CN101769720B - Space displacement sensor - Google Patents
Space displacement sensor Download PDFInfo
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- CN101769720B CN101769720B CN2010101045976A CN201010104597A CN101769720B CN 101769720 B CN101769720 B CN 101769720B CN 2010101045976 A CN2010101045976 A CN 2010101045976A CN 201010104597 A CN201010104597 A CN 201010104597A CN 101769720 B CN101769720 B CN 101769720B
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Abstract
The invention discloses a space displacement sensor which comprises a compliant mechanism and a monomode optical fiber grating, wherein the compliant mechanism is formed by connecting a plurality of rigid bar pieces and a plurality of short arm flexible hinges in series in a staggered way; the monomode optical fiber grating is formed by connecting a plurality of grating sections in series in a staggered way through monomode optical fibers; and the central wavelengths of the grating sections are different. When the space displacement sensor is in use, the monomode optical fiber grating is connected to an optical fiber grating demodulating instrument, the grating sections are respectively pasted to the short arm flexible hinges of the compliant mechanism, and both ends of the compliant mechanism are respectively fixed to the positions to be measured on the measured object. The invention is realized on the basis of the compliant mechanism and the optical fiber grating sensing technique. The sensor has the advantages of multidimensional detection capability, favorable self-reference performance and high precision, and is free from electromagnetic interference.
Description
Technical field
The present invention relates to mechanical engineering and optical measurement field, be specifically related to a kind of space displacement sensor based on compliant mechanism and fiber grating sensing technology.
Background technology
Existing fiber-optic grating sensor can realize axially and the induction of radial strain that though precision reaches wavelength magnitude (nm), the monitoring that it is merely able to realize " one dimension " also can't realize the accurate measurement to complex mechanical system far away.
Owing to have very strong antijamming capability and very high accuracy of detection, the simple relatively field of large scale that is applied in civil and military that the fiber grating detection technique is comparatively ripe at present or motion, as: fiber grating sensing technology is all adopted in the safety monitoring of the nearly all bridge of developed country, companies such as Siemens have been used for large-size machine and high-tension electricity transmission cable, space shuttle X-33 goes up temperature, strain monitoring, U.S. aerospace research institute fiber grating adaptive wing.The above mode of using all be with fiber grating simply attached to the measurand surface, carry out simple axial strain and measure, the detection of this " one dimension " has little significance to complex mechanical structure or system's " higher-dimension " deformation measurement.
At present constituent parts is in measuring " higher-dimension " distortion, employedly mostly is survey instrument such as six-dimension force sensor, and is electrometric sensor, has the precision deficiency, is subject to the defective of electromagnetic interference (EMI).
Summary of the invention
The object of the present invention is to provide a kind of space displacement sensor, this sensor has the detectability of various dimensions, and has degree of precision, and is not subjected to electromagnetic interference (EMI).
A kind of space displacement sensor provided by the invention, it is characterized in that: this space displacement sensor comprises compliant mechanism and single-mode fiber grating, compliant mechanism is made of n rigid bar and n-1 the gentle hinge of galianconism interleaved series, the single-mode fiber grating is made of by the single-mode fiber interleaved series n-1 grating section, the centre wavelength difference of each grating section, n is the positive integer more than or equal to 4; During use, the single-mode fiber grating is connected on the fiber Bragg grating (FBG) demodulator, each grating section sticks on the gentle hinge of each galianconism position of compliant mechanism respectively, and the two ends of compliant mechanism is separately fixed at the position to be measured of measurand.
Compared with prior art, the present invention has following technical characterstic:
(1) the present invention is based on compliant mechanism and fiber grating sensing technology realization.Owing to utilize compliant mechanism that fiber grating original " one dimension " detectability is expanded to the detectability of various dimensions, so increased the application of fiber grating sensing technology in complex mechanical system to a certain extent.
(2) because the detection information that fiber-optic grating sensor is exported is the wavelength change amount that measures, so displacement transducer has certainly with reference to property; Since its with light signal as propagation medium, so the antijamming capability of measuring is strong; Whole displacement transducer is owing to adopt " gatherer " of compliant mechanism as want deflection to be measured, so simple in structure, operation and measurement are conveniently; Can design different compliant mechanisms in order to paste fiber grating, so the applicability of this space displacement sensor is strong for different objects to be measured.
(3) material of compliant mechanism belongs to spring steel material, and the machining property of structure is good, is convenient to produce.
Description of drawings
Fig. 1 is the measurement mechanism schematic diagram of space displacement sensor of the present invention.
Fig. 2 is the measuring principle figure of a kind of structure of two-dimensional space displacement transducer among the present invention.
Fig. 3 is the measuring principle figure of a kind of structure of two-dimensional space displacement transducer among the present invention.
Fig. 4 .1 is used to measure the front view of the compliant mechanism of three dimensions displacement for the present invention, and Fig. 4 .2 is the right view of Fig. 4 .1, and Fig. 4 .3 is the vertical view of Fig. 4 .1, and Fig. 4 .4 is a stereographic map,
Fig. 5 is the measuring principle figure of example with the two-dimensional space displacement transducer for the present invention.
Embodiment
Compliant mechanism is wherein formed by a plurality of rigid bars and the gentle hinge of galianconism textural association.Here the gentle hinge of the galianconism that relates to is the one section circular arc thin-wall construction with higher flexibility that connects two sections rigid body rod members, and the two ends of circular arc link to each other with two rigid body rod members respectively, and three's material is identical.Fix and another rod member when stressed when one of them rod member, the circular arc thin-walled that connects two sections rod members bends, and produces on inside and outside two surfaces of thin-walled and to stretch or racking strains.This strain can detect by the fiber-optic grating sensor that pastes this position.According to the correlation theory of the gentle hinge of galianconism, its crooked equivalence can be regarded as the rotation of common hinge, and when utilizing this sensor measurement two-dimensional space displacement, the axis of circular arc is perpendicular with the two-dimensional space that will measure in the structure.The number needs of the gentle hinge of galianconism will be determined according to measured deformation characteristics, so if only adopt the gentle hinge of a galianconism in this compliant mechanism, then can only do circular motion by movable rigid bar, does not meet actual measurement; If adopt the structure of the gentle hinge series connection of two galianconism, then compliant mechanism can't be described the straight line relative motion in the plane; When compliant mechanism adopts the structure of the gentle hinge series connection of three galianconism and three axis not in same plane, the various motions in the plane can be described fully promptly; If adopt structure more than the gentle hinge series connection of three galianconism, then the measurement performance of compliant mechanism is identical with the gentle hinge series connection of three galianconism, and need the more optical fiber grating, increased the use cost of device, so this compliant mechanism adopts the structure of the gentle hinge series connection of three galianconism, so not only can describe rotation but also can describe rectilinear motion.
In the time need measuring to the relative shift in the three dimensions, can change the quantity and the direction of the gentle hinge of galianconism according to actual conditions, principle is identical with measurement two-dimensional space displacement, so be used for measuring the compliant mechanism of the relative shift in the three dimensions except that the gentle hinge of three galianconism structure of the structure of needs reservation two-dimensional space displacement measurement, also need to add again the gentle hinge of the galianconism structure of three series connection, and the axis of circular arc is perpendicular with arc axis before, the alternately series connection of the gentle hinge of six galianconism of both direction structure.In addition, the designed structure of the gentle hinge of galianconism will make things convenient for the stickup of fiber-optic grating sensor.As compliant mechanism 5 by the axis of seven rigid bars and six thin-walled circular arcs not the gentle hinge of the galianconism in same plane interleaved series constitute, and be used to measure the gentle hinge of galianconism on a plane with leg-of-mutton mode layout with three respectively, with other three gentle hinges equally with leg-of-mutton mode layout of galianconism that are used to measure another plane, the orderings of six gentle hinges of galianconism are according to measuring the required layout of carrying out.
The layout of the gentle hinge of galianconism will consider to make things convenient for machining simultaneously to satisfy relative motion to be measured.With the compliant mechanism that is used to measure relative displacement in the two-dimensional space is example, and the formation of this space displacement sensor is described, as shown in Figure 1, space displacement sensor is made up of compliant mechanism 5 and single-mode fiber grating 3.Compliant mechanism 5 is made of four rigid bars and three the gentle hinge of galianconism interleaved series, the gentle hinge of three galianconism is distributed in the position of a right angle drift angle and two 45 degree acute angles respectively with the layout type of isosceles right triangle.Single-mode fiber grating 3 is made of by the single-mode fiber interleaved series three grating sections 2.This structure is to be priority condition to make things convenient for machining.Grating section 2 according to different request for utilizations, can be made multistage grating section 2, the centre wavelength difference of each grating section 2 for one section zone through having the strain sensitive characteristic after the processing processing on the single-mode fiber grating 3 on same single-mode fiber grating 3.
Among Fig. 1-3, the arc axis of the gentle hinge of three galianconism are all perpendicular to measurement plane, and not in a plane.Be reacted in the gentle hinge of three galianconism structure by all distortion in the plane of measurand 4 caused compliant mechanisms 5 are concentrated.
Before the measurement, single-mode fiber grating 3 is connected on the fiber Bragg grating (FBG) demodulator 1, three grating sections 2 stick on the gentle hinge of three galianconism position (A, B, C) of compliant mechanism respectively, afterwards the two ends of compliant mechanism 5 are separately fixed at the position to be measured of measurand 4.
During measurement, fiber Bragg grating (FBG) demodulator 1 can send laser, and laser is along 3 transmission of single-mode fiber grating.When laser arrives the grating section 2 that is positioned at the gentle hinge of each galianconism position, according to formula λ
B=2 η Λ, with the light reflected back optical fiber grating demodulation instrument 1 of different wave length, fiber Bragg grating (FBG) demodulator 1 carries out demodulation after receiving reflected light, and with digital form output wave long value.When the distortion of measurand 4 generations makes two positions to be measured that relative motion 8 take place, compliant mechanism 5 deforms, and distortion is embodied a concentrated reflection of the circular arc thin-walled position of the gentle hinge of galianconism, because stretching or racking strain that the bending of the gentle hinge of galianconism is produced on circular arc thin-walled surface, drive is pasted on lip-deep fiber-optic grating sensor generation axial strain, make that the grating reflection optical wavelength changes in the grating section 2, the wavelength of the variation numerical information that output wavelength changes after fiber Bragg grating (FBG) demodulator demodulation 1.
After the measurement, numerical information by fiber Bragg grating (FBG) demodulator 1 output is calculated grating reflection optical wavelength variable quantity in the grating section 2, extrapolate the strain that grating section 2 takes place, calculate the surface strain amount of circular arc thin-walled again according to the strain formula, geometric parameter and mechanics of materials formula according to the gentle hinge of galianconism calculate the gentle corner that cuts with scissors of galianconism, the rotation information of the gentle hinge of last comprehensive a plurality of galianconism and the geometric parameter of rigid bar draw the relative motion result at compliant mechanism 5 two ends, are the relative motion 9 of two positions to be measured on the measurand 4.
Among Fig. 4, the gentle arc axis that cuts with scissors A, B, C in the structure of galianconism is parallel to each other distribution triangular in shape among the figure; The arc axis of D, E, F is parallel to each other, distribution triangular in shape; And the arc axis of A, B, C is vertical mutually with the arc axis of D, E, F.The measurement characteristics that the compliant mechanism of this kind mechanism can be realized fiber-optic grating sensor from one-dimensional measurement to three-dimensional expansion.
Among Fig. 5, the fixed position of 6 expression compliant mechanisms and measurand (as, screw is fastening), 7 expression measurands are deformation state (initial state) not, state after the 8 expression measurand distortion, the spatial position change (relative motion of position to be measured) of compliant mechanism end before and after the 9 expression distortion.The space displacement sensor both sides are connected with the position to be measured of measurand 4 by screw 6.When measurand 4 is subjected to a power and makes an end with respect to the other end a relative space displacement take place, the state 8 after the distortion of being is with respect to the spatial position change 9 of deformation state 7 not.Space displacement sensor of the present invention can obtain the relevant information of spatial position change 9, so that subsequent treatment,
The above is preferred embodiment of the present invention, but the present invention should not be confined to the disclosed content of this embodiment and accompanying drawing.So everyly do not break away from the equivalence of finishing under the spirit disclosed in this invention or revise, all fall into the scope of protection of the invention.
Claims (3)
1. space displacement sensor, it is characterized in that: this space displacement sensor comprises compliant mechanism (5) and single-mode fiber grating (3), compliant mechanism (5) is made of n rigid bar and n-1 the gentle hinge of galianconism interleaved series, single-mode fiber grating (3) is made of by the single-mode fiber interleaved series n-1 grating section (2), the centre wavelength difference of each grating section (2), n is the positive integer more than or equal to 4; During use, single-mode fiber grating (3) is connected on the fiber Bragg grating (FBG) demodulator (1), each grating section (2) sticks on the gentle hinge of each galianconism position of compliant mechanism respectively, and the two ends of compliant mechanism (5) is separately fixed at the position to be measured of measurand (4).
2. space displacement sensor according to claim 1, it is characterized in that: the compliant mechanism (5) that is used to measure the two-dimensional space displacement by the axis of four rigid bars and three thin-walled circular arcs not the gentle hinge of the galianconism in same plane interleaved series constitute, and the gentle hinge of three galianconism is distributed in the positions of a right angle drift angle and two 45 degree acute angles respectively with the layout type of isosceles right triangle.
3. space displacement sensor according to claim 1, it is characterized in that: the compliant mechanism (5) that is used to measure the three dimensions displacement by the axis of seven rigid bars and six thin-walled circular arcs not the gentle hinge of the galianconism in same plane interleaved series constitute, and respectively with three gentle hinges of galianconism that are used to measure a plane, with other three gentle hinges of galianconism that are used to measure another plane equally with leg-of-mutton mode layout with leg-of-mutton mode layout.
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| Application Number | Priority Date | Filing Date | Title |
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| CN2010101045976A CN101769720B (en) | 2010-01-29 | 2010-01-29 | Space displacement sensor |
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| CN2010101045976A CN101769720B (en) | 2010-01-29 | 2010-01-29 | Space displacement sensor |
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| CN101769720A CN101769720A (en) | 2010-07-07 |
| CN101769720B true CN101769720B (en) | 2011-06-29 |
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| Publication number | Priority date | Publication date | Assignee | Title |
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| CN102435178A (en) * | 2011-09-14 | 2012-05-02 | 天津大学 | Fiber grating sensing bar for monitoring building settlement and monitoring method |
| CN105222720B (en) * | 2015-09-01 | 2018-11-02 | 华中科技大学 | A kind of propeller processing deformation measuring device and method |
| CN110514131B (en) * | 2019-08-26 | 2021-01-19 | 西安交通大学 | Intelligent layered fiber grating two-dimensional strain sensor |
| CN114136214B (en) * | 2021-12-02 | 2024-03-26 | 中国人民解放军军事科学院国防科技创新研究院 | Displacement sensor based on double-rigidity square wave-shaped structure |
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