WO2005095909A1 - 振動計測装置 - Google Patents
振動計測装置 Download PDFInfo
- Publication number
- WO2005095909A1 WO2005095909A1 PCT/JP2005/005756 JP2005005756W WO2005095909A1 WO 2005095909 A1 WO2005095909 A1 WO 2005095909A1 JP 2005005756 W JP2005005756 W JP 2005005756W WO 2005095909 A1 WO2005095909 A1 WO 2005095909A1
- Authority
- WO
- WIPO (PCT)
- Prior art keywords
- vibration
- waveguide
- measuring device
- vibration measuring
- light
- Prior art date
Links
Classifications
-
- G—PHYSICS
- G01—MEASURING; TESTING
- G01H—MEASUREMENT OF MECHANICAL VIBRATIONS OR ULTRASONIC, SONIC OR INFRASONIC WAVES
- G01H9/00—Measuring mechanical vibrations or ultrasonic, sonic or infrasonic waves by using radiation-sensitive means, e.g. optical means
- G01H9/004—Measuring mechanical vibrations or ultrasonic, sonic or infrasonic waves by using radiation-sensitive means, e.g. optical means using fibre optic sensors
Definitions
- the present invention relates to a device for measuring vibration.
- a laser Doppler optical fiber sensor to a vibration sensor.
- the principle of this method is roughly as follows. First, a light source is connected to one end of the optical fiber. At the other end of the fiber, a reflecting mirror that reflects input light and returns it to the fiber is attached.
- the optical path length in the fiber changes as the fiber expands and contracts. If the time change of the optical path length is dL / dt, the light reflected at the fiber end changes its frequency in proportion to dLZdt due to the Doppler effect. Therefore, the vibration can be measured by measuring the frequency change between the reflected light from the fiber end and the input light.
- Such a sensor has the problem of being low-sensitivity, although wideband.
- the present inventor has bent an optical fiber, applied vibration to the bent portion, and observed a frequency change between input light and output light passing through the fiber. As a result, a frequency change corresponding to the minute vibration occurs in the curved portion, and the knowledge has already been obtained.
- Patent Document 1 International Publication WO03 / 002956
- This vibration measuring device includes an input unit 1, an optical fiber 2, a detection unit 3, and an A ⁇ M (Acoustic Optical Modulator) 4.
- a ⁇ M Acoustic Optical Modulator
- the input unit 1 is for inputting input light to the optical fiber 2. Specifically, the input unit 1 , A laser using a semiconductor, a gas, or the like. The input unit 1 is connected to the optical fin 2 via a force bra. A half mirror 11 for transmitting a part of the input light to the AOM 4 is arranged between the input unit 1 and the coupler 21.
- the optical fiber 2 has a curved portion 20 to which a vibration to be measured is applied.
- the curved portion 20 is formed by orbiting the optical fiber 2.
- the bending portion 20 is arranged at a position where vibration is to be measured.
- the curved portion 20 is fixed to the measurement location by fixing means such as an adhesive or an adhesive tape.
- the detecting unit 3 detects a frequency change between the output light from the optical fiber 2 and the input light from the input unit 1, which has passed through the bending unit 20. Specifically, the input light sent through the half mirror 11, A ⁇ M4 (described later) and the half mirror 31 and the output light from the optical fiber 2 are beaten to detect a change in the beat frequency. It has become. As a result, a frequency change between input and output light is detected.
- the detection unit 3 is connected to the fiber 2 via a force bra 22.
- the AOM 4 changes the input optical frequency f to f + f (f includes positive and negative).
- a vibration measuring method using this device is as follows.
- the curved portion 20 of the fiber 2 is arranged at a measurement location using an arbitrary fixing means (for example, an adhesive).
- an arbitrary fixing means for example, an adhesive
- the input light is sent from the input unit 1 to the fiber 2.
- vibration elastic wave
- the frequency of light passing through the bending portion 20 changes according to the vibration. That is, the frequency of the output light changes.
- This frequency change is detected by the detection unit 3.
- the force S for detecting the vibration applied to the bending portion 20 as a frequency change can be obtained.
- the present inventor has obtained, in addition to the above-mentioned knowledge, knowledge about the shape of an arc portion that can control directivity in vibration measurement.
- the present invention has been made based on this finding, and it is an object of the present invention to provide a vibration measurement device that can control directivity in vibration measurement. Means for solving the problem
- a vibration measurement device includes an input unit, a waveguide, and a detection unit.
- the input section is for inputting input light to the waveguide.
- the waveguide has an elliptical portion to which a vibration to be measured is applied. The oval portion allows the input light to pass therethrough.
- the detection unit detects a frequency change between the output light from the waveguide that has passed through the elliptical portion and the input light.
- the elliptical portion may include two arc portions and two linear portions connecting the openings of the two arc portions.
- the waveguide is, for example, an optical fiber.
- the elliptical portion may be formed by circling the optical fiber.
- the vibration measuring device may have directivity in vibration measurement.
- the vibration measuring method according to the present invention controls directivity in vibration measurement by adjusting a ratio of a radius of curvature R of the arc portion to a length 1 of the linear portion in the vibration measuring device. Configuration.
- an elliptical portion 120 is used instead of the curved portion 20 in FIG.
- the oval portion 120 is configured by orbiting the optical fiber 2 as one waveguide in an oval shape.
- the oval portion 120 includes two arc portions 121 and two linear portions 122 connecting the openings of the two arc portions 121.
- the straight portions 122 are substantially parallel in this embodiment.
- the linear portion 122 may have a shape whose curvature radius is significantly larger than that of the circular arc portion 121 (that is, a shape close to a straight line). Further, the curvature of the arc portion 121 may not be constant. According to The shape of the elliptical portion 120 may be a flat ellipse.
- the type of the optical fiber 2 is not particularly limited, and for example, an appropriate type such as a GI type, an SI type, a single mode type, or a multi-mode type can be used. Also, instead of optical fiber 2,
- waveguides eg hollow metal pipes or optical paths microfabricated on glass substrates.
- a material that undergoes reversible deformation that is, elastic deformation is preferable.
- Elastics include almost all industrial materials, such as metallic materials such as steel, glass, ceramics, and plastics.
- the elliptical portion 120 of the fiber 2 is arranged at a position to be measured using an arbitrary fixing means (for example, an adhesive or an adhesive tape).
- the fixing means is optional. Further, as long as vibration can be transmitted to the elliptical portion 120, the elliptical portion 120 does not have to be fixed.
- the input light is transmitted from the input unit 1 to the fiber 2.
- vibration elastic wave
- the frequency of light passing through the oval portion 120 changes according to the vibration. That is, the frequency of the output light changes.
- This frequency change is detected by the detection unit 3.
- the vibration applied to the oval portion 20 can be detected as a frequency change.
- the vibration that can be detected in the oval portion 120 is considered to be a vibration having a vector component in the radial direction of the arc portion 121.
- the frequency of the input light input to the detection unit 3 can be changed.
- the amount of frequency change in AOM4 it is possible to know whether the frequency change of the light passing through the oval portion 120 is in the positive or negative direction.
- f and c are the frequency of the light source and the speed of light in a vacuum
- n is the light waveguide and the like.
- vector V is displacement velocity vector of linear element ds
- ⁇ is curvature of linear element ds
- vector r and vector n are unit direction vector and unit normal vector of linear element ds, respectively.
- R is the average value of the radius of the N-turned loop. With N turns, the sensitivity becomes N times.
- FIG. 1 is an explanatory diagram for explaining an outline of a conventional vibration measuring device.
- FIG. 2 is an explanatory view showing the shape of an oval portion in the vibration measuring device according to one embodiment of the present invention.
- FIG. 3 is an explanatory diagram for explaining directivity control based on a waveguide shape.
- FIG. 4 is an explanatory diagram for explaining directivity control based on a waveguide shape.
- FIG. 5 is an explanatory diagram for explaining directivity control based on a waveguide shape.
Landscapes
- Physics & Mathematics (AREA)
- General Physics & Mathematics (AREA)
- Measurement Of Mechanical Vibrations Or Ultrasonic Waves (AREA)
- Testing Of Optical Devices Or Fibers (AREA)
Abstract
Description
Claims
Applications Claiming Priority (2)
Application Number | Priority Date | Filing Date | Title |
---|---|---|---|
JP2004-100728 | 2004-03-30 | ||
JP2004100728A JP2005283469A (ja) | 2004-03-30 | 2004-03-30 | 振動計測装置 |
Publications (1)
Publication Number | Publication Date |
---|---|
WO2005095909A1 true WO2005095909A1 (ja) | 2005-10-13 |
Family
ID=35063886
Family Applications (1)
Application Number | Title | Priority Date | Filing Date |
---|---|---|---|
PCT/JP2005/005756 WO2005095909A1 (ja) | 2004-03-30 | 2005-03-28 | 振動計測装置 |
Country Status (2)
Country | Link |
---|---|
JP (1) | JP2005283469A (ja) |
WO (1) | WO2005095909A1 (ja) |
Cited By (1)
Publication number | Priority date | Publication date | Assignee | Title |
---|---|---|---|---|
JPWO2021084940A1 (ja) * | 2019-10-29 | 2021-05-06 |
Families Citing this family (1)
Publication number | Priority date | Publication date | Assignee | Title |
---|---|---|---|---|
JP5350999B2 (ja) * | 2009-11-27 | 2013-11-27 | 株式会社レーザック | 光ファイバを用いた振動計測装置 |
Citations (3)
Publication number | Priority date | Publication date | Assignee | Title |
---|---|---|---|---|
JPH07198471A (ja) * | 1993-12-29 | 1995-08-01 | Anritsu Corp | 振動源位置検出器及び振動源位置検出装置 |
JPH07243902A (ja) * | 1994-03-08 | 1995-09-19 | Mitsubishi Heavy Ind Ltd | 光ファイバーパッシブ音響センサー |
WO2003002956A1 (fr) * | 2001-06-27 | 2003-01-09 | Center For Advanced Science And Technology Incubation, Ltd. | Dispositif et procede de mesure de vibration |
-
2004
- 2004-03-30 JP JP2004100728A patent/JP2005283469A/ja not_active Withdrawn
-
2005
- 2005-03-28 WO PCT/JP2005/005756 patent/WO2005095909A1/ja active Application Filing
Patent Citations (3)
Publication number | Priority date | Publication date | Assignee | Title |
---|---|---|---|---|
JPH07198471A (ja) * | 1993-12-29 | 1995-08-01 | Anritsu Corp | 振動源位置検出器及び振動源位置検出装置 |
JPH07243902A (ja) * | 1994-03-08 | 1995-09-19 | Mitsubishi Heavy Ind Ltd | 光ファイバーパッシブ音響センサー |
WO2003002956A1 (fr) * | 2001-06-27 | 2003-01-09 | Center For Advanced Science And Technology Incubation, Ltd. | Dispositif et procede de mesure de vibration |
Cited By (3)
Publication number | Priority date | Publication date | Assignee | Title |
---|---|---|---|---|
JPWO2021084940A1 (ja) * | 2019-10-29 | 2021-05-06 | ||
WO2021084940A1 (ja) * | 2019-10-29 | 2021-05-06 | 日本電気株式会社 | 音響センサ |
JP7363915B2 (ja) | 2019-10-29 | 2023-10-18 | 日本電気株式会社 | 音響センサ |
Also Published As
Publication number | Publication date |
---|---|
JP2005283469A (ja) | 2005-10-13 |
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