition to the light of a specific wavelength that meets the Bragg condition, which will be reflected to form reflected light 305, the penetrating light 306 of the remaining wavelengths will penetrate this fiber Bragg grating 303. When the fiber Bragg grating 303 is subjected to external force or temperature change and generates strain (ε B ), the grating period A changes accordingly and the wavelength of the reflected light 305 of the fiber Bragg grating 303 changes. The original center (peak) wavelength λ of the reflected light 305 of the fiber Bragg grating 303 is B , its change Δλ B With ε B The relationship is as follows:

[0007] Δλ B =0.74λ B ε B or

[0008] The wavelength λ of the commonly used fiber Bragg grating 303 B The wavelength change Δλ that the fiber Bragg grating reading system can identify is between 1525 and 1575 nm. B According to formula (1), when using fiber Bragg grating for strain measurement, the Δλ corresponding to each 1pm is B Slightly below 10 -6 Strain (με), making the fiber Bragg grating a stable and sensitive strain gauge.

[0009] Previous optoelectronic technologies are prone to short circuits when deployed in humid environments for extended periods. Electronic signals also drift over time, resulting in instability and expensive repairs. Fiber Bragg gratings (FBGs) and optical fibers are non-conductors, making their stability unaffected by moisture or lightning strikes. FBGs use light wavelength to measure strain, unaffected by light source intensity, resulting in long-term stability. This makes them ideal for sensing units used in humid environments.

[0010] Therefore, the inventor, in view of the shortcomings of the conventional technology, thought of improving the invention and finally conceived a device and method for determining the horizontal displacement of a vertical cycloid. [Summary of the invention]

[0011] The primary objective of the present invention is to provide a device and method for determining the horizontal displacement of a vertical cycloid. The device utilizes a fiber Bragg grating (FBG) as a sensing element and is coupled with a simple mechanical architecture to achieve low-cost, durable, moisture-resistant, and well-suited for long-term use in harsh conditions.

[0012] In order to achieve the above-mentioned purpose of the present invention, the present invention provides a device for determining the horizontal displacement of a vertical cycloid. The device is installed in a structure having a vertical cavity, and the device includes: a first rectangular guide rail, a second rectangular guide rail and a slider. The short side of the first rectangular guide rail is coupled to the inner wall of the vertical cavity with the first fiber grating through a first elastic sheet. The short side of the second rectangular guide rail is coupled to the inner wall of the vertical cavity with the second fiber grating through a second elastic sheet. The first rectangular guide rail and the second rectangular guide rail are vertically intersected to form a vertical intersection space. The slider is arranged in the vertical intersection space and is in contact with the first rectangular guide rail and the second rectangular guide rail. The slider has a central through hole so that the vertical cycloid passes through the central through hole. When the structure is deformed, the horizontal displacement of the vertical cycloid is calculated based on the strain of the first fiber grating and the second fiber grating.

[0013] The present invention also provides a method for determining the horizontal displacement of a vertical cycloid. The method is applicable to a structure having a vertical cavity and includes the following steps. First, a first rectangular guide rail and a second rectangular guide rail are provided. The short side of the first rectangular guide rail is coupled to the first fiber grating on the inner wall of the vertical cavity through a first elastic plate. The short side of the second rectangular guide rail is coupled to the second fiber grating on the inner wall of the vertical cavity through a second elastic plate. The first rectangular guide rail and the second rectangular guide rail are vertically intersected to form a vertical intersection space. Then, a slider is set in the vertical intersection space and contacts the first rectangular guide rail and the second rectangular guide rail. The slider has a central through hole so that the vertical cycloid passes through the central through hole. Then, when the structure is deformed, the horizontal displacement of the vertical cycloid is calculated based on the strain of the first fiber grating and the second fiber grating.

[0014] In summary, the present invention's device and method for determining the horizontal displacement of a vertical cycloid utilizes fiber Bragg grating (FBG) as a sensing unit and incorporates a simple mechanical structure. This combines the advantages of FBG, including data stability, durability, and resistance to humid environments, making it ideal for long-term use in harsh conditions.

Brief Description of the Drawings

[0015] The above-mentioned objects and advantages of the present invention will become more immediately apparent to those having ordinary knowledge in the art after reading the following detailed description and the accompanying drawings.

[0016] Figure 1 : Schematic diagram showing the installation and use of a conventional cycloid instrument in a concrete dam;

[0017] Figure 2 : Schematic diagram showing the installation and use of a conventional inverse cycloid instrument in a concrete dam;

[0018] Figure 3 : Schematic diagram showing the reflection principle of conventional fiber Bragg gratings;

[0019] Figure 4 : A schematic top view of a device for determining the horizontal displacement of a vertical cycloid according to a specific embodiment of the present invention;

[0020] Figure 5 : A schematic side view showing an apparatus for determining the horizontal displacement of a vertical cycloid according to an embodiment of the present invention; and

[0021] Figure 6 : A schematic diagram showing how the device for determining the horizontal displacement of a vertical cycloid of the present invention converts the steering angle of a rectangular guide rail into displacement; and

[0022] Figure 7 : A schematic flow chart showing a method for determining the horizontal displacement of a vertical cycloid according to the present invention. [Specific implementation method]

[0023] Please read the following detailed description with reference to the drawings of the present disclosure, wherein the drawings of the present disclosure are provided by way of example to introduce various embodiments of the present disclosure and to provide an understanding of how to implement the present disclosure. The embodiments of the present disclosure provide sufficient content for those skilled in the art to implement the embodiments disclosed by the present disclosure, or to implement embodiments derived from the contents disclosed by the present disclosure. It should be noted that these embodiments are not mutually exclusive, and some embodiments can be appropriately combined with one or more other embodiments to form new embodiments, that is, the implementation of the present disclosure is not limited to the embodiments disclosed below. In addition, for the sake of simplicity and clarity of illustration, the relevant details will not be excessively disclosed in each embodiment. Even if specific details are disclosed, they are only used as examples to make the reader understand. The relevant specific details in each embodiment are not intended to limit the disclosure of this case.

[0024] See also Figure 4 and Figure 5 , which are schematic top and side views of a device for determining the horizontal displacement of a vertical cycloid according to a specific embodiment of the present invention. Device 400 for determining the horizontal displacement of a vertical cycloid can be installed at a certain height within a structure (not shown) having a vertical cavity. If the vertical cycloid is fixed to the top of the structure, device 400 is called a positive cycloid. If the fixed end of the vertical cycloid is located at the bottom of the structure, device 400 is called a negative cycloid. Generally, a vertical cycloid can be constructed using a steel cable with a diameter of several millimeters, but the scope of the present invention is not limited to this. In a positive cycloid, a weight of approximately 30 kg is used to straighten the vertical cycloid from its bottom. In a negative cycloid, a buoyancy force is used to straighten the vertical cycloid from its top, applying a tension of approximately 30 kg. The weight or buoyancy device is immersed in an oil tank to provide damping. A cavity is reserved within the structure during construction for installing the positive cycloid. The bottom of the negative cycloid is grouting the fixed end of the cycloid to the bottom of a drilled hole. The tension end of the inverse cycloid is installed in a cavity reserved during construction. The positive cycloid can be installed at multiple displacement measurement points at different elevations within the structure to determine the distribution of the structure's lateral displacement.

[0025] In the present invention, the device 400 mainly includes a first fixed base 401, a second fixed base 411, a first elastic clip 402, a second elastic clip 412, a first fiber Bragg grating 403, a second fiber Bragg grating 413, a first steerable rectangular guide rail fixing unit 404, a second steerable rectangular guide rail fixing unit 414, a first rectangular guide rail 405, a second rectangular guide rail 415, and a slider 407. The first fixed base 401 and the second fixed base 411 are respectively fixed in a vertical cavity (not shown). The first steerable rectangular guide rail fixing unit 404 is connected to the first fixed base 401 via the first elastic clip 402 and the first fiber Bragg grating 403. Similarly, the second steerable rectangular guide rail fixing unit 414 is connected to the second fixed base 411 via the second elastic clip 412 and the second fiber Bragg grating 413. In one embodiment, the extension directions of the first fixing base 401 and the second fixing base 411 are perpendicular, so that the extension directions of the first steerable rectangular guide rail fixing unit 404 and the second steerable rectangular guide rail fixing unit 414 are also perpendicular.

[0026] exist Figure 4 and Figure 5 , the short side of the first rectangular guide rail 405 is fixed to the first steerable rectangular guide rail fixing unit 404, and the short side of the second rectangular guide rail 415 is fixed to the second steerable rectangular guide rail fixing unit 414. In one specific embodiment, the first rectangular guide rail 405 and the second rectangular guide rail 415 are perpendicularly intersected, so that the vertical cycloid 406 passes through the perpendicular intersection of the first rectangular guide rail 405 and the second rectangular guide rail 415. In one specific embodiment, the first elastic piece 402 is aligned with the central axis (not shown) of the first rectangular guide rail 405, and the second elastic piece 412 is aligned with the central axis (not shown) of the second rectangular guide rail 415. In this way, when the vertical cycloid 406 is laterally displaced relative to the surrounding structure, the first rectangular guide rail 405 in the x-direction and the second rectangular guide rail 415 in the y-direction will respectively generate θ relative to their bottoms. x and θ y The above θ x and θ y The steering amount can also be represented by the strain of the first fiber grating 403 and the strain of the second fiber grating 413.

[0027] exist Figure 4 and Figure 5In the embodiment, slider 407 has a groove 409 cut into central through-hole 408. The width of groove 409 and the diameter of central through-hole 408 are approximately equal to the diameter of vertical cycloid 406, allowing vertical cycloid 406 to be squeezed into central through-hole 408. In one embodiment, slider 407 is a cylinder formed of polytetrafluoroethylene (PTFE, commonly known as Teflon). In one embodiment, mutually perpendicular first and second rectangular guide rails 405 and 415 each contact slider 407 with slight pressure. In one embodiment, slider 407 is vertically adjusted to a height such that slider 407 is simultaneously surrounded by first and second rectangular guide rails 405 and 415, and contacts both with slight pressure. In one embodiment, groove 409 of slider 407 avoids contact with first and second rectangular guide rails 405 and 415. In a specific embodiment, when the structure is deformed, the horizontal displacement of the vertical cycloid 406 is calculated based on the strain of the first fiber grating 403 and the strain of the second fiber grating 413 .

[0028] like Figure 6 As shown in , it is a schematic diagram of the device for determining the horizontal displacement of the vertical cycloid of the present invention, which converts the steering angle of the rectangular guide rail into displacement. A coordinate system is set, whose origin (0,0) corresponds to the center of the vertical cycloid 406. The first fixed seat 401 perpendicular to the x-direction is at a distance L0 from the origin (0,0), and the second fixed seat 411 perpendicular to the y-direction is at a distance L0 from the origin (0,0). When the slider 407 produces a horizontal displacement along the vertical cycloid 406, the center coordinates of the vertical cycloid 406 are transferred to (x,y). At the same time, the first fiber grating 403 and the second fiber grating 413 respectively sense the steering amount θ of the first rectangular guide rail 405 and the second rectangular guide rail 415. x and θ y , we get the following relationship:

[0029] x=(K0-y)tanθ y (2)

[0030] y=(L0+x)tanθ x (3) Set θ x and θ y , in the counterclockwise direction is positive, x and y can be calculated as follows,

[0031]

[0032]

[0033] Under normal use, the displacement in the x and y directions is limited, so θ x and θ y It will be much lower than 90 degrees, so as not to cause t anθ x or ta nθ y Close to infinity.

[0034] Therefore, with Figure 4 and Figure 5 The present invention provides a method for determining the horizontal displacement of a vertical cycloid, including the following steps. First, in step S701, a first fixing base 401 and a second fixing base 411 are provided on the inner wall of a vertical cavity (not shown). Next, in step S702, a first steerable rectangular guide rail fixing unit 404 is provided, coupled to the first fixing base 401 via a first elastic plate 402 and a first fiber grating 403, and a second steerable rectangular guide rail fixing unit 414 is provided, coupled to the second fixing base 411 via a second elastic plate 412 and a second fiber grating 413. In one embodiment, the extension directions of the first fixing base 401 and the second fixing base 411 are perpendicular, so that the extension directions of the first steerable rectangular guide rail fixing unit 404 and the second steerable rectangular guide rail fixing unit 414 are also perpendicular.

[0035] Next, in step S703, a first rectangular guide rail 405 is provided, the short side of which is coupled to the first elastic piece 402 and the first fiber Bragg grating 403 via the first steerable rectangular guide rail fixing unit 404, and a second rectangular guide rail 415 is provided, the short side of which is coupled to the second elastic piece 412 and the second fiber Bragg grating 413 via the second steerable rectangular guide rail fixing unit 414. In one embodiment, the first rectangular guide rail 405 and the second rectangular guide rail 415 are perpendicularly intersected, so that the vertical cycloid 406 passes through the perpendicular intersection of the first rectangular guide rail 405 and the second rectangular guide rail 415. In one embodiment, the first elastic piece 402 is aligned with the central axis (not shown) of the first rectangular guide rail 405, and the second elastic piece 412 is aligned with the central axis (not shown) of the second rectangular guide rail 415. In this way, when the vertical cycloid 406 is laterally displaced relative to the surrounding structure, the first rectangular guide rail 405 in the x-direction and the second rectangular guide rail 415 in the y-direction will respectively generate θ relative to their bottoms. x and θ y The above θ x and θ y The steering amount can also be represented by the strain of the first fiber grating 403 and the strain of the second fiber grating 413.

[0036] However, it should be noted that the above-mentioned composition is only an illustrative example. In other embodiments, the first elastic piece 402 and the first fiber grating 403 and the second elastic piece 412 and the second fiber grating 413 can also be directly fixed to the inner wall of the vertical cave (not shown) without the need for the first fixing seat 401 and the second fixing seat 411. In addition, in other embodiments, the short side of the first rectangular guide rail 405 and the short side of the second rectangular guide rail 415 can also be directly coupled to the first elastic piece 402 and the first fiber grating 403 and the second elastic piece 412 and the second fiber grating 413 without the need for the first steerable rectangular guide rail fixing unit 404 and the second steerable rectangular guide rail fixing unit 414.

[0037] Next, in step S704, slider 407 is positioned within the vertical intersection formed by first rectangular guide rail 405 and second rectangular guide rail 415. In one embodiment, slider 407 includes a groove 409 extending into central through-hole 408. The width of groove 409 and the diameter of central through-hole 408 are approximately equal to the diameter of vertical cycloid 406, allowing vertical cycloid 406 to be squeezed into central through-hole 408, as described in step S705. In one embodiment, slider 407 is a cylinder formed of polytetrafluoroethylene (PTFE, commonly known as Teflon). In one embodiment, first rectangular guide rail 405 and second rectangular guide rail 415, which are perpendicular to each other, each contact slider 407 with slight pressure. In one embodiment, the slider 407 is vertically adjusted to a height such that the slider 407 is simultaneously surrounded by the first rectangular guide rail 405 and the second rectangular guide rail 415 and contacts the first rectangular guide rail 405 and the second rectangular guide rail 415 with slight pressure. In one embodiment, the groove 409 of the slider 407 avoids contact with the first rectangular guide rail 405 and the second rectangular guide rail 415.

[0038] Finally, in step S706 , when the structure is deformed, the horizontal displacement of the vertical cycloid 406 is calculated according to the strain of the first fiber grating 403 and the strain of the second fiber grating 413 .

[0039] The proposed device and method for determining the horizontal displacement of a vertical cycloid uses fiber Bragg grating (FBG) as a sensing unit and is paired with a simple mechanical structure. This combines the advantages of fiber Bragg grating (FBG), including data stability, durability, and immunity to humid environments, making it ideal for long-term use in harsh conditions.

[0040] Although the present invention is disclosed above with reference to several embodiments or examples, they are not intended to limit the present invention. Anyone skilled in the art may make slight changes and modifications without departing from the spirit and scope of the present invention. Therefore, the scope of protection of the present invention shall be determined by the scope of the appended patent applications.

[0041]

Explanation of symbols

[0042] 10: Cycloid

[0043] 101: Cycloid

[0044] 102: Heavy Block

[0045] 103: Fixed end

[0046] 11: Concrete dam

[0047] 12: Reservoir

[0048] 13: Oil tank

[0049] 14: Cave

[0050] 20: Inverse cycloid

[0051] 201: Cycloid

[0052] 202: Buoyancy device

[0053] 203: Fixed end

[0054] 21: Basic Territory

[0055] 22: Immovable Bedrock

[0056] 24: Cave

[0057] 300: Fiber Optic

[0058] 301: Core

[0059] 302: Outer layer

[0060] 303: Fiber Bragg Grating

[0061] 304: Incident light

[0062] 305:Reflected Light

[0063] 306: Penetrating Light

[0064] 400: Device

[0065] 401: First fixed seat

[0066] 402: First Shrapnel

[0067] 403: First Fiber Bragg Grating

[0068] 404: First steerable rectangular guide rail fixing unit

[0069] 405: first rectangular guide rail

[0070] 406: Vertical Cycloid

[0071] 407: Slider

[0072] 408: Center through hole

[0073] 409: Groove

[0074] 411: Second fixed seat

[0075] 412: Second Shrapnel

[0076] 413: Second Fiber Bragg Grating

[0077] 414: Second steerable rectangular guide rail fixing unit

[0078] 415: Second rectangular guide rail

[0079] S701~S706: Steps

Claims

1. A device for determining the horizontal displacement of a vertical cycloid, installed in a structure having a vertical cavity, comprising: a first rectangular guide rail and a second rectangular guide rail, wherein a short side of the first rectangular guide rail is coupled to an inner wall of the vertical cavity via a first elastic piece and a first fiber Bragg grating, and a short side of the second rectangular guide rail is coupled to the inner wall of the vertical cavity via a second elastic piece, and the first rectangular guide rail and the second rectangular guide rail are vertically intersected to form a vertical intersection space; and A slider is arranged in the vertical intersection space and contacts the first rectangular guide rail and the second rectangular guide rail, wherein the slider has a central through hole so that the vertical cycloid passes through the central through hole, and when the structure is deformed, the horizontal displacement of the vertical cycloid is calculated according to the strain of the first fiber grating and the second fiber grating.

2. The device as claimed in claim 1 , wherein one end of the first spring piece and one end of the first fiber grating are coupled to the inner wall of the vertical cave via a first fixing base fixed on the inner wall of the vertical cave, and one end of the second spring piece and one end of the second fiber grating are coupled to the inner wall of the vertical cave via a second fixing base fixed on the inner wall of the vertical cave.

3. The device as claimed in claim 2, wherein the short side of the first rectangular guide rail is coupled to the other end of the first spring sheet and the other end of the first fiber grating via a first steerable rectangular guide rail fixing unit, and the short side of the second rectangular guide rail is coupled to the other end of the second spring sheet and the other end of the second fiber grating via a second steerable rectangular guide rail fixing unit.

4. The device as claimed in claim 1, wherein one end of the vertical cycloid is fixed to the top of the structure, and the other end is fastened to a weight.

5. The device as claimed in claim 1, wherein one end of the vertical cycloid is fixed to the bottom of the structure, and the other end is tied to a device providing tension. 6 . The device of claim 1 , wherein the first elastic piece is aligned with a central axis of the first rectangular guide rail, and the second elastic piece is aligned with a central axis of the second rectangular guide rail.

7. The return device as claimed in claim 1, wherein the slider has a groove cut into the central through hole, so that the vertical cycloid can be squeezed into the central through hole. 8 . The device of claim 7 , wherein a width of the groove of the slider and a diameter of the central through hole are equal to a diameter of the vertical cycloid. 9 . The device of claim 7 , wherein the groove of the slider avoids contact with the first rectangular guide rail and the second rectangular guide rail.

10. The device of claim 2, wherein the horizontal displacement of the vertical cycloid in the x-direction and the y-direction when the structure is deformed is expressed as in, The first rectangular guide rail is arranged on the x-axis and the second rectangular guide rail is arranged on the negative y-axis. The vertical cycloid corresponds to the origin (0, 0) when the structure is not deformed. The distances between the vertical cycloid and the first fixed seat and the second fixed seat are L0 respectively. The strain of the first fiber grating and the strain of the second fiber grating respectively correspond to the steering amount θ of the first rectangular guide rail. x The turning amount θ of the second rectangular guide rail y .

11. A method for determining the horizontal displacement of a vertical cycloid, applicable to a structure having a vertical cavity, the method comprising: A first rectangular guide rail and a second rectangular guide rail are provided, wherein a short side of the first rectangular guide rail is coupled to an inner wall of the vertical cavity via a first elastic piece and a first fiber Bragg grating (FBG), and a short side of the second rectangular guide rail is coupled to the inner wall of the vertical cavity via a second elastic piece and a second fiber Bragg grating (FBG), and the first rectangular guide rail and the second rectangular guide rail are perpendicularly intersected to form a vertical intersection space; Disposing a slider in the vertical intersection space and in contact with the first rectangular guide rail and the second rectangular guide rail, wherein the slider has a central through hole so that the vertical cycloid passes through the central through hole; and When the structure is deformed, the horizontal displacement of the vertical cycloid is calculated according to the strains of the first fiber grating and the second fiber grating.

12. The method of claim 11 , wherein one end of the first spring piece and one end of the first fiber grating are coupled to the inner wall of the vertical cave via a first fixing base fixed on the inner wall of the vertical cave, and one end of the second spring piece and one end of the second fiber grating are coupled to the inner wall of the vertical cave via a second fixing base fixed on the inner wall of the vertical cave.

13. The method of claim 12, wherein the short side of the first rectangular guide rail is coupled to the other end of the first spring sheet and the other end of the first fiber grating via a first steerable rectangular guide rail fixing unit, and the short side of the second rectangular guide rail is coupled to the other end of the second spring sheet and the other end of the second fiber grating via a second steerable rectangular guide rail fixing unit.

14. The method of claim 11, wherein one end of the vertical cycloid is fixed to the top of the structure, and the other end is fastened with a weight.

15. The method of claim 11, wherein one end of the vertical cycloid is fixed to the bottom of the structure, and the other end is tied to a device providing tension. 16 . The method of claim 11 , wherein the first elastic piece is aligned with a central axis of the first rectangular guide rail, and the second elastic piece is aligned with a central axis of the second rectangular guide rail.

17. The method of claim 11, wherein the slider has a groove cut into the central through hole so that the vertical cycloid can be squeezed into the central through hole. 18 . The method of claim 17 , wherein a width of the groove of the slider and a diameter of the central through hole are equal to a diameter of the vertical cycloid. 19 . The method of claim 17 , wherein the groove of the slider avoids contact with the first rectangular guide rail and the second rectangular guide rail.

20. The method of claim 12, wherein the horizontal displacement of the vertical cycloid in the x-direction and the y-direction when the structure is deformed is expressed as in, The first rectangular guide rail is arranged on the x-axis and the second rectangular guide rail is arranged on the negative y-axis. The vertical cycloid corresponds to the origin (0, 0) when the structure is not deformed. The distances between the vertical cycloid and the first fixed seat and the second fixed seat are L0 respectively. The strain of the first fiber grating and the strain of the second fiber grating respectively correspond to the steering amount θ of the first rectangular guide rail. x The turning amount θ of the second rectangular guide rail y .

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