CN109945806A - A kind of two-dimensional fiber bragg grating obliquity sensor - Google Patents
A kind of two-dimensional fiber bragg grating obliquity sensor Download PDFInfo
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- CN109945806A CN109945806A CN201910297183.0A CN201910297183A CN109945806A CN 109945806 A CN109945806 A CN 109945806A CN 201910297183 A CN201910297183 A CN 201910297183A CN 109945806 A CN109945806 A CN 109945806A
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Abstract
A kind of two-dimensional fiber bragg grating obliquity sensor of the invention, comprising: weighted spherical ball monitors fiber grating, compensated optical fiber grating, and stainless steel short column protects shell, optical fiber loose tube.Main structure is by protection shell, stainless steel short column and induction structure composition.Protection shell is square boxlike, and two corners are opened aperture and are pierced by for optical fiber loose tube.Stainless steel short column is located at square protection shell quadrangle, and section is circle, is used to support protection shell, induction structure is by monitoring fiber grating, weighted spherical ball, compensated optical fiber optical grating constitution.A kind of two-dimensional fiber bragg grating obliquity sensor of the present invention is mainly using the equilibrium principle of power as theoretical basis, monitoring mechanism is to generate change with the variation of angle outside sensor plane so as to cause the bragg reflection wavelength of fiber grating by planar generating both direction component when weighted spherical ball stress balance.In addition, solving the problems, such as that optical fiber grating temperature strains cross sensitivity using compensated optical fiber grating.Two-dimension tilt angle sensor structure stress of the present invention is clear, fast response time, and measurement accuracy is high, and stability is good, has the function of temperature self-compensation, and easy to manufacture, and electromagnetism interference has preferable future in engineering applications.
Description
Technical field
It is a kind of for monitoring the soil body, rock and building inclination angle the present invention is based on fiber grating sensing technology
High precision instrument belongs to technical field of optical fiber sensing.
Background technique
Large scale civil engineering telecommunication tower engineering, science of bridge building, housing project and large-scale water tower engineering etc. are due to ground
The easy run-off the straight phenomenon of base foundation uneven settlement, not only influences the normal usage function of structure, and causes additional stress very
To causing structure to be destroyed, life and property loss is caused.Therefore, having very much through the structures slope status monitoring for constructing and runing the phase must
It wants.Traditional obliquity sensor, for basic principle, can reach higher precision and resolution ratio with galvanomagnetic-effect, capacity effect etc.,
But such light current formula sensor haves the shortcomings that electromagnetism interference performance is poor, cable run loss is big, transmission range is close, strong
Electromagnetic field environment, antistatic environment such as coal mine and oil depot etc. are difficult to be applicable in.Fiber-optic grating sensor has measurement sensitivity high, anti-
Strong electromagnetic, corrosion resistant advantage are suitable for structure real time on-line monitoring.Therefore, it is badly in need of researching and developing a kind of for long-term real-time
Monitor the optical fiber grating inclination angle sensor of the soil body, rock and building inclination angle.
Summary of the invention
The present invention relates to a kind of structure is simple, performance is stable, reliable, high sensitivity, anti-strong electromagnetic, corrosion-resistant, uses
In the long-term real-time monitoring soil body, the sensor of rock and building two-dimensional tilting angle.
To achieve the goals above, the present invention, which solves the technical solution of technical problem, is:
A kind of two-dimensional fiber bragg grating obliquity sensor, mainly include weighted spherical ball, monitor fiber grating, compensated optical fiber grating,
Stainless steel short column protects shell, optical fiber loose tube；The protection shell is square box structure, and stainless steel short column is located at just
Rectangular protection shell quadrangle, section are circle, are used to support protection shell；Two corners are opened aperture and are pierced by for optical fiber loose tube；Match
Heavy ball is placed in square protection shell center, then by being in criss-cross monitoring fiber grating drawknot；Weighted spherical ball matter
Heart position is opened aperture and is passed through for monitoring fiber grating, then encapsulating sealing of hole；Stainless steel is fixed in four monitoring fiber grating ends
On short column, mass ball is undertaken along the weight component in x/y plane direction, inclination angle and inclination direction are determined by its wavelength shift；It mends
It repays fiber grating and is pasted on the position that protection shell closes on stainless steel short column；Monitor the tail optical fiber and compensated optical fiber grating of fiber grating
Tail optical fiber both pass through protection housing side aperture after, put on using optical fiber loose tube.
Due to using the above structure, so that the present invention has following advantages and effect:
1. life cycle management monitoring can be carried out to component tilt angle.
The present invention directly obtains the strain that the tension that weighted spherical ball inclination generates monitors fiber grating, monitoring by fiber grating
High sensitivity, electromagnetism interference is corrosion-resistant, can theoretically realize that component tilt angle life cycle management monitors.
2. range is big, measurement accuracy is adjustable.
By structure design it is found that this obliquity sensor range reaches -90 ° to 90 °, meet civil engineering large scale structure inclination angle
Requirement in terms of range.In addition, axial point is generated when the principle of the present invention is weighted spherical ball stress balance on monitoring fiber grating
Power causes to monitor fiber grating generation axial strain.Therefore the quality size of weighted spherical ball directly affects unit angle change and draws
The size of the monitoring fiber grating axial strain risen can be changed the monitoring accuracy of sensor by changing factors above, keep it full
The different required precision of foot.
3. any direction inclination angle in plane can be surveyed.
It is designed by structure it is found that the monitoring fiber grating in this obliquity sensor is using bi-directional symmetrical configuration, any direction
When inclination angle occurs, it can all cause the variation of fiber grating strain, by theoretical calculation it can be seen that inclined direction and angle.
4. monitoring fast response time.
Axial thrust load is generated on monitoring fiber grating when the present invention is based on weighted spherical ball stress balance, by monitoring optical fiber
Grating strain is to obtain fiber bragg grating center wavelength knots modification and instead speculate that point inclination angle and inclination direction, principle are simple, knot
Structure stress is clearly concise, without lengthy and jumbled mechanical conductive device, therefore sensor fast response time.
5. arrangement is various.
The present invention is sealing box type design, monitored position needed for both being directly arranged in, and can also be embedded in prefabricated components in advance
In, survival rate of the sensor in construction monitoring can be improved.
6. applied widely.
The present invention is small in size and seals, and accommodative ability of environment is strong, is not only applicable to the knot in terms of the soil body, rock and building
The monitoring of structure tilt quantity can also carry out real-time monitoring to deflection of bridge structure using the invention.
Structure is reasonable for two-dimension tilt angle sensor of the present invention, fast response time, measurement accuracy height and adjustable, stability
It is good, have the function of temperature self-compensation, and easy to manufacture, electromagnetism interference has preferable future in engineering applications.
Detailed description of the invention
The present invention is described in further details with reference to the accompanying drawings and detailed description.
Fig. 1 is a kind of two-dimensional fiber bragg grating obliquity sensor internal structure main view of the present invention.
Fig. 2 is a kind of two-dimensional fiber bragg grating obliquity sensor internal structure schematic three dimensional views of the present invention.
Fig. 3 is a kind of two-dimensional fiber bragg grating obliquity sensor Complete three-dimensional schematic diagram of the present invention.
Fig. 4 is a kind of two-dimensional fiber bragg grating obliquity sensor of the present invention and horizontal line angle schematic diagram.
Fig. 5 is a kind of two-dimensional fiber bragg grating obliquity sensor of the present invention and inclined direction schematic diagram.
Specific embodiment
The present invention will be described in further detail combined with specific embodiments below, but protection scope of the present invention is not had
The embodiment of body is limited, and is subject to claims.In addition, with without prejudice under the premise of technical solution of the present invention, to this hair
Any modifications or changes easy to accomplish of those of ordinary skill in the art made by bright fall within claim model of the invention
Within enclosing.
Fig. 1, a kind of two-dimensional fiber bragg grating obliquity sensor of the invention shown in 2,3, comprising: weighted spherical ball monitors optical fiber light
Grid, compensated optical fiber grating, stainless steel short column protect shell, optical fiber loose tube.Main structure is by protection shell, stainless steel short column
It is formed with induction structure.Protection shell 6 is square boxlike, and two corners are opened aperture and are pierced by for optical fiber loose tube 1.Stainless steel short column
2 are located at 6 four jiaos of shell of square protection, and section is circle, are used to support protection shell 6, induction structure is by monitoring fiber grating
3, weighted spherical ball 4, compensated optical fiber grating 5 is constituted.Wherein weighted spherical ball 4 is placed in square guarantor by monitoring the drawknot of fiber grating 3
6 center of protective case body, 4 centroid position of weighted spherical ball open aperture and pass through rear encapsulating sealing of hole for monitoring fiber grating 3.Four monitoring light
Fine 3 end of grating is fixed on stainless steel short column, is undertaken mass ball along the weight component in x/y plane direction, is passed through its wave length shift
It measures and determines inclination angle and inclination direction.Compensated optical fiber grating 5 is pasted on the position that protection shell 6 closes on stainless steel short column 2.Monitor light
The tail optical fiber 1 of fine grating 3 and compensated optical fiber grating 5 both passes through protection 6 side aperture of shell and puts on optical fiber loose tube.
A kind of working principle of two-dimensional fiber bragg grating obliquity sensor of the invention is as follows:
As fiber grating principle it is found that axial strain measured by this sensor meets relationship:
A=π r2 (2)
In formula, Δ λBFor center changed wavelength, kεFor fiber grating strain sensitivity coefficient, A is fiber grating net section
Area, r fiber grating section radius.N is axial force on optical fiber, meets fundamental equation:
N=mgcos θ (3)
Wherein m is weighted spherical ball quality, and ρ is weighted spherical ball density of material, and V is counterweight sphere volume, and θ is sensor and horizontal direction
Between angle, as shown in Figure 4.(2) (3) (4), which are brought into (1), to be obtained:
And then have
It enablesThen have:
θ=arccosK Δ λB (7)
In formula, K is material coefficient.
It needs to be monitored i.e. θ to sensor and horizontal direction initial angle when placementJust, thus can in later monitoring
Obtain the actual angle of inclination α of measuring point1。
α1=θIt surveys-θJust (8)
There is α1=arccosK Δ λB is surveyed-arccosKΔλAt the beginning of B (9)
Thus formula can be seen that by monitoring real-time center changed wavelength Δ λB is surveyedWith central wavelength knots modification Δ when placement
λAt the beginning of B, to obtain measuring point current inclination α1As a result, and α1It is positive and illustrates to tilt counterclockwise, α1It is negative and illustrates to tilt clockwise.
In addition, further relating to inclined direction problem, inclined direction is by angle α2It determines, as shown in Figure 5.
It can be obtained by (10) (11):
The inclined direction and tilt angle of detected material generation, α can be obtained by (13) (14)1It can indicate tilt angle, α2It can table
Show inclined horizontal direction, α1It is positive and illustrates to tilt counterclockwise, α1It is negative and illustrates to tilt clockwise, α2± 45 ° are not exceeded, because
For all directions tension optical fiber direction difference, two optical fiber of tension can be obtained by comparing each optic fiber grating wavelength drift band
Grating, so that it is determined that inclined direction.
A kind of specific packaged type of two-dimensional fiber bragg grating obliquity sensor of the invention are as follows:
First fiber grating is use up in the preformed hole in the middle part of end insertion stainless steel short column, encapsulating is fixed.By fiber grating by suitable
Sequence passes through weighted spherical ball, diagonal stainless steel short column, and applies certain prestressing force and make the horizontal tension of fiber grating holding, later
Drop takes a small amount of cyanacrylate at the contact surface of fiber grating and diagonal stainless steel short column, protects shell in square
The center of bottom, which is marked, marks the position of weighted spherical ball, after fiber grating is fixed again by diagonal stainless steel short column with match
The duct encapsulating of heavy ball.In the same way, wall surface closes on the position for monitoring fiber grating in square protective shell body
Upper stickup compensated optical fiber grating.After a small amount of 704 glue is smeared on tail optical fiber surface, protected with optical fiber loose tube.
Square protection shell is combined by aluminium sheet, and is fixed by bolts, and two apertures are wherein reserved on the aluminium sheet of side, are used
To be pierced by tail optical fiber.Stainless steel short column is bolted to protection shell quadrangle.Weighted spherical ball is the uniform ball being made of stainless steel
Body, center of gravity, which is boxed out, makes to monitor fiber grating across weighted spherical ball center of gravity, and weighted spherical ball is by four monitoring fiber grating drawknots four
On root stainless steel short column, equidirectional monitoring fiber grating series connection, one end is cementing on stainless steel short column, and the stainless steel of the other end is short
Column, which is boxed out, passes through monitoring fiber grating tail optical fiber Loose tube, encapsulating sealing of hole in all hole holes.
Claims (5)
1. a kind of two-dimensional fiber bragg grating obliquity sensor, which is characterized in that mainly include weighted spherical ball, monitor fiber grating, compensation
Fiber grating, stainless steel short column protect shell, optical fiber loose tube；
The protection shell is square box structure, and stainless steel short column is located at square protection shell quadrangle, and section is circle,
It is used to support protection shell；Two corners are opened aperture and are pierced by for optical fiber loose tube；
Weighted spherical ball is placed in square protection shell center, then by being in criss-cross monitoring fiber grating drawknot；
Weighted spherical ball centroid position is opened aperture and is passed through for monitoring fiber grating, then encapsulating sealing of hole；Four monitoring fiber grating ends
It is fixed on stainless steel short column, undertakes mass ball along the weight component in x/y plane direction, inclination angle is determined by its wavelength shift
And inclination direction；Compensated optical fiber grating is pasted on the position that protection shell closes on stainless steel short column；Monitor the tail optical fiber of fiber grating
After both passing through protection housing side aperture with the tail optical fiber of compensated optical fiber grating, put on using optical fiber loose tube.
2. a kind of two-dimensional fiber bragg grating obliquity sensor according to claim 1, it is characterised in that: the sensing element is
Bragg grating.
3. a kind of two-dimensional fiber bragg grating obliquity sensor according to claim 1, it is characterised in that: the induction structure is
Symmetric construction.
4. a kind of two-dimensional fiber bragg grating obliquity sensor according to claim 1, it is characterised in that: the monitoring mechanism
Axial thrust load is generated on optical fiber when being weighted spherical ball stress balance, causes optical fiber that axial strain occurs, by monitoring fiber grating
Axial strain is to obtain fiber bragg grating center wavelength knots modification and obtain measuring point inclination angle and inclination direction by formula.
5. a kind of two-dimensional fiber bragg grating obliquity sensor according to claim 1, it is characterised in that:
Working principle is as follows:
As fiber grating principle it is found that axial strain measured by this sensor meets relationship:
A=π r2 (2)
In formula, Δ λBFor center changed wavelength, kεFor fiber grating strain sensitivity coefficient, A is fiber grating net section face
Product, r fiber grating section radius；N is axial force on optical fiber, meets fundamental equation:
N=mg cos θ (3)
Wherein m is weighted spherical ball quality, and ρ is weighted spherical ball density of material, and V is counterweight sphere volume, and θ is between sensor and horizontal direction
Angle；(2) (3) (4), which are brought into (1), to be obtained:
And then have
It enablesThen have:
θ=arccos K Δ λB (7)
In formula, K is material coefficient；
It needs to be monitored i.e. θ to sensor and horizontal direction initial angle when placementJust, to can must be surveyed in later monitoring
The actual angle of inclination α of point1；
α1=θIt surveys-θJust (8)
There is α1=arccos K Δ λB is surveyed-arccos KΔλAt the beginning of B(9)
Thus formula can be seen that by monitoring real-time center changed wavelength Δ λB is surveyedWith central wavelength knots modification Δ λ when placementAt the beginning of B, from
And obtain measuring point current inclination α1As a result, and α1It is positive and illustrates to tilt counterclockwise, α1It is negative and illustrates to tilt clockwise；In addition, also
It is related to inclined direction problem, inclined direction is by angle α2It determines；
It can be obtained by (10) (11):
The inclined direction and tilt angle of detected material generation, α can be obtained by (13) (14)1It can indicate tilt angle, α2It can indicate to incline
Oblique horizontal direction, α1It is positive and illustrates to tilt counterclockwise, α1It is negative and illustrates to tilt clockwise, α2± 45 ° are not exceeded, because respectively
A direction tension optical fiber direction is different, and two optical fiber light of tension can be obtained by comparing each optic fiber grating wavelength drift band
Grid, so that it is determined that inclined direction.
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| CN110530282A (en) * | 2019-09-04 | 2019-12-03 | 苏州热工研究院有限公司 | Three spindle-type fiber grating strain measurement sensors of adjustable sensitivity |
| CN112484669A (en) * | 2020-12-10 | 2021-03-12 | 哈尔滨工业大学 | Small-size two-dimensional vector optical fiber inclination angle sensing probe and sensing device |
| CN112833809A (en) * | 2021-01-13 | 2021-05-25 | 苏州热工研究院有限公司 | Fiber grating high-temperature strain gauge and calibration method thereof |
| CN113310461A (en) * | 2021-04-23 | 2021-08-27 | 中铁第一勘察设计院集团有限公司 | Temperature insensitive optical fiber two-dimensional tilt angle sensor |
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Cited By (6)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| CN110530282A (en) * | 2019-09-04 | 2019-12-03 | 苏州热工研究院有限公司 | Three spindle-type fiber grating strain measurement sensors of adjustable sensitivity |
| CN112484669A (en) * | 2020-12-10 | 2021-03-12 | 哈尔滨工业大学 | Small-size two-dimensional vector optical fiber inclination angle sensing probe and sensing device |
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| CN113310461A (en) * | 2021-04-23 | 2021-08-27 | 中铁第一勘察设计院集团有限公司 | Temperature insensitive optical fiber two-dimensional tilt angle sensor |
| CN113310461B (en) * | 2021-04-23 | 2023-02-17 | 中铁第一勘察设计院集团有限公司 | Temperature insensitive optical fiber two-dimensional tilt angle sensor |
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