CN204854656U - Two -way deviational survey sensor based on fiber grating - Google Patents

Abstract

The utility model discloses a two -way deviational survey sensor based on fiber grating, including the sensor housing, be provided with the mounting in the the sensor housing, the mounting is used for fixed equal strength cantilever beam, and equal strength cantilever beam bottom is pasted and is had the quality piece, and fiber grating draws forth from the the sensor housing top, is connected with the demodulation appearance after emboliaing hollow protection tube, when the sensor run -off the straight, vertical equal strength cantilever beam can produce the slope under the effect of quality piece to deformation taking place, and then change fiber grating's center wavelength, through optic fibre wavelength demodulated equipment demodulation fiber grating center wavelength's change, records the angle of corresponding equal strength cantilever beam slope. The utility model discloses a relation that changes with fiber grating center wavelength of meeting an emergency of equal strength cantilever beam records the angle of slope during the slope. Simple structure measures accurately.

Description

Based on the two-way deviational survey sensor of fiber grating

Technical field

The utility model relates to technical field of optical fiber sensing, is specifically related to a kind of two-way deviational survey sensor based on fiber grating.

Background technology

Since the nineties in 20th century, owing to having not by electromagnetic interference influence, size is little, lightweight, the advantages such as long service life, and fiber grating sensing technology development rapidly.Traditional movable type, fixed deviational survey sensor have been widely used in the monitoring of gradient in various engineering, apply the lateral deformation that tiltmeter detects embankment weak soil as F.A.Tavenas proposes in Geotechnical Engineering; Wang Chunxiao adopts the orthogonal Magnetic sensor of three axle normal acceleration sensor measurements, terrestrial gravitation vector three axle to measure geomagnetic fieldvector to measure gradient.But there is larger deficiency in traditional deviational survey sensor, as data acquisition instrument there will be drift error, the wearing and tearing of tiltmeter guide wheel, skew etc. can bring error etc.Fiber grating sensing technology is as the new stage of sensing technology, and it meets the high precision of measurement, remote and chronicity requirement, provides good technological means for solving above-mentioned key issue.Therefore fiber grating deviational survey sensor is just progressively applied in various engineering.As flexure theory formula and the difference algorithm of Pei Hua Futong lintel, the change of its gradient is tried to achieve in the strain of trying to achieve each measuring point of original position tiltmeter according to the linear relationship between Fiber Bragg Grating FBG wavelength variations and strain.

Seldom report about the investigation and application of the fiber-optic grating sensor of two-way deviational survey at present.The utility model records the angle of inclination by the relation that strain and the fiber bragg grating center wavelength of equi intensity cantilever during inclination change.

Utility model content

For solving the deficiency that prior art exists, the utility model discloses the two-way deviational survey sensor based on fiber grating, the utility model adopts fiber grating as sensitive element, is realized the measurement in extraneous angle of inclination and direction by fiber grating.

For achieving the above object, concrete scheme of the present utility model is as follows:

Based on the two-way deviational survey sensor of fiber grating, comprise sensor outer housing, fixture is provided with in described sensor outer housing, described fixture is used for fixing equi intensity cantilever, mass is pasted with bottom equi intensity cantilever, fiber grating is drawn from sensor outer housing top, is connected after being inserted in hollow protection tube with (FBG) demodulator;

When sensor run-off the straight, vertical equi intensity cantilever can produce inclination under the effect of mass, thus generation deformation, and then change the centre wavelength of fiber grating, by the change of fiber optic wavelength demodulated equipment demodulating fiber bragg grating centre wavelength, record the angle that corresponding equi intensity cantilever tilts.

Described fiber grating comprises temperature compensation grating, responsive grating and optical fiber pigtail, inwall is also pasted with temperature compensation grating to sensor outer housing, equi intensity cantilever is stained with responsive grating, temperature compensation grating and responsive grating are in series, and optical fiber pigtail is drawn from transducer tip.

Described sensor outer housing is cylindrical, sensor outer housing upper end is provided with the sensor upper cover be used in combination with it, sensor outer housing lower end is provided with the sensor base be used in combination with it, and on sensor, tops has screw thread mouth to realize the extraction of optical fiber pigtail.

Described fixture comprises the first fixture and the second fixture, first fixture and the second fixture are two unequal rectangular parallelepiped blocks of size, both first fixture and the second fixture are high equal, but the appearance etc. of wide and second fixture of the first fixture, the first fixture is screwed in sensor upper cover inwall top.

Described second fixture is screwed in the first fixture side, accompanies equi intensity cantilever between the first fixture and the second fixture.

Described first fixture centre is porose to communicate with the screw thread mouth of tops on sensor, and the responsive grating tail optical fiber being pasted on equi intensity cantilever surface is drawn in hole thus.

Described equi intensity cantilever, selects carbon fiber board as matrix, and for ensureing that its uniform force produces homogeneous deformation, equi intensity cantilever is set to isosceles triangle in effective field of load.

Described mass, Material selec-tion is copper, and shape is cylindrical, is pasted onto equi intensity cantilever bottom, for generation of acting force.

Described responsive grating, is pasted on grid region on equi intensity cantilever with ECA.

Described temperature compensation grating, is pasted on sensor outer housing inwall with ECA by grid region, with responsive gratings in series.

When recording the angle of corresponding equi intensity cantilever inclination, suppose that pitch angle is θ, then the stress model of semi-girder is:

F _tangentially=Fsin θ (2)

Therefore the pass between wavelength and angle of inclination is

$\mathrm{\Δ}{\mathrm{\λ}}_B=0.78*\frac{6\mathrm{Fl}\·\sin \mathrm{\θ}}{{\mathrm{Eb}}_0{h}^2}*{\mathrm{\λ}}_B---\left(3\right)$

So $\mathrm{\θ}=\arcsin \frac{0.21\mathrm{\Δ}{\mathrm{\λ}}_B{\mathrm{Eb}}_0{h}^2}{{\mathrm{\λ}}_B\mathrm{Fl}}---\left(4\right)$

Wherein, ε is equi intensity cantilever surface strain, and F is external forces, and l is the length of semi-girder; b ₀wide for stiff end; H is the thickness of semi-girder; E is the elastic modulus of semi-girder, λ _bfor grating wavelength, Δ λ _bfor grating wavelength change, F _tangentiallytangentially stressed for semi-girder.

The beneficial effects of the utility model:

Two-way deviational survey sensor based on fiber grating described in the utility model, using fiber grating as core sensitive element, deformation due to equi intensity cantilever is two-way, can tension stress, also can compression chord, so the responsive grating being pasted on equi intensity cantilever surface has the strain of both direction, during tension stress, the change of grating centre wavelength is large, and during compression chord, centre wavelength diminishes.When sensor tilts to the left or to the right, just its angle tilted and direction can be recorded by the change of centre wavelength.

Accompanying drawing explanation

Fig. 1 is the schematic appearance of two-way deviational survey sensor;

Fig. 2 is two-way deviational survey sensor internal structural drawing;

Fig. 3 is equi intensity cantilever schematic diagram;

Fig. 4 is sensor outer housing schematic diagram;

Fig. 5 is sensor base schematic diagram;

Fig. 6 is sensor upper cover schematic diagram;

Fig. 7 is mass schematic diagram;

Fig. 8 is the first fixture schematic diagram;

Fig. 9 is the second fixture schematic diagram;

Figure 10 a equi intensity cantilever accepts model original state front elevation;

Figure 10 b equi intensity cantilever accepts model original state side view;

It is θ state front elevation that Figure 11 a equi intensity cantilever accepts model inclination angle;

It is θ side view of the state that Figure 11 b equi intensity cantilever accepts model inclination angle;

In figure: 1, optical fiber pigtail, 2, sensor outer housing, 3, sensor upper cover, 4, sensor base, the 5, second fixture, 6, equi intensity cantilever, 7, mass, the 8, first fixture, 9, responsive grating, 10, temperature compensation grating.

Embodiment:

Below in conjunction with accompanying drawing, the utility model is described in detail:

The schematic appearance of the two-way deviational survey sensor based on fiber grating involved by the utility model as shown in figs. 1-7.This sensor mainly comprises sensor outer housing 2, interior fixtures is the first fixture 8 and the second fixture 5, equi intensity cantilever 6, mass 7, responsive grating 9, temperature compensation grating 10, sensor upper cover 3 and sensor base 4.An equi intensity cantilever 6 is fixed with two interior fixtures in sensor outer housing 2; equi intensity cantilever 6 is stained with responsive grating 9; and mass 7 is equipped with in bottom; temperature compensation grating 10 is pasted on the inwall of sensor outer housing 2 after connecting with responsive grating 9; optical fiber pigtail 1 is drawn from transducer tip, is connected after being inserted in hollow protection tube with (FBG) demodulator.

As shown in Figure 3, the equi intensity cantilever 6 for generation of strain selects carbon fiber board as matrix, selects ECA as the bonding agent of fiber grating and strain beam.For ensureing that its uniform force produces homogeneous deformation, equi intensity cantilever 6 is designed to isosceles triangle in effective field of load.For generation of the mass 7 of acting force, Material selec-tion is copper, and shape is cylindrical, is pasted onto equi intensity cantilever 6 bottom.Every partial interior fixture is small one and large one two rectangular parallelepiped blocks, and centre is fixed with equi intensity cantilever 6, and rectangular parallelepiped block is fixed on sensor inwall top.

As shown in Figure 8, inner first fixture 8 centre is porose to be connected with the screw thread mouth of sensors topside, and both sides have two screw thread mouths to be fixed in sensor inwall.

As shown in Figure 9, inner second fixture 5 there are two screw thread mouths itself and equi intensity cantilever 6 to be fixed on the first fixture 8.Sensor outer housing 2 is cylindrical, and material is 304 stainless steels, and there is screw thread mouth at top to realize the extraction of optical fiber pigtail 1.

Sensor measurement principle further illustrates as follows: when sensor run-off the straight, and vertical equi intensity cantilever 6 can produce under the effect of mass 7, thus deformation occurs, and then changes the centre wavelength of fiber grating.By the change of fiber optic wavelength demodulated equipment demodulating fiber bragg grating centre wavelength, record the angle that corresponding equi intensity cantilever 6 tilts.Relational expression between equi intensity cantilever 6 surface strain ε and external forces F:

$\mathrm{\ϵ}=\frac{6\mathrm{Fl}}{{\mathrm{Eb}}_0{h}^2}---\left(1\right)$

In formula, the length of l semi-girder; b ₀stiff end wide; The thickness of h semi-girder; The elastic modulus of E semi-girder.

Grating wavelength changes:

Δλ _B＝0.78*ε*λ _B

Equi intensity cantilever 6 stress model original state, as shown in Figure 10 a-10b, supposes that the stress model of pitch angle for θ then equi intensity cantilever 6 is as shown in Figure 11 a-11b:

F _tangentially=Fsin θ (2)

Therefore the pass between wavelength and angle of inclination is

$\mathrm{\Δ}{\mathrm{\λ}}_B=0.78*\frac{6\mathrm{Fl}\·\sin \mathrm{\θ}}{{\mathrm{Eb}}_0{h}^2}*{\mathrm{\λ}}_B---\left(3\right)$

So $\mathrm{\θ}=\arcsin \frac{0.21\mathrm{\Δ}{\mathrm{\λ}}_B{\mathrm{Eb}}_0{h}^2}{{\mathrm{\λ}}_B\mathrm{Fl}}---\left(4\right)$

By reference to the accompanying drawings embodiment of the present utility model is described although above-mentioned; but the restriction not to the utility model protection domain; one of ordinary skill in the art should be understood that; on the basis of the technical solution of the utility model, those skilled in the art do not need to pay various amendment or distortion that creative work can make still within protection domain of the present utility model.

Claims (9)

1. based on the two-way deviational survey sensor of fiber grating; it is characterized in that; comprise sensor outer housing; fixture is provided with in described sensor outer housing; described fixture is used for fixing equi intensity cantilever; be pasted with mass bottom equi intensity cantilever, fiber grating is drawn from sensor outer housing top, is connected after being inserted in hollow protection tube with (FBG) demodulator.

2. as claimed in claim 1 based on the two-way deviational survey sensor of fiber grating, it is characterized in that, described fiber grating comprises temperature compensation grating, responsive grating and optical fiber pigtail, inwall is also pasted with temperature compensation grating to sensor outer housing, equi intensity cantilever is stained with responsive grating, temperature compensation grating and responsive grating are in series, and optical fiber pigtail is drawn from transducer tip.

3. as claimed in claim 1 based on the two-way deviational survey sensor of fiber grating, it is characterized in that, described sensor outer housing is cylindrical, sensor outer housing upper end is provided with the sensor upper cover be used in combination with it, sensor outer housing lower end is provided with the sensor base be used in combination with it, and on sensor, tops has screw thread mouth to realize the extraction of optical fiber pigtail.

4. as claimed in claim 1 based on the two-way deviational survey sensor of fiber grating, it is characterized in that, described fixture comprises the first fixture and the second fixture, first fixture and the second fixture are two unequal rectangular parallelepiped blocks of size, both first fixture and the second fixture are high equal, but the appearance etc. of wide and second fixture of the first fixture, the first fixture is screwed in sensor upper cover inwall top.

5., as claimed in claim 4 based on the two-way deviational survey sensor of fiber grating, it is characterized in that, described second fixture is screwed in the first fixture side, accompanies equi intensity cantilever between the first fixture and the second fixture.

6. as claimed in claim 4 based on the two-way deviational survey sensor of fiber grating, it is characterized in that, described first fixture centre is porose to communicate with the screw thread mouth of tops on sensor, and the responsive grating tail optical fiber being pasted on equi intensity cantilever surface is drawn in hole thus.

7. as claimed in claim 1 based on the two-way deviational survey sensor of fiber grating, it is characterized in that, described equi intensity cantilever, select carbon fiber board as matrix, for ensureing that its uniform force produces homogeneous deformation, equi intensity cantilever is set to isosceles triangle in effective field of load.

8., as claimed in claim 1 based on the two-way deviational survey sensor of fiber grating, it is characterized in that, described mass, Material selec-tion is copper, and shape is cylindrical, is pasted onto equi intensity cantilever bottom, for generation of acting force.

9., as claimed in claim 2 based on the two-way deviational survey sensor of fiber grating, it is characterized in that, described responsive grating, is pasted on equi intensity cantilever with ECA by grid region;

Described temperature compensation grating, is pasted on sensor outer housing inwall with ECA by grid region, with responsive gratings in series.