CN106949850B - A kind of the optical fiber shape sensing measuring method and system of HIGH SENSITIVITY AND HIGH PRECISION - Google Patents

A kind of the optical fiber shape sensing measuring method and system of HIGH SENSITIVITY AND HIGH PRECISION Download PDF

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CN106949850B
CN106949850B CN201710195526.3A CN201710195526A CN106949850B CN 106949850 B CN106949850 B CN 106949850B CN 201710195526 A CN201710195526 A CN 201710195526A CN 106949850 B CN106949850 B CN 106949850B
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bending
strain
shape
frequency shift
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CN106949850A (en
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董永康
傅程
陈曦
张聃旸
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Harbin Institute of Technology Shenzhen
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    • G—PHYSICS
    • G01—MEASURING; TESTING
    • G01B—MEASURING LENGTH, THICKNESS OR SIMILAR LINEAR DIMENSIONS; MEASURING ANGLES; MEASURING AREAS; MEASURING IRREGULARITIES OF SURFACES OR CONTOURS
    • G01B11/00—Measuring arrangements characterised by the use of optical techniques
    • G01B11/24—Measuring arrangements characterised by the use of optical techniques for measuring contours or curvatures

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Abstract

The present invention provides the optical fiber shape sensing measuring methods and system of a kind of HIGH SENSITIVITY AND HIGH PRECISION.In method, shape sensor is divided into several segments, each section of Brillouin shift knots modification is averaged, it finds out it and corresponds to bending curvature of the curvature as this section, each section in this way of curvature, which can be found out, to be come, we have just obtained the circular arc of one section of one section of equal arc length before circular arc splices in this way, first select the coordinate and its tangential direction of the initial segment endpoint, then it needs to determine the bending direction of circular arc, then the tail end of this series of arc the preceding paragraph and next section of head end are connected, keep tangential direction identical at tie point, this completes the reduction of global shape.System includes: laser, 50:50 coupler, Polarization Controller one, arbitrary-function generator, electrooptic modulator one, EDFA Erbium-Doped Fiber Amplifier, circulator, filter, sensor, photodetector, data collecting card, isolator, electrooptic modulator two, microwave source and Polarization Controller two.

Description

A kind of the optical fiber shape sensing measuring method and system of HIGH SENSITIVITY AND HIGH PRECISION
Technical field
The present invention relates to the optical fiber shape sensing measuring methods and system of a kind of HIGH SENSITIVITY AND HIGH PRECISION, belong to optical fiber shape Sensing measuring method and systems technology field.
Background technique
With occurring quantum jump the 1960s in terms of fibre loss, optical fiber is passed as an effectively reliable light Defeated medium is widely used in communication and sensory field.Ordinary optic fibre main component is SiO2, abundant raw materials, manufacturing cost It is low；Since it is relative to common metal sensor and cable, density is small, therefore under equidistant, having smaller volume, more Light quality is conducive to lay and integrate.And optical fiber also has that electromagnetism interference, electrical insulating property are good, stability is good etc. Plurality of advantages has the incomparable advantage of electric sensor in sensory field, defense military, aerospace, deep-sea detecting, The numerous areas such as Industry Control, civil construction, which have, to be widely applied.
Distributed Optical Fiber Sensing Techniques are to utilize the parameter of light wave distribution along optical fiber, while acquisition quilt in sensitive zones Measurement at any time with the distributed intelligence of spatial variations, be it is a kind of can over long distances, the continuous sensing technology that uses on a large scale.Optical fiber The Brillouin frequency shifts amount in somewhere depends on the temperature and strain being subject at the position.The change of temperature and strain can make cloth In deep frequency displacement change, by repeatedly measuring the frequency shift value of optical fiber everywhere, temperature and Ying Bianfen along optical fiber can be obtained Cloth situation.After decades of development, very high level, and technology are substantially accomplished on distance sensing and sensing accuracy It is very mature, have many advantages, such as spatial resolution is high, measurement accuracy is high, distance sensing is long etc..Yongkang in 2012 Dong et al. realizes the spatial resolution of 2cm using differential pulse to Brillouin optical time domain analysis technology on the optical fiber of 2km (Dong Y,Zhang H,Chen L,et al.2cm spatial-resolution and 2km range Brillouin optical fiber sensor using a transient differential pulse pair[J].Applied optics,2012,51(9):1229-1235)。
Optical fiber shape sensing technology is then to pass through spy using the multiple strain transducers acquisition data being integrated on optical fiber Fixed algorithm is handled and is restored.Single crooked sensory is sensed from basic bending curvature, till now, has been developed To the degree for how carrying out sensing reduction to entire shape.Luna company, the U.S. etches FBG (optical fiber on 1.1m optical fiber within 2006 Grating, Fiber Bragg Grating), in conjunction with optical frequency domain reflection technology (Optical Frequency Domain Reflectometry optical fiber shape sensing (Duncan R G, Raum M T.Characterization of a) is realized fiber-optic shape and positionsensor[C].Smart Structures and Materials.International Society for Optics andPhotonics,2006:616704-616704- 11).Chinese patent " a kind of distribution light that application publication number is CN105423944A, data of publication of application is on March 23rd, 2016 Fine curvature sensor ", application publication number CN105371781A, data of publication of application are the Chinese patent " one on March 2nd, 2016 Kind method for measuring three-dimensional shape ", application publication number CN105371785A, data of publication of application are that the China on March 2nd, 2016 is special Sharp " a kind of curvature measurement method ", they propose that the Distributed Measurement System acquisition based on Brillouin scattering obtains spatial discrimination Rate is the strain data of 20cm.
For existing optical fiber shape sensor, majority is all based on (fiber grating, Mach increasing Dare interference of interference formula Instrument etc.) full distributed monitoring can not be carried out, mostly handled optical fiber, excessive processing meeting so that optical fiber loss It increased dramatically, distance sensing is limited by very large.The technology space resolution ratio (>=20cm) proposed in terms of long-distance sensing It is not enough to cope with the small scene of certain bending radius, there are short slabs.
Summary of the invention
The purpose of the present invention is to solve the above-mentioned problems of the prior art, and then it is high-precision to provide a kind of high sensitivity The optical fiber shape sensing measuring method and system of degree.
The purpose of the present invention is what is be achieved through the following technical solutions:
A kind of measurement method of the optical fiber shape sensing of HIGH SENSITIVITY AND HIGH PRECISION.
When object generates bending, side is stretched, and the other side is compressed, it is assumed that fiber core divides with a distance from neutral axis It Wei not d1、d2, strain is respectively ε after bending1、ε2, non-length before bending be L, bending radius R, then:
L1=(1+ ε1)L (0-1)
L2=(1+ ε2)L (0-2)
Geometrical relationship are as follows:
Three equatioies obtain the relationship of strain and bending radius above simultaneous:
κ is curvature in formula, is the inverse of bending radius；
There are Brillouin shift knots modification and temperature, the relational expression for straining knots modification again are as follows:
△vB=CT·△T+Cε·△ε (0-5)
△ v in formulaBFor Brillouin shift knots modification, CTFor Brillouin shift temperature coefficient, △ T is temperature knots modification, CεFor The Brillouin shift coefficient of strain, △ ε are strain knots modification, and Cong Shizhong finds out, Brillouin shift knots modification is in strain knots modification Linear relationship obtains when temperature-resistant:
△vB=Cε·△ε (0-6)
There is Brillouin shift knots modification directly proportional to knots modification is strained, if initial strain is 0, have:
△vB=Cε·ε (0-7)
Relationship of the formula (0-4) between fibre strain and bending radius, formula (0-7) be optical fiber Brillouin frequency displacement knots modification with Relationship between strain, the two simultaneous have:
△vB=CεD κ=A κ (0-8)
Brillouin shift can be mapped with curvature；
The Brillouin shift of optical fiber when without bending is first measured as substrate, sensor is then put into arbitrary shape, The Brillouin shift of optical fiber is measured again, finds out the Brillouin shift knots modification of curved shape everywhere by subtracting substrate； Then the radius of curvature of bending everywhere is released using formula (0-8), and then recovers corresponding curved shape；
When carrying out shape recovery, used algorithm is circular arc splicing method, and this method, will using the method for segmentation mean value Shape sensor is divided into several segments, and each section of Brillouin shift knots modification is averaged, and finds out it and corresponds to curvature as this section Bending curvature, each section in this way of curvature, which can be found out, to be come, we have just obtained the circular arc of one section of one section of equal arc length in this way；
Before circular arc is spliced, the coordinate and its tangential direction of the initial segment endpoint are first selected, is then needed to circular arc Bending direction is determined, is then connected the tail end of this series of arc the preceding paragraph and next section of head end, tie point Place keeps tangential direction identical, and this completes the reduction of global shape.
A kind of optical fiber shape sensor-based system of HIGH SENSITIVITY AND HIGH PRECISION, comprising: laser, 50:50 coupler, Polarization Control Device one, arbitrary-function generator, electrooptic modulator one, EDFA Erbium-Doped Fiber Amplifier, circulator, filter, sensor, photodetection Device, data collecting card, isolator, electrooptic modulator two, microwave source and Polarization Controller two, the output end of the laser with The input terminal of 50:50 coupler is connected, two output ends of 50:50 coupler respectively with the input terminal of Polarization Controller one and The input terminal of Polarization Controller two is connected, and the output end of Polarization Controller one is connected with the input terminal of electrooptic modulator one, The output end of electrooptic modulator one is connected with the input terminal of EDFA Erbium-Doped Fiber Amplifier, the output end and ring of EDFA Erbium-Doped Fiber Amplifier The end a of shape device is connected, and the end b of circulator is connected with sensor, the output end and electrooptic modulator two of Polarization Controller two Input terminal be connected, the output end of electrooptic modulator two is connected with isolator one end, the other end and sensor of isolator It is connected, arbitrary-function generator is connected with electrooptic modulator one, and microwave source is connected with electrooptic modulator two, data acquisition Card be connected with one end of photodetector, the other end of photodetector is connected with one end of filter, filter it is another One end is connected with the end c of circulator.
Beneficial effects of the present invention:
In shape sensing, bending radius is smaller, and the bigger strain the easier to be detected, but bending radius is smaller corresponding Arc length is with regard to smaller, it is therefore desirable to which raising is spatial resolution in order to avoid lack sampling causes data error excessive.Bending radius is bigger, It strains and smaller is less susceptible to be detected, it is therefore desirable to improve it to curved susceptibility.The present invention for both of these problems into Improvement is gone.The present invention acquires data using DPP-BOTDA system, relative to interference sensor, does not need to do optical fiber Additional processing and processing, optical fiber inherently shape sensor, the step of reducing sensor production, are conducive to later period sensing Changing the outfit after device damage.FBG is etched on optical fiber compared to FBG type sensor and carries out strain monitoring, and resolution ratio is determined by FBG density Fixed, once the problem of fixation is difficult to change, and fibre loss increases after etching FBG, the present invention can squeeze into optical fiber by changing The width of pulse realizes the variation of spatial resolution.Relative to the shape sensing technology based on Brillouin scattering of existing proposition, Its spatial resolution is high not enough, can not cope with the small situation of certain bending radius, spatial resolution can reach in embodiment 5cm, sensitivity A coefficient are 740.615MHzm, are able to achieve the shape sensing of high spatial resolution, and complete going back for shape Original weight structure.
Detailed description of the invention
Fig. 1 is a kind of structural schematic diagram of the optical fiber shape sensor system of HIGH SENSITIVITY AND HIGH PRECISION of the present invention.
Fig. 2 is differential pulse to raising spatial resolution schematic illustration.
Fig. 3 is bending radius and strain stress relation schematic diagram.
Fig. 4 is the different connecting method schematic diagram of two dimension.
Fig. 5 is that circular arc splices method schematic diagram on two-dimensional surface.
Fig. 6 is a kind of two-dimensional shapes sensor schematic.
Fig. 7 is Frequency Shift when being bent into standard radius of circle.
Fig. 8 is frequency displacement and bending curvature relationship and matched curve figure.
Fig. 9 is experiment real shooting photo.
Figure 10 is that shape tests schematic diagram.
Figure 11 is shape recovery back schematic diagram.
Appended drawing reference in figure, 1 is laser, and 2 be 50:50 coupler, and 3 be Polarization Controller one, and 4 send out for arbitrary function Raw device, 5 be electrooptic modulator one, and 6 be EDFA Erbium-Doped Fiber Amplifier, and 7 be circulator, and 8 be filter, and 9 be sensor, and 10 be photoelectricity Detector, 11 be data collecting card, and 12 be isolator, and 13 be V0-V′、V0、V0+ V ' modulation generates lower sideband, and 14 be electric light tune Device two processed, 15 be microwave source, and 16 be Polarization Controller two, and 17 be pump light, and 18 be detection light.
Specific embodiment
Below in conjunction with attached drawing, the present invention is described in further detail: the present embodiment is being with technical solution of the present invention Under the premise of implemented, give detailed embodiment, but protection scope of the present invention is not limited to following embodiments.
A kind of measurement method of the optical fiber shape sensor-based system of HIGH SENSITIVITY AND HIGH PRECISION, as shown in Figure 3 and Figure 5.
When optical fiber generates bending, optical fiber side is stretched, and the other side is compressed.It is assumed that fiber core is (curved from neutral axis Song does not change length, i.e., without strain) distance be respectively d1、d2, strain is respectively ε after bending1、ε2, non-length before bending is L, Bending radius is R, then:
L1=(1+ ε1)L (0-1)
L2=(1+ ε2)L (0-2)
Geometrical relationship are as follows:
Three equatioies obtain the relationship of strain and bending radius above simultaneous:
κ is curvature in formula, is the inverse of bending radius；
There are Brillouin shift knots modification and temperature, the relational expression for straining knots modification again are as follows:
△vB=CT·△T+Cε·△ε (0-5)
△ v in formulaBFor Brillouin shift knots modification, CTFor Brillouin shift temperature coefficient, △ T is temperature knots modification, CεFor The Brillouin shift coefficient of strain, △ ε are strain knots modification, and Cong Shizhong finds out, Brillouin shift knots modification is in strain knots modification Linear relationship obtains when temperature-resistant:
△vB=Cε·△ε (0-6)
There is Brillouin shift knots modification directly proportional to knots modification is strained, if initial strain is 0, have:
△vB=Cε·ε (0-7)
Relationship of the formula (0-4) between fibre strain and bending radius, formula (0-7) be optical fiber Brillouin frequency displacement knots modification with Relationship between strain, the two simultaneous have:
△vB=CεD κ=A κ (0-8)
Brillouin shift can be mapped with curvature (or bending radius).
In implementation process, it would be desirable to first measure the Brillouin shift of optical fiber when without bending as substrate, then will Sensor is put into arbitrary shape, then measures to the Brillouin shift of optical fiber, we can be asked by subtracting substrate in this way The Brillouin shift knots modification of curved shape everywhere out.
Then the radius of curvature of bending everywhere can be released using formula (0-8), and then recovers corresponding curved shape.
When carrying out shape recovery, the algorithm that we use is circular arc splicing method.This method uses the method for segmentation mean value, Shape sensor is divided into several segments, each section of Brillouin shift knots modification is averaged, and finds out it and corresponds to curvature as the section Bending curvature, each section in this way of curvature can find out come, so that we have just obtained the circular arc of one section of one section of equal arc length.
Before circular arc is spliced, the coordinate and its tangential direction of the initial segment endpoint are first selected, is then needed to circular arc Bending direction is determined, is then connected the tail end of this series of arc the preceding paragraph and next section of head end, tie point Place keeps tangential direction identical, and this completes the reduction of global shape.The schematic diagram of two-dimensional shapes reduction step such as Fig. 5 institute Show.It should be noted that acquired arc length gets over hour, restore that obtained shape is more accurate, certainly the also essence of original shape True degree is also related with the spatial resolution of acquisition system.From formula (0-4) if can be seen that fiber core not in shaft core position, It can be sensitive to bending.Here the shape sensor mentioned is not limited to the dimension sensor in embodiment, including other using it The sensor or optical fiber structure that it lays off axis.
A kind of optical fiber shape sensor-based system of HIGH SENSITIVITY AND HIGH PRECISION involved in the present embodiment, as shown in Figure 1, comprising: Laser 1,50:50 coupler 2, Polarization Controller 1, arbitrary-function generator 4, electrooptic modulator 1, erbium-doped fiber amplification Device 6, circulator 7, filter 8, sensor 9, photodetector 10, data collecting card 11, isolator 12, electrooptic modulator two 14, the output end of microwave source 15 and Polarization Controller 2 16, the laser 1 is connected with the input terminal of 50:50 coupler 2, Two output ends of 50:50 coupler 2 input terminal phase with the input terminal of Polarization Controller 1 and Polarization Controller 2 16 respectively Connection, the output end of Polarization Controller 1 are connected with the input terminal of electrooptic modulator 1, the output end of electrooptic modulator 1 It is connected with the input terminal of EDFA Erbium-Doped Fiber Amplifier 6, the output end of EDFA Erbium-Doped Fiber Amplifier 6 is connected with the end a of circulator 7, The end b of circulator 7 is connected with sensor 9, the input terminal phase of the output end and electrooptic modulator 2 14 of Polarization Controller 2 16 Connection, the output end of electrooptic modulator 2 14 are connected with 12 one end of isolator, and the other end of isolator 12 is connected with sensor 9 It connects, arbitrary-function generator 4 is connected with electrooptic modulator 1, and microwave source 15 is connected with electrooptic modulator 2 14, and data are adopted Truck 11 is connected with one end of photodetector 10, and the other end of photodetector 10 is connected with one end of filter 8, filter The other end of wave device 8 is connected with the end c of circulator 7.
The sensor 9 is shape sensor.
The light that laser 1 issues is divided into two beams by 50:50 coupler 2, a branch of to pass through Polarization Controller 1, arbitrarily Function generator 4 controls electrooptic modulator 1 and is modulated to pulsed light, amplifies by erbium-doped fiber amplifier 6, passes through annular Device 7 enters shape sensor 9.
Another beam of laser passes through Polarization Controller 2 16, and microwave source 15 controls electrooptic modulator 2 14 and modulated up and down Side frequency enters shape sensor 9 by isolator 12.
In shape sensor 9, two-way laser interaction is optical fiber Brillouin frequency displacement when two-way laser has difference Light time generates stimulated Brillouin scattering, scatters light from the port circulator b into the port c goes out, and filters out other through wave filter 8 Light only retains scattered signal light, is detected by photodetector 10, by 11 acquisition and recording of data collecting card.When some position of optical fiber Set be strained either temperature change when, the Brillouin shift of the position will generate variation.By recording Brillouin shift Variation, temperature or the knots modification of strain on optical fiber can be obtained.
In a fiber, the corresponding spatial resolution of the optical signal of pulse 10ns is 1m, since Brillouin scattering is in optical fiber It is generated by acousto-optic interaction, so pulse is influenced by phonon lifetime (~10ns), when light pulse is less than the phonon longevity When life, interact insufficient, it may occur that Brillouin spectrum broadening, signal-to-noise ratio decline, therefore unconfined can not reduce.And we Using DPP-BOTDA technology, two pulses are squeezed into optical fiber, respectively obtain two gain signals, and gain signal subtracts each other Differential pulse can be obtained to time difference corresponding spatial resolution, the influence of phonon lifetime is thus overcome, obtain more High spatial resolution, we use difference for the pulse pair of 0.5ns, can theoretically obtain the spatial resolution of 5cm.
When optical fiber is generated bending, optical fiber side is stretched, and side is compressed.It is assumed that fiber core is from neutral axis (bending Do not change length, i.e., without strain) distance be respectively d1、d2, strain is respectively ε after bending1、ε2, non-length before bending is L, curved Bilge radius is R, then has:
General single mode fiber is insensitive to bending strain, illustrate its neutral axis just at optical fiber axle center, therefore general single mode Optical fiber can only monitor axial strain, and bending is unable to monitor, it is therefore desirable to do an axis to fiber core and deviate, usually adopt Optical fiber is exactly pasted on changing object or is utilized multi-core optical fiber by method.Deviate the fibre core of central axis so just to curved The strain that song generates is monitored, and has multiple fibre cores in multi-core optical fiber not at axle center, just there is one relative to axle center in this way Offset distance, sensitive to bending, offset distance is remoter, and susceptibility is higher.By being bent to sensor, optical fiber is measured Brillouin shift, frequency displacement when by stretching with optical fiber compares, so that it may obtain the Brillouin shift on along optical fiber Knots modification, if multifiber (or multi-core optical fiber) can further eliminate axial strain and temperature on sensor while on cloth The influence to frequency shift amount is spent, the corresponding frequency shift value of bending strain, frequency shift value and directly proportional, the polarization maintaining optical fibre of strain have thus been obtained Direct ratio coefficient is 0.0482MHz/ μ ε (Dong Y, Chen L, Bao X.High-Spatial-Resolution Time- Domain Simultaneous Strain and Temperature Sensor Using Brillouin Scattering and Birefringence in a Polarization-Maintaining Fiber[J].IEEE Photonics Technology Letters,2010,22(18):1364-1366).Thus there is Δ νB=A/R=A κ (Δ νBIt is frequency displacement Amount, A is coefficient, and A is bigger, and the maximum radius being capable of measuring is bigger, and R is radius, and κ is curvature).The coefficient of different optical fiber may slightly have Difference needs to be calibrated and demarcated by standard round before shape senses, obtains its A coefficient.It is each that we can obtain optical fiber The strain value at place can calculate its bending radius by strain value, to reconstruct the entire shape of fibre-optical bending.
Restructing algorithm we using circular arc splice method.The strain that circular arc splicing method is measured using system, by sensor Equal part, then each section of strain value is average, finds out corresponding bending radius under it is uniformly bent, is approximately by the bending of this section Coordinate and its tangent line side of the initial segment endpoint are selected in the bending (spatial resolution is higher, and error can be smaller) of the bending radius To, it is end to end by each section, keep tangential direction identical at tie point, then judge next section of bending direction, this Sample we just complete the reconstruct of entire shape.Two-dimensional shapes sensing on, due to bending direction only there are two (clockwise or Counterclockwise), therefore its bending direction will be first judged after its equal part, according to different bending directions, determine its connection type It is different.The judgement of bending direction is similarly carried out in three dimensions.
The foregoing is only a preferred embodiment of the present invention, these specific embodiments are all based on the present invention Different implementations under general idea, and scope of protection of the present invention is not limited thereto, it is any to be familiar with the art Technical staff in the technical scope disclosed by the present invention, any changes or substitutions that can be easily thought of, should all cover of the invention Within protection scope.Therefore, the scope of protection of the invention shall be subject to the scope of protection specified in the patent claim.

Claims (3)

1.一种高灵敏度高精度的光纤形状传感测量方法，其特征在于，1. a high-sensitivity and high-precision optical fiber shape sensing measurement method, is characterized in that, 当具有一定厚度的物体产生弯曲时，一侧被拉伸，另一侧被压缩，假定其上光纤纤芯离中性轴的距离分别为d1、d2，弯曲后应变分别为ε1、ε2，未弯曲前长度为L，弯曲半径为R，则：When an object with a certain thickness is bent, one side is stretched and the other side is compressed. It is assumed that the distances from the fiber core above the neutral axis are d 1 and d2, respectively, and the strains after bending are ε 1 and ε, respectively. 2 , the length before unbending is L, and the bending radius is R, then: L1＝(1+ε1)L (0-1)L 1 =(1+ε 1 )L (0-1) L2＝(1+ε2)L (0-2)L 2 =(1+ε 2 )L (0-2) 几何关系为：The geometric relationship is: 联立上面三个等式得到应变和弯曲半径的关系：Combine the above three equations to get the relationship between strain and bending radius: 式中κ为曲率，是弯曲半径的倒数；where κ is the curvature, which is the reciprocal of the bending radius; 又有布里渊频移改变量与温度、应变改变量的关系式为：There is also the relationship between the change of Brillouin frequency shift and the change of temperature and strain: △vB＝CT·△T+Cε·△ε (0-5)△v B =C T ·△T+C ε ·△ε (0-5) 式中△vB为布里渊频移改变量，CT为布里渊频移温度系数，△T为温度改变量，Cε为布里渊频移应变系数，△ε为应变改变量，从式中看出，布里渊频移改变量与应变改变量呈线性关系，当温度不变时，得到：where Δv B is the Brillouin frequency shift change, C T is the Brillouin frequency shift temperature coefficient, ΔT is the temperature change, C ε is the Brillouin frequency shift strain coefficient, Δε is the strain change, It can be seen from the formula that the Brillouin frequency shift change has a linear relationship with the strain change. When the temperature is constant, we get: △vB＝Cε·△ε (0-6)△v B =C ε ·△ε (0-6) 即有布里渊频移改变量与应变改变量成正比，若初始应变为0，则有：That is, the Brillouin frequency shift change is proportional to the strain change. If the initial strain is 0, there are: △vB＝Cε·ε (0-7)△v B =C ε ·ε (0-7) 式(0-4)为光纤应变和弯曲半径之间的关系，式(0-7)为光纤布里渊频移改变量与应变之间的关系，两者联立有：Equation (0-4) is the relationship between fiber strain and bending radius, and Equation (0-7) is the relationship between fiber Brillouin frequency shift change and strain. △vB＝Cε·d·κ＝A·κ (0-8)△v B =C ε ·d·κ=A·κ (0-8) 就能够将布里渊频移与曲率对应起来；The Brillouin frequency shift can be correlated with the curvature; 先测量出无弯曲时光纤的布里渊频移作为基底，然后将传感器摆成任意的形状，再对光纤的布里渊频移进行测量，通过减去基底求出弯曲形状各处的布里渊频移改变量；然后利用式(0-8)推出弯曲各处的曲率半径，进而恢复出相应的弯曲形状；First measure the Brillouin frequency shift of the fiber without bending as the base, then place the sensor into an arbitrary shape, then measure the Brillouin frequency shift of the fiber, and calculate the Brillouin frequency shift around the bending shape by subtracting the base. Yuan frequency shift change amount; then use formula (0-8) to deduce the curvature radius of the bending, and then restore the corresponding bending shape; 在进行形状恢复时，使用的算法是圆弧拼接法，该方法采用分段均值的办法，将形状传感器分成若干段，每一段的布里渊频移改变量做平均，求出其对应曲率作为该段的弯曲曲率，这样每一段的曲率都能够求出来，这样我们就得到了一段一段等弧长的圆弧在圆弧进行拼接前，先选定起始段端点的坐标及其切线方向，然后需要对圆弧的弯曲方向进行判定，然后将这一系列圆弧上一段的尾端和下一段的首端连接起来，连接点处保持切线方向相同，这样就完成了整体形状的还原。When performing shape recovery, the algorithm used is the arc splicing method. This method adopts the method of segmented mean value, divides the shape sensor into several segments, and averages the Brillouin frequency shift change of each segment to obtain its corresponding curvature as The bending curvature of this segment, so that the curvature of each segment can be calculated, so that we can obtain a segment of arcs of equal arc length. Before splicing the arcs, first select the coordinates of the endpoints of the starting segment and the tangent direction. Then it is necessary to determine the bending direction of the arc, and then connect the tail end of the first segment of this series of arcs with the head end of the next segment, and keep the same tangent direction at the connection point, thus completing the restoration of the overall shape. 2.一种权利要求1所述的高灵敏度高精度的光纤形状传感测量方法使用的测量系统，其特征在于，包括：激光器(1)、50∶50耦合器(2)、偏振控制器一(3)、任意函数发生器(4)、电光调制器一(5)、掺饵光纤放大器(6)、环形器(7)、滤波器(8)、传感器(9)、光电探测器(10)、数据采集卡(11)、隔离器(12)、电光调制器二(14)、微波源(15)和偏振控制器二(16)，所述激光器(1)的输出端与50:50耦合器(2)的输入端相连接，50:50耦合器(2)的两个输出端分别与偏振控制器一(3)的输入端和偏振控制器二(16)的输入端相连接，偏振控制器一(3)的输出端与电光调制器一(5)的输入端相连接，电光调制器一(5)的输出端与掺饵光纤放大器(6)的输入端相连接，掺饵光纤放大器(6)的输出端与环形器(7)的a端相连接，环形器(7)的b端与传感器(9)相连接，偏振控制器二(16)的输出端与电光调制器二(14)的输入端相连接，电光调制器二(14)的输出端与隔离器(12)一端相连接，隔离器(12)的另一端与传感器(9)相连接，任意函数发生器(4)与电光调制器一(5)相连接，微波源(15)和电光调制器二(14)相连接，数据采集卡(11)与光电探测器(10)的一端相连接，光电探测器(10)的另一端与滤波器(8)的一端相连接，滤波器(8)的另一端与环形器(7)的c端相连接。2. A measurement system used in the high-sensitivity and high-precision optical fiber shape sensing measurement method according to claim 1, characterized in that, comprising: a laser (1), a 50:50 coupler (2), a polarization controller-a (3), arbitrary function generator (4), electro-optical modulator one (5), erbium-doped fiber amplifier (6), circulator (7), filter (8), sensor (9), photodetector (10) ), a data acquisition card (11), an isolator (12), an electro-optical modulator two (14), a microwave source (15) and a polarization controller two (16), the output end of the laser (1) having a 50:50 The input end of the coupler (2) is connected, and the two output ends of the 50:50 coupler (2) are respectively connected with the input end of the polarization controller one (3) and the input end of the polarization controller two (16), The output end of the polarization controller one (3) is connected with the input end of the electro-optical modulator one (5), and the output end of the electro-optical modulator one (5) is connected with the input end of the erbium-doped fiber amplifier (6). The output end of the optical fiber amplifier (6) is connected with the a end of the circulator (7), the b end of the circulator (7) is connected with the sensor (9), and the output end of the polarization controller two (16) is connected with the electro-optic modulator The input ends of two (14) are connected, the output end of the electro-optical modulator two (14) is connected with one end of the isolator (12), the other end of the isolator (12) is connected with the sensor (9), the arbitrary function generator (4) is connected with the first electro-optical modulator (5), the microwave source (15) is connected with the second electro-optical modulator (14), the data acquisition card (11) is connected with one end of the photoelectric detector (10), and the photoelectric detection The other end of the filter (10) is connected with one end of the filter (8), and the other end of the filter (8) is connected with the c end of the circulator (7). 3.权利要求2所述的高灵敏度高精度的光纤形状传感测量方法使用的测量系统，其特征在于，所述传感器(9)为形状传感器。3. The measurement system used in the high-sensitivity and high-precision optical fiber shape sensing measurement method according to claim 2, wherein the sensor (9) is a shape sensor.
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