Multipoint vibration measurement test bench

Abstract

To provide a multipoint vibration measurement test bench for simultaneously measuring vibration information of a measurement object at a plurality of points by making it possible to cope with the case of simultaneously needing the vibration information at a plurality of points and making it possible to more correctly examine a vibration factor by acquiring vibration information of a wide area.SOLUTION: A multipoint vibration measurement test bench uses measuring light and reference light distributed into a plurality of light paths from a light source 1 through an optical distributor 110 to synchronously acquire vibration information of a plurality of measurement points two-dimensionally distributed on a measurement surface of a measurement object 5 by a plurality of multipoint vibration measurement parts 170A, 170B, ..., and an integration processing part 190 integrates vibration information of each local coordinates synchronously acquired by the plurality of multipoint vibration measurement parts into three-dimensional vibration information in global coordinates defining a three-dimensional space including a test bench, performs FFT analysis about the integrated three-dimensional vibration information of the global coordinates (Xglobal,Yglobal,Zglobal), and performs the specification of an earthquake location and image display of a vibration distribution.SELECTED DRAWING: Figure 2

Description

[Technical Field]

[0001] The present invention relates to a multi-point vibration measurement test bench that uses light to simultaneously measure vibration information at multiple points on an object to be measured. [Background technology]

[0002] Test benches for carrying out various performance tests of drive units such as internal combustion engines, electric motors, or combinations of internal combustion engines and electric motors (so-called hybrid drive units) have been known (see, for example, Patent Documents 1-3).

[0003] The test bench is used to evaluate the performance, reliability, and safety of the drive unit, and the drive unit is operated on the test bench to perform reliability tests to identify abnormal behavior or problems, such as vibration, temperature, noise, and electrical stability.

[0004] In order to investigate the causes of vibration and the load caused by vibration, it is necessary to measure the vibration distribution within the surface of the object being measured. For example, in the case of steady vibration, the vibration distribution within the surface can be measured by measuring the vibration while shifting the location in accordance with the vibration period.

[0005] However, when you want to measure transiently changing vibrations in real time, when you do not know in advance what frequency components the vibration contains, or when you need vibration information from several points simultaneously, you need a vibration measuring device that can measure vibration information from several points simultaneously.

[0006] In addition, while conventional laser Doppler vibrometers can generally measure the amplitude of vibrations in a velocity range of about 10 m / s, they cannot synchronize and measure the vibration distribution at multiple points simultaneously, nor can they obtain the height in a static state.

[0007] The applicant of the present application has previously proposed a vibration measuring device and a vibration measuring method that, in a vibrometer that analyzes vibration information on a measurement surface of an object by detecting interference light between coherent reference light and measurement light, which has a spectrum with a predetermined frequency interval, and determining the phase difference between the reference light and measurement light, uses an optical demultiplexing / multiplexing head that demultiplexes the measurement light into frequency components and irradiates the demultiplexed light onto multiple points on the measurement surface of the object, thereby making it possible to simultaneously measure vibration information at multiple points on the measurement surface (see, for example, Patent Documents 4-6).

[0008] Furthermore, without using a frequency shifter, the center frequency f0 (Hz) and the frequency interval f m The optical comb is generated as a probe light, with a center frequency of f0 (Hz) and a frequency interval of f m +Δf m A vibrometer capable of multi-point measurement with a simplified device configuration has been proposed by generating an optical comb as a reference light (see, for example, Patent Document 7).

[0009] Furthermore, a multi-point measurement type laser Doppler vibrometer has been proposed that uses an optical comb generator that makes it possible to generate a wideband optical comb with multiple modes using a single modulator (Patent Document 8). [Prior art documents] [Patent documents]

[0010] [Patent Document 1] Japanese Patent Application Laid-Open No. 2016-035575 [Patent Document 2] Japanese Patent Application Laid-Open No. 2003-207421 [Patent Document 3] Special Publication No. 2021-507251 [Patent Document 4] Patent No. 5336921 [Patent Document 5] Japanese Patent Application Laid-Open No. 2010-203860 [Patent Document 6] Patent No. 5363231 [Patent Document 7] Patent No. 7276051 [Patent Document 8] Japanese Patent Publication No. 2022-47249 Summary of the Invention [Problem to be solved by the invention]

[0011] In a multi-point vibration measurement device using an optical comb, various optical elements are provided in the optical system that propagates the reference light and measurement light through space, such as an interference optical system into which reference light and measurement light are input, an optical demultiplexing element that demultiplexes the measurement light to be irradiated onto the measurement surface into each frequency component of the optical comb, and an optical element that irradiates the measurement surface with the measurement light of each frequency component demultiplexed by the optical demultiplexing element and returns the reflected light (scattered light) from the measurement surface to the optical demultiplexing element.While it is possible to measure the vibration of the measurement surface of an object that is located in front as seen from the irradiation side, it is not possible to measure the side of the object where the angle of incidence of the light rays is shallow, or the back of the object that is in the shadow of the measurement light.

[0012] Here, by modularizing the input and output of the interference optical system 2 to optical fibers and sending reference light and measurement light, as in the multipoint vibration measurement device 10 shown in Figure 1, it is possible to use modularized optical elements with various functions, making it easier to assemble and repair the device. Also, by using free-space optical systems and optical fibers to make some functional elements into optical integrated circuits, the device can be made smaller.

[0013] This multipoint vibration measuring device 10 uses coherent measurement light L output from a light source 1. S and reference beam L R The optical fiber 2 includes an interference optical system 2 into which the measurement light LS is input, and the frequency components contained in the measurement light LS input through the interference optical system 2 are demultiplexed by an optical multiplexer / demultiplexer 3 into, for example, m×n (m and n are any positive integers) kinds of frequency components to generate the measurement light L S The measurement light L is reflected at the m×n measurement points on the measurement surface of the measurement object 5 and returns via the projection optical system 4. SThe reflected light of each frequency component is multiplexed by the optical multiplexer / demultiplexer 3 to obtain the measurement light L consisting of the reflected light of each frequency component reflected at the m×n measurement points on the measurement surface. S ' is input to the interference optical system 2.

[0014] The light source 1 emits linearly polarized measurement light L S and reference beam L R The first and second optical comb generators (COMB1) 1A and (COMB2) 1B each output a polarization-maintaining fiber (PMF) and an optical fiber FB 12A ,FB 12B The PMF is connected to an interference optical system 2 via a photoelastic effect and structural changes to generate birefringence, where the effective refractive index differs between the vertical and horizontal directions of the core, thereby improving the polarization-maintaining properties of the transmitted light.

[0015] The first optical comb generator (COMB1) 1A and the second optical comb generator (COMB2) 1B generate the measurement light L S and reference beam L R The intensity or phase of each is periodically modulated to generate two types of optical combs with different modulation frequencies.

[0016] The interference optical system 2 includes an optical fiber FB 12A Measurement light L through S is input, and the second optical comb generator (COMB2) 1B outputs the optical fiber FB 12B via the reference beam L R is entered.

[0017] The interference optical system 2 is an optical fiber FB using a PMF. 2A1 ,FB 2A2 ,FB 2B1 ,FB 2B2 ,FB 2C Five optical couplers connected by OC A ,OC B ,OC C ,OC D ,OCE Optical coupler OC A Externally connected optical fiber FB 12A The measurement light L is emitted from the first optical comb generator (COMB1) 1A via S is input and the optical coupler OC B Externally connected optical fiber FB 12B Reference light L is output from the second optical comb generator (COMB2) 1B via R is entered.

[0018] In this interference optical system 2, the optical coupler OCA has two optical fibers FB 2A1 ,FB 2A2 Two optical couplers via OC D ,OC E Internally connected to the optical coupler OC B There are two optical fiber FB 2B1 ,FB 2B2 Two optical couplers via OC C ,OC D is internally connected, and the optical coupler OC E Optical fiber FB 2C via optical coupler OC C are internally connected.

[0019] The measurement light L input to the interference optical system 2 S is the optical coupler OC E Optical fiber FB using PMF externally connected to 23 The light is input to the optical multiplexer / demultiplexer element 3 via the optical fiber 10.

[0020] The measurement light L input to the optical multiplexer / demultiplexer 3 S is the measurement light L in the optical multiplexing / demultiplexing element 3. S The multiple frequency components contained in are demultiplexed, and multiple (m × n) optical fibers FB using PMF for each frequency component are 3411 ,FB 3421 ,FB 3431 ,···,FB 34m1 ,···,FB 34mn through a plurality of (m×n) condenser lenses 4 of the projection optical system 4. A11 ,4 A21 ,4A31 ,···,4 Am1 ,···,4 Amn and multiple (m×n) types of frequency components are input to multiple (m×n) condenser lenses 4 A11 ,4 A21 ,4 A31 ,···,4 Am1 ,···,4 Amn and the light is collected by the quarter-wave plate 4 B11 ,4 B21 ,4 B31 ,···,4 Bm1 ,···,4 Bmn The light is irradiated onto a plurality of measurement points on the measurement surface of the object 5 via the

[0021] Then, the light is reflected at a plurality of measurement points on the measurement surface of the measurement object 5 and passes through the projection optical system 4 and the optical fiber FB 3411 ,FB 3421 ,FB 3431 ,···,FB 34m1 ,···,FB 34mn The measurement light L returns via the S The reflected light of each frequency component is multiplexed by the optical multiplexer / demultiplexer element 3, and is output from the optical multiplexer / demultiplexer element 3 to the optical fiber FB as reflected light consisting of each frequency component reflected at a plurality of measurement points on the measurement surface. 23 The optical coupler OC of the interference optical system 2 E is entered into

[0022] Here, the optical coupler OC E The measurement light L is composed of reflected light of each frequency component reflected at a plurality of measurement points on the measurement surface. S ' is the optical coupler OC E Measurement light L output from S Each frequency component of the quarter wave plate 4 B11 ,4 B21 ,4 B31 ,···,4 Bm1 ,···,4 Bmn By passing through the measuring light LS' twice, the polarization of the measuring light LS' is perpendicular to that of the measuring light Ls, and the measuring light L S ,L S' denotes the optical coupler OC above, which functions as a polarization beam combiner / splitter. E This allows separation by the polarization plane, and the polarized light is S The measurement light L is composed of reflected light of each frequency component reflected at multiple measurement points on the measurement surface, which is a component orthogonal to the S ' is an optical coupler OC E From optical fiber FB 2C via optical coupler OC C is entered into

[0023] In the interference optical system 2, measurement light L consisting of reflected light of each frequency component reflected at a plurality of measurement points on the measurement surface is S ' and the reference light L input from the light source 1. R The interference light from the optical coupler OC C and the measurement light L input from the light source 1. S and reference beam L R The interference light from the optical coupler OC D Output from

[0024] The interference light detector 6, to which the measurement interference light and the reference interference light obtained by the interference optical system 2 are input, includes a measurement light detector 6A and a reference light detector 6B, each of which is a balanced photodetector. C Two optical fiber FBs externally connected to 26A1 ,FB 26A2 Through the above optical coupler OC C The measurement light detector 6A receives the measurement interference light input from the S and the optical coupler OC D Two optical fiber FBs externally connected to 26B1 ,FB 26B2 Through the above optical coupler OC D The reference interference light is detected by a reference photodetector 6B that receives the reference interference light input from the reference photodetector 6B, and converted into an electrical signal to generate a reference interference signal S R Output.

[0025] The balanced photodetectors used as the measurement interference light detector 6A and reference interference light detector 6B have two photodiodes connected in such a way that their photocurrents cancel each other out, canceling out the common-mode noise of the two incident light beams and converting the difference in light intensity into an electrical signal as a displacement signal. They combine beats with frequencies corresponding to the frequency difference between the frequency components of the optical combs of the input measurement light and reference light into a single electrical signal. The frequency difference between the measurement light and reference light described here is sufficiently small compared to the spacing between the frequency components of the optical comb, and is therefore not split by the optical multiplexing and splitting elements described below. The bandwidth of the balanced photodetector is sufficiently smaller than the spacing between the frequency components of the optical comb, yet large enough to detect the frequency difference between the measurement light and reference light.

[0026] In the multipoint vibration measuring device 10, the signal processing unit 7 converts the measurement interference signal S obtained by the interference light detection unit 6 into S and the reference interference signal S R The measurement light L input in the discrete Fourier transform (DFT) (including the fast Fourier transform (FFT)) analysis is S and reference beam L R By calculating the phase difference between beats having frequencies corresponding to the frequency differences of the optical combs, vibration information at multiple measurement points on the measurement surface is analyzed, and the distribution of vibrations on the measurement surface is measured.

[0027] As in this multipoint vibration measuring device 10, the input and output of the interference optical system 2 are configured with optical fibers, and the measurement light L S and reference beam L R By sending the optical fiber FB from the interference optical system 2, it is possible to use modularized optical elements with various functions, which makes it easier to assemble and repair the device. 23A problem arises in that a portion of the measurement light LS input to the optical multiplexer / demultiplexer element 3 via the optical fiber 1 is reflected by the optical multiplexer / demultiplexer element 3 and returns to the interference optical system 2, where it is mixed with the interference light required for multi-point vibration measurement, causing measurement errors.

[0028] For example, when an arrayed waveguide grating is used for the optical multiplexer / demultiplexer 3, it is small and has high resolution, but the return loss (RL) is about 40 dB. This reflection occurs inside the optical multiplexer / demultiplexer 3 and at the connection between the optical fiber and the optical multiplexer / demultiplexer 3. Furthermore, if the optical path from the interference optical system 2 to the optical multiplexer / demultiplexer is optical fiber, reflection from the optical fiber connector, etc., cannot be ignored.

[0029] That is, the optical multiplexing / demultiplexing element 3 may be a triangular prism, an arrayed waveguide grating (AWG), a plurality of wavelength division multiplexing filters, a diffraction grating, or the like, but the problem is that the RL is small.

[0030] On the other hand, the amount of reflected light returning from the measurement surface to the optical multiplexer / demultiplexer element 3 is greatly attenuated depending on the surface properties and shape of the measurement surface.

[0031] Furthermore, the insertion loss (IL) of the optical multiplexer / demultiplexer 3 is also large, about 6.5 dB for an AWG with a spacing of 25 GHz, and when used in both directions, the loss becomes about 13 dB, so the influence of RL becomes relatively large.

[0032] If the reflection from the measurement surface is not large enough, the measurement light (first optical comb) L S It becomes difficult to distinguish reflections from the measurement surface.

[0033] In such a case, there is a problem that the vibration information calculated by the signal processing unit 7 becomes erroneous.

[0034] Furthermore, a single multi-point vibration measurement head can obtain vibration information only from the surface that can be irradiated with the measurement light, but it cannot measure the vibration of the back surface that is shaded by the measurement light or the side surface where the angle of incidence of the measurement light is shallow, which results in a problem that the information obtained as a measurement of the three-dimensional vibration distribution of the object being measured is limited.

[0035] Therefore, the present invention has been devised in consideration of the above-mentioned conventional situation, and aims to provide a multi-point vibration measurement test bench that can be used in cases where vibration information from multiple points is required simultaneously, such as when it is desired to measure transiently changing vibrations in real time or when it is not known in advance what frequency components are included in the vibration, and that can acquire vibration information from a wide area to more accurately investigate the cause of vibration, and that can be used to detect abnormal vibrations and for full inspection in the manufacturing process, by measuring vibration information from multiple points on the object to be measured simultaneously using light.

[0036] Another object of the present invention is to eliminate measurement errors caused by unwanted reflection components from various optical elements, such as optical multiplexers and splitters, that are provided in the optical path through which the measurement light irradiated onto the measurement surface via an interference optical system passes, in a multi-point vibration measurement test bench that uses light to simultaneously measure vibration information at multiple points on the measurement object, thereby performing high-precision multi-point vibration measurement, acquiring three-dimensional vibration information, and enabling the display, analysis, epicenter estimation, frequency analysis, etc. of the three-dimensional vibration information.

[0037] Other objects of the present invention and specific advantages obtained by the present invention will become more apparent from the following description of the embodiments. [Means for solving the problem]

[0038] In the present invention, multi-point vibration analysis is performed by capturing three-dimensional vibrations, including transient vibrations of an object, in real time using synchronous measurement by multiple heads, including a single vibration measurement head, and coordinate transformation.

[0039] The present invention provides a multi-point vibration measurement test bench that uses light to simultaneously measure vibration information at multiple points on a measurement object, the test bench comprising: a light source that outputs coherent measurement light and reference light, each having a spectrum with a predetermined frequency interval; an optical distributor that distributes the measurement light and reference light output from the light source to multiple optical paths; a plurality of multi-point vibration measurement units that are arranged in a three-dimensional space in which the measurement object is located on the test bench, and that synchronously acquire vibration information at multiple measurement points that are two-dimensionally distributed on a measurement surface of the measurement object using the measurement light and reference light distributed to the multiple optical paths by the optical distributor; and an integration processing unit that integrates the vibration information synchronously acquired by the plurality of multi-point vibration measurement units into three-dimensional vibration information, the integration processing unit integrating ... vibration information being measured at an origin set on the test bench or at a point on the test bench in the three-dimensional space in which the test bench is located. The method is characterized in that the mounting positions and orientations of the multiple multi-point vibration measurement units are given in global coordinates based on an origin set on the installed measurement object, the local coordinates and ray vectors of each irradiation point at which the multiple multi-point vibration measurement units irradiate multiple measurement points distributed two-dimensionally on the measurement surface of the measurement object with measurement light are converted into global coordinates that define the three-dimensional space in which the test bench is installed based on information such as the global coordinates, mounting angle, and measurement light emission angle of each multi-point vibration measurement unit, and the vibration information of each local coordinate acquired synchronously by the multiple multi-point vibration measurement units is integrated into three-dimensional vibration information in global coordinates that define the three-dimensional space.

[0040] In the multipoint vibration measurement test bench according to the present invention, the multipoint vibration measurement unit includes an interference optical system to which the measurement light and the reference light distributed to the plurality of optical paths by the optical distributor are respectively input, an optical branching element that branches off each frequency component contained in the measurement light input from the interference optical system, a projection optical system that irradiates each frequency component branched by the optical branching element onto a plurality of measurement points on a measurement surface of the measurement object, an optical combining element that combines each frequency component of the measurement light reflected and returned from the plurality of measurement points on the measurement surface and inputs the combined light into the interference optical system, and a projection optical system that inputs each frequency component contained in the measurement light branched by the optical branching element into the projection optical system. and a measurement interference light detection unit that receives measurement interference light obtained by interfering, in the interference optical system, measurement light including each of the frequency components reflected at a plurality of measurement points on the measurement surface and returning via the optical multiplexing element provided in the multipoint measurement head, with a reference light output from the light source, and converts the measurement interference light into an electrical signal to obtain a measurement interference signal including vibration information at a plurality of measurement points distributed two-dimensionally on the measurement surface of the object to be measured.

[0041] Furthermore, a multi-point vibration measurement test bench according to the present invention includes at least one single-point vibration measurement unit that is arranged in a three-dimensional space in which the measurement object is located and that synchronously acquires vibration information of one measurement point on the measurement surface of the measurement object using measurement light and reference light that are distributed to multiple optical paths by the optical distributor, and the integrated processing unit assigns the mounting positions and orientations of the multiple multi-point vibration measurement units in global coordinates based on an origin set on the test bench or an origin set on the measurement object placed on the test bench in the three-dimensional space in which the test bench is placed, and calculates the local coordinates and ray vectors of each irradiation point at which the multiple multi-point vibration measurement units irradiate multiple measurement points distributed two-dimensionally on the measurement surface of the measurement object with measurement light, respectively, based on the global coordinates of the multi-point vibration measurement units, the mounting angle, measurement light emission angle, etc. and converting the information into global coordinates that define the three-dimensional space in which the test bench is installed based on the information of the multi-point vibration measurement units and the at least one single-point vibration measurement unit into global coordinates that define the three-dimensional space in which the test bench is installed, and assigning the mounting position and orientation of the at least one single-point vibration measurement unit in global coordinates based on an origin set on the test bench or an origin set on the measurement object installed on the test bench, and converting the local coordinates and ray vector of the irradiation point at which the at least one single-point vibration measurement unit irradiates one measurement point on the measurement surface of the measurement object with measurement light into global coordinates that define the three-dimensional space in which the test bench is installed based on information such as the global coordinates, mounting angle, and measurement light emission angle of the at least one single-point vibration measurement unit, and integrating the vibration information acquired synchronously by the multiple multi-point vibration measurement units and the at least one single-point vibration measurement unit into three-dimensional vibration information.

[0042] Furthermore, in the multi-point vibration measurement test bench according to the present invention, the single-point vibration measurement unit includes at least one single-point measurement head including an interference optical system into which the measurement light and reference light distributed to a plurality of optical paths by the optical distributor are input, an optical multiplexing / demultiplexing optical system into which the measurement light is input via the interference optical system, and a projection optical system into which one frequency component of a plurality of frequency components contained in the measurement light obtained by dividing the measurement light by the optical multiplexing / demultiplexing optical system is input, the projection optical system irradiates the input measurement light of the one frequency component onto one measurement point on the measurement surface of the object to be measured, and inputs reflected light of the measurement light of the one frequency component reflected and returned from the one measurement point on the measurement surface into the optical multiplexing / demultiplexing optical system; and a single-point vibration measurement head into which the interference light obtained by the interference optical system is input. The single-point measurement head may include a measurement interference light detection processing unit, and the interference optical system may receive measurement light consisting of reflected light of at least one frequency component obtained by multiplexing, using the optical multiplexing / demultiplexing optical system, reflected light of one frequency component of the measurement light that is reflected at at least one measurement point on the measurement surface and returned via the single-point measurement head, thereby obtaining single-point measurement interference light by causing interference between the reference light input from the optical distributor and the measurement light consisting of reflected light of at least one frequency component, and the single-point measurement interference light detection unit may receive the single-point measurement interference light obtained by the single-point measurement interference light detection unit and convert it into an electrical signal to obtain a single-point measurement interference signal including vibration information at at least one measurement point on the measurement surface.

[0043] Furthermore, in the multi-point vibration measurement test bench according to the present invention, the multi-point measurement head can be configured to separate each frequency component contained in the measurement light into one frequency component by the optical demultiplexing element, irradiate each frequency component onto a plurality of measurement points on the measurement surface of the measurement object via the projection optical system, and combine each frequency component of the measurement light reflected and returned from the plurality of measurement points on the measurement surface by an optical combining element.

[0044] Furthermore, in the multi-point vibration measurement test bench according to the present invention, the multi-point measurement head can be configured to separate each frequency component contained in the measurement light into multiple frequency components using the optical demultiplexing element, irradiate each frequency component onto multiple measurement points on the measurement surface of the object to be measured via the projection optical system, and combine each frequency component of the multiple frequency components of the measurement light reflected and returned from the multiple measurement points on the measurement surface using an optical combining element.

[0045] Furthermore, the multi-point vibration measurement test bench according to the present invention may be configured such that the coupling optical system is built into the projection optical system.

[0046] Furthermore, in the multi-point vibration measurement test bench according to the present invention, the optical demultiplexing element demultiplexes each frequency component contained in the measurement light input from the interference optical system via one optical fiber and outputs the demultiplexed signal via multiple optical fibers, the optical multiplexing element multiplexes each frequency component input via the multiple optical fibers and outputs the multiplexed signal via one optical fiber, and the combining optical system can include a polarization optical element that aligns the optical axes of two light beams output from the two optical fibers and having orthogonal polarization directions.

[0047] In the multi-point vibration measurement test bench according to the present invention, the polarizing optical element may be made of a birefringent crystal.

[0048] In the multi-point vibration measurement test bench according to the present invention, the polarizing optical element may be a Wollaston prism.

[0049] Furthermore, in the multi-point vibration measurement test bench according to the present invention, the coupling optical system comprises a polarizing optical element array in which the polarizing optical elements are arranged two-dimensionally, and each frequency component of the measurement light input via the polarizing optical element array is collected by a collecting optical element and output toward the measurement surface of the measurement object, and each frequency component of the measurement light reflected and returned by the measurement surface is collected by the collecting optical element and input to the polarizing optical element array. [Effects of the Invention]

[0050] In the multi-point vibration measurement test bench according to the present invention, a measurement light and a reference light output from a light source are respectively distributed to a plurality of optical paths by an optical distributor, and a plurality of multi-point vibration measurement units arranged in a three-dimensional space in which a measurement object is located use the measurement light and the reference light distributed to the plurality of optical paths by the optical distributor to synchronously acquire vibration information of a plurality of measurement points distributed two-dimensionally on a measurement surface of the measurement object, and an integrated processing unit assigns each mounting position and orientation of the plurality of multi-point vibration measurement units in global coordinates based on an origin set on the test bench or an origin set on a measurement object placed on the test bench, and the plurality of multi-point vibration measurement units irradiate the measurement light onto a plurality of measurement points distributed two-dimensionally on a measurement surface of the measurement object with the measurement light. Local coordinates and ray vectors are converted into global coordinates that define the three-dimensional space in which the test bench is installed based on the global coordinates of each multi-point vibration measurement unit, the mounting angle, the measurement light emission angle, and other information. The vibration information of each local coordinate acquired synchronously by the multiple multi-point vibration measurement units is then integrated into three-dimensional vibration information in the global coordinates that define the three-dimensional space. This makes it possible to handle cases where vibration information from several points is required simultaneously, such as when transiently changing vibrations need to be measured in real time or when it is not known in advance what frequency components are contained in the vibration. Obtaining vibration information over a wide area makes it possible to more accurately investigate the causes of vibration, and this can be used for detecting abnormal vibrations and for full inspection of all products during the manufacturing process.

[0051] In addition, the multi-point vibration measurement test bench according to the present invention can perform multi-point vibration analysis by capturing three-dimensional vibrations, including transient vibrations of the object being measured, in real time by combining synchronized measurement of multiple heads, including a single vibration measurement head, and coordinate transformation. This can also be used in in-line inspection processes by narrowing down the inspection items of the object being measured and shortening inspection time by speeding up information collection.

[0052] Furthermore, in the present invention, the functions of the optical demultiplexing element and the optical multiplexing element are operated separately, and the measurement light output from the light source through the interference optical system is demultiplexed into a plurality of frequency components contained in the measurement light and irradiated onto a plurality of measurement points on the measurement surface of the object to be measured, and the optical path is separated into another optical path in which the plurality of frequency components reflected and returned from the plurality of measurement points on the measurement surface are combined and input to the interference optical system. This makes it possible to prevent unwanted reflection components from the optical demultiplexing element that demultiplexes into the plurality of frequency components from mixing into the interference light required for multi-point vibration measurement. In a multi-point vibration measurement test bench that uses light to simultaneously measure vibration information from a plurality of points on the object to be measured, measurement errors caused by unwanted reflection components from various optical elements such as an optical demultiplexer / multiplexer provided in the optical path through which the measurement light irradiated onto the measurement surface through the interference optical system passes can be eliminated, making it possible to perform multi-point vibration measurement with high accuracy, acquire three-dimensional vibration information, and perform display, analysis, epicenter estimation, frequency analysis, etc. of the three-dimensional vibration information. [Brief explanation of the drawings]

[0053] [Figure 1] FIG. 1 is a schematic diagram showing the configuration of a multi-point vibration measurement device in which the input and output of an interference optical system are modularized to use optical fibers. [Figure 2] FIG. 2 is a schematic diagram showing the configuration of a multi-point vibration measurement test bench to which the present invention is applied. [Figure 3] FIG. 3 is a schematic diagram showing the configuration of a multi-point measurement head provided in the multi-point vibration measurement test bench. [Figure 4] Figures 4(A) and (B) are diagrams explaining the functions of the optical demultiplexing element and optical multiplexing element provided in the multi-point measurement head. (A) shows the function of demultiplexing each frequency component of the optical comb contained in the measurement light into individual frequency components using the optical demultiplexing element, and (B) shows the function of multiplexing each frequency component demultiplexed into individual frequency components using the optical multiplexing element. [Figure 5] FIG. 5 is a perspective view of the multi-point vibration measurement test bench for an engine, which diagrammatically shows a state in which three multi-point measurement heads are arranged in a three-dimensional space in which an object to be measured is located, in the multi-point vibration measurement test bench. [Figure 6] FIG. 6 is a perspective view of the multipoint vibration measurement test bench for an electric motor, which diagrammatically shows a state in which four multipoint measurement heads are arranged in a three-dimensional space in which an object to be measured is located. [Figure 7] 7A and 7B are schematic diagrams showing a test bench for an electric motor in the multi-point vibration measurement test bench 100, which is equipped with a test tunnel in which five multi-point measurement heads are arranged in the three-dimensional space in which the measurement object 5 is located, where (A) is a front view of the test bench for an electric motor and (B) is a side view of the test bench for an electric motor. [Figure 8] FIG. 8 is a schematic diagram showing another example of the configuration of the multi-point measurement head provided in the multi-point vibration measurement test bench. [Figure 9] Figures 9(A) and (B) are diagrams showing an example of the configuration of a projection optical element used in a projection optical system with a built-in coupling optical element provided in the multi-point measurement head, where (A) is a schematic diagram showing the configuration of the projection optical element, and (B) is a front view of a two-core capillary provided in the projection optical element. [Figure 10] Figures 10(A) and (B) show another example of the configuration of the projection optical element used in the projection optical system with the built-in coupling optical element, where (A) is a schematic diagram showing the configuration of the projection optical element, and (B) is a front view of the two-core capillary provided in the projection optical element. [Figure 11] FIG. 11 is a schematic diagram showing the configuration of a multipoint measurement head equipped with a projection optical system incorporating a coupling optical element, which uses a coupling optical element array formed by two-dimensionally arranging a plurality of projection optical elements. [Figure 12] 12A and 12B are diagrams showing an example of the configuration of the above-mentioned coupling optical element array, where (A) is a vertical sectional side view of the coupling optical element array, and (B) is a vertical sectional front view of the coupling optical element array. [Figure 13] FIG. 13 is a schematic diagram showing another example of the configuration of a multi-point measurement head in a multi-point vibration measurement test bench to which the present invention is applied. [Figure 14] FIG. 14 is a schematic diagram showing another example of the configuration of the multi-point measurement head in the multi-point vibration measurement test bench to which the present invention is applied. [Figure 15] FIG. 15 is a schematic diagram showing another example of the configuration of a multi-point measurement head in a multi-point vibration measurement test bench to which the present invention is applied. [Figure 16] FIG. 16 is a schematic diagram showing the software hierarchy executed by an integration processing unit in the multi-point vibration measurement test bench, which integrates the vibration information acquired synchronously by the multiple multi-point vibration measurement units into three-dimensional vibration information. [Figure 17] FIG. 17 is a schematic diagram showing another example of the configuration of a multi-point vibration measurement test bench to which the present invention is applied. [Figure 18] FIG. 18 is a schematic diagram showing an example of the configuration of a single-point vibration measurement unit provided in the multi-point vibration measurement test bench. [Figure 19] FIG. 19 is a schematic diagram showing another example of the configuration of the single-point vibration measurement unit provided in the multi-point vibration measurement test bench. [Figure 20] FIG. 20 is a schematic diagram showing another example of the configuration of the single-point vibration measurement unit provided in the multi-point vibration measurement test bench. [Figure 21] FIG. 21 is a perspective view that schematically shows a state in which four multi-point measurement heads and one single-point measurement head are arranged in the three-dimensional space in which the measurement object is located in the multi-point vibration measurement test bench. [Figure 22] Figure 22 is a schematic diagram showing the software hierarchy executed by an integration processing unit in the multi-point vibration measurement test bench, which integrates each piece of vibration information acquired synchronously by the multiple single-point vibration measurement units into three-dimensional vibration information. [Figure 23] FIG. 23 is a schematic diagram showing the software hierarchy of the integration process executed by the integration processing unit 190 when a multi-point optical head and a single-point measurement head are mixed. DETAILED DESCRIPTION OF THE INVENTION

[0054] Hereinafter, embodiments of the present invention will be described in detail with reference to the drawings. Common components will be described by using common reference numerals in the drawings. Furthermore, the present invention is not limited to the following examples, and can be modified as desired without departing from the spirit of the present invention.

[0055] FIG. 2 is a schematic diagram showing the configuration of a multi-point vibration measurement test bench 100 to which the present invention is applied.

[0056] This multipoint vibration measurement test bench 100 is an improved version of the multipoint vibration measurement device 10 shown in FIG. 1, and is configured as shown in FIG. 3. A plurality of multipoint vibration measurement units 170 are arranged in a three-dimensional space where a measurement object 5 is located, and vibration information of the measurement object 5 is measured at multiple points simultaneously using laser light. S and reference beam L R The vibration measuring device 100 includes a measuring unit 180 consisting of a plurality of multipoint vibration measuring units 170A, 170B, ... to which the vibration information obtained by the measuring unit 180 is distributed to a plurality of optical paths and input, and an integrated processing unit 190 to which the vibration information obtained by the measuring unit 180 is input.

[0057] In this multipoint vibration measurement test bench 100, the same components as those in the multipoint vibration measurement device 10 are denoted by the same reference numerals in the drawings, and detailed description thereof will be omitted.

[0058] The light source 1 emits a coherent measurement light L having a spectrum with a predetermined frequency interval. S and reference beam L R The intensity or phase of each is periodically modulated to generate two types of optical combs with different modulation frequencies.

[0059] The optical distributor 110 is connected to the light source 1 via a pair of optical fibers, and is also connected to a plurality of multipoint vibration measuring units 170A, 170B, ... of the measuring unit 180 via optical fibers each using a pair of PMFs, and the measurement light L output from the light source 1 is S and reference beam L Rare distributed to a plurality of optical paths and input to a plurality of multipoint vibration measuring units 170A, 170B, . . . of the measuring unit 180.

[0060] The plurality of multipoint vibration measurement units 170A, 170B, etc. each consist of multipoint measurement heads 150A, 150B, etc. connected to the optical distributor 110 via optical fibers each using a pair of PMFs, and optical detection processing units 160A, 160B, etc. connected to the multipoint measurement heads 150A, 150B, etc. via optical fibers each using a pair of SMFs.

[0061] The integrated processing unit 190 is made up of a PC 190C on which a communication board 190A and a DIO board 190B are mounted.

[0062] The PC 190C mounted on the integrated processing unit 190 has a function of transmitting and receiving data by serial communication with the plurality of light detection processing units 160A, 160B, ... of the measurement unit 180 via a communication optical fiber connected to the transmit terminal T and receive terminal R of the communication board 190A, and also has a function of supplying a trigger signal to the plurality of light detection processing units 160A, 160B, ... of the measurement unit 180 via a coaxial cable connected to the strobe terminal S of the DIO board 190B.

[0063] In addition, the PC 190C mounted on the integrated processing unit 190 is connected to the light source 1 via a USB cable, and is capable of monitoring the operating status of the two optical comb generators (COMB1, COMB2) that make up the light source 1.

[0064] In the multipoint vibration measurement test bench 100, the optical distributor 110 distributes the measurement light L from the light source 1. S and reference beam L R is input, and a reference signal is supplied from the light source 1, and the measurement light L S and reference beam L R are distributed to multiple optical paths.

[0065] Moreover, the optical distributor 110 has a function of supplying the reference signal R to a plurality of light detection processing units 160A, 160B, . . . of the measurement unit 180.

[0066] Moreover, the optical distributor 110 has a function of supplying the reference signal to a plurality of light detection processing units 160A, 160B, . . . of the measurement unit 180.

[0067] Here, for the plurality of multipoint vibration measuring units 170A, 170B, etc., a multipoint vibration measuring unit 170 having a configuration as shown in FIG. 3, for example, can be used.

[0068] FIG. 3 is a schematic diagram showing the configuration of the multipoint vibration measurement unit 170 provided in the multipoint vibration measurement test bench 100. As shown in FIG.

[0069] The multipoint vibration measurement unit 170 is connected to the optical distributor 110 via an optical fiber FB 12A ,FB 12B a multi-point measurement head 150 connected to the multi-point measurement head 150 via an optical fiber FB 26A1 ,FB 26A2 ,FB 26B1 ,FB 26B2 The light detection processing unit 160 is connected via

[0070] This multipoint vibration measurement unit 170 is equipped with a multipoint measurement head 150 which is an improved version of the multipoint vibration measurement device 10 shown in Figure 1, in which the optical splitter / multiplexer element 3 in the multipoint vibration measurement device 10 shown in Figure 1 functions as an optical splitter element and an optical multiplexer element separately, thereby preventing unnecessary reflected components from mixing into the interference light required for multipoint vibration measurement.

[0071] That is, the multipoint measurement head 150 receives the measurement light L distributed to multiple optical paths by the optical distributor 110. S and reference beam L R are the optical fibers FB 12A ,FB 12B and an interference optical system 120 through which the measurement light L SA light multiplexing and dividing optical system 130, which is composed of a light dividing element 130A and a light combining element 130B, and the measurement light L separated by the light dividing element 130A are disposed between a projection optical system 4 that irradiates each frequency component of the above onto a plurality of points (for example, m×n measurement points arranged two-dimensionally in a matrix) on the measurement surface of the measurement object 5. S is input to the projection optical system 4, and the measurement light L is reflected and returned from a plurality of measurement points on the measurement surface. S and a coupling optical system 135 for inputting each of the frequency components into the optical coupling element 130B.

[0072] The interference optical system 120 includes an optical fiber FB using a PMF. 2A2 ,FB 2B1 ,FB 2B2 Four optical couplers connected by OC A ,OC B ,OC C ,OC D Optical coupler OC A Externally connected optical fiber FB 12A Measurement light L through S is input and the optical coupler OC B Externally connected optical fiber FB 12B via the reference beam L R is entered.

[0073] In this interference optical system 120, an optical coupler OC A Optical fiber FB 2A2 via optical coupler OC D is internally connected, and the optical coupler OC B There are two optical fiber FB 2B1 ,FB 2B2 Two optical couplers via OC C ,OC D are internally connected.

[0074] The above optical coupler OC A The optical fiber FB using PMF is 23A The optical demultiplexing element 130A of the optical demultiplexing / multiplexing optical system 130 is externally connected via CThe optical fiber FB using PMF is 23C The optical multiplexing element 130B of the optical multiplexing / demultiplexing optical system 130 is externally connected via the optical multiplexing / demultiplexing element 130B.

[0075] The measurement light L input to the interference optical system 120 S is the optical coupler OC A Externally connected optical fiber FB 23A The light is input to the optical demultiplexer 130A via the optical demultiplexer 130B.

[0076] The optical demultiplexing element 130A of the optical demultiplexing / multiplexing optical system 130 includes a plurality of (m×n) optical fibers FB 3411 ,FB 3421 ,FB 3431 ,···,FB 34m1 ,···,FB 34mn The coupling optical system 135 includes a plurality of (m×n) optical couplers OC C11 ,OC C21 ,OC C31 ,···,OC C1 ,···,OC Cmn , and the optical multiplexing element 130B of the optical multiplexing and demultiplexing optical system 130 is connected to a plurality of (m×n) optical fibers FB 4311 ,FB 4321 ,FB 4331 ,···,FB 43m1 ,···,FB 43mn The coupling optical system 135 includes a plurality of (m×n) optical couplers OC C11 ,OC C21 ,OC C31 ,···,OC C1 ,···,OC Cmn is connected to.

[0077] The measurement light L input to the optical demultiplexer 130A S is the measurement light L in the optical demultiplexing element 130A. S are demultiplexed, and the multiple (m×n) optical fibers FB are used for each frequency component. 3411 ,FB 3421 ,FB 3431 ,···,FB 34m1 ,···,FB 34mnThe coupling optical system 135 includes a plurality of (m×n) optical couplers OC C11 ,OC C21 ,OC C31 ,···,OC C1 ,···,OC Cmn is entered into

[0078] The coupling optical system 135 includes a plurality of (m×n) optical couplers OC C11 ,OC C21 ,OC C31 ,···,OC C1 ,···,OC Cmn The fiber optics FB consists of multiple (m×n) optical fibers using PMF. 4411 ,FB 4421 ,FB 4431 ,···,FB 44m1 ,···,FB 44mn through the plurality of (m×n) projection optical elements 44 of the projection optical system 4. 11 ,44 21 ,44 31 ,···,44 m1 ,···44 mn is connected to.

[0079] The projection optical element 44 of the projection optical system 4 11 ,44 21 ,44 31 ,···,44 m1 ,···44 mn are the condenser lenses 4 A11 ,4 A21 ,4 A31 ,···,4 Am1 ,···,4 Amn and quarter wave plate 4 B11 ,4 B21 ,4 B31 ,···,4 Bm1 ,···,4 Amn It consists of:

[0080] Then, the measurement light L demultiplexed by the optical demultiplexing element 130A is S The multiple frequency components included in are transmitted from the coupling optical system 135 to the multiple (m×n) optical fibers FB 4411 ,FB 4421 ,FB 4431,···,FB 44m1 ,···,FB 44mn The projection optical system 4 includes a plurality of (m×n) condenser lenses 4 A11 ,4 A21 ,4 A31 ,···,4 Am1 ,···,4 Amn and multiple (m×n) types of frequency components are input to multiple (m×n) condenser lenses 4 A11 ,4 A21 ,4 A31 ,···,4 Am1 ,···,4 Amn and multiple (m×n) types of frequency components are input to multiple (m×n) condenser lenses 4 A11 ,4 A21 ,4 A31 ,···,4 Am1 ,···,4 Amn and the light is collected by the quarter-wave plate 4 B11 ,4 B21 ,4 B31 ,···,4 Bm1 ,···,4 Amn The light is irradiated onto a plurality of measurement points on the measurement surface of the object 5 via the

[0081] That is, in this multipoint measurement head 150, the optical fiber FB 23A The measurement light L is input to the optical demultiplexing element 130A of the optical demultiplexing / multiplexing optical system 130 via S is the measurement light L in the optical demultiplexing element 130A. S are demultiplexed, and the multiple (m×n) optical fibers FB are used for each frequency component. 3411 ,FB 3421 ,FB 3431 ,···,FB 34m1 ,···,FB 34mn The coupling optical system 135 includes a plurality of (m×n) optical couplers OC C11 ,OC C21 ,OC C31 ,···,OC C1 ,···,OC Cmn and optical coupler OC C11 ,OC C21 ,OC C31,···,OC C1 ,···,OC Cmn Multiple (m×n) optical fibers FB 4411 ,FB 4421 ,FB 4431 ,···,FB 44m1 ,···,FB 44mn The projection optical system 4 includes a plurality of (m×n) condenser lenses 4 A11 ,4 A21 ,4 A31 ,···,4 Am1 ,···,4 Amn and multiple (m×n) types of frequency components are input to multiple (m×n) condenser lenses 4 A11 ,4 A21 ,4 A31 ,···,4 Am1 ,···,4 Amn and multiple (m×n) frequency components are condensed into a condenser lens 4 A11 ,4 A21 ,4 A31 ,···,4 Am1 ,···,4 Amn and the light is collected by the quarter-wave plate 4 B11 ,4 B21 ,4 B31 ,···,4 Bm1 ,···,4 Amn The light is irradiated onto a plurality of points (for example, m×n measurement points arranged two-dimensionally in a matrix) on the measurement surface of the measurement object 5 via the laser.

[0082] Then, the light is reflected at each measurement point on the measurement surface of the measurement object 5 and passes through the projection optical system 4 and the optical fiber FB 4411 ,FB 4421 ,FB 4431 ,···,FB 44m1 ,···,FB 44mn The optical coupler OC of the coupling optical system 135 is C11 ,OC C21 ,OC C31 ,···,OC C1 ,···,OC Cmn The measurement light L returns to S The reflected light of each frequency component is C11 ,OC C21 ,OCC31 ,···,OC C1 ,···,OC Cmn From the above optical fiber FB 4311 ,FB 4321 ,FB 4331 ,···,FB 43m1 ,···,FB 43mn The measurement light L is input to the optical multiplexing element 130B of the optical multiplexing / demultiplexing optical system 130 via the optical multiplexing element 130B, and is multiplexed by the optical multiplexing element 130B to form the measurement light L consisting of reflected light of each frequency component reflected at each measurement point on the measurement surface. S ' from the optical multiplexing element 130B to the optical fiber FB 23C the optical coupler OC of the interference optical system 120 via C is entered into

[0083] That is, in the multi-point measurement head 150, the condenser lens 4 A11 ,4 A21 ,4 A31 ,···,4 Am1 ,···,4 Amn Through the quarter wave plate 4 Bm ,···,4 Bmn Measurement light L output from S The respective frequency components are circularly polarized and irradiated onto the measurement object 5, and the reflected light returning from the measurement object 5 is reflected by the quarter wave plate 4. B11 ,4 B21 ,4 B31 ,···,4 Bm1 ,···,4 Bmn Through a condenser lens 4 A11 ,4 A21 ,4 A31 ,···,4 Am1 ,···,4 Amn For the output light of 4 A11 ,4 A21 ,4 A31 ,···,4 Am1 ,···,4 Amn The reflected light components input to the reflector 11 have orthogonal polarization planes.

[0084] From the projection optical system 4 to the optical fiber FB 4411 ,FB 4421 ,FB 4431,···,FB 44m1 ,···,FB 44mn The optical coupler OC of the coupling optical system 135 is C11 ,OC C21 ,OC C31 ,···,OC C1 ,···,OC Cmn The frequency components of the reflected light returning to the optical fiber FB 3411 ,FB 3421 ,FB 3431 ,···,FB 34m1 ,···,FB 34mn Through the above optical coupler OC C11 ,OC C21 ,OC C31 ,···,OC C1 ,···,OC Cmn Measurement light L input to S and the optical coupler OC C11 ,OC C21 ,OC C31 ,···,OC C1 ,···,OC Cmn From the above optical fiber FB 4311 ,FB 4321 ,FB 4331 ,···,FB 43m1 ,···,FB 43mn The light is input to the optical multiplexing element 130B of the optical multiplexing and demultiplexing optical system 130 via the optical multiplexing element 130B.

[0085] Here, in the multipoint measurement head 150 in the multipoint vibration measurement unit 170, as shown in FIG. 4A, the measurement light L S The optical demultiplexing element 130A demultiplexes each frequency component included in the signal, and each frequency component is irradiated onto a plurality of measurement points on the measurement surface of the measurement object 5 via the projection optical system 4. As shown in FIG. 4B, measurement light L is generated, which is made up of reflected light of each frequency component reflected from the measurement surface and returned. S ' are multiplexed by the optical multiplexing element 130B.

[0086] The interference optical system 120 generates measurement light L consisting of reflected light of each frequency component reflected at a plurality of measurement points on the measurement surface. S' and the reference light L input from the light source 1 via the light distributor 110. R The interference light from the optical coupler OC C and the measurement light L input from the light source 1 via the optical distributor 110. S and reference beam L R The interference light from the optical coupler OC D Output from

[0087] The light detection processing unit 160 of the multipoint vibration measuring unit 170 includes an interference light detecting unit 6 to which the measurement interference light and the reference interference light obtained by the interference optical system 120 are input, and a measurement interference signal S S and the reference interference signal S R The signal processor 7 receives the signal.

[0088] The interference light detection unit 6 of the light detection processing unit 160 includes a measurement light detector 6A and a reference light detector 6B, each of which is a balanced photodetector. C Two optical fiber FBs externally connected to 26A1 ,FB 26A2 Through the above optical coupler OC C A measurement light detector 6A receives the measurement interference light input from the measurement object 5, detects the measurement interference light, and converts it into an electrical signal to generate a measurement interference signal S containing vibration information at a plurality of measurement points distributed two-dimensionally on the measurement surface of the measurement object 5. S and the optical coupler OC D Two optical fiber FBs externally connected to 26B1 ,FB 26B2 Through the above optical coupler OC D The reference interference light is detected by a reference photodetector 6B that receives the reference interference light input from the reference photodetector 6B, and converted into an electrical signal to generate a reference interference signal S R Output.

[0089] Here, in the balanced photodetector used as the measurement photodetector 6A and the reference photodetector 6B, the input measurement light L S and reference beam LR Beats with frequencies corresponding to the frequency differences of the optical combs of each frequency component are combined into one, converted into an electrical signal, and output.

[0090] The signal processing unit 7 then processes the measurement interference signal S obtained by the interference light detection unit 6. S and the reference interference signal S R The phase of each frequency component is calculated using DFT analysis, and the above measurement interference signal S S and the reference interference signal S R By calculating the phase difference for each frequency component resulting from the Doppler shift caused by vibration at multiple measurement points on the measurement surface between the two, vibration information at multiple measurement points on the measurement surface, such as vibration velocity, movement distance, acceleration, etc., is analyzed to measure the vibration distribution on the measurement surface.

[0091] In this way, in the multipoint vibration measurement unit 170, the measurement light L S The measurement light L output from the interference optical system 120 provided with the optical demultiplexing element 130A that demultiplexes a plurality of frequency components included in S and the measurement light L passing through the optical multiplexing element 130B, which multiplexes the reflected light of each frequency component reflected at a plurality of measurement points on the measurement surface of the measurement object 5. S Since the optical path for inputting the measurement light L′ to the interference optical system 120 is split, the measurement light L S Even if a part of the reflected light is reflected by the optical demultiplexer 130A and an unnecessary reflected component is generated, this reflected component is reflected by the optical fiber FB 23A via the optical coupler OC of the interference optical system 120. A Returning to this branch optical coupler OC A From optical fiber FB 12A Therefore, even if unwanted reflected components are generated by reflection at the optical demultiplexing element 130A, these reflected components are absorbed by the optical coupler OC C The reference light L output from R and the above measurement light L S' interference light, that is, the measurement interference light, and the optical coupler OC D The reference light L output from R and the above measurement light L S The interference light for reference, i.e., the interference light for reference, is not affected.

[0092] Therefore, in the multipoint vibration measurement unit 170, the measurement light L irradiating the measurement surface via the interference optical system 120 S an optical coupler OC of the coupling optical system 135; C11 ,OC C21 ,OC C31 ,···,OC C1 ,···,OC Cmn This eliminates measurement errors caused by unwanted reflection components from various optical elements such as those mentioned above being mixed into the interference light required for multi-point vibration measurement, thereby enabling highly accurate multi-point vibration measurement.

[0093] Here, in the interference optical system 120 in the multipoint vibration measuring unit 170, the reference light L R is the time required for measurement light L from the light source 1 to be input to the optical coupler OCC. S is output and then the measurement light L S ' is the optical coupler OC of the interference optical system 120. C The delay is set to the reference light L R The delay fiber FB is a delay optical system that provides 2B1 ' is the reference light L from the light source 1 above. R is input to the optical coupler OC B and an optical coupler OC that outputs interference light for measurement. C and the optical fiber FB that is internally connected 2B1 It is set up in.

[0094] The above optical fiber FB 2B1 The delay optical system is a delay fiber FB. 2B1 ' is provided, the measurement light L output from the light source 1 S The measurement light L is reflected by the reflecting surface of the measurement object 5. SThe optical coupler OC of the interference optical system 120 is C The measurement light L S , L S The optical path length through which the reference light L ′ passes and the reference light L output from the light source 1 R is the optical coupler OC of the interference optical system 120. C The reference light L R That is, the optical path lengths through which the measurement light L output from the light source 1 passes are made equal. S is the optical coupler OC of the interference optical system 120. C The measurement light L S and the optical path length through which the reference light L output from the light source 1 passes. R is the optical coupler OC of the interference optical system 120. C The reference light L R The optical path lengths through which the light passes are made equal.

[0095] In this way, the measurement light L output from the light source 1 S and reference beam L R However, the above optical fiber FB 23C The measurement light L containing the above frequency components returns via S ' and the above reference light L R and the reference light L are made to interfere with each other in the interference optical system 120 and output as interference light for measurement. R The optical path through which the delay fiber FB passes is a delay optical system. 2B1 ', and a measuring light LS and a measuring light L including each of the frequency components reflected on the measuring surface are provided. S The optical path length of the optical path through which the reference light L R By making the optical path lengths of the optical paths through which the measurement interference light and the reference interference light obtained by the interference optical system 120 pass equal, the reference interference signal S output from the interference light detection unit 6 of the light detection processing unit 160 which detects the measurement interference light and the reference interference light obtained by the interference optical system 120 is R , the measurement interference signal S S Measurement light L S and reference beam L R The difference in the phase fluctuation of the measurement light L S and reference beam L RThis can reduce measurement errors caused by phase fluctuations in the delay fiber FB. 2B1 Instead of the above, a space propagation delay optical system having the required optical path length can be adopted.

[0096] Here, assuming that the first optical comb generator (COMB1) 1A and the second optical comb generator (COMB2) 1B of the light source 1 generate optical combs by electro-optic modulation, the effect of the delay optical system will be explained using mathematical formulas.

[0097] The phase fluctuation of the laser, which is the seed light source of the light source 1, is Φ Laser (t), the phase fluctuations of the oscillators modulating the first optical comb generator (COMB1) 1A and the second optical comb generator (COMB2) 1B are Φ fm1 (t), Φ fm2 (t), and the vibration information component Φ due to the phase fluctuation component and the phase fluctuation caused by the Doppler shift Bn Consider (t).

[0098] The measurement light L output from the first optical comb generator (COMB1) 1A S The phase fluctuation Φ of the optical comb component with index n relative to the carrier of the comb Sn (t) is Φ Sn (t)=Φ Laser (t)+nΦ fm1 (t) Formula (A) The reference light L output from the second optical comb generator (COMB2) 1A is R Phase fluctuation Φ of the optical comb component Rn (t) is Φ Rn (t)=Φ Laser (t)+nΦ fm2 (t) Formula (B) Here, Φ fm1 (t), fm2 Since (t) is a harmonic, it is multiplied by n, where n is the sideband index and the carrier is set to 0.

[0099] Measurement light L returning via the measurement object 5 SPhase fluctuation of the optical comb component Φ Sn '(t) is the delay of the optical system, and Φ is the vibration information component due to the phase fluctuation caused by the Doppler shift due to vibration. Bn When (t) is used, Φ Sn '(t)=Φ Bn (t+τ / 2)+Φ Laser (t+τ)+nΦ fm1 (t+τ) Formula (C) τ is the incremental component of the delay when traveling back and forth to the measurement object 5, and the phase component Φ Bn The delay of (t+τ / 2) is set to +τ / 2 because we only experienced the return time for one way trip.

[0100] The fluctuation due to the phase difference between the frequency components of the index n optical comb 1 and the index n optical comb 2 included in the signal interference light detection unit 6A is expressed as the measurement interference signal S S (t) is obtained by FFT analysis, and this is Ssn (t), then equation (C) - equation (B), i.e., Φ Ssn (t)=Φ Sn '(t)-Φ Rn (t) =Φ Bn (t+τ / 2)+Φ Laser (t+τ)+nΦ fm1 (t+τ) -Φ Laser (t)-nΦ fm2 (t) Equation (1) This becomes:

[0101] On the other hand, the fluctuation due to the phase difference between the frequency components of the index n optical comb 1 and the index n optical comb 2 included in the reference interference light detection unit 6B is expressed as the reference interference signal S R (t) is obtained by FFT analysis, and this is SRn (t), then equation (A) - equation (B), that is, Φ SRn (t)=Φ Sn (t)-Φ Rn (t) =nΦ fm1 (t) -nΦ fm2(t) Equation (2) This becomes:

[0102] The measurement interference signal S shown in equation (1) S Fluctuation of (t) Φ Ssn (t) and the reference interference signal S shown in equation (2) R Fluctuation of (t) Φ SRn When the difference (equation (1)-equation (2)) of (t) is calculated by the signal processing unit 150, Φ Sn '(t)-Φ Sn (t)=Φ Bn (t+τ / 2)+Φ Laser (t+τ) +nΦ fm1 (t+τ)-Φ Laser (t)-nΦ fm1 (t) Equation (3) This becomes:

[0103] where Φ Sn '(t)-Φ Sn Since (t) is not simultaneous, the fluctuation component does not become 0.

[0104] However, it cannot be applied to a rangefinder that requires a large dynamic range, but it can be used in cases where the distance to the target object is almost fixed, such as a vibrometer, by using the reference light L. R The delay fiber FB gives a delay equivalent to +τ in the optical path through which 2B1 ' above the reference light L R The optical fiber FB through which 2B1 By inserting into, the above equation (1) becomes Φ Ssn_Delay (t)=Φ Sn '(t)-Φ Rn (t+τ) =Φ Bn (t+τ / 2)+nΦ fm1 (t+τ)-nΦ fm2 (t+τ) Equation (4) The phase fluctuations of the lasers disappear. Since both optical combs 1 and 2 are made from the same laser, the phase fluctuations of the lasers are in phase, and the in-phase fluctuations are eliminated.

[0105] The difference between the above formula (4) and formula (2) (formula (4) - formula (2)) is calculated by the signal processing unit 150, Φ Ssn_Delay (t)-Φ SRn (t)=Φ Bn (t+τ / 2)+nΦ fm1 (t+τ) -nΦ fm2 (t+τ)-nΦ fm1 (t)+nΦ fm2 (t) Equation (5) In this equation (5), the phase fluctuation of the laser is canceled, but the phase fluctuation of the oscillator cannot be completely removed because it is uncorrelated.

[0106] Therefore, the time to compare the phases is determined by the reference interference signal S R and the measurement interference signal S S For example, the reference interference signal S R cable or optical fiber FB 26B1 and FBFB 26B2 , or FB 2A2 and FB 2B2 The length of the reference interference signal S R If the delay is increased, the above equation (2) is delayed by the time τ Φ SRn_Delay (t)=Φ SRn (t+τ) =nΦ fm1 (t+τ)-nΦ fm2 (t+τ) Equation (6) The phase difference between the above equations (4) and (6) (equation (4) - equation (6)) is Φ Ssn_Delay (t)-Φ SRn_Delay (t)=Φ Bn (t+τ / 2) Equation (7) Thus, the phase fluctuation of the oscillator is cancelled out, and what remains is the phase change component due to the vibration.

[0107] Here, the reference interference signal S R cable or optical fiber FB 26B1 and FBFB 26B2 , or FB 2A2 and FB 2B2Although τ was adjusted by the length of the reference interference signal S R and the measurement interference signal S S is digitized by the signal processor 150, it can be adjusted digitally by adding a time delay by shifting the calculation start point. By matching the delay to the component with the largest delay and keeping all other delays the same, noise can be minimized.

[0108] In a multipoint vibration measurement test bench 100 in which a plurality of multipoint measurement heads 150 of the multipoint vibration measurement unit 170 configured as described above are arranged in a three-dimensional space in which the measurement object 5 is located, and vibration information of the measurement object 5 is measured at a plurality of points simultaneously, an integrated processing unit 190 connected to a measurement unit 180 consisting of a plurality of multipoint vibration measurement units 170A, 170B, ... monitors the operating states of two optical comb generators (COMB1, COMB2) constituting the light source 1 using an installed personal computer (PC) 190C, and calculates the measurement light L output from the light source 1. S and reference beam L R a distribution operation by the optical distributor 110 that distributes the measurement light L S and reference beam L R The measurement unit 180 performs control to synchronize the measurement processing operation to acquire vibration information at a plurality of measurement points on the measurement surface of the measurement object 5 using the above-mentioned. Also, the surface plate 200 on which the measurement object 5 is placed, i.e., the three-dimensional space on which the test bench is installed, is set as the origin O. global global coordinates (X global ,Y global ,Z global ) and the origin o set on the test bench or the measurement object 5 installed on the test bench is defined as Aglobal ,o Bgloball , the global coordinate (x Aglobal ,y Aglobal ,z Aglobal ) ,(x Bglobal , Y Bglobal ,z Bglobal) ··· give the mounting position and orientation of each of the plurality of multi-point measurement heads 150A, 150B, ···, and the local coordinates and ray vectors of each irradiation point at which the plurality of multi-point measurement heads 150A, 150B, ··· irradiate a plurality of measurement points distributed two-dimensionally on the measurement surface of the measurement object 5 with measurement light are respectively expressed as global coordinates (x Aglobal ,y Aglobal ,z Aglobal ) ,(x Bglobal ,y Bglobal ,z Bglobal ) and the installation angle, the measurement light emission angle, etc., are used to define the global coordinates (X global ,Y global ,Z global ), and the local coordinates (x Alocal ,y Alocal ,z Alocal ) ,(x Blocal ,y Blocal ,z Blocal The vibration information of the global coordinates (X global ,Y global ,Z global ) into three-dimensional vibration information, and the vibration information acquired by serial communication from the plurality of light detection processing units 160A, 160B, ... of the measurement unit 180 via the communication board 190A is output to a monitor screen or the like as a multi-point vibration measurement result.

[0109] That is, in this multi-point vibration measurement test bench 100, as shown in, for example, FIGS. 5, 6, and 7, a plurality of multi-point measurement heads 150 (150A, 150B, . . . ) are arranged in a three-dimensional space where the measurement object 5 is located, and vibration information is acquired at a plurality of measurement points distributed two-dimensionally on a plurality of measurement surfaces of the measurement object 5. The vibration information acquired by each multi-point measurement head 150 (150A, 150B, . . . ) is expressed as the local coordinates (x Alocal ,y Alocal ,z Alocal ) ,(xBlocal ,y Blocal ,z Blocal )···, so In the integrated processing unit 190, the personal computer (PC) 190C defines a three-dimensional space in which the measurement object 5 placed on the test bench is located as an origin O global global coordinates (X global ,Y global ,Z global ), and the internal origin o of each of the plurality of multi-point measurement heads 150 (150A, 150B, . . . ) is defined as Aglobal ,o Bglobal ,..., and each origin o defined based on Alocal o Blocal , the local coordinates (x Alocal ,y Alocal ,z Alocal ) ,(x Blocal ,y Blocal ,z Blocal ) ··· and each origin o based on the origin set on the test bench or the origin set on the measurement object 5 installed on the test bench Aglobal o Bglobal , the global coordinates (x Aglobal ,y Aglobal ,z Aglobal ) ,(x Bglobal ,y Bglobal ,z Bglobal ) are assigned to the plurality of multipoint vibration measuring units 170A, 170B, and the plurality of multipoint vibration measuring units 170A, 170B, irradiate a plurality of measurement points distributed two-dimensionally on the measurement surface of the measurement object 5 with measurement light, and the local coordinates and ray vectors of each irradiation point are converted into global coordinates (x Aglobal ,y Aglobal ,z Aglobal ) ,(x Bglobal ,y Bglobal ,z Bglobal ) ···, and the origin O that defines the above three-dimensional space based on information such as the installation angle and the measurement light emission angle. global global coordinates (X global ,Y global ,Z global), and each vibration information acquired synchronously by the plurality of multipoint vibration measurement units 170A, 170B, . . . is converted into a global coordinate (X global ,Y global ,Z global ) and integrate it into three-dimensional vibration information.

[0110] FIG. 5 is a perspective view of an engine test bench, schematically showing the state in which three multipoint measurement heads 150A, 150B, and 150C are arranged in the three-dimensional space in which the measurement object 5 placed on the base plate 200 is located in the multipoint vibration measurement test bench 100.

[0111] Figure 6 is a perspective view of a test bench for an electric motor, showing a state in which a total of four multi-point measurement heads 150A, 150B, 150C, and 150D are arranged in the three-dimensional space in which the measurement object 5 is located in the multi-point vibration measurement test bench 100, with three on the outer periphery of the measurement object 5 and one in the direction of the rotation axis of the measurement object 5.

[0112] 7A and 7B are schematic diagrams showing a test bench for an electric motor in the multi-point vibration measurement test bench 100, which is provided with a test tunnel 250 in which five multi-point measurement heads 150A, 150B, 150C, 150D, and 150E are arranged on the outer periphery of the measurement object 5 in a three-dimensional space where the measurement object 5 is placed on a base plate 200, where (A) is a front view of the test bench for an electric motor and (B) is a side view of the test bench for an electric motor.

[0113] In this test bench for electric motors, the object to be measured 5 is an electric motor 53 connected to a load 51 via a transaxle (reduction gear) 52, and the test bench is a tunnel-type measuring instrument equipped with a test tunnel 250 which is one size larger than the object to be measured 5 and on which the five multi-point measurement heads 150A, 150B, 150C, 150D, and 150E are installed.By transporting and installing the test tunnel 250 to the test site where the electric motor 53 is installed, the electric motor 53 can be driven with a mechanical load 51 applied to the electric motor 53 via the transaxle (reduction gear) 52, and a vibration test can be performed within a specified range of rotation speeds to check for abnormalities in frequency, amplitude, mode, detection location, etc.

[0114] FIG. 8 is a schematic diagram showing another example of the configuration of the multi-point measurement head 150 provided in the multi-point vibration measurement test bench 100. In FIG.

[0115] The multi-point measurement head 1500 shown in Figure 8 is a head in which the coupling optical system 135 and projection optical system 4 in the multi-point measurement head 150 are replaced with a projection optical system 140 incorporating a coupling optical element that has the functions of the coupling optical system 135.In this multi-point measurement head 1500, the same components as those in the multi-point measurement head 150 are given the same symbols in the figure, and detailed explanations of them will be omitted.

[0116] This multipoint measurement head 1500 has a light demultiplexing element 131A of the light demultiplexing / multiplexing optical system 130 and a plurality of optical fibers FB 3411 ,FB 3421 ,FB 3431 ,···,FB 34m1 ,···,FB 34mn and multiple optical fiber FB 4311 ,FB 4321 ,FB 4331 ,···,FB 43m1 ,···,FB 43mn a plurality of projection optical elements 44 connected to the optical demultiplexing element 130A of the optical demultiplexing / multiplexing optical system 130 via A11 ,44 A21 ,44 A31 ,···,44 Am1 ,···,44 AmnThe projection optical system 140 includes a coupling optical element.

[0117] The plurality of projection optical elements 44 A11 ,44 A21 ,44 A31 ,···,44 Am1 ,···,44 Amn For example, a projection optical element 44A having a configuration as shown in FIGS. 9(A) and 9(B) is used for each of the projection optical elements 44A.

[0118] 9A and 9B are diagrams showing an example of the configuration of the projection optical element 44A used in the projection optical system 140A with a built-in coupling optical element, where (A) is a schematic diagram showing the configuration of the projection optical element 44A, and (B) is a front view of the two-core capillary 4C1 provided in the projection optical element 44A.

[0119] This projection optical element 44A is provided with a coupling optical section 4CA consisting of a two-core capillary 4C1 and a coupling optical element 4C2 having optical properties for matching the axes of light beams whose polarization directions are orthogonal to each other and output from the tips of the two optical fibers inserted into this two-core capillary 4C1, and a coupling optical element 4C2 is provided with an optical fiber FB 34 and the output optical fiber FB 43 is externally derived.

[0120] The stress-applying direction of the polarization-maintaining (PM) fiber inserted into the two-core capillary 4C1 provided in the coupling optical unit 4CA is arranged orthogonal to the direction of the stress-applying part, as shown in Figure 9 (B), and the optical module elements connected to all optical fibers are made to a unified standard so that the stress-applying direction becomes the polarization plane.

[0121] The input optical fiber FB led out from the two-core capillary 4C1 to the outside 34 is connected to the optical demultiplexing element 130A of the optical demultiplexing / multiplexing optical system 130, and is connected to the output side optical fiber FB led out from the two-core capillary 4C1 to the outside. 43 is connected to the optical multiplexing element 130B of the optical multiplexing / demultiplexing optical system 130.

[0122] In the projection optical element 44A, the optical fiber FB 34 The measurement light L is input through S The frequency component of L S is input to the condenser lens 4A via the coupling optical element 4C2. The frequency component l S is irradiated onto the measurement surface of the measurement object 5 via the quarter-wave plate 4B. The light reflected by the measurement surface is converted into the frequency component l via the quarter-wave plate 4B. S is the frequency component l of the polarization plane that is perpendicular to the polarization direction. S The quarter-wave plate 4B can be replaced with a Faraday rotator.

[0123] The above frequency component l S is the frequency component l of the polarization plane that is perpendicular to the polarization direction. S ' is condensed by the condenser lens 4A and passes through the coupling optical element 4C2 of the coupling optical unit 4CA to the output side optical fiber FB 43 and the output side of this optical fiber FB 43 The light is input to the optical multiplexing element 130B of the optical multiplexing and demultiplexing optical system 130 via the optical multiplexing element 130B.

[0124] The coupling optical element 4C2 may be made of a birefringent crystal for splitting light beams by utilizing walk-off, for example.

[0125] Furthermore, in the projection optical system 140A with a built-in coupling optical element, instead of the irradiation coupling optical element 4C2 using the birefringent crystal, a projection optical element 44B using a coupling optical element 4C2' configured with a Wollaston prism 4Cb or the like as shown in Figures 10(A) and 10(B) can also be used.

[0126] Figures 10(A) and (B) show an example of the configuration of the projection optical element 44B used in the projection optical system 140A with a built-in coupling optical element, where (A) is a schematic diagram showing the configuration of the projection optical element 44B, and (B) is a front view of the two-core capillary 4C1 provided in the projection optical element 44B.

[0127] The projection optical element 44B includes a double-core capillary 4C1 and a coupling optical unit 4CB including a coupling optical element 4C2' having optical properties for matching the axes of light beams whose polarization directions are orthogonal to each other and output from the tips of the two optical fibers inserted into the double-core capillary 4C1. 34 and the output optical fiber FB 43 is externally derived.

[0128] The directions of the stress applying portions of the polarization maintaining (PM) fibers inserted into the two-core capillary 4C1 provided in the coupling optical unit 4CB are arranged to be orthogonal to each other, as shown in FIG. 10(B).

[0129] The coupling optical element 4C2' is configured by disposing a Wollaston prism 4Cb between two collimator lenses 4Ca and 4Cc.

[0130] In this projection optical element 44B, too, the optical fiber FB 34 The measurement light L is input through S The frequency component of l S is input to the condenser lens 4A via the coupling optical element 4C2′, and the frequency component l S is irradiated onto the measurement surface of the measurement object 5 via the quarter-wave plate 4B. The light reflected by the measurement surface is converted into the frequency component l via the quarter-wave plate 4B. S is the frequency component l of the polarization plane that is perpendicular to the polarization direction. S The quarter-wave plate 4B may be replaced with a Faraday rotator.

[0131] The above frequency component lS is the frequency component l of the polarization plane that is perpendicular to the polarization direction. S The light is collected by the collecting lens 4A and is output to the output side optical fiber FB via the coupling optical element 4C2'. 43 and the output side of this optical fiber FB 43 The light is input to the optical multiplexing element 130B of the optical multiplexing and demultiplexing optical system 130 via the optical multiplexing element 130B.

[0132] In the projection optical elements 44A and 44B, as shown in Figures 9B and 10B, the optical input whose polarization plane is in the direction of the stress applying portion, which is input from fiber end faces Port1 and Port2 of the two-core capillary 4C1, in which the stress applying portions of the inserted polarization maintaining (PM) fibers are arranged so as to be perpendicular to each other, to the coupling optical elements 4C2 and 4C2', becomes coaxial by passing through the coupling optical elements 4C2 and 4C2', and is output in the same direction. S The frequency component of l S The polarization plane is the same as that of the stress-applying part of Port 1 (the input optical fiber FB 34 ) and the frequency component l reflected by the measurement surface S The polarization plane is the same as that of the stress-applying part of Port 2, and Port 2 (output optical fiber FB 43 ) can receive light.

[0133] Here, in the optical multiplexing / demultiplexing head 130 in the multipoint vibration measurement test bench 100 described above, the optical multiplexing / demultiplexing optical system 130 is configured to be connected to the projection optical system 4 via the coupling optical system 135. However, in the multipoint vibration measurement test bench 100A, the coupling optical system 135 and the projection optical system 4 in the multipoint vibration measurement test bench 100 are replaced with a coupling optical element-integrated projection optical system 140A that has the function of the coupling optical system 135. As a result, the fiber FB connecting the coupling optical system 135 and the projection optical system 140 is 4311 ,FB 4321 ,FB 4331 ,···,FB 43m1 ,···,FB 43mnTherefore, the optical multiplexing / demultiplexing head 130A can be configured with two optical systems, the optical multiplexing / demultiplexing optical system 130 and the projection optical system 140A with a built-in coupling optical element. This not only simplifies the configuration but also reduces the need for the above-mentioned fiber FB 4311 ,FB 4321 ,FB 4331 ,···,FB 43m1 ,···,FB 43mn There is no generation of unnecessary reflected light from the end faces.

[0134] That is, using an element such as a coupling optical element as the coupling optical system 135, as in the optical multiplexer / demultiplexer head 130 in the multipoint vibration measurement test bench 100, complicates the optical system and causes problems such as reflections inside the coupling optical element and the extinction ratio of the PM fiber. Furthermore, using a coupling optical element module or the like increases the number of components. Reflections from the multiple lenses and fiber end faces inside the coupling optical element module can also be problematic. However, in the multipoint vibration measurement test bench 100A, by providing the optical multiplexer / demultiplexer head 130A with a projection optical system 140A incorporating a coupling optical element, it is not necessary to use a separate coupling optical element module or the like. This allows for a configuration with a larger directional coupling loss from Port 1 to Port 2, thereby resolving these problems.

[0135] In the projection optical system 140A with a built-in Wollaston prism type coupling optical element provided in the optical multiplexing / demultiplexing head 130A, a directional coupling loss from Port 1 to Port 2 of 80 dB to 90 dB was actually measured.

[0136] Then, in the optical multiplexing element 130B of the optical multiplexing / demultiplexing optical system 130, the measurement light L reflected at a plurality of measurement points on the measurement surface of the measurement object 5 and returning via the projection optical system 140A with built-in coupling optical element is S The frequency components of the above are combined, and the measurement light L is composed of the reflected light of each frequency component reflected at a plurality of measurement points on the measurement surface. S ' is the optical fiber FB 23C Through interference optical system 120 optical coupler OC C is entered into

[0137] The optical coupler OC of the interference optical system 120 C is the measurement light L consisting of reflected light of each frequency component reflected at a plurality of measurement points on the measurement surface. S ' is the above optical fiber FB 23C and the second optical comb generator (COMB2) 1B of the light source 1 is inputted via the optical fiber FB 12B via optical coupler OC B Reference light L input to R Optical fiber FB 2B1 The measurement light L is input through S ' and the reference beam L R The optical coupler OC of the interference optical system 120 outputs the interference light with the optical coupler OC as interference light for measurement. D is a signal from the first optical comb generator (COMB1) 1A of the light source 1 to the optical fiber FB 12A via optical coupler OC A Measurement light L input to S Optical fiber FB 2A2 and the second optical comb generator (COMB2) 1B of the light source 1 is inputted via the optical fiber FB 12B via optical coupler OC B Reference light L input to R Optical fiber FB 2B2 The measurement light L is input through S and reference beam L R The interference light with the reference light is output as reference interference light.

[0138] In the interference light detector 6 of the light detection processing unit 160 to which the measurement interference light and the reference interference light obtained by the interference optical system 120 are input, the optical coupler OC C Two optical fiber FBs externally connected to 26A1 ,FB 26A2 The measurement interference light is detected by a measurement photodetector 6A that receives the measurement interference light via the S and the optical coupler OC D Two optical fiber FBs externally connected to 26B1 ,FB 26B2The reference interference light is detected by an interference light detector 6B that receives the reference interference light via the R Output.

[0139] Then, in the signal processing unit 7 of the detection processing unit 160, the measurement interference signal S obtained in the interference light detection unit 6 is S and the reference interference signal S R The phase of each frequency component is calculated by DFT analysis, and the phase difference for each frequency component caused by the Doppler shift due to vibration at multiple measurement points on the measurement surface is obtained, thereby analyzing vibration information at multiple measurement points on the measurement surface of the object 5 to be measured, and measuring the distribution of vibration on the measurement surface.

[0140] In this multi-point vibration measurement test bench 100A, the measurement light L S The measurement light L output from the interference optical system 120 provided with the optical demultiplexing element 130A that demultiplexes a plurality of frequency components included in S and the measurement light L passing through the optical multiplexing element 130B, which multiplexes the reflected light of each frequency component reflected at a plurality of measurement points on the measurement surface of the measurement object 5. S Since the optical path for inputting the measurement light L ′ to the interference optical system 120 is split, the measurement light L ′ irradiated to the measurement surface of the measurement object 5 via the interference optical system 120 S This eliminates measurement errors caused by unwanted reflection components from the optical demultiplexer 130A provided in the optical path through which the light passes, which are mixed into the interference light required for multi-point vibration measurement, thereby enabling highly accurate multi-point vibration measurement.

[0141] Then, the signal processing unit 7 of the detection processing unit 160 converts the measurement interference signal S obtained in the interference light detection unit 6 into S and the reference interference signal S R The phase of each frequency component is calculated using DFT analysis, and the above measurement interference signal S S and the reference interference signal S RBy calculating the phase difference for each frequency component resulting from the Doppler shift caused by vibration at multiple measurement points on the measurement surface between the two or more measurement points, vibration information at the multiple measurement points on the measurement surface, such as vibration velocity, movement distance, acceleration, etc., is analyzed to measure the vibration distribution on the measurement surface.

[0142] Here, in the multipoint vibration measurement test bench 100, the multipoint vibration measurement units 170A, 170A, ... can be replaced with a multipoint vibration measurement unit 1701 having a configuration as shown in Figure 11.

[0143] FIG. 11 shows (m×n) coupling optical elements 144 A11 ,144 A21 ,144 A31 ,···,144 Am1 ,···,144 Amn This is a schematic diagram showing the configuration of a multi-point vibration measurement unit 1701 equipped with a projection optical system 1400 incorporating a coupling optical element using a two-dimensionally arranged coupling optical element array 144 as shown in Figures 12(A) and (B) in a multi-point measurement head 1501.

[0144] This multipoint vibration measurement unit 1701 is a unit for measuring the vibration of the projection optical element 44 of the projection optical system 140 incorporating a coupling optical element in the multipoint measurement head 1500. A11 ,44 A21 ,44 A31 ,···,44 Am1 ,···,44 Amn (m×n) coupling optical elements 144 A11 ,144 A21 ,144 A31 ,···,144 Am1 ,···,144 Amn a coupling optical element array 144 in which the above-mentioned coupling optical element is integrated, and a condenser lens 4 of the projection optical system 140 A11 ,4 A21 ,4 A31 ,···,4 Am1 ,···,4 Amn That is, a set of optical systems 4Aab consisting of condensing optical elements 4Aa and 4Ab functioning as projection optical elements, and a quarter wavelength plate 4B11 ,4 B21 ,4 B31 ,···,4 Bm1 ,···,4 Bmn The optical system 4Aab shown in the figure is a bilateral telecentric optical system, which is simply represented as a bilateral telecentric optical system. In reality, the bilateral telecentric optical system is composed of a number of lenses. The bilateral telecentric optical system is configured by a combination of a coupling optical element array 144 and a measuring light beam L 1 , which is output perpendicularly from the coupling optical element array 144. S can be projected and focused vertically onto a horizontal measurement object 5. This is the most sensitive projection optical system. For large measurement objects 5, a telecentric optical system can be used on only one side and an fθ optical system on the other side. It is also possible to select an optical system that suits the size and shape of the measurement object 5 without using a telecentric optical system.

[0145] In this multipoint vibration measurement section 1701, the same components as those in the multipoint vibration measurement section 170 of the multipoint vibration measurement test bench 100 are given the same reference numerals in the drawing, and detailed description thereof will be omitted.

[0146] 12A and 12B are diagrams showing an example of the configuration of the coupling optical element array 144, where (A) is a vertical cross-sectional side view of the coupling optical element array 144 and (B) is a vertical cross-sectional front view of the coupling optical element array 144.

[0147] The projection optical system 1400 with built-in coupling optical elements includes a plurality of (m×n) coupling optical elements 144 as shown in FIGS. 12A and 12B. A11 ,144 A21 ,144 A31 ,···,144 Am1 ,···,144 Amn The optical coupling element array 144 is a modular combination of two-dimensionally arranged optical elements.

[0148] The plurality of (m×n) coupling optical elements 144 in the coupling optical element array 144 A11 ,144 A21 ,144 A31 ,···,144 Am1,···,144 Amn In order to use the walk-off to demultiplex the light beam, a coupling optical element 4C2 using a birefringent crystal and a coupling optical element 4C2' consisting of a Wollaston prism or the like are used, and the input optical fiber and the output optical fiber are led out from each of the two-core capillaries.

[0149] In this coupling optical element array 144, the input optical fiber FB 3411 ,FB 3421 ,FB 3431 ,···,FB 34m1 ,···,FB 34mn and the output optical fiber FB 4311 ,FB 4321 ,FB 4331 ,···,FB 43m1 ,···,FB 43mn Although it has been assumed that each of the optical fibers is led out to the outside through a two-core capillary, it is also possible to adopt a structure in which the direction of the PMF can be controlled by precisely positioning multiple optical fibers, such as a structure in which multiple optical fibers are led out to the outside through multiple insertion holes provided in a substrate, without using a two-core capillary.

[0150] In addition, in the projection optical system 1400 with the built-in coupling optical element, the measurement light L S A plurality of (m×n) coupling optical elements 144 are used to irradiate each of the frequency components onto m×n measurement points arranged two-dimensionally in a matrix. A11 ,144 A21 ,144 A31 ,···,144 Am1 ,···,144 Amn However, depending on the measurement object 5, a plurality of coupling optical elements 144 may be used. A11 ,144 A21 ,144 A31 ,···,144 Am1 ,···,144 Amn Alternatively, a modularized coupling optical element array may be employed in which the optical elements are arranged two-dimensionally in a fine lattice pattern (for example, a hexagonal fine lattice pattern).

[0151] The modularized multiple coupling optical elements 144 A11 ,144 A21 ,144 A31 ,···,144 Am1 ,···,144 Amn are the multiple FBs on the input side 3411 ,FB 3421 ,FB 3431 ,···,FB 34m1 ,···,FB 34mn and a plurality of (m×n) optical fibers FB 4311 ,FB 4321 ,FB 4331 ,···,FB 43m1 ,···,FB 43mn 1. The optical multiplexing element 130B of the optical multiplexing / demultiplexing optical system 130 is connected to the optical multiplexing element 130B via the optical multiplexing / demultiplexing element 130B.

[0152] This projection optical system 1400 with built-in coupling optical element employs a modularized coupling optical element array 144, and thereby transmits light from the optical demultiplexing element 130A of the optical demultiplexing / multiplexing optical system 130 to a plurality of optical fibers FB 3411 ,FB 3421 ,FB 3431 ,···,FB 34m1 ,···,FB 34mn The measurement light L is input through S The multiple frequency components can be focused by a set of optical systems 4Aab consisting of the focusing optical elements 4Aa and 4Ab, and irradiated onto multiple measurement points on the measurement surface of the object to be measured 5 via a single quarter-wave plate 4B.

[0153] The reflected light reflected at a plurality of measurement points on the measurement surface of the measurement object 5 is collected by the set of optical systems 4Aab as frequency components with a polarization plane perpendicular to the polarization direction of the irradiated frequency components via the quarter-wave plate 4B, and is output from the coupling optical element array 144 to a plurality of optical fibers FB 4311 ,FB 4321 ,FB 4331 ,···,FB 43m1 ,···,FB 43mnThe light is input to the optical multiplexing element 130B of the optical multiplexing and demultiplexing optical system 130 via the optical multiplexing element 130B.

[0154] The optical multiplexing element 130B of the optical multiplexing / demultiplexing optical system 130 receives the measurement light L reflected at a plurality of measurement points on the measurement surface of the measurement object 5 and returns via the projection optical system 140B. S The frequency components of the above are multiplexed, and the measurement light L is composed of reflected light of each frequency component reflected at a plurality of measurement points on the measurement surface of the measurement object 5. S ' is the optical fiber FB 23C via the optical coupler OC of the interference optical system 120. C is entered into

[0155] In the interference optical system 120, measurement light L consisting of reflected light of each frequency component reflected at a plurality of measurement points on the measurement surface is S ' and the second optical comb generator (COMB2) 1B of the light source 1 is connected to the optical fiber FB 12B via optical coupler OC B Reference light L input to R The interference light from this was used as the measurement interference light by the optical coupler OC C and the first optical comb generator (COMB1) 1A of the light source 1 is outputted from the optical fiber FB 12A via optical coupler OC A Measurement light L input to S and the above optical coupler OC B The reference light L R The interference light from the optical coupler OC D Output from

[0156] The interference light detector 6 of the measurement detection processor 160 receives the interference light for measurement and the interference light for reference obtained by the interference optical system 120. The interference light detector 6 detects the interference light by the optical coupler OC of the interference optical system 120. C Two optical fiber FBs externally connected to 26A1 ,FB 26A2 The measurement interference light is detected by a measurement photodetector 6A that receives the measurement interference light via the S and the optical coupler OCD Two optical fiber FBs externally connected to 26B1 ,FB 26B2 The reference interference light is detected by an interference light detector 6B that receives the reference interference light via the R Output.

[0157] Then, in the signal processing unit 7 of the detection processing unit 160, the measurement interference signal S obtained in the interference light detection unit 6 is S and the reference interference signal S R The phase of each frequency component is calculated by DFT analysis for each frequency component, and the phase difference for each frequency component resulting from the Doppler shift due to vibration at the plurality of measurement points on the measurement surface is obtained, thereby analyzing vibration information at the plurality of measurement points on the measurement surface and measuring the distribution of vibration on the measurement surface.

[0158] Also, in the multipoint vibration measurement unit 1702 shown in FIG. S The measurement light L output from the interference optical system 120 provided with the optical demultiplexing element 130A that demultiplexes a plurality of frequency components included in S and the measurement light L passing through the optical multiplexing element 130B, which multiplexes the reflected light of each frequency component reflected at a plurality of measurement points on the measurement surface of the measurement object 5. S Since the optical path for inputting the measurement light L ′ to the interference optical system 120 is split, the measurement light L ′ irradiated to the measurement surface of the measurement object 5 via the interference optical system 120 S This eliminates measurement errors caused by unwanted reflection components from the optical demultiplexer 130A provided in the optical path through which the light passes, which are mixed into the interference light required for multi-point vibration measurement, thereby enabling highly accurate multi-point vibration measurement.

[0159] This multipoint vibration measurement section 1702 can also be employed in the multipoint vibration measurement sections 170A, 170B, etc. in the multipoint vibration measurement test bench 100A.

[0160] Here, in the interference optical system 120 in the multipoint vibration measurement test bench 100, 100A, the measurement light L output from the light source 1 Sand reference beam L R The interference light of the light source 1 is output as a reference interference light, and the measurement light L S is irradiated onto the measurement surface of the measurement object 5 from the interference optical system 120 via the multipoint measurement heads 150, 150A, and 150B, and is reflected by the measurement surface and returned via the multipoint measurement heads 150, 150A, and 150B. S ' and the above reference light L R The interference light detecting unit 6 includes a measurement light detector 6A that receives the interference light for measurement output from the interference optical system 120, and an interference light detector 6B that receives the interference light for reference output from the interference optical system 120. The measurement interference light is detected by the measurement light detector 6A and converted into an electrical signal to generate a measurement interference signal S S and a reference interference signal S obtained by detecting the reference interference light by the interference light detector 6B and converting it into an electric signal. R I try to get it.

[0161] In the multipoint vibration measurement test benches 100 and 100A, the signal processing unit 7 of the detection processing unit 160 converts the measurement interference signal S obtained by the interference light detection unit 6 into S and the reference interference signal S R The phase of each frequency component is calculated by DFT analysis for the above, and the phase difference for each frequency component caused by the Doppler shift due to vibration at the plurality of measurement points on the measurement surface is obtained, thereby analyzing vibration information at the plurality of measurement points on the measurement surface. S is the measurement light L reflected by the measurement surface and returned. S ' and the reference beam L R Since the interference signal is obtained by detecting the interference light for measurement, which is the interference light of S By calculating the phase for each frequency component using DFT analysis only, it is possible to obtain the phase difference for each frequency component caused by the Doppler shift due to vibration at multiple measurement points on the measurement surface.

[0162] That is, the multipoint vibration measurement units 170A, 170B, etc. in the above-mentioned multipoint vibration measurement test benches 100, 100A can be configured to include an interference optical system 1200 that outputs only interference light for measurement, and a detection processing unit 1600 that detects only interference light for measurement output from this interference optical system 1200, such as the multipoint vibration measurement unit 1702 shown in FIG. 13, the multipoint vibration measurement unit 1703 shown in FIG. 14, and the multipoint vibration measurement unit 1704 shown in FIG. 15.

[0163] The detection processing unit 1600 detects the measurement interference signal S obtained by the interference light detection unit 6′ that receives only the measurement interference light output from the interference optical system 1200. S The signal processing unit 7' calculates the phase for each frequency component by DFT analysis, and determines the phase difference for each frequency component caused by the Doppler shift due to vibration at multiple measurement points on the measurement surface of the object 5 to be measured.

[0164] In the multipoint vibration measurement units 1702, 1703, and 1704, the same components as those in the multipoint vibration measurement unit 170 of the multipoint vibration measurement test bench 100 are given the same reference numerals in the drawings, and detailed description thereof will be omitted.

[0165] Here, Fig. 16 is a schematic diagram showing the software hierarchy of the integration process executed by the integration processing unit 190. Fig. 16 shows the software hierarchy of the integration process that integrates the vibration information synchronously acquired by the plurality of multipoint vibration measuring units 170A, 170B, ... into three-dimensional vibration information.

[0166] That is, in the integrated processing unit 190, each piece of vibration information synchronously acquired by the plurality of multipoint vibration measuring units 170A, 170B, . . . is converted into local coordinates (x Alocal ,y Alocal ,z Alocal ) ,(x Blocal ,y Blocal ,z Blocal),... are added to the vibration information, and are integrated into local coordinates for each local coordinate. Each piece of vibration information integrated into local coordinates is calculated based on the mounting orientation of each head, the origin set on the test bench, or the origin set on the measurement object 5 installed on the test bench. Aglobal o Bglobal , the global coordinates (x Aglobal ,y Aglobal ,z Aglobal ) ,(x Bglobal ,y Bglobal ,z Bglobal ) based on the local coordinate (x Alocal ,y Alocal ,z Alocal ) ,(x Blocal ,y Blocal ,z Blocal ),... are all converted into global coordinates at once, and are assigned to the three-dimensional space in which the test bench is installed. global ,Y global ,Z global ) vibration information. Then, each vibration information that has been converted into global coordinates is converted into global coordinates (X global ,Y global ,Z global ) three-dimensional vibration information is collected and integrated as an integrated global coordinate (X global ,Y global ,Z global ) three-dimensional vibration information is subjected to FFT analysis to identify the epicenter location and display an image of the vibration distribution.

[0167] FIG. 17 is a schematic diagram showing another example of the configuration of a multi-point vibration measurement test bench to which the present invention is applied.

[0168] The multi-point vibration measurement test bench 100A shown in Figure 17 is configured by adding a single-point measurement unit 280 equipped with multiple (here, two) single-point vibration measurement units 270A, 270B to the multi-point vibration measurement test bench 100, and components that are the same as those of the multi-point vibration measurement test bench 100 are given the same symbols in the figure and detailed explanations thereof will be omitted.

[0169] That is, the multi-point vibration measurement test bench 100 is arranged in a three-dimensional space where the measurement object 5 is located, like a multi-point vibration measurement test bench 100A shown in FIG. 17, and the measurement light L S and reference beam L R By providing at least one single-point vibration measuring unit 270 (270A, 270B) that synchronously acquires vibration information of one measurement point on the measurement surface of the measurement object 5 using the above, vibration measurements are synchronously performed at a plurality of measurement points on the measurement surface 5A, 5B, ... of the measurement object 5 by the plurality of multipoint vibration measuring units 170A, 170B, ..., as well as vibration measurements at one measurement point on each of the measurement surfaces 5A1, 5A2, ..., 5B1, 5B2, ... of the measurement object 5 by the at least one single-point vibration measuring unit 270 (270A, 270B), and the acquired vibration information is integrated into three-dimensional vibration information by an integration processing unit 190, and the integrated global coordinates (X global ,Y global ,Z global ) three-dimensional vibration information can be subjected to FFT analysis to identify the epicenter location and display an image of the vibration distribution.

[0170] In this multi-point vibration measurement test bench 100A, the single-point vibration measurement units 270A, 270B comprise interference optical systems 210A, 210B connected to the optical distributor 110 via optical fibers each using a pair of PMFs, optical multiplexing and demultiplexing optical systems 220A, 220B connected to the interference optical systems 210A, 210B via optical fibers each using a pair of PMFs, a plurality of single-point measurement heads 250A1, 250A2,..., 250B1, 250B2,... connected to the optical multiplexing and demultiplexing optical systems 220A, 220B via optical fibers each using a pair of PMFs, and single-point measurement optical detection processing units 260A, 260B,... connected to the interference optical systems 210A, 210B via optical fibers each using a four-piece SMF.

[0171] The single-point vibration measuring units 270A and 270B are, like the single-point vibration measuring unit 270 shown in FIG. 18, optical fiber FB using PMF. 22A2 ,FB22B1 ,FB 22B2 Four optical couplers interconnected by OC A ,OOC B ,OC C ,OC D The optical distributor 110 is connected to the optical coupler OC via two optical fibers FB212A and FB212B using PMF. A ,OOC B and an optical fiber FB 2341 , FB2431, the optical multiplexing / demultiplexing optical system 230 is connected to the optical coupler OC A and optical coupler OC C The optical system 220 is externally connected to the optical fiber 210.

[0172] FIG. 18 is a schematic diagram showing an example of the configuration of the single-point vibration measurement units 270A and 270B provided in the multi-point vibration measurement test bench 100A.

[0173] In the interference optical system 220 of this one-point vibration measurement unit 270, the optical coupler OCA has an optical fiber FB 22A2 via optical coupler OC D is internally connected, and the optical coupler OC B There are two optical fiber FB 22B1 ,FB 22B2 Two optical couplers via OC C ,OC D are internally connected.

[0174] The interference optical system 220 then receives the measurement light L distributed to multiple optical paths by the optical distributor 110. S and reference beam L R is transmitted through the optical fibers FB212A and FB212B to the optical coupler OC A ,OC B The input measurement light L S The above optical coupler OC A From optical fiber FB 2341 The light is input to the optical demultiplexing element 231A of the optical demultiplexing / multiplexing optical system 230 via the optical demultiplexing / multiplexing element 231B.

[0175] The optical multiplexing / demultiplexing optical system 230 is connected to the optical coupler OCA Optical fiber FB 2341 and multiple optical fiber FBs 4411 ,FB 4421 ,FB 4431 , . . . , an optical demultiplexing element 231A connected to a plurality of one-point measurement heads 2501, 2502, . . . , and a plurality of optical fibers FB 5311 ,FB 5321 ,FB 5331 , and are connected via an optical fiber FB 2431 The optical coupler OC C 231B connected to the optical multiplexer 231A.

[0176] The optical demultiplexing element 231A demultiplexes the measurement light L input from the optical distributor 110. S Each frequency component included in the 4411 ,FB 4421 ,FB 4431 ,··· to a plurality of single-point measurement heads 2501, 2502,···.

[0177] The one-point measurement heads 2501, 2502, . . . irradiate the measurement light for each of the one frequency components input from the optical demultiplexing element 231A onto one measurement point in each of the plurality of measurement areas of the measurement object 5, and transmit the reflected light of each of the one frequency components that is reflected and returned from each of the one measurement points on the measurement surfaces 5A1, 5A2, . . . , 5B1, 5B2, . . . to the plurality of optical fibers FB 5311 ,FB 5321 ,FB 5331 , . . . and are input to the optical multiplexing element 231B.

[0178] The optical multiplexing element 231B of the optical multiplexing / demultiplexing optical system 230 multiplexes the reflected light of each frequency component for each of the frequency components that is reflected at each measurement point on the measurement surfaces 5A1, 5A2, ..., 5B1, 5B2, ... and returns via the single-point measurement heads 2501, 2502, ...

[0179] The optical multiplexing element 231B multiplexes the reflected light of each frequency component to generate the measurement light L S ' the optical coupler OC of the interference optical system 220 C Output to.

[0180] In the interference optical system 220, the reflected light of each frequency component reflected and returned from each measurement point on the measurement surfaces 5A1, 5A2, . . . , 5B1, 5B2, . . . is combined by the optical combining element 231B of the optical multiplexing / demultiplexing optical system 230 to obtain measurement light L S ' and the optical fiber FB 212B Through the above optical coupler OC B Reference light L input to R The interference light from the optical coupler OC C and the optical distributor 110 outputs the optical signal to the optical fiber FB 212A ,FB 212B Through the above optical coupler OC A ,OC B The measurement light L input to S and reference beam L R The interference light from the optical coupler OC D Output from

[0181] Here, one frequency component reflected at each measurement point on the measurement surface 5A1, 5A2, . . . , 5B1, 5B2, . . . of the measurement object 5 has a phase fluctuation caused by a Doppler shift due to vibration at each measurement point on the measurement surface 5A1, 5A2, . . . , 5B1, 5B2, . . . R The interference light with one frequency component of the above, i.e., the interference light for measurement, is accompanied by a phase fluctuation due to the Doppler shift. Therefore, as will be described later, the interference light detector 6 of the single-point measurement light detection processing unit 260 can obtain a single-point measurement interference signal containing vibration information at each of the measurement points on the measurement surfaces 5A1, 5A2, . . . , 5B1, 5B2, .

[0182] The optical coupler OC of the interference optical system 220 C The measurement interference light output from the optical coupler OOCD The reference interference light output from the optical fiber FB using a set of four SMFs 226A1 ,FB 226A2 ,FB 226B1 ,FB 226B2 The signal is input to the interference light detection unit 6 of the one-point measurement light detection processing unit 260 via the optical fiber 210.

[0183] The single-point measurement light detection processing unit 260 in the single-point vibration measurement unit 270 can employ a configuration similar to that of the light detection processing unit 160 of the multipoint vibration measurement unit 170, and an interference light detection unit 6 of the single-point measurement light detection processing unit 260 to which the measurement interference light and the reference interference light are input from the interference optical system 220 obtains a single-point measurement interference signal and a reference interference signal containing vibration information at each measurement point on the measurement surfaces 5A1, 5A2, . . ., 5B1, 5B2, . . ., and a signal processing unit 7 performs DFT analysis on the single-point measurement interference signal and the reference interference signal for each frequency component. By calculating the phase of the single-point measurement interference signal and the reference interference signal, and determining the phase difference for each frequency component between the single-point measurement interference signal and the reference interference signal due to the Doppler shift caused by vibration at each measurement point on the measurement surface, vibration information at each measurement point on the measurement surfaces 5A1, 5A2, ..., 5B1, 5B2, ..., such as vibration velocity, movement distance, acceleration, etc., can be analyzed to measure the vibration distribution at each measurement point on the measurement surfaces 5A1, 5A2, ..., 5B1, 5B2, ....

[0184] Here, in the multi-point vibration measurement test bench 100A, the two single-point vibration measurement units 270A, 270B use a plurality of single-point measurement heads 250A1, 250A2, ..., 250B1, 250B2, ... to measure the vibration distribution at each measurement point on the measurement surface 5A1, 5A2, ..., 5B1, 5B2, .... However, the test bench 100A may be provided with a single-point measurement unit 280 having at least one single-point measurement head 250, and for example, one single-point measurement head 250A1 provided in the single-point vibration measurement unit 270A may be used to obtain vibration information at one measurement point on the measurement surface 5A1 of the measurement object 5.

[0185] Here, FIG. 19 is a schematic diagram showing another example of the configuration of the single-point vibration measurement unit provided in the multi-point vibration measurement test bench according to the present invention.

[0186] That is, in the multi-point vibration measurement test bench 100A, two single-point vibration measurement units 270A, 270B are provided, each having a single-point vibration measurement unit 270 configured as shown in FIG. 18, and a plurality of single-point measurement heads 250A1, 250A2, ..., 250B1, 250B2, ... are used to measure the vibration distribution at each measurement point on the measurement surfaces 5A1, 5A2, ..., 5B1, 5B2, ...; however, like the single-point vibration measurement unit 270 in the multi-point vibration measurement test bench 1500A shown in FIG. 19, a part of the multi-point optical head 140 shown in FIG. 14 can be separated and used as a single-point measurement head 250.

[0187] 20, a part of the multi-point optical head 1400 shown in FIG. 15 may be separated and used as a single-point measurement head 250. In the case of a single-point vibration measurement unit 270 shown in FIG.

[0188] Figure 21 is a perspective view showing a schematic diagram of the multi-point vibration measurement test bench 100A, in which four multi-point measurement heads 150A, 150B, 150C, and 150D and one single-point measurement head 250 are arranged in the three-dimensional space in which the measurement object 5 is located.

[0189] In this multi-point vibration measurement test bench 100A, a plurality of multi-point measurement heads 150 (150A, 150B,...) are arranged in a three-dimensional space where the measurement object 5 is located, and vibration information is acquired at a plurality of measurement points distributed two-dimensionally on a plurality of measurement surfaces of the measurement object 5, and a plurality of single-point measurement heads 250A1, 250A2,..., 250B1, 250B2,... provided in the two single-point vibration measurement units 270A, 270B acquire vibration information at each measurement point on the measurement surfaces 5A1, 5A2,..., 5B1, 5B2,..., and the integrated processing unit 190 uses a personal computer (PC) 190C to calculate the three-dimensional space where the measurement object 5 placed on the test bench is located from an origin O.global global coordinates (X global ,Y global ,Z global ), and the internal origin o of each of the plurality of multi-point measurement heads 150 (150A, 150B, . . . ) is defined as Aglobal ,o Bglobal ,..., and each origin o defined based on Alocal o Blocal , the local coordinates (x Alocal ,y Alocal ,z Alocal ),(x Blocal ,y Blocal ,z Blocal ), ···, and each origin o based on the origin set on the test bench or the origin set on the measurement object 5 installed on the test bench Aglobal o Bglobal , the global coordinates (x Aglobal ,y Aglobal ,z Aglobal ),(x Bglobal ,y Bglobal ,z Bglobal ), ··· are assigned to the plurality of multipoint vibration measuring units 170A, 170B, ···, and the plurality of multipoint measuring heads 150 (150A, 150B, ···) provided in the plurality of multipoint vibration measuring units 170A, 170B, ··· irradiate a plurality of measurement points distributed two-dimensionally on the measurement surface of the measurement object 5 with measurement light, and the local coordinates and ray vectors of each irradiation point are converted into global coordinates (x Aglobal ,y Aglobal ,z Aglobal ) ,(x Bglobal ,y Bglobal ,z Bglobal ),..., and the origin O that defines the above three-dimensional space based on information such as the installation angle and the measurement light emission angle. global global coordinates (X global ,Y global ,Z global ), and the internal origins o of the plurality of single-point measurement heads 250A1, 250A2, . . . , 250B1, 250B2, . . . provided in the two single-point vibration measurement units 270A, 270B are SA1global ,o SA2global,···,o SB1global ,o SB2global ,..., and each origin o defined based on SA1local ,o SA2local ,···,o SB1local ,o SB2 local , the local coordinates (x A1local ,y A1local ,z A1local ),(x A2local ,y A2local ,z A2local ) ,···,(x B1local ,y B1local ,z B1local ),(x B2local ,y B2loca1 ,z B2local ) ··· and each origin o based on the origin set on the test bench or the origin set on the measurement object 5 installed on the test bench SA1global ,o SA2global ,···,o SB1global ,o SB2global , the global coordinates (x A1global ,y A1global ,z A1global ),(x A2global ,y A2global ,z A2global ) ,···,(x B1global ,y B1global ,z B1global ),(x B2global ,y B2global ,z B2global ) are assigned to the two single-point vibration measuring units 270A and 270B, and the local coordinates and ray vectors of each irradiation point at which the plurality of single-point measuring heads 250A1, 250A2, . . . , 250B1, 250B2, . . . provided in the two single-point vibration measuring units 270A and 270B irradiate a plurality of measurement points distributed two-dimensionally on the measurement surface of the measurement object 5 with measurement light are converted into global coordinates (x Aglobal ,y Aglobal ,z Aglobal ) ,(x Bglobal ,y Bglobal ,z Bglobal ) ···, and the origin O that defines the above three-dimensional space based on information such as the installation angle and the measurement light emission angle. globalglobal coordinates (X global ,Y global ,Z global ), and the vibration information acquired synchronously by the plurality of multipoint vibration measurement units 170A, 170B, and the single-point vibration measurement units 270A and 270B is converted into global coordinates (X global ,Y global ,Z global ) into the three-dimensional vibration information, and then the integrated global coordinate (X global ,Y global ,Z global ) three-dimensional vibration information is subjected to FFT analysis to identify the epicenter location and display images of vibration distribution.

[0190] In addition, in the integration process that integrates each piece of vibration information acquired synchronously by the single-point vibration measuring units 270A, 270B into three-dimensional vibration information, unlike the integration process that integrates each piece of vibration information acquired synchronously by the multi-point vibration measuring units 150A, 150B into three-dimensional vibration information, it is not possible to perform batch coordinate conversion, and global coordinate input must be performed for each head.

[0191] FIG. 22 is a schematic diagram showing the software hierarchy of the integration process executed by the integration processing unit 190 in the multi-point vibration measurement test bench 100A, which integrates each piece of vibration information acquired synchronously by the plurality of single-point vibration measurement units 270A, 270B into three-dimensional vibration information.

[0192] That is, in the integrated processing unit 190, each piece of vibration information synchronously acquired by the plurality of single-point measurement heads 250A1, 250A2, . . . , 250B1, 250B2, . . . provided in the two single-point vibration measurement units 270A and 270B is expressed as a head-based local coordinate (x A1local ,y A1local ,z A1local ),(x A2local ,y A2local ,z A2local ) ,···,(x B1local ,y B1local ,z B1local ),(x B2local ,y B2loca1 ,z B2localThe vibration information for each of the single-point vibration measuring units 270A and 270B, which has been integrated into local coordinates, is expressed as a global coordinate (x A1global ,y A1global ,z A1global ),(x A2global ,y A2global ,z A2global ) ,···,(x B1global ,y B1global ,z B1global ),(x B2global ,y B2global ,z B2global ) ···, each of the single-point vibration measuring units 270A, 270B is subjected to global coordinate conversion and converted into vibration information in global coordinates (Xglobal, Yglobal, Zglobal) assigned to the three-dimensional space in which the test bench is provided. Then, the vibration information acquired by the plurality of single-point measuring heads 250A1, 250A2, ···, 250B1, 250B2, ··· and converted into global coordinates is collected and integrated as three-dimensional vibration information in global coordinates (Xglobal, Yglobal, Zglobal), and the integrated global coordinates (X global ,Y global ,Z global ) three-dimensional vibration information is subjected to FFT analysis to identify the epicenter location and display an image of the vibration distribution.

[0193] Here, the multiple single-point measurement heads 250A1, 250A2, ..., 250B1, 250B2, ... in the multi-point vibration measurement test bench 100A are arranged to measure the vibration of the measurement object 5, but it is also possible to measure the vibration of a jig 280 that holds the measurement object 5, for example, as in the single-point measurement head 250' shown in Fig. 21. The vibration of the measurement object 5 and the vibration of the jig 280 can be measured separately, and the jig vibration component included in the vibration information obtained by the multi-point measurement heads 150 (150A, 150B, ...) can be removed from the single-point measurement head 250' by using the jig vibration information obtained by the single-point measurement head 250'.

[0194] When a part of the multi-point optical head 140 is separated and used as a single-point measurement head 250, as in the multi-point vibration measurement test bench 1500A shown in Fig. 19, an integration process for integrating the vibration information acquired synchronously by the multi-point optical head 140 and the single-point measurement head 250 into three-dimensional vibration information is executed by the integration processing unit 190. Fig. 23 is a schematic diagram showing the software hierarchy of the integration process executed by the integration processing unit 190 when a multi-point optical head and a single-point measurement head are mixed.

[0195] That is, the integrated processing unit 190 performs coordinate conversion on each piece of vibration information acquired synchronously by the multi-point optical head 140 and the single-point measuring head 250.

[0196] For the vibration information acquired by the multi-point optical head 140, local coordinate integration and conversion to global coordinates are performed according to the procedure shown in the schematic diagram of Figure 16, and for the vibration information acquired by the single-point measurement head 250, local coordinate integration and conversion to global coordinates are performed according to the procedure shown in the schematic diagram of Figure 22.

[0197] Even if there is a mixture of multi-point optical heads and single-point measurement heads, after each is converted into global coordinates using a predetermined procedure, it becomes possible to handle each vibration information in a unified manner, and the integration processing unit 190 collects and integrates each vibration information acquired by the multi-point optical head 140 and converted into global coordinates, and vibration information acquired by the single-point measurement head 250 and converted into global coordinates, and performs FFT analysis on the integrated three-dimensional vibration information in global coordinates, making it possible to identify the epicenter position and display an image of the vibration distribution, etc. [Explanation of symbols]

[0198] 1 Light source, 1A First optical comb generator (COMB1), 1B Second optical comb generator (COMB2), 2,120,220 Interference optical system, 3 Optical multiplexer / demultiplexer, 4,240 Projection optical system, 4 A11 ,4 A21 ,4 A31 ,···,4 Am1 ,···,4 Amn ,4A condenser lens, 4 B11 ,4 B21 ,4 B31 ,···,4 Bm1 ,···,4 Bmn ,4B 1 / 4 wave plate, 4Aa, 4Ab focusing optical element, 4Aab complete optical system, 4C1, 2-core capillary, 4CA, 4CB coupling optical unit, 4C2, 4C2', 144 11 ,144 21 ,144 31 ,···,144 m1 ,···,144 mn Coupling optical element, 4Ca, 4Cc collimator lens, 4Cb Wollaston prism, 5 measurement object, 5A1, 5A2, ···, 5B1, 5B2, ··· measurement surface, 6, 6' interference light detection unit, 6A measurement photodetector, 6B reference photodetector, 7, 7' signal processing unit, 10 multi-point vibration measurement device, 44 11 ,44 21 ,44 31 ,···,44 m1 ,···44 mn ,44 A11 ,44 A21 ,44 A31 ,···,44Am1 ,···,44 Amn ,44A,44B,244 Projection optical element, 44 Coupling optical element array, 100,100A Multi-point vibration measurement test bench, 110 Optical distributor, 130 Optical multiplexing / demultiplexing optical system, 130A Optical multiplexing element, 130B Optical multiplexing element, 135 Coupling optical system, 140,140A,140B,1400 Projection optical system with built-in coupling optical element, 144 Coupling optical element array, 150,150A,150B,··· Multi-point measurement head, 160,160A,160B,···,1600 Optical detection processing unit, 170,170A,170B,···,1701,1702,1703,1704 Multi-point vibration measurement unit, 180 Measurement unit, 190 Integrated processing unit, 190A Communication board, 190B DIO board, 190C PC, 210A, 210B Optical multiplexer / demultiplexer, 250, 250', 250A1, 250A2, 250B1, 250B2, Single-point measurement head, 260A, 260B, Single-point measurement optical detection processing unit, 270 Single-point measurement unit, 270A, 270B Single-point vibration measurement unit, 1500, 1501, 1502, 1503, 1504 Multi-point measurement head, FB 12A ,FB 12B ,FB 2A1 ,FB 2A2 ,FB 2B1 ,FB 2B2 ,FB 22A2 ,FB 22B1 ,FB 22B2 ,FB 23 ,FB 23A ,FB 23C ,FB 2341 ,FB 26A1 ,FB 26A2 ,FB 26B1 ,FB 26B2 ,FB 34 ,FB 43 ,FB212A,FB212B,FB 3411 ,FB 3421 ,FB 3431 ,···,FB 34m1 ,···,FB 34mn ,FB 4311 ,FB 4321 ,FB 4331 ,···,FB 43m1 ,···,FB 43mn ,FB 4411 ,FB4421 ,FB 4431 ,···,FB 44m1 ,···,FB 44mn ,FB 226A1 ,FB 226A2 ,FB 226B1 ,FB 226B2 ,FB 3341 , Optical fiber, FB 2B1 ' Delay Fiber, OC A ,OC B ,OC C ,OC D ,OC E ,OC C11 ,OC C21 ,OC C31 ,···,OC C1 ,···,OC Cmn Optical coupler, L S ,L S ' Measuring light, L R Reference light, l S ,l S ' Frequency component, S R Reference interference signal, S S Interference signal for measurement

Claims

1. A multi-point vibration measurement test bench that uses light to simultaneously measure vibration information at multiple points on a measurement object, a light source that outputs coherent measurement light and reference light, the measurement light and reference light having a spectrum with a predetermined frequency interval; an optical distributor that distributes the measurement light and the reference light output from the light source to a plurality of optical paths; a plurality of multi-point vibration measurement units that are arranged in a three-dimensional space where the measurement object installed on the test bench is located, and that synchronously acquire vibration information from a plurality of measurement points that are two-dimensionally distributed on the measurement surface of the measurement object using the measurement light and reference light that are respectively distributed to a plurality of optical paths by the optical distributor; an integration processing unit that integrates each piece of vibration information synchronously acquired by the plurality of multipoint vibration measurement units into three-dimensional vibration information; Equipped with a multi-point vibration measurement test bench configured to integrate the vibration information of each of the local coordinates acquired synchronously by the multiple multi-point vibration measurement units into three-dimensional vibration information in the global coordinates that defines the three-dimensional space; and a multi-point vibration measurement test bench configured to integrate the vibration information of each of the local coordinates acquired synchronously by the multiple multi-point vibration measurement units into three-dimensional vibration information in the global coordinates that defines the three-dimensional space.

2. The multipoint vibration measurement unit is a multi-point measurement head including an interference optical system into which the measurement light and the reference light distributed to the plurality of optical paths by the optical distributor are respectively input, an optical branching element that branches off each frequency component contained in the measurement light input from the interference optical system, a projection optical system that irradiates each frequency component branched by the optical branching element onto a plurality of measurement points on a measurement surface of an object to be measured, an optical combining element that combines each frequency component of the measurement light reflected and returned from the plurality of measurement points on the measurement surface and inputs the combined light to the interference optical system, and a coupling optical system that inputs each frequency component contained in the measurement light branched by the optical branching element to the projection optical system and inputs each frequency component of the measurement light reflected and returned from the plurality of measurement points on the measurement surface to the optical combining element; in the interference optical system, a measurement interference light detection unit that receives measurement interference light obtained by interfering measurement light including each frequency component that is reflected at a plurality of measurement points on the measurement surface and returned via the optical multiplexing element provided in the multi-point measurement head with reference light output from the light source, and converts the measurement interference light into an electrical signal to obtain a measurement interference signal including vibration information at a plurality of measurement points that are two-dimensionally distributed on the measurement surface of the measurement object; 2. The multi-point vibration measurement test bench according to claim 1, comprising:

3. at least one single-point vibration measuring unit that is arranged in a three-dimensional space where the measurement object is located and that synchronously acquires vibration information of one measurement point on a measurement surface of the measurement object using measurement light and reference light that are respectively distributed to a plurality of optical paths by the optical distributor; The integrated processing unit assigns the mounting positions and orientations of the plurality of multi-point vibration measurement units in global coordinates based on an origin set on the test bench or an origin set on the measurement object set on the test bench in the three-dimensional space in which the test bench is installed, converts the local coordinates and ray vectors of each irradiation point at which the plurality of multi-point vibration measurement units irradiate a plurality of measurement points distributed two-dimensionally on the measurement surface of the measurement object with measurement light, into global coordinates that define the three-dimensional space in which the test bench is installed based on information such as the global coordinates, mounting angle, and measurement light emission angle of each multi-point vibration measurement unit, and converts the local coordinates and ray vectors of each irradiation point at which the plurality of multi-point vibration measurement units irradiate a plurality of measurement points distributed two-dimensionally on the measurement surface of the measurement object with measurement light into global coordinates that define the three-dimensional space in which the test bench is installed, and converts the local coordinates and ray vectors of each irradiation point into global coordinates that define the three-dimensional space in which the test bench is installed based on information such as the global coordinates, mounting angle, and measurement light emission angle of each multi-point vibration measurement unit, and converts the local coordinates and ray vectors of each irradiation point into global coordinates that define the three-dimensional space in which the test bench is installed, based on information such as the origin set on the test bench or an origin set on the test bench the at least one single-point vibration measurement unit converts the local coordinates and ray vector of an irradiation point at which the at least one single-point vibration measurement unit irradiates one measurement point on the measurement surface of the measurement object with measurement light into global coordinates that define the three-dimensional space in which the test bench is installed, based on the global coordinates, the installation angle of the at least one single-point vibration measurement unit, the measurement light emission angle, and other information; and integrates each piece of vibration information acquired synchronously by the plurality of multi-point vibration measurement units and the at least one single-point vibration measurement unit into three-dimensional vibration information.

4. The single-point vibration measurement unit is an interference optical system into which the measurement light and the reference light distributed to the plurality of optical paths by the optical distributor are input; an optical multiplexing / demultiplexing optical system into which the measurement light is input via the interference optical system; at least one single-point measurement head comprising a projection optical system that receives one frequency component of a plurality of frequency components contained in the measurement light obtained by splitting the measurement light by the optical multiplexing and splitting optical system, irradiates the input measurement light of the one frequency component onto one measurement point on a measurement surface of a measurement object, and inputs reflected light of the measurement light of the one frequency component that is reflected and returned from the one measurement point on the measurement surface into the optical multiplexing and splitting optical system; a single-point measurement interference light detection processing unit to which interference light obtained by the interference optical system is input, The interference optical system receives measurement light consisting of reflected light of at least one frequency component obtained by combining, using the optical multiplexing / demultiplexing optical system, reflected light of one frequency component of the measurement light that is reflected at at least one measurement point on the measurement surface and returned via the single-point measurement head, and causes interference between the reference light input from the optical distributor and the measurement light consisting of reflected light of at least one frequency component, thereby obtaining interference light for single-point measurement, The single-point measurement interference light detection unit receives the single-point measurement interference light obtained by the single-point measurement interference light detection unit and converts it into an electrical signal to obtain a single-point measurement interference signal including vibration information at at least one measurement point on the measurement surface.

4. The multi-point vibration measurement test bench according to claim 3.

5. 5. The multi-point vibration measurement test bench according to claim 1, wherein the multi-point measurement head separates each frequency component contained in the measurement light into one frequency component by the optical demultiplexing element, irradiates each frequency component onto a plurality of measurement points on the measurement surface of the measurement object via the projection optical system, and combines each frequency component of the measurement light reflected and returned from the plurality of measurement points on the measurement surface by an optical combining element.

6. 5. The multi-point vibration measurement test bench according to claim 1, wherein the multi-point measurement head separates each frequency component contained in the measurement light into multiple frequency components using the optical demultiplexing element, irradiates each frequency component onto multiple measurement points on the measurement surface of the object via the projection optical system, and combines each frequency component of the multiple frequency components of the measurement light reflected and returned from the multiple measurement points on the measurement surface using an optical combining element.

7. 5. The multipoint vibration measurement test bench according to claim 1, wherein the coupling optical system is built into the projection optical system.

8. The optical demultiplexing element demultiplexes each frequency component contained in the measurement light input from the interference optical system via one optical fiber and outputs the demultiplexed signal via a plurality of optical fibers, and the optical combining element combines each frequency component input via a plurality of optical fibers and outputs the combined signal via one optical fiber, 8. The multi-point vibration measurement test bench according to claim 7, wherein the coupling optical system includes a polarization optical element that aligns the optical axes of two light beams whose polarization directions are orthogonal to each other and output from the two optical fibers.

9. 9. The multi-point vibration measurement test bench according to claim 8, wherein the polarizing optical element is made of a birefringent crystal.

10. 9. The multi-point vibration measurement test bench according to claim 8, wherein the polarizing optical element is a Wollaston prism.

11. The multi-point vibration measurement test bench according to claim 8, characterized in that the coupling optical system is composed of a polarizing optical element array in which the polarizing optical elements are arranged two-dimensionally, and each frequency component of the measurement light input through the polarizing optical element array is collected by a collecting optical element and output toward the measurement surface of the measurement object, and each frequency component of the measurement light reflected and returned from the measurement surface is collected by the collecting optical element and input to the polarizing optical element array.

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