CN215064495U - Inclination angle measuring device - Google Patents
Inclination angle measuring device Download PDFInfo
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- CN215064495U CN215064495U CN202121000492.6U CN202121000492U CN215064495U CN 215064495 U CN215064495 U CN 215064495U CN 202121000492 U CN202121000492 U CN 202121000492U CN 215064495 U CN215064495 U CN 215064495U
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- cantilever beam
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Abstract
The invention discloses a dip angle measuring device, comprising: a housing; the cantilever beam is arranged in the shell, the other end of the cantilever beam is provided with a heavy object, and the heavy object acts on the cantilever beam; the first fiber Bragg grating is arranged on the surface of the cantilever beam and used for detecting the inclination angle of the cantilever beam; the second fiber Bragg grating is close to the fixed end and located above the central line of the cantilever beam to detect the temperature change of the cantilever beam, and the first fiber Bragg grating and the second fiber Bragg grating are connected in series. By utilizing the cross sensitivity characteristic of the fiber grating technology to temperature and deformation, when a detected object generates a tiny inclination angle, the force of the gravity of a weight acting on a cantilever beam changes to cause the change of the wavelength of a first Bragg fiber grating, the inclination angle of the detected structure is calculated according to the change of the wavelength, and meanwhile, a second Bragg fiber grating which is not influenced by external force is arranged in the fiber grating to measure the influence of the temperature change, so that the tensioned grating is compensated.
Description
Technical Field
The invention relates to the technical field of structural inclination angle detection, in particular to an inclination angle measuring device.
Background
In order to acquire the health condition of an object structure and ensure the safety of a building, particularly in the field of buildings, the deformation condition of a bridge structure can be acquired in time, and safety accidents can be effectively prevented. The dip angle detection is one of the conditions for judging whether the structure is unstable and damaged, and when the load-bearing member of the building deforms beyond a certain dip angle, the structure is about to be unstable and damaged.
The fiber grating sensor can be widely applied and researched in the field of fiber sensing by virtue of the characteristics of simple structure, capability of realizing direct measurement of physical quantities such as temperature, strain and the like and high sensitivity, but because the fiber bragg grating has sensitivity to strain and temperature at the same time, when the fiber bragg grating is used as the sensor, the influence of the fiber bragg grating on the temperature and the strain needs to be measured respectively by a certain means.
Disclosure of Invention
The present invention is directed to solve at least one of the problems of the prior art, and an object of the present invention is to provide an inclination angle measuring device capable of improving detection accuracy by providing a temperature correction function.
According to an embodiment of the first aspect of the present invention, there is provided an inclination angle measuring apparatus including:
one end of the shell is set to be a fixed end, and the bottom of the shell is used for being connected with a detected structure;
the cantilever beam is arranged in the shell, one end of the cantilever beam is fixedly connected with the fixed end of the shell so as to enable the shell and the cantilever beam to incline at the same angle, the other end of the cantilever beam is provided with a heavy object, and the self weight of the heavy object acts on the cantilever beam;
the first fiber Bragg grating is arranged on the surface of the cantilever beam and used for detecting the inclination angle of the cantilever beam;
and the second fiber Bragg grating is arranged close to the fixed end of the cantilever beam and is positioned above the central line of the cantilever beam so as to be free from the influence of external force and used for detecting the temperature change of the cantilever beam, and the first fiber Bragg grating is connected with the second fiber Bragg grating in series.
Has the advantages that: the inclination angle measuring device utilizes the cross sensitivity characteristic of the fiber grating technology to temperature and deformation, when a detected object has a tiny inclination angle, the force of the gravity of a heavy object acting on a cantilever beam changes, the wavelength of a first Bragg fiber grating changes, the inclination angle of a detected structure is calculated according to the change of the wavelength, and meanwhile, another second Bragg fiber grating which is not influenced by external force is built in the device and used for measuring the influence of the temperature change, so that the tensioned grating is compensated.
According to the tilt angle measuring device of the embodiment of the first aspect of the present invention, the first fiber bragg grating is configured as a tension sensor, and the second fiber bragg grating is configured as a temperature compensation sensor.
According to the inclination angle measuring device of the embodiment of the first aspect of the present invention, the top surface of the cantilever beam is provided with an optical fiber outlet, and the detection end of the first bragg fiber grating is led out from the optical fiber outlet.
According to the inclination angle measuring device provided by the embodiment of the first aspect of the invention, the weight comprises a steel ball box and a plurality of steel balls arranged in the steel ball box, and the inner wall of the steel ball box is tightly attached to each steel ball.
According to the inclination angle measuring device of the embodiment of the first aspect of the present invention, the cantilever beam, the housing and the steel ball box are all made by 3D printing.
According to the inclination measuring device of the embodiment of the first aspect of the present invention, the housing is provided as a rectangular bar-shaped member.
Drawings
In order to more clearly illustrate the technical solution in the embodiments of the present invention, the drawings used in the description of the embodiments will be briefly described below. It is clear that the described figures are only some embodiments of the invention, not all embodiments, and that a person skilled in the art can also derive other designs and figures from them without inventive effort.
FIG. 1 is a schematic structural diagram of an embodiment of the present invention;
fig. 2 is an enlarged view of a in fig. 1.
Detailed Description
Reference will now be made in detail to the present preferred embodiments of the present invention, examples of which are illustrated in the accompanying drawings, wherein like reference numerals refer to like elements throughout.
In the description of the present invention, it should be understood that the orientation or positional relationship referred to in the description of the orientation, such as the upper, lower, front, rear, left, right, etc., is based on the orientation or positional relationship shown in the drawings, and is only for convenience of description and simplification of description, and does not indicate or imply that the device or element referred to must have a specific orientation, be constructed and operated in a specific orientation, and thus, should not be construed as limiting the present invention.
In the description of the present invention, the meaning of a plurality of means is one or more, the meaning of a plurality of means is two or more, and larger, smaller, larger, etc. are understood as excluding the number, and larger, smaller, inner, etc. are understood as including the number. If the first and second are described for the purpose of distinguishing technical features, they are not to be understood as indicating or implying relative importance or implicitly indicating the number of technical features indicated or implicitly indicating the precedence of the technical features indicated.
In the description of the present invention, unless otherwise explicitly limited, terms such as arrangement, installation, connection and the like should be understood in a broad sense, and those skilled in the art can reasonably determine the specific meanings of the above terms in the present invention in combination with the specific contents of the technical solutions.
Referring to fig. 1 to 2, a tilt angle measuring apparatus includes: the optical fiber detection device comprises a shell 10, a cantilever beam 20, a first fiber Bragg grating 41 and a second fiber Bragg grating 42, wherein one end of the shell 10 is set to be a fixed end, and the bottom of the shell is used for being connected with a detected structure; the cantilever beam 20 is arranged in the shell 10, preferably, the extension direction of the shell 10 is the same as that of the cantilever beam 20, one end of the cantilever beam 20 is fixedly connected with the fixed end of the shell 10, so that the shell 10 and the cantilever beam 20 are inclined at the same angle, the other end of the cantilever beam 20 is provided with the heavy object 30, the self weight of the heavy object 30 acts on the cantilever beam 20, the heavy object 30 can generate different gravity effects on the cantilever beam 20 along with the inclination of the angle, the detection of the first Bragg fiber grating 41 is facilitated, the gravity is increased, and the detection sensitivity of the device is improved along with the increase of the gravity; wherein the first fiber Bragg grating 41 is arranged on the surface of the cantilever beam 20 and is used for detecting the inclination angle of the cantilever beam 20; the second fiber bragg grating 42 is disposed near the fixed end of the cantilever beam 20 and above the center line of the cantilever beam 20, so that the second fiber bragg grating 42 is not affected by external force and is used for detecting temperature change of the cantilever beam 20, and the first fiber bragg grating 41 and the second fiber bragg grating 42 are connected in series. The inclination angle measuring device utilizes the cross sensitivity characteristic of the fiber grating technology to temperature and deformation, when a detected object has a tiny inclination angle, the force of the gravity of the weight 30 acting on the cantilever beam 20 changes, which causes the change of the wavelength of the first Bragg fiber grating 41, the inclination angle of the detected structure is calculated according to the change of the wavelength, and meanwhile, another second Bragg fiber grating 42 which is not influenced by external force is arranged in the device for measuring the influence of the temperature change, thereby compensating the tensioned grating.
Preferably, the first fiber bragg grating 41 is arranged as a tension sensor and the second fiber bragg grating 42 is arranged as a temperature compensation sensor. When the detected structure is inclined at a certain angle, the device and the detected object are inclined at the same angle, at the moment, the acting force of the gravity of the heavy object 30 in the device on the cantilever beam 20 is changed, so that the first Bragg fiber grating 41 is stretched and deformed, and the external demodulator can acquire the value of the change of the wavelength.
Preferably, the cantilever 20 has a top surface provided with a fiber exit hole, and the detection end of the first fiber bragg grating 41 is led out from the fiber exit hole.
Preferably, the weight 30 comprises a steel ball box 32 and a plurality of steel balls 31 arranged in the steel ball box 32, and the inner wall of the steel ball box 32 is tightly attached to each steel ball 31. The device is used for limiting the shaking of the steel ball 31 inside and avoiding the influence on the detection result. The number, size and weight of the steel balls 31 are determined according to the detection requirements, theoretically, the number of the steel balls 31 is increased, the weight is increased, and the detection sensitivity of the device is improved.
Preferably, the cantilever beam 20, the housing 10 and the steel ball box 32 are all made by 3D printing.
Preferably, the housing 10 is provided as a rectangular bar-shaped member.
A method of manufacturing a tilt angle measuring device, comprising the steps of:
confirming the number and the diameter of the steel balls 31 to be used;
when the joint of the cantilever beam 20 and the steel ball box 32 is printed, the size of the steel ball box 32 is confirmed according to the number and the diameter of the steel balls 31, the bottom surface and four side surfaces of the steel ball box 32 can be ensured to be tightly attached to the steel balls 31 to be used, each steel ball 31 is placed into the steel ball box 32, and then the top surface printing of the steel ball box 32 is completed;
the first fiber bragg grating 41 and the second fiber bragg grating 42 are connected in series, wherein the second fiber bragg grating 42 is embedded at a fixed end close to the cantilever beam 20, and the second fiber bragg grating 42 is located above the center line of the cantilever beam 20 and is used for detecting the temperature change of the cantilever beam 20, wherein the first fiber bragg grating 41 is arranged on the surface of the cantilever beam 20 and is used for detecting the inclination angle of the cantilever beam 20.
The working principle of the inclination angle measuring device is as follows: the bottom of the rectangular shell 10 is closely attached to the detected structure, and when the detected structure is not inclined at an angle, the steel ball 31 has the self weight G1Acting on the cantilever beam 20, wherein the cantilever beam 20 forms an angle theta with the horizontal line1Corresponding to a Bragg wavelength of λ1. When the detected structure is inclined at a certain angle, the device of the invention and the detected object are inclined at the same angle, so that the included angle between the cantilever beam 20 and the horizontal line is theta2At this time, the acting force of the gravity of the steel ball 31 in the device on the cantilever beam 20 is G2Thereby stretching the first Bragg fiber grating 41 to make it stretch and deform, and the external demodulator can acquire the wavelength variation value of λ2Knowing the length l of the cantilever beam 20 and the mass m of the steel ball 31, the following formula can be obtained according to the basic principle of the fiber grating sensor:
ΔλB＝λB(1-pB)ε#(1)
ε＝εy+sx#(2)
Py＝mg cosθ#(5)
Px＝mg sinθ#(7)
equations (1), (2), (3), (4), (5), (6) and (7) are combined to obtain:
in the formula: lambda [ alpha ]B-bragg reflecting the initial wavelength;
ΔλB-changing the wavelength;
pB-the effective elastic optical constant of the optical fiber;
ε -the total strain of the cantilever beam 20;
εydeformation perpendicular to the length of the cantilever beam 20;
sxstrain along the length of the cantilever beam 20;
a, b-relative start and end point coordinates of the effective length of the optical fiber;
c-effective length of fiber;
e-modulus of elasticity of the cantilever beam 20;
i-the section moment of inertia of the cantilever beam 20;
l-length of cantilever beam 20.
In the formula (6) < theta >1Corresponding to a grating wavelength of λ1，θ2Corresponding to a grating wavelength of λ2The simultaneous equations can calculate the inclination angle of the cantilever beam 20 when the wavelength of the fiber grating changes, which is equal to the measured inclination angle of the detected object.
For example, taking the effective elasto-optic constant p of the fiberBIs 0.22, Bragg reflection initial wavelength lambdaB1550.000nm, and a Bragg emission wavelength λ at 0 ° when θ is 0 ° without considering the influence of temperatureB1565.543 nm; when the angle is +/-0.1 DEG, the Bragg emission wavelength is lambdaB1565.553nm, and when the device is tilted at an angle of + -0.1 deg., the angle is Delta lambdaBIs 10 pm.
Because the first fiber bragg grating 41 is a tension sensor and the second fiber bragg grating 42 is a temperature compensation sensor inside the device, when the first fiber bragg grating 41 and the second fiber bragg grating 42 act simultaneously, the influence of the environmental temperature on the structure can be eliminated while the inclination angle of the structure is detected.
The embodiments of the present invention have been described in detail with reference to the accompanying drawings, but the present invention is not limited to the above embodiments, and various changes can be made within the knowledge of those skilled in the art without departing from the gist of the present invention.
Claims (6)
1. A tilt angle measuring device, comprising:
one end of the shell is set to be a fixed end, and the bottom of the shell is used for being connected with a detected structure;
the cantilever beam is arranged in the shell, one end of the cantilever beam is fixedly connected with the fixed end of the shell so as to enable the shell and the cantilever beam to incline at the same angle, the other end of the cantilever beam is provided with a heavy object, and the self weight of the heavy object acts on the cantilever beam;
the first fiber Bragg grating is arranged on the surface of the cantilever beam and used for detecting the inclination angle of the cantilever beam;
and the second fiber Bragg grating is arranged close to the fixed end of the cantilever beam and is positioned above the central line of the cantilever beam so as to be free from the influence of external force and used for detecting the temperature change of the cantilever beam, and the first fiber Bragg grating is connected with the second fiber Bragg grating in series.
2. The tilt angle measuring device according to claim 1, wherein: the first fiber Bragg grating is arranged as a tension sensor, and the second fiber Bragg grating is arranged as a temperature compensation sensor.
3. The tilt angle measuring device according to claim 1, wherein: and the top surface of the cantilever beam is provided with an optical fiber leading-out hole, and the detection end of the first Bragg fiber grating is led out from the optical fiber leading-out hole.
4. The tilt angle measuring device according to claim 1, wherein: the weight comprises a steel ball box and a plurality of steel balls arranged in the steel ball box, and the inner wall of the steel ball box is tightly attached to each steel ball.
5. The tilt angle measuring device according to claim 4, wherein: the cantilever beam, the shell and the steel ball box are all made through 3D printing.
6. The tilt angle measuring device according to claim 5, wherein: the housing is provided as a rectangular rod-like member.
Priority Applications (1)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| CN202121000492.6U CN215064495U (en) | 2021-05-11 | 2021-05-11 | Inclination angle measuring device |
Applications Claiming Priority (1)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| CN202121000492.6U CN215064495U (en) | 2021-05-11 | 2021-05-11 | Inclination angle measuring device |
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| Publication Number | Publication Date |
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| CN215064495U true CN215064495U (en) | 2021-12-07 |
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| CN202121000492.6U Active CN215064495U (en) | 2021-05-11 | 2021-05-11 | Inclination angle measuring device |
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2021
- 2021-05-11 CN CN202121000492.6U patent/CN215064495U/en active Active
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