CN202330457U - Temperature compensation type optical fiber grating accelerator probe - Google Patents
Temperature compensation type optical fiber grating accelerator probe Download PDFInfo
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- CN202330457U CN202330457U CN2011204425784U CN201120442578U CN202330457U CN 202330457 U CN202330457 U CN 202330457U CN 2011204425784 U CN2011204425784 U CN 2011204425784U CN 201120442578 U CN201120442578 U CN 201120442578U CN 202330457 U CN202330457 U CN 202330457U
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- fiber grating
- optical fiber
- inertial mass
- housing
- strain
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Abstract
The utility model discloses a temperature compensation type optical fiber grating accelerator probe, which comprises a shell, wherein two spring pieces, an inertial mass block and an elastic tube are arranged in the shell; the two spring pieces are positioned on the same horizontal plane and are symmetrically arranged on the two sides of the inertial mass block; one end of each spring piece is fixed to the shell, and the other end of each spring piece is fixed to the inertial mass block; the elastic tube is vertically placed, the upper end of the elastic tube is fixed to the shell, and the lower end of the elastic tube is positioned above the inertial mass block; a first optical fiber grating and a second optical fiber grating are arranged in the elastic tube; the first optical fiber grating is rigidly adhered to the inner wall of the elastic tube; the second optical fiber grating is connected to the lower end of the first optical fiber grating through an optical fiber; and the upper end of the first optical fiber grating is connected to the exterior of the shell through an optical fiber. When acceleration is available, a steel tube produces strain through vertical vibration force of the inertial mass block, the optical fiber grating is driven to strain, the size of the acceleration can be obtained by detecting the strain of the optical fiber grating, and the influence of temperature and phase nose can be reduced.
Description
Technical field
The utility model relates to technical fields such as fiber grating sensing technology, engineering mechanics and Photoelectric Detection, and particularly a kind of electromagnetic interference (EMI), size temperature compensating type fiber grating accelerometer little, that can eliminate temperature noise automatically of not receiving popped one's head in.
Background technology
Concentrate and to produce a kind of amplitude small (10 owing to stress in the heavy construction structures such as concrete dykes and dams, satellites transmits platform and offshore production platform
-8-10
-10M) stress wave.Generally below 100Hz, it extensively is present in the practical applications field this stress wave vibration frequency, and it has reflected the essential status flag that is in little object that shakes, and is its vibration acceleration and characterize the most direct parameter of this stress wave.Through acceleration being carried out state analysis and the fault diagnosis that distributed accurate measurement can realize vibrating mass.In the vibration monitor system vibration signal being picked up main dependence electromagnetism class acceleration transducer realizes; Though electromagnetism class acceleration transducer has obtained widespread use in vibration survey; But many defectives that himself exists make the application of electromagnetism class acceleration transducer in the vibration survey field receive very big restriction; Can not fundamentally eliminate like electromagnetic interference (EMI) and temperature noise; Cross-talk between the signal, measuring sonde are complicated, and the electric wire cumulative volume is big, arrangement space receives easily etc., and problem is difficult to solve.In recent years, many Fibre Optical Sensors are applied in vibration monitoring and the information acquisition, and receive extensive concern and widely popularize, and wherein (fiber Bragg grating, FBG) sensor has development prospect most to Fiber Bragg Grating FBG.
Summary of the invention
The purpose of the utility model provides a kind of temperature compensating type fiber grating accelerometer probe; It designs based on Fiber Bragg Grating FBG; On the basis that can realize the low-frequency vibration acceleration analysis, it is little to have size, the characteristics of light weight; When using, do not receive the influence of power swing in electromagnetic interference (EMI) and the light path etc., and can eliminate the influence of temperature noise and phase noise automatically.
For realizing above-mentioned purpose, the technical scheme that the utility model is taked is: a kind of temperature compensating type fiber grating accelerometer probe, comprise housing, and be provided with spring leaf, inertial mass and Flexible pipe fitting in the housing; Spring leaf quantity is 2, and 2 spring leafs are positioned on the same surface level, and the both sides that are installed on inertial mass of symmetry; One end of each spring leaf is fixed on the housing, and the other end is fixed on the inertial mass; Flexible pipe fitting is vertically placed, and its upper end is fixed on the housing, and the lower end is positioned at the top of inertial mass; Be provided with first fiber grating and second fiber grating in the Flexible pipe fitting, the first fiber grating rigidity is pasted on the inwall of Flexible pipe fitting, and second fiber grating connects the lower end of first fiber grating through optical fiber; The upper end of first fiber grating is connected to outside through optical fiber.
As a kind of improvement, the utility model also comprises pedestal, and pedestal connects the housing lower end, and the pedestal upper surface center overlaps with center, housing lower surface; The floorage of pedestal is greater than the area of housing lower surface.Pedestal and housing can be one-piece construction, and the setting of pedestal can make the probe of the utility model when using, be convenient to install or place, and the interference of better avoiding other vibration to cause guarantees sensitivity and the degree of accuracy measured.
Further, the cross section of the said spring leaf of the utility model is a rectangle, and the equal in length of two spring leafs.The spring leaf of square-section can make that when inertial mass vibrates the steel pipe that causes and the strain of fiber grating are linear strain, is convenient to analyze.
Further; Flexible pipe fitting described in the utility model is a steel pipe; Acting as of Flexible pipe fitting: when acceleration is arranged; The up-down vibration of inertial mass can cause the strain of steel pipe, and rigidity is pasted on the fiber grating of just having shut and also has same strain, thereby can realize the purpose of the utility model signal processing and analysis.Flexible pipe fitting is chosen as the elasticity coefficient that steel pipe both can satisfy the strain requirement, can in strain path, not cause damage to fiber grating because of elasticity is excessive again.
The projection of above-mentioned steel pipe lower end on inertial mass is positioned at the middle part of inertial mass upper surface.When acceleration was arranged, steel pipe was corresponding with the position of the displacement amplitude maximum of inertial mass, the sensitivity that can improve the utility model.
Preferably, the said inertial mass of the utility model is a cube.Two spring leafs support inertial mass and retrain the direction of vibration of mass.The inertial mass of regular shape is more conducive to analyze, and can guarantee the measuring accuracy of the utility model.
In application, when acceleration, inertial mass up-down vibration power makes steel pipe produce strain and drives fiber grating strain, and the strain through the detection fiber grating can obtain acceleration magnitude.
Beneficial effect
The utility model adopts fiber grating as sensitive element, can avoid electromagnetic interference (EMI), is suitable for complex electromagnetic environment and uses.Application principle is the centre wavelength drift value that steel pipe dependent variable that degree of will speed up causes converts fiber grating into, does not receive that the light path power swing influences in the measuring system.In the double optical fiber grating structure; Wherein a fiber grating is pasted on the steel pipe inwall; With steel pipe same strain is arranged, freely place and another fiber grating is unsettled, temperature variation is identical to the influence of two fiber grating; Therefore in measurement, can carry out the automatic compensation of temperature, overcome general fiber-optic grating sensor temperature, strain cross sensitivity problem.The utility model structure is comparatively simple simultaneously, and volume is less, is easy to form the distributed sensing network, carries out the multiple spot acceleration analysis, and cost is lower simultaneously, installs simply, is easy to promote.
Description of drawings
Shown in Figure 1 is the utility model structural representation;
Shown in Figure 2 is the broken section front view of Fig. 1;
Shown in Figure 3 is the fiber grating sensing system synoptic diagram.
Embodiment
For the content that makes the utility model is more obviously understandable, do to further describe below in conjunction with accompanying drawing and embodiment.
In conjunction with Fig. 1 and Fig. 2, the utility model comprises housing 1, is provided with spring leaf 3, inertial mass 2 and Flexible pipe fitting 6 in the housing 1; Spring leaf 3 quantity are 2, and 2 spring leafs 3 are positioned on the same surface level, and the both sides that are installed on inertial mass 2 of symmetry; One end of each spring leaf 3 is fixed on the housing 1, and the other end is fixed on the inertial mass 2; Flexible pipe fitting 6 is vertically placed, and its upper end is fixed on the housing 1, and the lower end is positioned at the top of inertial mass 2; Flexible pipe fitting 6 is a steel pipe, and its inside is provided with first fiber grating 41 and second fiber grating, 42, the first fiber gratings, 41 rigidity are pasted on the inwall of Flexible pipe fitting 6, and second fiber grating 42 connects the lower end of first fiber grating 41 through optical fiber; The upper end of first fiber grating 41 is connected to housing 1 outside through optical fiber.
The lower end of housing 1 is connected with pedestal 11, and pedestal 11 overlaps with the center of housing 1; The floorage of pedestal 11 is greater than housing 1 lower end contour area.Pedestal 11 is an one-piece construction with housing 1, and the setting of pedestal 11 can make the utility model when using, be convenient to install or place, and the interference of better avoiding other vibration to cause guarantees sensitivity and the degree of accuracy measured.
The be hit by a bullet cross section of reed 3 of the utility model is a rectangle, and the equal in length of two spring leafs 3, and inertial mass 2 is a cube, and two spring leafs support inertial mass and retrain the direction of vibration of mass; The projection of steel pipe lower end on inertial mass 2 is positioned at the middle part of inertial mass upper surface, and promptly when acceleration was arranged, steel pipe was corresponding with the position of the displacement amplitude maximum of inertial mass, the sensitivity that can improve the utility model.The spring leaf of square-section can make that when inertial mass vibrates the steel pipe that causes and the strain of fiber grating are linear strain, is convenient to analyze.
The utility model based on theory of the fiber optical, is specially when using:
The cross sensitivity of ignoring temperature and strain is investigated the only sensing characteristics of FBG under single temperature or effects of strain respectively.The fiber grating Bragg wavelength that temperature causes changes formula
Δλ
B/λ
B＝(α+ξ)ΔT＝K
TΔT
In its Chinese style
Be the thermal expansivity of optical fiber,
Be the thermo-optical coeffecient of optical fiber, K
TBe fiber grating relative wavelength temperature control coefficient.Can know Δ T and Δ λ by (1) formula
BExist linear relationship,, can confirm the dut temperature variable quantity through detecting the displacement of wavelength.
The fiber grating Bragg wavelength that fiber axis causes to strain stress changes formula
Δλ
B/λ
B＝(1-P
e)ε
z＝K
εε
In the formula, P
eBe effective elasto-optical coefficient,
P wherein
11, P
12Be elasto-optical coefficient, υ is the optical fiber Poisson ratio; K
εBe fiber grating relative wavelength ga(u)ge factor.With temperature classes seemingly, Δ λ
BAlso linear with ε, by Δ λ
BCan obtain extraneous strain stress easily.
By on can know that grating Bragg wavelength change and strain and variation of temperature relation does
Δλ
B/λ
B＝(α+ξ)ΔT+(1-P
e)ε＝K
TΔT+K
εε (1)
Obviously, grating foveal reflex wavelength all is responsive to strain and temperature, when measuring an amount, certainly will will receive the influence of another amount.This shows that the problem that solves strain and temperature cross sensitivity is the key of FBG sensing detection technical applicationization.
Be illustrated in figure 3 as the fiber grating sensing system synoptic diagram.The light that sends from wideband light source is sent on the sensing grating through coupling mechanism, and centre wavelength of sensing grating reflected back is the Bragg wavelength X
BThe arrowband light wave, (strain, temperature etc.) to be measured are added in and make λ on the sensing grating
BProduce drift delta λ
B, this reflection arrowband light wave that produces drift imports the wavelength detection system through coupling mechanism again, therefrom detects Δ λ
B, and then confirm to be measured.
The utility model structural design and principle of work:
Temperature compensating type fiber grating accelerometer sonde configuration is like Fig. 1, shown in 2.Probe mainly contains inertial mass, two compositions such as spring leaf, steel pipe, housing, pedestal and two each and every one fiber gratings.Two spring leafs are the square-section, and level, symmetry are installed on centre position, inertial mass both sides, and a side is fixed on the mass, and opposite side is fixed on the housing.Two spring leafs support inertial mass and retrain the direction of vibration of mass.Inertial mass adopts cube structure.Steel pipe vertically is fixed on centre position, inertial mass top, and the other end is fixed on the housing.Two fiber grating series weldings are connected on the optical fiber, and wherein fiber grating one (FBG1) rigidity is pasted on the steel pipe inwall, and guarantee the fastness and the collimation of pasting, and fiber grating two (FBG2) is unsettled freely to be placed, and sensor signal is through tail optical fiber output.
When acceleration, the inertial mass up-down vibration, establishing its vibration acceleration is a, then the suffered inertial force of inertial mass is F=ma.Under mass inertial force F effect, steel pipe produces radial strain to be changed, and FBG1 also produces same strain variation, and the steel pipe strain does not influence FBG2.
If spring leaf thickness is h, length is l, and width is b, and the elasticity coefficient that can get two spring leafs according to the mechanics of materials and Elasticity knowledge does
E in the formula
1Be the spring leaf elastic modulus.If steel pipe length is L, internal diameter and external diameter are respectively d
1And d
2, elastic modulus is E
2, the elasticity coefficient of steel pipe does
Therefore, the elasticity coefficient of probe mass-spring system is K=K
t+ K
gIn conjunction with formula F=ma, the strain stress of the fiber grating that inertial force causes does
L in the formula
fLength for FBG.Strain stress and vibration acceleration that formula (2) has provided fiber grating are the mathematical relation of a.Therefore, can obtain extraneous accekeration through the instantaneous strain of measuring FBG.
When light signal passed through FBG1 and FBG2, because they are on all four fiber gratings, when not having vibration signal, establishing FBG foveal reflex wavelength was λ
B1=1540nm.When mass vibrated with acceleration a, FBG1 produced strain variation, changed thereby influence its reflectance spectrum, and centre wavelength produces drift.Suppose that ambient temperature is changed to Δ T, according to formula (1), the centre wavelength drift value of two fiber gratings is respectively
Δλ
B1＝λ
B11-λ
B1＝λ
B1(K
TΔT+K
εε) (3)
Δλ
B2＝λ
B12-λ
B1＝λ
B1K
TΔT (4)
λ in the formula
B11Be the centre wavelength of exporting after FBG1 strain variation and the temperature effect; λ
B12Be the centre wavelength of exporting behind the FBG2 temperature influence.The central wavelength difference that is obtained FBG1 and FBG2 by formula (3), (4) does
Δλ
B＝Δλ
B1-Δλ
B2＝λ
B1K
εε
According to formula (2), following formula is converted into
So drift value Δ λ through detection fiber grating centre wavelength
BJust can detect vibration acceleration a.
Because in the engineering survey, the strain sensitivity of FBG is 2 * 10
-3Nm/ μ ε, and temperature control is 0.03nm/ ℃, visible when acceleration analysis, temperature compensation is very important.Can know that by formula (5) this sensing probe can compensate temperature well.
The case of practical implementation described in the utility model is merely the preferable case study on implementation of the utility model, is not the practical range that is used for limiting the utility model.Be that all equivalences of doing according to the content of the utility model claim change and modification, all should be as the technological category of the utility model.
Claims (6)
1. a temperature compensating type fiber grating accelerometer probe is characterized in that, comprises housing, is provided with spring leaf, inertial mass and Flexible pipe fitting in the housing; Spring leaf quantity is 2, and 2 spring leafs are positioned on the same surface level, and the both sides that are installed on inertial mass of symmetry; One end of each spring leaf is fixed on the housing, and the other end is fixed on the inertial mass; Flexible pipe fitting is vertically placed, and its upper end is fixed on the housing, and the lower end is positioned at the top of inertial mass; Be provided with first fiber grating and second fiber grating in the Flexible pipe fitting, the first fiber grating rigidity is pasted on the inwall of Flexible pipe fitting, and second fiber grating connects the lower end of first fiber grating through optical fiber; The upper end of first fiber grating is connected to outside through optical fiber.
2. temperature compensating type fiber grating accelerometer probe according to claim 1 is characterized in that also comprise pedestal, pedestal connects the housing lower end, and the pedestal upper surface center overlaps with center, housing lower surface; The floorage of pedestal is greater than housing lower end contour area.
3. temperature compensating type fiber grating accelerometer probe according to claim 1 and 2 is characterized in that the cross section of said spring leaf is a rectangle, and the equal in length of two spring leafs.
4. temperature compensating type fiber grating accelerometer probe according to claim 1 and 2 is characterized in that said Flexible pipe fitting is a steel pipe.
5. temperature compensating type fiber grating accelerometer probe according to claim 4 is characterized in that the projection of said steel pipe lower end on inertial mass is positioned at the middle part of inertial mass upper surface.
6. temperature compensating type fiber grating accelerometer probe according to claim 1 and 2 is characterized in that said inertial mass is a cube.
Priority Applications (1)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| CN2011204425784U CN202330457U (en) | 2011-11-09 | 2011-11-09 | Temperature compensation type optical fiber grating accelerator probe |
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| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| CN2011204425784U CN202330457U (en) | 2011-11-09 | 2011-11-09 | Temperature compensation type optical fiber grating accelerator probe |
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|---|---|
| CN202330457U true CN202330457U (en) | 2012-07-11 |
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|---|---|---|---|
| CN2011204425784U Expired - Fee Related CN202330457U (en) | 2011-11-09 | 2011-11-09 | Temperature compensation type optical fiber grating accelerator probe |
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Cited By (7)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| CN102840908A (en) * | 2012-08-17 | 2012-12-26 | 苏州南智传感科技有限公司 | Vibration sensor of three-component fiber grating |
| CN105277739A (en) * | 2014-06-10 | 2016-01-27 | 黄辉 | Strain cantilever fiber accelerometer and manufacturing method thereof |
| CN105510631A (en) * | 2016-01-11 | 2016-04-20 | 昆明理工大学 | High-frequency acceleration sensor with optical fiber Bragg gratings and application method of high-frequency acceleration sensor |
| CN108351367A (en) * | 2015-11-16 | 2018-07-31 | 雷斯昂公司 | The insensitive open loop of heat with different swirl sensing suspends mass acceleration meter |
| CN110221096A (en) * | 2019-07-16 | 2019-09-10 | 蚌埠学院 | A kind of limit-type fiber grating accelerometer based on cross force of fin |
| CN110974604A (en) * | 2019-12-06 | 2020-04-10 | 宿州学院 | Acceleration sensing system of exoskeleton device for lower limb rehabilitation training |
| CN111879966A (en) * | 2020-06-24 | 2020-11-03 | 南京邮电大学 | Fiber bragg grating acceleration sensor for multi-direction detection |
-
2011
- 2011-11-09 CN CN2011204425784U patent/CN202330457U/en not_active Expired - Fee Related
Cited By (9)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| CN102840908A (en) * | 2012-08-17 | 2012-12-26 | 苏州南智传感科技有限公司 | Vibration sensor of three-component fiber grating |
| CN102840908B (en) * | 2012-08-17 | 2014-10-29 | 苏州南智传感科技有限公司 | Vibration sensor of three-component fiber grating |
| CN105277739A (en) * | 2014-06-10 | 2016-01-27 | 黄辉 | Strain cantilever fiber accelerometer and manufacturing method thereof |
| CN105277739B (en) * | 2014-06-10 | 2018-05-04 | 黄辉 | One kind strain cantilevered fibers acceleration transducer and preparation method thereof |
| CN108351367A (en) * | 2015-11-16 | 2018-07-31 | 雷斯昂公司 | The insensitive open loop of heat with different swirl sensing suspends mass acceleration meter |
| CN105510631A (en) * | 2016-01-11 | 2016-04-20 | 昆明理工大学 | High-frequency acceleration sensor with optical fiber Bragg gratings and application method of high-frequency acceleration sensor |
| CN110221096A (en) * | 2019-07-16 | 2019-09-10 | 蚌埠学院 | A kind of limit-type fiber grating accelerometer based on cross force of fin |
| CN110974604A (en) * | 2019-12-06 | 2020-04-10 | 宿州学院 | Acceleration sensing system of exoskeleton device for lower limb rehabilitation training |
| CN111879966A (en) * | 2020-06-24 | 2020-11-03 | 南京邮电大学 | Fiber bragg grating acceleration sensor for multi-direction detection |
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Legal Events
| Date | Code | Title | Description |
|---|---|---|---|
| C14 | Grant of patent or utility model | ||
| GR01 | Patent grant | ||
| CF01 | Termination of patent right due to non-payment of annual fee |
Granted publication date: 20120711 Termination date: 20151109 |
|
| EXPY | Termination of patent right or utility model |