CN201037786Y - Chirped optical fibre grating weighing sensor - Google Patents
Chirped optical fibre grating weighing sensor Download PDFInfo
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- CN201037786Y CN201037786Y CNU2007200843741U CN200720084374U CN201037786Y CN 201037786 Y CN201037786 Y CN 201037786Y CN U2007200843741 U CNU2007200843741 U CN U2007200843741U CN 200720084374 U CN200720084374 U CN 200720084374U CN 201037786 Y CN201037786 Y CN 201037786Y
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Abstract
The utility model provides a chirped fiber grating weighing sensor which is essentially used for vehicle weighing while driving. The utility model adopts an equi-intensity cantilever structure, and selects reflection spectrum wavelength matched chirped fiber gratings as a sensing grating 7 and a demolulation grating 8. The two chirped fiber gratings are connected together in series. The equi-intensity cantilever 1 is arranged on a weighing instrument base 5 by a screw through a screw hole 2, and the free end of the equi-intensity cantilever 1 is provided with a bearing 3 which is arranged on two sides of the equi-intensity cantilever 1 by a bolt 4. Signals provided by the utility model can be transmitted a long distance and broadly applied to road, bridge and various dynamic weighing and charging systems. The utility model has the advantages of long term reliable work under dampness, water accumulation, electromagnetic interference and other worse outdoor environment, high measurement precision and low cost.
Description
Technical field
The present invention relates to a kind of chirp optical fiber grating sensor, vehicle weighs in being specially adapted to travel.
Technical background
Present existing dynamic vehicle weighing system is divided into two kinds, and a kind of is portable weighing instrument, and another kind is fixing weighing instrument, and what be used for freeway management and charge is fixing weighing instrument.This class weighing instrument overwhelming majority of Chinese and foreign documents report is to adopt electrical sensor, comprising: resistance strain gage, piezoelectric sensor, electric capacity bar, linear variable difference transformer etc.Because fixedly weighing instrument all is installed in and carries out work under the outdoor rugged surroundings, therefore, reliability is relatively poor, being subject to electromagnetic interference (EMI), fearness humidity and signal can not long-distance transmissions.Dynamic vehicle weighing system is installed on the highway mostly, its work under bad environment, and transducing part is positioned at below the road surface all the time, is immersed in the ponding easily.Therefore, existing LOAD CELLS is damaged easily, can not work reliably and with long-term, need take into full account drainage problem simultaneously, so complex structure.For addressing the above problem, the U.S. discloses a patent, and the patent No. is 4560016 " Method and Apparatus for measuring the weight of a vehicle while the vehicleis in motion ".This invention utilizes the principle of optical fiber micro-bending effect, invents a kind of weighing instrument, and this weighing instrument has been avoided the shortcoming of electrical sensor, still, adopts optical fiber micro-bending as sensor mechanism, and its measuring accuracy is low, poor reliability and complex structure.
Advantages such as fiber-optic grating sensor is the novel sensing technology that grew up in the last few years, and it adopts Wavelength-encoding, has the measuring accuracy height, and reliable long-term working is good.Yet higher based on the wavelength demodulation device cost of Fabry one perot filter, this class sensor-based system only is fit to be applied to the heavy construction field that Distributed Multi is measured, and is restricted in the application of the instrument field of single-point or a small amount of point measurement.In the document " Identical broadband chirped Grating interrogation technique for temperature and strain sensing ", people such as R.W.Fallon propose to utilize identical two chirped fiber gratings to carry out sensing and demodulating strain, temperature measurement system, avoid using the wavelength demodulation device of Fabry one perot filter, reduced cost.But this system does not solve the cross sensitivity problem of temperature and strain; Report in the document that in addition the demodulation chirped fiber grating is to adopt the transmission connected mode, the light signal that needs to use fiber coupler that sensing grating is reflected is input in the demodulation grating, needs two optical fiber to be connected complex structure between sensor and the system.
Summary of the invention
Purpose of the present invention is developed precision exactly and met the requirements, and can work reliably and with long-term under outdoor rugged surroundings, and is simple in structure, and lower-cost fiber grating LOAD CELLS and signal demodulating system.
In order to reach above-mentioned requirements, the present invention designs a kind of highway dynamic weighing sensor, this system adopts two chirped fiber gratings, two identical chirped fiber gratings are serially connected, adopt the connected mode of the reflectance spectrum of measuring grating, designed two chirp optical fiber grating sensors and demodulating system thereof that a kind of highway dynamic weighing uses.This system has not only solved the cross sensitivity problem of temperature and strain, and have that system architecture is simple, cost is low, long transmission distance, anti-electromagnetic interference (EMI), measuring accuracy height, good long term stability, be very suitable for the dynamic weighing system of highway.
This invention chirp optical fiber grating sensor adopts the equi intensity cantilever structure.Select two identical chirped fiber gratings of reflectance spectrum, one of them chirp grating is used to respond to strain, stick on the pressure-sensitive area of sensor, be called sensing grating, another chirp grating sticks on the non-sensitive district of pressure of sensor, be called the demodulation grating, sensing grating by optical fiber splitter 13, is connected with photoelectric commutator 15 with wideband light source 14 respectively after conciliating light modulation grid serial connection, photoelectric commutator 15 is connected with computing machine 16, has formed pressure sensing.Sensor is made up of the beam of uniform strength 1, screw 2, bearing 3, bolt 4, base 5, base screw 6, sensing grating 7, demodulation grating 8, optical fiber 9, the beam of uniform strength 1 is fixed on the weighing instrument base 5 by screw 2 with screw during detection, the beam of uniform strength 1 free end is installed bearing 3, and bearing 3 is installed on the both sides of the beam of uniform strength 1 by bolt 4.Sensing grating 7 is conciliate the chirped fiber grating of light modulation grid 8 for the reflectance spectrum coupling, and wherein sensing grating 7 sticks on the sensitizing range of pressure, owing to adopt the equal strength design, this regional strain evenly distributes.And demodulation grating 8 sticking areas are fixed by screw and base, are the insensitive zones of pressure, but consider the transmission of strain, and we laterally paste chirped fiber grating, with the influence that guarantees that it is not strained.Because the force side of the beam of uniform strength, ambient pressure acts on the beam of uniform strength by bearing, and this effect can only be accepted longitudinal pressure, avoids the influence of side knock to weighing results.When pressure acts on the bearing, bearing passes to the beam of uniform strength with longitudinal pressure, the strain of the sensing grating sensing beam of uniform strength, load pressure is converted into the drift of sensing grating reflectance spectrum, and demodulation optical grating reflection spectrum is constant, and the area under this moment two grating reflection spectral envelopes just equals two optical grating reflection light intensity.Obviously, the changes delta P of two grating total reflected light intensity is proportional to the distance, delta λ of sensing grating spectral shift, promptly
ΔP＝K1·Δλ (1)
In the formula, K1 is a proportionality constant.The changed wavelength of sensing grating is corresponding with the strain facies of the beam of uniform strength, and then is directly proportional with beam of uniform strength pressure, is provided by following formula
Δλ＝K2·F (2)
In the formula, K2 is a proportionality constant.With (2) formula substitution (1) formula,
ΔP＝K·F (3)
In the formula, K=K1K2
The fiber grating reflected light signal is converted into voltage by photoelectric tube, sends into and analyzes in the computing machine and handle.Voltage V and sensor load F are also linear so, and its proportionality constant can be determined by rating test in advance.Therefore, computing machine is as long as can obtain weighing results by simple computation.
Because adopt technique scheme, dynamic vehicle weighing system provided by the invention has following beneficial effect:
1 pressure can effectively be offset the influence of the horizontal direction impulsive force of running automobile to weighing results by the bearing transmission, to improve weighing accuracy.
The 2 on-the-spot no electronic components of weighing, sensor can be worked under rugged surroundings such as moist ponding, electromagnetic interference (EMI) reliably and with long-term.
3 these set of sensors " sensing " and " demodulation " function are in one, and directly the output intensity signal requires low to rear end equipment.
4 signal measurement precision height, good reproducibility.
Description of drawings
Fig. 1 is a chirp optical fiber grating sensor-based system fundamental diagram
Fig. 2 is a chirped fiber grating reflection spectrogram
Fig. 3 is the chirp optical fiber grating sensor structural representation
Fig. 4 is the assembly drawing of chirp optical fiber grating sensor and weighing unit
Fig. 5 is that chirped fiber grating is laid scheme 1
Fig. 6 is that chirped fiber grating is laid scheme 2
Fig. 7 is that chirped fiber grating is laid scheme 3
Among the figure, 1-beam of uniform strength, 2-screw, 3-bearing, 4-bolt, 5-base, 6-base screw, 7-sensing grating 1,8-demodulation grating, 9-optical fiber, 10-chirp optical fiber grating sensor, 11 1 weighing units, 12-upper cover plate, 13-optical fiber splitter, 14-wideband light source, 15-photoelectric commutator, 16-computing machine, 17-sensing grating 2
Embodiment
Be further described below in conjunction with 1,2,3,4,5,6,7 pairs of technical schemes of the present invention of accompanying drawing.
Chirp optical fiber grating sensor structural representation of the present invention as shown in Figure 3, sensor adopts the beam of uniform strength 1 structure.Screw is fixed on the beam of uniform strength 1 on the sensor base 5 by screw 2.Beam of uniform strength free end is installed bearing 3, and bearing 3 is installed on beam of uniform strength both sides by bolt 4.Sensing grating 7, demodulation grating 8 serial connections are pasted on beam of uniform strength surface.The concrete laying of two chirped fiber gratings can have three kinds of modes.
In use, chirp optical fiber grating sensor 10 is fixed on the framework of weighing instrument by screw on the base 6 and screw, and the installation direction of sensor and position are as shown in Figure 4.The direction of arrow is the highway direction among the figure, also is vehicle heading.Weighing unit 11 upper surfaces are concordant with the road surface, and LOAD CELLS only bearing contacts with lower surface.Can offset driving vehicle impulsive force in the horizontal direction by the motion of bearing, thereby improve the influence of the speed of a motor vehicle weighing results.
Fig. 1 is the fundamental diagram of chirp optical fiber grating sensor-based system, after fixing sensing grating 7 is conciliate light modulation grid 8 serial connections on the chirp optical fiber grating sensor 10, be connected with photoelectric commutator 15 with wideband light source 14 respectively by optical fiber splitter 13, the light that wideband light source 14 sends is transferred to sensing grating 7 through optical fiber 9 and conciliates light modulation grid 8, the optical grating reflection light signal enters photoelectric tube 15 through optical fiber 9 transmission and is converted into voltage signal, enters computing machine 16 and carries out Treatment Analysis and show weighing results.
The present invention selects the Wavelength matched chirp grating of reflectance spectrum to conciliate light modulation grid 8 as sensing grating 7 respectively.Wherein sensing grating 7 sticks on the sensitizing range of pressure, owing to adopt the equal strength design, this regional strain evenly distributes.And demodulation grating 8 sticking areas are fixed by screw and base, are the insensitive zones of pressure, but consider the transmission of strain, and we laterally paste chirped fiber grating, with the influence that guarantees that it is not strained.Chirp optical fiber grating sensor is to utilize grating strain to cause wave length shift, thereby causes principle work that reflective light intensity changes.The reflectance spectrum top reflectivity of the chirped fiber grating of saturated exposure approaches 1, and it is very smooth, the reflectance spectrum that the sensing grating 7 that we select is conciliate light modulation grid 8 mates fully, two gratings serial connections back reflection spectrum is shown in solid line among Fig. 2, and this moment, two grating reflection light intensities just equaled the area that solid line and X-axis are comprised.Strong F does the time spent on the beam of uniform strength, the reflectance spectrum translation Δ λ of sensing grating 7, as shown in phantom in Figure 2, and the reflectance spectrum of demodulation grating 8 remains unchanged, and this moment, two grating reflection light intensities equaled the area that two optical grating reflections spectral envelope line and X-axis are comprised.Obviously, the change amount of two grating total reflected light intensity is proportional to sensing grating 7 translation distance Δ λ.Therefore, can know the displacement of sensing grating reflectance spectrum by detecting the grating reflection light intensity, thus the size of the F that exerts pressure on the calculating sensor.Chirped fiber grating has three kinds of laying modes.In conjunction with the accompanying drawings, elaboration laying position mode and reflected light situation of change are as follows.
Fiber grating is laid scheme one: as shown in Figure 5, adopt two chirp gratings that reflectance spectrum is Wavelength matched, two gratings all stick on beam of uniform strength upper surface, and sensing grating 7 is parallel to beam of uniform strength symmetry axis to be pasted, and is the best to be positioned at the axis.Demodulation grating 8 is pasted perpendicular to beam of uniform strength symmetry axis.Beam of uniform strength free end is under pressure and does the time spent, and sensing grating 7 stretches, and its reflectance spectrum is being guaranteed under the constant situation of spectral pattern to the translation of long wave direction.Obviously, the variable quantity of two grating total reflected light intensity is proportional to sensing grating 7 translation distance Δ λ.In this scheme, sensing grating 7 also Pasting in beam of uniform strength lower surface, this moment, strong F did the time spent on the beam of uniform strength, and the reflectance spectrum of sensing grating 7 is to shortwave direction translation Δ λ, but the variable quantity of two grating total reflected light intensity still is proportional to sensing grating 7 translation distance Δ λ.
Fiber grating is laid scheme two: as shown in Figure 6, adopt two chirp gratings that reflectance spectrum is Wavelength matched, two gratings are sensing grating, promptly sticking on beam of uniform strength pressure-sensitive area, be parallel to beam of uniform strength symmetry axis and paste, is the best to be positioned at the axis, sensing grating 7 is pasted on beam of uniform strength upper surface, for drawing grid, another sensing grating 17 is pasted on beam of uniform strength lower surface, for pressing grid.Beam of uniform strength free end is under pressure and does the time spent, and sensing grating 7 stretches, and its reflectance spectrum is being guaranteed under the constant situation of spectral pattern to the translation of long wave direction, and sensing grating 17 compressions, its reflectance spectrum is being guaranteed under the constant situation of spectral pattern to the translation of shortwave direction.Two grating total reflected light intensity equal the area that two optical grating reflections spectral envelope line and X-axis are comprised.Total reflected light Strength Changes amount is still than in two sensing gratings, 7,17 translation distance sum Δ λ
1+ Δ λ
2Adopt this scheme, can increase the variable quantity of reflective light intensity, thereby increase the resolution of weighing.
Fiber grating is laid scheme three: as shown in Figure 7, adopt three chirp gratings that reflectance spectrum is Wavelength matched, two gratings are sensing grating, promptly sticking on beam of uniform strength pressure-sensitive area, be parallel to beam of uniform strength symmetry axis and paste, is the best to be positioned at the axis, sensing grating 7 is pasted on beam of uniform strength upper surface, for drawing grid, sensing grating 17 is pasted on beam of uniform strength lower surface, for pressing grid.Demodulation grating 8 is positioned at the non-sensitive district of pressure, pastes perpendicular to beam of uniform strength symmetry axis.Beam of uniform strength free end is under pressure and does the time spent, the reflectance spectrum of demodulation grating 8 remains unchanged, and sensing grating 7 stretches, and its reflectance spectrum is being guaranteed under the constant situation of spectral pattern to the translation of long wave direction, and sensing grating 17 compressions, its reflectance spectrum is being guaranteed under the constant situation of spectral pattern to the translation of shortwave direction.This moment, three grating reflection light intensities equaled the area that three optical grating reflections spectral envelope line and X-axis are comprised.The total reflected light Strength Changes is still than in two sensing gratings, 7,17 translation distance sum Δ λ
1+ Δ λ
2Adopt this scheme, can further increase the maximum variable quantity of reflective light intensity, increase total reflective light intensity, thereby increase weighing precision.
Claims (1)
1. chirp optical fiber grating sensor, it is characterized in that: this sensor is by the beam of uniform strength (1), screw (2), pulley (3), bolt (4), base (5), base screw (6), sensing grating (7), demodulation grating (8), optical fiber (9) is formed, the beam of uniform strength (1) is fixed on the weighing instrument base (5) by screw (2) with screw during detection, the beam of uniform strength (1) free end is installed bearing (3), bearing (3) is installed on the both sides of the beam of uniform strength (1) by bolt (4), sensing grating (7) is conciliate light modulation grid (8) and is serially connected, and sticks on the beam of uniform strength (1).
Priority Applications (1)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| CNU2007200843741U CN201037786Y (en) | 2007-04-27 | 2007-04-27 | Chirped optical fibre grating weighing sensor |
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| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| CNU2007200843741U CN201037786Y (en) | 2007-04-27 | 2007-04-27 | Chirped optical fibre grating weighing sensor |
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| CN201037786Y true CN201037786Y (en) | 2008-03-19 |
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| CNU2007200843741U Expired - Lifetime CN201037786Y (en) | 2007-04-27 | 2007-04-27 | Chirped optical fibre grating weighing sensor |
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Cited By (3)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| CN102565952A (en) * | 2012-01-31 | 2012-07-11 | 武汉理工大学 | Full-duplex three-terminal upper-lower carrier wave division multiplexer |
| CN106996819A (en) * | 2017-04-12 | 2017-08-01 | 东北大学 | A kind of multistage weighing sensor of the fiber grating based on Telescopic rod structure |
| CN110108340A (en) * | 2019-06-04 | 2019-08-09 | 西北铁道电子股份有限公司 | A kind of automobile dynamically weighing device |
-
2007
- 2007-04-27 CN CNU2007200843741U patent/CN201037786Y/en not_active Expired - Lifetime
Cited By (5)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| CN102565952A (en) * | 2012-01-31 | 2012-07-11 | 武汉理工大学 | Full-duplex three-terminal upper-lower carrier wave division multiplexer |
| CN102565952B (en) * | 2012-01-31 | 2014-05-14 | 武汉理工大学 | Full-duplex three-terminal upper-lower carrier wave division multiplexer |
| CN106996819A (en) * | 2017-04-12 | 2017-08-01 | 东北大学 | A kind of multistage weighing sensor of the fiber grating based on Telescopic rod structure |
| CN110108340A (en) * | 2019-06-04 | 2019-08-09 | 西北铁道电子股份有限公司 | A kind of automobile dynamically weighing device |
| CN110108340B (en) * | 2019-06-04 | 2024-03-22 | 西北铁道电子股份有限公司 | Dynamic weighing device for automobile |
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Legal Events
| Date | Code | Title | Description |
|---|---|---|---|
| C14 | Grant of patent or utility model | ||
| GR01 | Patent grant | ||
| ASS | Succession or assignment of patent right |
Owner name: WUHAN PHYSICS AND ENGINEERING CONQUER CO., LTD. Free format text: FORMER OWNER: WUHAN UNIV. OF SCIENCE AND ENGINEERING Effective date: 20091218 |
|
| C41 | Transfer of patent application or patent right or utility model | ||
| TR01 | Transfer of patent right |
Effective date of registration: 20091218 Address after: 122 Road, Hubei city of Wuhan province Wuchang Luoshi road zip code: 430070 Patentee after: Wuhan Ligong Guangke Co., Ltd. Address before: 122 Road, Hubei city of Wuhan province Wuchang Luoshi road zip code: 430070 Patentee before: Wuhan University of Technology |
|
| CX01 | Expiry of patent term | ||
| CX01 | Expiry of patent term |
Granted publication date: 20080319 |