Multi-point vibration measurement test bench

Abstract

It is possible to handle the case where vibration information of a plurality of points is required simultaneously, and by acquiring vibration information in a wide area, it becomes possible to more accurately investigate the vibration cause, and a multi-point vibration measurement test bench is provided for simultaneously measuring vibration information of a plurality of points of a measurement object. 【Solution means】Using the measurement light and reference light distributed to a plurality of optical paths from the light source 1 via the optical distributor 110, a plurality of multi-point vibration measurement units 170A, 170B,... synchronously acquire vibration information of a plurality of measurement points two-dimensionally distributed on the measurement surface of the measurement object 5. In the integration processing unit 190, the vibration information of each local coordinate synchronously acquired by the plurality of multi-point vibration measurement units is integrated into three-dimensional vibration information in the global coordinates defining the three-dimensional space where the test bench is installed. The integrated global coordinates (X global , Y global , Z global ) Perform FFT analysis on the three-dimensional vibration information, such as identifying the source position and displaying an image of the vibration distribution.

Description

Technical Field

[0001] The present invention relates to a multi-point vibration measurement test bench that simultaneously measures vibration information of a measurement target at a plurality of points using light.

Background Art

[0002] Conventionally, test benches for performing various performance tests of drive units such as, for example, internal combustion engines, electric motors, or combinations consisting of internal combustion engines and electric motors (so-called hybrid drive devices) are known (see, for example, Patent Documents 1-3).

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

[0004] In order to investigate the cause of vibration and the load due to vibration, measurement of the vibration distribution in the plane of the measurement target is required. For example, in the case of steady vibration, the vibration distribution in the plane can be measured by performing vibration measurement while shifting the location in accordance with the period of the vibration.

[0005] However, when it is desired to measure transiently changing vibrations in real time, when it is not known in advance what frequency components of vibrations are included, or when several points of vibration information are required simultaneously, a vibration measurement device capable of simultaneously measuring several points of vibration information is required.

[0006] Also, conventional laser Doppler vibrometers can generally measure the amplitude of vibrations at a speed range of about 10 m per second, but cannot simultaneously measure the vibration distribution at multiple points synchronously. Also, the height in the stationary state cannot be obtained.

[0007] The applicant of this application has previously proposed a vibration measuring device and a vibration measuring method that can simultaneously measure vibration information at a plurality of points on a measurement surface by using an optical multiplexing / demultiplexing head that demultiplexes measurement light for each frequency component and irradiates a plurality of points on the measurement surface of the object to be measured, and detecting the interference light between the interfering reference light and the measurement light, and obtaining the phase difference between the reference light and the measurement light, thereby analyzing the vibration information of the measurement surface of the object to be measured (see, for example, Patent Documents 4-6).

[0008] Also, without using a frequency shifter, an optical comb with a center frequency f0 (Hz) and a frequency interval f m is generated as a probe light, and an optical comb with a center frequency f0 (Hz) and a frequency interval f m +Δf m is generated as a reference light, thereby proposing a vibration meter with a simplified device configuration that can perform multi-point measurement (see, for example, Patent Document 7).

[0009] Furthermore, a multi-point measurement type laser Doppler vibrometer using an optical comb generator that enables generation of a broadband optical comb having a large number of modes with a single modulator has been proposed (Patent Document 8).

Prior Art Documents

Patent Documents

[0010]

Patent Document 1

Patent Document 2

Patent Document 3

Patent Document 4

Patent Document 5

Patent Document 6

Patent Document 7

Patent Document 8

Summary of the Invention

Problems to be Solved by the Invention

[0011] In a multi-point vibration measurement device using an optical communication, an interference optical system into which reference light and measurement light are input, an optical demultiplexing element that demultiplexes the measurement light irradiated on the measurement surface for each frequency component of the optical communication, and measurement light of each frequency component demultiplexed by this optical demultiplexing element are irradiated on the measurement surface, and various optical elements such as an optical element that returns the reflected light (scattered light) from the measurement surface to the optical demultiplexing element are provided in the optical system that spatially propagates the reference light and measurement light. Although it is possible to measure the vibration of the measurement surface of the measurement object in the front when viewed from the irradiation side, it is not possible to measure the side surface of the measurement object where the incident angle of the light beam becomes shallow or the back surface of the measurement object that is in the shadow of the measurement light.

[0012] Here, as in the multi-point vibration measurement device 10 shown in FIG. 1, by modularizing the input / output of the interference optical system 2 so as to be an optical fiber and sending the reference light and measurement light, it is possible to use an element in which optical elements having each function are modularized, and the assembly and repair of the device become easy. In addition, the device can be miniaturized by using some functional elements as an optical integrated circuit using a spatial optical system and an optical fiber.

[0013] This multi-point vibration measurement device 10 includes an interference optical system 2 into which the coherent measurement light L S and the reference light L R are input. Each frequency component included in the measurement light LS input through this interference optical system 2 is demultiplexed by an optical multiplexer / demultiplexer 3 into, for example, m×n (m and n are arbitrary positive integers) types of frequency components, and each frequency component of the measurement light L S is irradiated through a projection optical system 4 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, and the measurement light L S reflected at the m×n measurement points on the measurement surface of the measurement object 5 and returning through the projection optical system 4The measurement light L composed of the reflected light of each frequency component reflected at the m×n measurement points on the measurement surface obtained by combining the reflected light of each frequency component by the optical multiplexer 3 S ’ is input to the interference optical system 2.

[0014] The light source 1 is a first optical comb generator (COMB1) 1A and a second optical comb generator (COMB2) 1B that output linearly polarized measurement light L S and reference light L R and is connected to the interference optical system 2 via optical fibers FB 12A , FB 12B respectively. Here, the PMF is an optical fiber that utilizes the photoelastic effect and structural changes to generate birefringence with different effective refractive indices in the vertical and horizontal directions of the core, and enhances the polarization plane retention characteristics of the transmitted light.

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

[0016] The measurement light L 12A is input to the interference optical system 2 via the optical fiber FB from the first optical comb generator (COMB1) 1A, and the reference light L S is input to the interference optical system 2 via the optical fiber FB from the second optical comb generator (COMB2) 1B. 12B and the reference light L R is input.

[0017] The interference optical system 2 is composed of five optical couplers OC 2A1 , OC 2A2 , OC 2B1 , OC 2B2 , OC 2C connected by optical fibers FB A , OC B , OC C , OC D , OCE comprises an optical coupler OC A to which an optical fiber FB is externally connected 12A and through which measurement light L is input from the first optical comb generator (COMB1) 1A S and an optical fiber FB is externally connected to the optical coupler OC B and through which reference light L is input from the second optical comb generator (COMB2) 1B 12B R

[0018] In this interference optical system 2, two optical fibers FB 2A1 , FB 2A2 are internally connected to two optical couplers OC D , OC E through the optical coupler OCA, and two optical fibers FB B , FB 2B1 are internally connected to two optical couplers OC 2B2 , OC C through the optical coupler OC, and an optical fiber FB D is internally connected to an optical coupler OC E through the optical coupler OC 2C through the optical fiber FB C

[0019] Then, the measurement light L input to this interference optical system 2 S is input to the optical multiplexer / demultiplexer 3 through an optical fiber FB using a PMF externally connected to the optical coupler OC E 23

[0020] The measurement light L input to the optical multiplexer / demultiplexer 3 S is demultiplexed in the optical multiplexer / demultiplexer 3 into a plurality of frequency components included in the measurement light L S and a plurality (m×n) of optical fibers FB using a PMF for each frequency component 3411 , FB 3421 , FB 3431 , ···, FB 34m1 , ···, FB 34mn and is incident on a plurality (m×n) of condenser lenses 4 of the projection optical system 4 A11 , 4 A21 , 4​​​​​A31 , ···, 4 Am1 , ···, 4 Amn is input, and a plurality (m×n) of frequency components are collected by a plurality (m×n) of condenser lenses 4 A11 , 4 A21 , 4 A31 , ···, 4 Am1 , ···, 4 Amn and are condensed by the respective 1 / 4 wavelength plates 4 B11 , 4 B21 , 4 B31 , ···, 4 Bm1 , ···, 4 Bmn and are irradiated onto a plurality of measurement points on the measurement surface of the object to be measured 5 through the respective 1 / 4 wavelength plates 4

[0021] Then, the measurement light L reflected at a plurality of measurement points on the measurement surface of the object to be measured 5 returns from the projection optical system 4 through the optical fiber FB 3411 , FB 3421 , FB 3431 , ···, FB 34m1 , ···, FB 34mn The reflected light of each frequency component of the measurement light L that returns through the optical fiber FB S is combined by the optical multiplexer / demultiplexer 3, and the measurement light L composed of the reflected lights of the respective frequency components reflected at a plurality of measurement points on the measurement surface is output from the optical multiplexer / demultiplexer 3 through the optical fiber FB 23 and is input to the optical coupler OC E of the interference optical system 2

[0022] Here, the measurement light L E input to the optical coupler OC, which is composed of the reflected lights of the respective frequency components reflected at a plurality of measurement points on the measurement surface S ’ is such that the polarization of the measurement light LS’ becomes orthogonal to that of the measurement light Ls when each frequency component of the measurement light L E output from the optical coupler OC S passes through the 1 / 4 wavelength plate 4 B11 , 4 B21 , 4 B31 , ···, 4 Bm1 , ···, 4 Bmn twice, and the measurement light L S , L S' functions as a polarization beam combiner / splitter, the optical coupler OC E can be separated by the polarization plane by the above, and the polarization is L S The measurement light L is composed of the reflected light of each frequency component reflected at a plurality of measurement points on the measurement plane, which is a component orthogonal to S ' is the optical coupler OC E from the optical coupler OC 2C through the optical fiber FB C is input.

[0023] In the interference optical system 2, the measurement light L composed of the reflected light of each frequency component reflected at a plurality of measurement points on the measurement plane S ' and the reference light L input from the light source 1 R The interference light between them is used as the measurement interference light and output from the optical coupler OC C At the same time, the interference light between the measurement light L S input from the light source 1 and the reference light L R is used as the reference interference light and output from the optical coupler OC D is output.

[0024] The interference light detection unit 6 into 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 composed of a balanced photodetector, and the optical coupler OC of the interference optical system 2 C Two optical fibers FB 26A1 , FB 26A2 The measurement light detector 6A that receives the measurement interference light input from the optical coupler OC C through the above outputs the measurement interference signal S obtained by detecting the measurement interference light and converting it into an electrical signal S At the same time, the two optical fibers FB D externally connected to the optical coupler OC of the interference optical system 2 26B1 , FB 26B2 The reference light detector 6B that receives the reference interference light input from the optical coupler OC D through the above outputs the reference interference signal S obtained by detecting the reference interference light and converting it into an electrical signal R is output.

[0025] Here, the balanced photodetector used as the measurement interference light detector 6A and the reference interference light detector 6B connects two photodiodes in directions that cancel out the photocurrents respectively, cancels out the common mode noise of the two incident lights, converts the difference in light quantity into an electrical signal as a displacement signal, and outputs it. It combines into one the beats having frequencies corresponding to the frequency differences of the respective optical carriers of the respective frequency components of the optical carriers of the input measurement light and reference light, converts them into electrical signals, and outputs them. The frequency differences between the respective optical carriers of the measurement light and the reference light described here are sufficiently small compared to the intervals between the respective frequency components of the optical carriers, and are not split by the optical multiplexing element and the optical demultiplexing element described below. Also, the bandwidth of the balanced photodetector is sufficiently smaller than the intervals between the respective frequency components of the optical carrier, and is sufficiently large to detect the frequency differences between the respective optical carriers of the measurement light and the reference light.

[0026] And in this multi-point vibration measuring device 10, in the signal processing unit 7, the measurement interference signal S obtained by the interference light detection unit 6 S and the reference interference signal S R are input for discrete Fourier transform (DFT: discrete Fourier transform) (including fast Fourier transform (FFT: fast Fourier transform)) analysis, and the respective phase differences of the beats having frequencies corresponding to the frequency differences between the respective optical carriers of the measurement light L S and the reference light L R are calculated, thereby analyzing the vibration information at a plurality of measurement points on the measurement surface and measuring the distribution of vibration on the measurement surface.

[0027] Like this multi-point vibration measuring device 10, by configuring the input and output of the interference optical system 2 with optical fibers and sending the measurement light L S and the reference light L R through the optical fibers, it is possible to use an element in which optical elements having respective functions are modularized, and the assembly and repair of the device become easy. However, from the interference optical system 2 to the optical fiber FB 23A part of the measurement light LS input to the optical multiplexer / demultiplexer 3 is reflected by the optical multiplexer / demultiplexer 3 and returns to the interference optical system 2, which causes a measurement error by mixing into the interference light necessary for multi-point vibration measurement.

[0028] For example, when an arrayed waveguide grating is used for the optical multiplexer / demultiplexer 3, it is small in size and high in resolution, but the reflection loss (RL: Return Loss) 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. Also, when the optical path from the interference optical system 2 to the optical multiplexer / demultiplexer is an optical fiber, the reflection from the connector of the optical fiber cannot be ignored.

[0029] That is, as the optical multiplexer / demultiplexer 3, a triangular prism, an arrayed waveguide grating (AWG: Arrayed Waveguide Grating), a plurality of wavelength division multiplexing filters, a diffraction grating, etc. are used, but the problem was that the RL was small.

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

[0031] Also, the insertion loss (IL: Insertion loss) of the optical multiplexer / demultiplexer 3 is about 6.5 dB for an AWG at intervals of 25 GHz, for example. When used back and forth, the loss becomes about 13 dB, and relatively, the influence of RL becomes large.

[0032] Due to the RL inside the optical multiplexer / demultiplexer 3, it becomes difficult to distinguish the reflection of the measurement light (the first optical comb) L S from the measurement surface when the reflection from the measurement surface is not large enough.

[0033] In such a case, there was a problem that the vibration information calculated by the signal processing unit 7 would be incorrect.

[0034] In addition, with a single multi-point vibration measurement head, vibration information can only be obtained for the surface that can be irradiated with the measurement light. However, since vibration measurement cannot be performed on the back surface that is in the shadow of the measurement light or on the side surface where the incident angle of the measurement light is shallow, there is a problem that the information as the measurement of the three-dimensional vibration distribution of the object to be measured is limited.

[0035] Therefore, the present invention has been devised in view of the above-described conventional circumstances. When it is desired to measure transiently changing vibrations in real time, or when it is not known in advance what frequency components of vibrations are included, etc., it is possible to cope with cases where vibration information at multiple points is required simultaneously, and it becomes possible to more accurately investigate the vibration cause by acquiring vibration information in a wide area. An object of the present invention is to provide a multi-point vibration measurement test bench that simultaneously measures vibration information at multiple points of a measurement object using light that can be used for detecting abnormal vibrations and for full inspection of the manufacturing process.

[0036] Another object of the present invention is to eliminate measurement errors caused by unnecessary reflection components from various optical elements such as an optical multiplexer provided in the optical path through which the measurement light irradiated onto the measurement surface passes via an interference optical system in a multi-point vibration measurement test bench that simultaneously measures vibration information at multiple points of a measurement object using light, perform multi-point vibration measurement with high accuracy, acquire three-dimensional vibration information, and enable display, analysis, source 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 clearer from the description of the embodiments described below.

Means for Solving the Problems

[0038] In the present invention, synchronous measurement and coordinate transformation of a plurality of heads including a single vibration measurement head are combined to capture three-dimensional vibrations including transient vibrations of an object in real time and perform multi-point vibration analysis.

[0039] The present invention relates to a multi-point vibration measurement test bench for simultaneously measuring vibration information of a measurement object at multiple points using light. It includes a light source that outputs measurement light and reference light with a spectrum at a predetermined frequency interval and having interference; an optical distributor that distributes the measurement light and reference light output from the light source to a plurality of optical paths; a plurality of multi-point vibration measurement units arranged in a three-dimensional space where the measurement object installed on the test bench is located, and each of the multi-point vibration measurement units synchronously acquires vibration information of a plurality of measurement points two-dimensionally distributed on the measurement surface of the measurement object by using the measurement light and reference light distributed to the plurality of optical paths by the optical distributor; and an integration processing unit that integrates each vibration information synchronously acquired by the plurality of multi-point vibration measurement units into three-dimensional vibration information. In the integration processing unit, in the three-dimensional space where the test bench is installed, global coordinates are assigned to the mounting positions and orientations of the plurality of multi-point vibration measurement units with reference to the origin set on the test bench or the origin set on the measurement object installed on the test bench. The local coordinates and light ray vectors of each irradiation point where the plurality of multi-point vibration measurement units irradiate measurement light on the plurality of measurement points two-dimensionally distributed on the measurement surface of the measurement object are converted into global coordinates defining the three-dimensional space based on the global coordinates of the multi-point vibration measurement units and the mounting angles, Information on the measurement light emission angle and the vibration information of each local coordinate acquired synchronously by the plurality of multi-point vibration measurement units is integrated into three-dimensional vibration information in the global coordinates defining the three-dimensional space.

[0040] In the multi-point vibration measurement test bench according to the present invention, each multi-point vibration measurement unit includes an interference optical system into which the measurement light and reference light distributed to the plurality of optical paths by the optical distributor are respectively input; an optical wavelength division element that divides each frequency component included in the measurement light input from the interference optical system; and each frequency component divided by the optical wavelength division element The above-mentioned object to be measuredA multi-point measurement head including a projection optical system that irradiates a plurality of measurement points on a measurement surface, a multiplexing optical element that multiplexes each frequency component of the measurement light that is reflected back from the plurality of measurement points on the measurement surface and input to the interference optical system, and a coupling optical system that inputs each frequency component included in the measurement light demultiplexed by the optical demultiplexing element to the projection optical system and inputs each frequency component of the measurement light that is reflected back from the plurality of measurement points on the measurement surface to the multiplexing optical element; and a measurement interference light detection unit that receives, in the interference optical system, measurement interference light obtained by interfering measurement light including each frequency component that is reflected from the plurality of measurement points on the measurement surface and returns through the multiplexing optical element provided in the multi-point measurement head and reference light output from the light source, and converts the received light into an electrical signal to obtain a measurement interference signal including vibration information at a plurality of measurement points two-dimensionally distributed on the measurement surface of the measurement object.

[0041] Further, the multi-point vibration measurement test bench according to the present invention is arranged in a three-dimensional space where the measurement object is located, and includes at least one one-point vibration measurement unit that synchronously acquires vibration information of one measurement point on the measurement surface of the measurement object using measurement light and reference light respectively distributed to a plurality of optical paths by the optical distributor. In the integration processing unit, in the three-dimensional space where the test bench is installed, global coordinates are assigned to the attachment positions and orientations of the plurality of multi-point vibration measurement units with reference to an origin set on the test bench or an origin set on the measurement object installed on the test bench. The local coordinates and ray vectors of each irradiation point at which the plurality of multi-point vibration measurement units irradiate measurement light on a plurality of measurement points two-dimensionally distributed on the measurement surface of the measurement object are respectively the global coordinates and attachment angles of the multi-point vibration measurement units. Information on the measurement light emission angleConvert to the global coordinates that define the three-dimensional space where the test bench is installed based on the above, and assign the attachment position and orientation of the at least one single-point vibration measurement unit in the global coordinates with reference to the origin set on the test bench or the origin set on the measurement object installed on the test bench. Also, the local coordinates and the light vector of the irradiation point where the at least one single-point vibration measurement unit irradiates the measurement light on one measurement point of the measurement surface of the measurement object are related to the global coordinates and the attachment angle of the at least one single-point vibration measurement unit. Information on the measurement light emission angle Convert to the global coordinates that define the three-dimensional space where the test bench is installed based on the above, and it is possible to integrate each vibration information obtained 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.

[0042] Also, in the multi-point vibration measurement test bench according to the present invention, the single-point vibration measurement unit includes an interference optical system into which the measurement light and the 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 one frequency component among the plurality of frequency components included in the measurement light obtained by demultiplexing the measurement light by the optical multiplexing / demultiplexing optical system is input, and the input measurement light of the one frequency component The above-mentioned object to be measured is irradiated onto one measurement point on the measurement surface, and at least one single-point measurement head including a projection optical system that inputs the reflected light of the measurement light of the one frequency component that is reflected back from one measurement point on the measurement surface to the optical multiplexing / demultiplexing optical system, and a single-point measurement interference light detection processing unit into which the interference light obtained by the interference optical system is input. The interference optical system combines the reflected light of one frequency component of the measurement light that is reflected at at least one measurement point on the measurement surface and returns through the single-point measurement head, and the measurement light composed of at least one frequency component of the reflected light obtained by the optical multiplexing / demultiplexing optical system is input. By this, interference light for single-point measurement is obtained by interfering the reference light input from the optical distributor and the measurement light composed of the at least one frequency component of the reflected light. The above-mentioned interference light detection processing unit for single-point measurement is performed by the interference light detection unit for single-point measurementIt is possible to obtain an interference signal for single-point measurement that includes vibration information at at least one measurement point on the measurement surface, which receives interference light for single-point measurement and converts it into an electrical signal.

[0043] Further, in the multi-point vibration measurement test bench according to the present invention, in the multi-point measurement head, each frequency component included in the measurement light is separated by the optical wavelength division element for each frequency component, and each frequency component is passed through the projection optical system The above-mentioned object to be measured to irradiate a plurality of measurement points on the measurement surface, and it is possible to combine each frequency component for each frequency component of the measurement light reflected back from the plurality of measurement points on the measurement surface by a wavelength multiplexing element.

[0044] Further, in the multi-point vibration measurement test bench according to the present invention, in the multi-point measurement head, each frequency component included in the measurement light is separated by the optical wavelength division element for each plurality of frequency components, and each frequency component is passed through the projection optical system The above-mentioned object to be measured to irradiate a plurality of measurement points on the measurement surface, and it is possible to combine each frequency component for each plurality of frequency components of the measurement light reflected back from the plurality of measurement points on the measurement surface by a wavelength multiplexing element.

[0045] Further, the multi-point vibration measurement test bench according to the present invention can have the coupling optical system incorporated in the projection optical system.

[0046] Further, in the multi-point vibration measurement test bench according to the present invention, the optical wavelength division element separates each frequency component included in the measurement light input via one optical fiber from the interference optical system and outputs it via a plurality of optical fibers, and the wavelength multiplexing element combines each frequency component input via a plurality of optical fibers and outputs it via one optical fiber, and the coupling optical system can be provided with a polarization optical element that aligns the optical axes of two light beams with orthogonal polarization directions output from two optical fibers.

[0047] Further, in the multi-point vibration measurement test bench according to the present invention, the polarization optical element can be made of a birefringent crystal.

[0048] Further, in the multi-point vibration measurement test bench according to the present invention, the polarization optical element can be composed of a Wollaston prism.

[0049] Furthermore, in the multi-point vibration measurement test bench according to the present invention, the coupling optical system is composed of a polarization optical element array in which the polarization optical elements are two-dimensionally arranged, and each frequency component of the measurement light input through the polarization optical element array is condensed by a condenser optical element and output toward the measurement surface of the above Object to be measured It is possible to condense each frequency component of the measurement light reflected and returned from the measurement surface by the condenser optical element and input it to the polarization optical element array.

Effect of the Invention

[0050] In the multi-point vibration measurement test bench according to the present invention, the measurement light and the reference light output from the 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 the three-dimensional space where the measurement object is located respectively use the measurement light and the reference light distributed to the plurality of optical paths by the optical distributor to synchronously acquire the vibration information of a plurality of measurement points two-dimensionally distributed on the measurement surface of the measurement object. In the integration processing unit, the attachment positions and directions of the plurality of multi-point vibration measurement units are given in global coordinates based on the origin set on the test bench or the origin set on the measurement object installed on the test bench. The local coordinates and ray vectors of each irradiation point where the plurality of multi-point vibration measurement units irradiate the measurement light on a plurality of measurement points two-dimensionally distributed on the measurement surface of the measurement object are respectively the global coordinates and attachment angles of the multi-point vibration measurement units, Information on the measurement light emission angleBased on this, it is converted into global coordinates that define the three-dimensional space where the above test bench is installed, and the vibration information of each local coordinate synchronously acquired by the above plurality of multi-point vibration measurement units is integrated into three-dimensional vibration information in the global coordinates that define the above three-dimensional space. When it is desired to measure transiently changing vibrations in real time, when it is not known in advance what frequency components of vibrations are included, or when several points of vibration information are required simultaneously, etc., it is possible to handle such cases, and by acquiring vibration information over a wide area, it becomes possible to more accurately investigate the vibration causes and use it for detecting abnormal vibrations and performing full inspections of the manufacturing process, etc.

[0051] Also, in the multi-point vibration measurement test bench according to the present invention, it is possible to perform multi-point vibration analysis by simultaneously capturing three-dimensional vibrations including transient vibrations of the measurement object by combining synchronous measurement and coordinate transformation of a plurality of heads including a single vibration measurement head in real time, and it can be used in an in-line inspection process by narrowing down the inspection items of the measurement object and shortening the inspection time such as speeding up information collection.

[0052] Furthermore, in the present invention, the functions of the optical demultiplexing element and the optical multiplexing element are made to function individually, and the measurement light output from the light source through the interference optical system is demultiplexed into a plurality of frequency components included in the measurement light and irradiated onto a plurality of measurement points on the measurement surface of the measurement object, and the optical path for multiplexing the plurality of frequency components reflected back from the plurality of measurement points on the measurement surface and inputting them into the interference optical system is demultiplexed. Thus, unnecessary reflection components by the optical demultiplexing element that demultiplexes into the plurality of frequency components can be prevented from mixing into the interference light required for multi-point vibration measurement. In a multi-point vibration measurement test bench that measures vibration information of a measurement object at a plurality of points simultaneously using light, measurement errors caused by unnecessary reflection components by various optical elements such as an optical multiplexer / demultiplexer provided in the optical path through which the measurement light irradiating the measurement surface passes through the interference optical system mixing into the interference light required for multi-point vibration measurement are eliminated, enabling high-precision multi-point vibration measurement, obtaining three-dimensional vibration information, and performing display, analysis, source estimation, frequency analysis, etc. of the three-dimensional vibration information.

Brief Description of the Drawings

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Embodiments for Carrying Out the Invention

[0054] Hereinafter, embodiments of the present invention will be described in detail with reference to the drawings. For common components, common reference numerals are attached in the drawings for explanation. Needless to say, the present invention is not limited to the following examples and can be arbitrarily changed without departing from the gist 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 multi-point vibration measurement test bench 100 is configured by arranging a plurality of multi-point vibration measurement units 170 having a configuration as shown in FIG. 3, for example, which is an improvement of the multi-point vibration measurement device 10 shown in FIG. 1, in a three-dimensional space where the measurement object 5 is located, and simultaneously measuring vibration information of the measurement object 5 at a plurality of points using laser light. The measurement light L output from the light source 1 S and the reference light L R are distributed by the optical distributor 110 to a plurality of optical paths and input to a measurement unit 180 composed of a plurality of multi-point vibration measurement units 170A, 170B, ···, and an integration processing unit 190 to which the plurality of vibration information acquired by the measurement unit 180 is input.

[0057] In this multi-point vibration measurement test bench 100, for components identical to those of the multi-point vibration measurement device 10, the same reference numerals are used in the figures and detailed descriptions thereof are omitted.

[0058] The light source 1 emits measurement light L with a spectrum of a predetermined frequency interval and having interference, S and reference light L R as two types of optical combs whose intensities or phases are periodically modulated and whose modulation frequencies are different from each other.

[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 multi-point vibration measurement units 170A, 170B,... of the measurement unit 180 via optical fibers each using a pair of PMFs. The measurement light L S and reference light L R output from the light source 1 are respectively distributed to a plurality of optical paths and input to the plurality of multi-point vibration measurement units 170A, 170B,... of the measurement unit 180.

[0060] The plurality of multi-point vibration measurement units 170A, 170B,... each include multi-point measurement heads 150A, 150B,... connected to the optical distributor 110 via optical fibers each using a pair of PMFs, and photodetection processing units 160A, 160B,... connected to the multi-point measurement heads 150A, 150B,... via optical fibers each using a quadruple of SMFs.

[0061] The integrated processing unit 190 includes a PC 190C equipped with a communication board 190A and a DIO board 190B.

[0062] The PC 190C mounted on the integration processing unit 190 has a function of exchanging data through serial communication with a plurality of optical detection processing units 160A, 160B, ··· of the measurement unit 180 via an optical fiber for communication connected to the transmit (T) terminal and receive (R) terminal of the communication board 190A, and also has a function of supplying a trigger signal to a plurality of optical detection processing units 160A, 160B, ··· of the measurement unit 180 via a coaxial cable connected to the strobe (S) terminal of the DIO board 190B.

[0063] Further, the PC 190C mounted on the integration processing unit 190 is connected to the light source 1 via a USB cable, and is capable of monitoring the operating states of the two optical comb generators (COMB1, COMB2) constituting the light source 1.

[0064] And in this multi-point vibration measurement test bench 100, the optical distributor 110 receives the measurement light L S and the reference light L R and a reference signal is supplied from the light source 1, and distributes the measurement light L S and the reference light L R to a plurality of optical paths respectively.

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

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

[0067] Here, for the plurality of multi-point vibration measurement units 170A, 170B, ···, a multi-point vibration measurement unit 170 having a configuration as shown in FIG. 3, for example, can be adopted.

[0068] FIG. 3 is a schematic diagram showing the configuration of the multi-point vibration measurement unit 170 provided in the multi-point vibration measurement test bench 100 described above.

[0069] The multi-point vibration measurement unit 170 includes a multi-point measurement head 150 connected to the optical distributor 110 via optical fibers FB 12A , FB 12B and a photodetection processing unit 160 connected to the multi-point measurement head 150 via optical fibers FB 26A1 , FB 26A2 , FB 26B1 , FB 26B2 .

[0070] This multi-point vibration measurement unit 170 is an improved multi-point measurement head 150 of the multi-point vibration measurement device 10 described above, which causes the optical multiplexer / demultiplexer 3 in the multi-point vibration measurement device 10 shown in FIG. 1 to function individually as an optical demultiplexing element and an optical multiplexing element, and prevents unnecessary reflection components from being mixed into the interference light necessary for multi-point vibration measurement.

[0071] That is, the multi-point measurement head 150 includes an interference optical system 120 into which the measurement light L S and the reference light L R are respectively input via optical fibers FB 12A , FB 12B , and an optical multiplexing / demultiplexing optical system 130 including an optical demultiplexing element 130A and an optical multiplexing element 130B between the projection optical system 4 that irradiates each frequency component of the measurement light L S 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, and a coupling optical system 135 that inputs each frequency component of the measurement light L S demultiplexed by the optical demultiplexing element 130A into the projection optical system 4 and inputs each frequency component of the measurement light L S reflected back from the plurality of measurement points on the measurement surface into the optical multiplexing element 130B.

[0072] The interference optical system 120 uses optical fibers FB 2A2 , FB 2B1 , FB 2B2Four optical couplers OC connected by A , OC B , OC C , OC D consisting of, and the optical coupler OC A is externally connected to the optical fiber FB 12A and the measurement light L S is input through it, and the optical coupler OC B is externally connected to the optical fiber FB 12B and the reference light L R is input through it.

[0073] In this interference optical system 120, the optical coupler OC A is internally connected to the optical coupler OC 2A2 through the optical fiber FB D , and the optical coupler OC B is internally connected to two optical couplers OC 2B1 , FB 2B2 through two optical fibers FB C , OC D .

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

[0075] And the measurement light L S input to this interference optical system 120 A is input to the above optical demultiplexing element 130A through the optical fiber FB 23A externally connected to the above optical coupler OC

[0076] The optical demultiplexing element 130A of the above optical multiplexing / demultiplexing optical system 130 has a plurality (m×n) of optical fibers FB 3411 , FB 3421 , FB 3431 , ···, FB 34m1 , ···, FB34mn A plurality (m×n) of optical couplers OC of the combined optical system 135 via C11 , OC C21 , OC C31 , ···, OC C1 , ···, OC Cmn are connected, and the multiplexing element 130B of the optical multiplexing / demultiplexing optical system 130 is a plurality (m×n) of optical fibers FB 4311 , FB 4321 , FB 4331 , ···, FB 43m1 , ···, FB 43mn via a plurality (m×n) of optical couplers OC of the combined optical system 135 C11 , OC C21 , OC C31 , ···, OC C1 , ···, OC Cmn are connected.

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

[0078] A plurality (m×n) of optical couplers OC of the combined optical system 135 C11 , OC C21 , OC C31 , ···, OC C1 , ···, OC Cmn are provided with a plurality (m×n) of optical fibers FB using PMF 4411 , FB 4421 , FB 4431 , ···, FB 44m1 , ···, FB 44mnthrough a plurality (m×n) of projection optical elements 44 of the projection optical system 4 11 , 44 21 , 44 31 , ···, 44 m1 , ··· 44 mn are connected thereto.

[0079] The projection optical elements 44 of the projection optical system 4 11 , 44 21 , 44 31 , ···, 44 m1 , ··· 44 mn each consist of a condenser lens 4 A11 , 4 A21 , 4 A31 , ···, 4 Am1 , ···, 4 Amn and a quarter-wave plate 4 B11 , 4 B21 , 4 B31 , ···, 4 Bm1 , ···, 4 Amn .

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

[0081] That is, in this multi-point measurement head 150, the measurement light L input from the interference optical system 120 to the optical demultiplexing element 130A of the optical multiplexing / demultiplexing optical system 130 through the optical fiber FB 23A is demultiplexed into a plurality of frequency components included in the measurement light L by the optical demultiplexing element 130A, and the plurality (m×n) of optical fibers FB S are input to the plurality (m×n) of optical couplers OC S of the coupling optical system 135 through the plurality (m×n) of optical fibers FB 3411 , FB 3421 , FB 3431 , ···, FB 34m1 , ···, FB 34mn respectively, and from the optical couplers OC C11 , OC C21 , OC C31 , ···, OC C1 , ···, OC Cmn the plurality (m×n) of optical fibers FB C11 , OC C21 , OC C31 , ···, OC C1 , ···, OC Cmn are input to the plurality (m×n) of condenser lenses 4 4411 , FB 4421 , FB 4431 , ···, FB 44m1 , ···, FB 44mn of the projection optical system 4 through the plurality (m×n) of optical fibers FB A11 , 4 A21 , 4 A31 , ···, 4 Am1 , ···, 4 Amn respectively, and a plurality (m×n) of frequency components are input to the plurality (m×n) of condenser lenses 4 A11 , 4 A21 , 4 A31 , ···, 4 Am1 , ···, 4 Amnis input, and a plurality (m×n) of types of frequency components are condensed by the condenser lens 4 A11 , 4 A21 , 4 A31 , ···, 4 Am1 , ···, 4 Amn and are irradiated onto a plurality of points (for example, m×n measurement points two-dimensionally arranged in a matrix) on the measurement surface of the measurement object 5 through the quarter-wave plates 4 B11 , 4 B21 , 4 B31 , ···, 4 Bm1 , ···, 4 Amn .

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

[0083] That is, in this multi-point measurement head 150, in the projection optical system 4, the condenser lens 4 A11 ,4 A21 ,4 A31 ,···,4 Am1 ,···,4 Amn the measurement light L output from the quarter-wave plate 4 Bm ,···,4 Bmn becomes circularly polarized for each frequency component and is irradiated onto the measurement object 5, and the reflected light returning from the measurement object 5 passes through the above-mentioned quarter-wave plate 4 S For each frequency component of the measurement light L output from the quarter-wave plate 4 B11 ,4 B21 ,4 B31 ,···,4 Bm1 ,···,4 Bmn and the condenser lens 4 A11 ,4 A21 ,4 A31 ,···,4 Am1 ,···,4 Amn For the output light of the condenser lens 4 A11 ,4 A21 ,4 A31 ,···,4 Am1 ,···,4 Amn the polarization planes of the frequency components of the reflected light input to the condenser lens 4 are orthogonal to each other.

[0084] The reflected light returning from the projection optical system 4 to the optical coupler OC of the coupling optical system 135 through the optical fiber FB 4411 ,FB 4421 ,FB 4431 ,···,FB 44m1 ,···,FB 44mn For each frequency component of the reflected light, the polarization planes of the reflected light returning to the optical coupler OC of the coupling optical system 135 through the optical fiber FB C11 ,OC C21 ,OC C31 ,···,OC C1 ,···,OC Cmn are orthogonal to each other. 3411 ,FB 3421 ,FB 3431 ,···,FB 34m1 ,···,FB 34mn and the optical coupler OC C11 ,OC C21 ,OC C31 ,···,OC C1 ,···,OC CmnThe measurement light L input thereto S has a polarization plane orthogonal to the polarization plane of each frequency component of, and the optical coupler OC C11 , OC C21 , OC C31 , ···, OC C1 , ···, OC Cmn from the optical fiber FB 4311 , FB 4321 , FB 4331 , ···, FB 43m1 , ···, FB 43mn is input to the multiplexer 130B of the optical multiplexing / demultiplexing optical system 130 through the optical fiber FB

[0085] Here, in the multi-point measurement head 150 of this multi-point vibration measurement unit 170, as shown in FIG. 4(A), the measurement light L S is demultiplexed by the optical demultiplexer 130A for each frequency component included in the measurement light L, and each frequency component is irradiated onto a plurality of measurement points on the measurement surface of the measurement object 5 through the projection optical system 4. As shown in FIG. 4(B), the measurement light L S ' composed of the reflected light of each frequency component for each frequency component reflected and returned from the measurement surface is multiplexed by the multiplexer 130B

[0086] Then, in the interference optical system 120, the measurement light L S ' composed of the reflected light of each frequency component reflected at a plurality of measurement points on the measurement surface and the reference light L R input from the light source 1 through the optical distributor 110 are output as measurement interference light from the optical coupler OC C , and the interference light between the measurement light L S input from the light source 1 through the optical distributor 110 and the reference light L R is output as reference interference light from the optical coupler OC D

[0087] The light detection processing unit 160 of this multi-point vibration measurement unit 170 includes an interference light detection unit 6 into 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 obtained by the interference light detection unit 6 and a reference interference signal S R ​It consists of a signal processing unit 7 to which a signal is input.

[0088] The interference light detector 6 of this light detection processing unit 160 includes a measurement light detector 6A and a reference light detector 6B each consisting of a balanced photodetector, and the optical coupler OC of the interference optical system 120 C Two optical fibers FB externally connected to 26A1 ,FB 26A2 The measurement light detector 6A that receives the measurement interference light input from the optical coupler OC via C detects the measurement interference light and converts it into an electrical signal, and outputs a measurement interference signal S including vibration information at a plurality of measurement points two-dimensionally distributed on the measurement surface of the measurement object 5. S At the same time, the reference light detector 6B that receives the reference interference light input from the optical coupler OC of the interference optical system 120 via D Two optical fibers FB externally connected to 26B1 ,FB 26B2 The reference light detector 6B that receives the reference interference light input from the optical coupler OC via D detects the reference interference light and outputs a reference interference signal S converted into an electrical signal. R

[0089] Here, in the balanced photodetector used as the measurement light detector 6A and the reference light detector 6B, the optical combs of each frequency component of the input measurement light L S and the reference light L R are combined into one beat having a frequency corresponding to the frequency difference of each optical comb, converted into an electrical signal, and output.

[0090] Then, in the signal processing unit 7, for the measurement interference signal S S and the reference interference signal S R obtained by the interference light detector 6, the phase for each frequency component is calculated by DFT analysis, and the measurement interference signal S S and the reference interference signal S R ​By obtaining the phase difference for each frequency component caused by the Doppler shift due to vibration at a plurality of measurement points on the measurement surface between them, vibration information at a plurality of measurement points on the measurement surface, for example, vibration velocity, moving distance, acceleration, etc. is analyzed to measure the vibration distribution of the measurement surface.

[0091] Thus, in this multi-point vibration measurement unit 170, the measurement light L S from the interference optical system 120 provided with the optical demultiplexing element 130A that demultiplexes a plurality of frequency components included therein S and the optical multiplexing element 130B that 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 ' is input to the interference optical system 120, the optical path of the measurement light L S output from the interference optical system 120 is demultiplexed. Even if a part of the measurement light L 23A is reflected by the optical demultiplexing element 130A to generate an unnecessary reflection component, this reflection component passes through the optical fiber FB A and returns to the optical coupler OC A of the interference optical system 120, and from this branched optical coupler OC 12A returns to the first optical comb generator (COMB1) 1A of the light source 1 through the optical fiber FB C and is absorbed by the isolator built in the light source unit. Therefore, even if an unnecessary reflection component is generated by reflection in the optical demultiplexing element 130A, this reflection component does not affect the interference light of the reference light L R output from the optical coupler OC S of the interference optical system 120 and the measurement light L D ', that is, the measurement interference light, or the interference light of the reference light L R output from the optical coupler OC S of the interference optical system 120 and the measurement light L

[0092] Therefore, in this multi-point vibration measurement unit 170, the optical demultiplexing element 130A provided in the optical path through which the measurement light L S irradiates the measurement surface through the interference optical system 120, and the optical couplers OC C11 , OCC21 , OC C31 , ···, OC C1 , ···, OC Cmn Measurement errors caused by unnecessary reflection components from various optical elements such as this mixing into the interference light required for multi-point vibration measurement are eliminated, enabling high-precision multi-point vibration measurement.

[0093] Here, in the interference optical system 120 of this multi-point vibration measurement unit 170, the time required from when the reference light L is output from the light source 1 until it is input to the optical coupler OCC is the same as the time required from when the measurement light L is output from the light source 1 until the measurement light L R ' is input to the optical coupler OC of the interference optical system 120. A delay optical system, the delay fiber FB, is provided to give a delay to the reference light L S from when it is output from the light source 1 until the measurement light L S ' is input to the optical coupler OC of the interference optical system 120. The optical fiber FB C connects the optical coupler OC where the reference light L is input from the light source 1 R to the optical coupler OC that outputs the interference light for measurement. It is provided in the optical fiber FB 2B1 ' where the reference light L is input from the light source 1 R and the optical coupler OC where the reference light L is input B and the optical coupler OC that outputs the interference light for measurement C are internally connected. 2B1 It is provided.

[0094] By providing the delay fiber FB 2B1 ' as a delay optical system in the optical fiber FB 2B1 ', the optical path length that the measurement light L S output from the light source 1 passes through until it is reflected by the reflection surface of the measurement object 5 and then input to the optical coupler OC of the interference optical system 120 as the measurement light L S ' is made equal to the optical path length that the reference light L C output from the light source 1 passes through until it is input to the optical coupler OC of the interference optical system 120. That is, the optical path length that the measurement light L S , L S ' passes through until it is input to the optical coupler OC of the interference optical system 120 is made equal to the optical path length that the reference light L R output from the light source 1 passes through until it is input to the optical coupler OC of the interference optical system 120. That is, until the measurement light L C output from the light source 1 is input to the optical coupler OC of the interference optical system 120, the measurement light L R output from the light source 1 S is input to the optical coupler OC of the interference optical system 120 C until the measurement light LS The optical path length through which it passes, and the reference light L output from the light source 1 R before the reference light L enters the optical coupler OC of the interference optical system 120 C is made equal to the optical path length through which the reference light L passes R until it reaches the optical coupler OC of the interference optical system 120.

[0095] In this way, until the measurement light L and the reference light L output from the light source 1 S are interfered with in the interference optical system 120 to be output as measurement interference light, a delay fiber FB which is a delay optical system R is provided in the optical path through which the reference light L passes 23C so that the optical path length through which the measurement light L including each frequency component returning through the optical fiber FB S ' and the reference light L R passes is made equal to the optical path length through which the reference light L passes. By making the optical path length through which the measurement light LS and the measurement light L including each frequency component reflected by the measurement surface R ' passes equal to the optical path length through which the reference light L passes, the reference interference signal S output from the interference light detection unit 6 of the light detection processing unit 160 for detecting the measurement interference light and the reference interference light obtained by the interference optical system 120 2B1 can cancel out the difference in phase fluctuations between the measurement light L and the reference light L in the measurement interference signal S S and can reduce the measurement error caused by the phase fluctuations of the measurement light L and the reference light L. Note that instead of the delay fiber FB R ', a delay optical system with spatial propagation having a required optical path length can also be adopted. R The measurement interference signal S S in the measurement light L S and the reference light L R can cancel out the difference in phase fluctuations between the measurement light L and the reference light L in the measurement interference signal S S and can reduce the measurement error caused by the phase fluctuations of the measurement light L and the reference light L. Note that instead of the delay fiber FB R ', a delay optical system with spatial propagation having a required optical path length can also be adopted. 2B1 ', a delay optical system with spatial propagation having a required optical path length can also be adopted.

[0096] Here, on the premise 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 by a mathematical formula.

[0097] Let the phase fluctuation of the laser, which is the seed light source of the light source 1, be 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 respectively Φ fm1 (t), Φ fm2 (t), and consider the vibration information component Φ Bn (t) caused by this phase fluctuation component and the phase variation due to the Doppler shift.

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

[0099] The phase fluctuation Φ S ’ of the optical comb component of the measurement light L Sn ’(t) returning through the measurement object 5 is, when the vibration information component due to the phase variation caused by the Doppler shift due to vibration is Φ Bn (t), Φ Sn ’(t)=Φ Bn (t + τ / 2)+Φ Laser (t + τ)+nΦ fm1 (t + τ) Equation (C) becomes. τ is the increasing component of the delay when traveling to and from the measurement object 5, and the reason for setting the delay of the phase component Φ Bn (t + τ / 2) to +τ / 2 is that only the return time of one way is experienced.

[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 the measurement interference signal S S obtained by FFT analysis of (t), and let this be Φ Ssn (t). Then, Equation (C) - Equation (B), that is, 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) is obtained.

[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 the reference interference signal S R obtained by FFT analysis of (t), and let this be Φ 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) is obtained.

[0102] When the difference (Equation (1) - Equation (2)) between the fluctuation Φ S (t) of the measurement interference signal S Ssn (t) shown in Equation (1) and the fluctuation Φ R (t) of the reference interference signal S SRn (t) shown in Equation (2) is calculated by the signal processing unit 150, Φ Sn ’(t)-Φ Sn (t)=Φ Bn (t+τ / 2)+Φ Laser (t+τ) +nΦfm1 (t + τ) - Φ Laser (t) - nΦ fm1 (t), Equation (3) becomes as follows

[0103] Here, Φ Sn ’(t) - Φ Sn (t) has no simultaneity, so the fluctuation component does not become zero

[0104] However, although it cannot be applied to a rangefinder that requires a large dynamic range, as a means that can be applied when the distance to the target object is almost determined like a vibration meter, reference light L R a delay fiber FB that imparts a delay corresponding to +τ in the optical path through which it passes 2B1 ’ to the above reference light L R the optical fiber FB through which the above reference light L 2B1 passes is inserted, and 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) and the phase fluctuation of the laser disappears. Since originally both optical comb 1 and optical comb 2 are made from the same laser, the phase fluctuations of the lasers are in phase, and the in-phase fluctuations are removed

[0105] The difference between the above Equation (4) and Equation (2) (Equation (4) - Equation (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) becomes as follows. 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 for comparing phases is the reference interference signal S R and the measurement interference signal S S are made to have a time difference of τ. For example, the cable of the reference interference signal S R , or the optical fibers FB 26B1 and FBFB 26B2 , or FB 2A2 and FB 2B2 is increased in length by an amount corresponding to the time τ to increase the delay of the reference interference signal S R . Then, the above equation (2) becomes Φ SRn_Delay (t)=Φ SRn (t + τ) =nΦ fm1 (t + τ)-nΦ fm2 (t + τ) Equation (6) . The difference between the above equations (4) and (6) (the phases according to equations (4) - (6) are Φ Ssn_Delay (t)-Φ SRn_Delay (t)=Φ Bn (t + τ / 2) Equation (7) , and the phase fluctuations of the oscillator are canceled out, leaving only the phase change component due to vibration.

[0107] Here, the cable of the reference interference signal S R , or the optical fibers FB 26B1 and FBFB 26B2 , or FB 2A2 and FB 2B2 is used to adjust τ. However, since the reference interference signal S R and the measurement interference signal S S are digitized by the signal processing unit 150, it is possible to digitally adjust by adding a time delay by shifting the calculation start point. By making all other delays the same according to the component with the largest delay, noise can be minimized.

[0108] And in a multi-point vibration measurement test bench 100 in which a plurality of multi-point measurement heads 150 of the multi-point vibration measurement unit 170 having such a configuration are arranged in a three-dimensional space where the measurement object 5 is located to simultaneously measure vibration information at a plurality of points, the integrated processing unit 190 connected to the measurement unit 180 composed of a plurality of multi-point vibration measurement units 170A, 170B, ··· monitors the operating states of the two optical comb generators (COMB1, COMB2) that constitute the light source 1 by the mounted personal computer (PC) 190C, and the measurement light L S and the reference light L R are respectively distributed to a plurality of optical paths by the distribution operation of the optical distributor 110, and the measurement light L S and the reference light L R are used to perform control to synchronize the measurement processing operation of acquiring vibration information at a plurality of measurement points on the measurement surface of the measurement object 5 by the measurement unit 180. At the same time, the surface plate 200 on which the measurement object 5 is placed, that is, the three-dimensional space where the test bench is installed, is defined as the global coordinates (X global , Y global , Z global ) of the origin O global ), and the origin set on the test bench or the origin o Aglobal , o Bglobal , ··· set on the measurement object 5 installed on the test bench is used as a reference, and the global coordinates (x Aglobal , y Aglobal , z Aglobal ), (x Bglobal , y Bglobal , z Bglobal ) ··· are used to assign the mounting positions and orientations of the plurality of multi-point measurement heads 150A, 150B, ···, and the local coordinates and light ray vectors of each irradiation point where the plurality of multi-point measurement heads 150A, 150B, ··· irradiate measurement light to a plurality of measurement points distributed two-dimensionally on the measurement surface of the measurement object 5 are respectively the global coordinates (x Aglobal , y Aglobal , z Aglobal ), (x Bglobal , y Bglobal , z Bglobal ) ··· of the multi-point vibration measurement units 170A, 170B, ··· and the mounting angles,Information on the measurement light emission angle Based on this, a global coordinate system (X global , Y global , Z global ) that defines the three-dimensional space where the above test bench is installed is defined, and the vibration information of each local coordinate (x Alocal , y Alocal , z Alocal ), (x Blocal , y Blocal , z Blocal )... synchronously acquired by the plurality of multi-point vibration measurement units 170A, 170B,... is integrated into three-dimensional vibration information in the global coordinate system (X global , Y global , Z global ) that defines the above three-dimensional space. Then, the vibration information acquired by serial communication from the plurality of optical detection processing units 160A, 160B,... of the measurement unit 180 via the communication board 190A is output as a multi-point vibration measurement result to a monitor screen or the like.

[0109] That is, in this multi-point vibration measurement test bench 100, for example, as shown in FIGS. 5, 6, and 7, it is arranged in the three-dimensional space where the measurement object 5 is located, and the vibration information at a plurality of measurement points two-dimensionally distributed on each of the plurality of measurement surfaces of the measurement object 5 is acquired by the plurality of multi-point measurement heads 150 (150A, 150B,...). However, the vibration information acquired by each multi-point measurement head 150 (150A, 150B,...) is the vibration information at each local coordinate (x Alocal , y Alocal , z Alocal ), (x Blocal , y Blocal , z Blocal )... of each multi-point measurement head 150 (150A, 150B,...). Therefore, in the above integration processing unit 190, the personal computer (PC) 190C defines the three-dimensional space where the measurement object 5 installed on the test bench is located as the global coordinate system (X global with the origin O global , Y global , Z global ), and the internal origin o Aglobal , o Bglobal, each origin o defined with respect to ··· Alocal , o Blocal , ··· 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 , ··· global coordinates (x Aglobal , y Aglobal , z Aglobal ), (x Bglobal , y Bglobal , z Bglobal ), ··· are assigned to the plurality of multi-point vibration measurement units 170A, 170B, ···, and the local coordinates and light vector of each irradiation point where the plurality of multi-point vibration measurement units 170A, 170B, ··· irradiate measurement light on a plurality of measurement points two-dimensionally distributed on the measurement surface of the measurement object 5 are the global coordinates (x Aglobal , y Aglobal , z Aglobal ), (x Bglobal , y Bglobal , z Bglobal ), ··· of the multi-point vibration measurement units 170A, 170B, ··· and the mounting angle. Information on the measurement light emission angle Based on the origin O that defines the three-dimensional space global global coordinates (X global , Y global , Z global ), the vibration information obtained synchronously by the plurality of multi-point vibration measurement units 170A, 170B, ··· is integrated into three-dimensional vibration information in the global coordinates (X global , Y global , Z global ) that define the three-dimensional space.

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

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

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

[0113] In this test bench for an electric motor, the measurement object 5 is an electric motor 53 connected to a load 51 via a transaxle (speed reducer) 52, and is a tunnel-type measuring instrument including a test tunnel 250 that is slightly larger than the measurement object 5 where the five multi-point measurement heads 150A, 150B, 150C, 150D, and 150E are installed. By transporting and installing it at the test site where the electric motor 53 is installed, the electric motor 53 is driven in a state where a mechanical load 51 is applied to the electric motor 53 via a transaxle (speed reducer) 52, and a vibration test is performed within a specified rotational speed range to check for abnormalities in terms of frequency, amplitude, mode, detection location, etc.

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

[0115] The multi-point measurement head 1500 shown in FIG. 8 replaces the coupling optical system 135 and the projection optical system 4 in the multi-point measurement head 150 with a projection optical system 140 incorporating a coupling optical element equipped with 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 denoted by the same reference numerals in the figure, and detailed descriptions thereof are omitted.

[0116] This multi-point measurement head 1500 is connected to a plurality of optical fibers FB 3411 , FB 3421 , FB 3431 , ···, FB 34m1 , ···, FB 34mn via the optical demultiplexing element 131A of the optical multiplexing / demultiplexing optical system 130, and a plurality of projection optical elements 44 4311 , FB 4321 , FB 4331 , ···, FB 43m1 , ···, FB 43mn are connected to the optical demultiplexing element 130A of the optical multiplexing / demultiplexing optical system 130 via the plurality of optical fibers FB A11 , 44 A21 , 44 A31 , ···, 44 Am1 , ···, 44 Amn to form a projection optical system 140 incorporating a coupling optical element.

[0117] For example, the projection optical elements 44A having the configurations shown in FIGS. 9(A) and 9(B) are respectively used for the plurality of projection optical elements 44 A11 , 44 A21 , 44 A31 , ···, 44 Am1 , ···, 44 Amn .

[0118] FIGS. 9(A) and 9(B) are diagrams showing configuration examples of the projection optical element 44A used in the projection optical system 140A incorporating a coupling optical element. (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 includes a coupling optical unit 4CA composed of a two-core capillary 4C1 and a coupling optical element 4C2 having optical characteristics for aligning the axes of light beams with orthogonal polarization directions output from the tips of the two-core optical fibers inserted into the two-core capillary 4C1. The input-side optical fiber FB 34 and the output-side optical fiber FB 43 are led out to the outside.

[0120] The stress application part directions of the polarization-maintaining (PM) fibers inserted into the two-core capillary 4C1 provided in the coupling optical unit 4CA are arranged to be orthogonal as shown in FIG. 9(B), and the optical module elements connected to all the optical fibers so that the stress application part directions become the polarization planes are manufactured with a unified standard.

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

[0122] In this projection optical element 44A, the frequency component L 34 of the measurement light L input through the input-side optical fiber FB from the optical demultiplexing element 130A S is input to the condenser lens 4A through the coupling optical element 4C2. The frequency component l S condensed by this condenser lens 4A is irradiated onto the measurement surface of the measurement object 5 through the quarter-wave plate 4B. The reflected light reflected from the measurement surface passes through the quarter-wave plate 4B and is returned to the condenser lens 4A as the frequency component l S with a polarization plane orthogonal to that of the frequency component l S '. Note that the quarter-wave plate 4B can be replaced with a Faraday rotator. S '. The quarter-wave plate 4B can be replaced with a Faraday rotator.

[0123] The frequency component l SIt is the frequency component l of the polarization plane with orthogonal polarization directions S ’ is condensed by the condenser lens 4A and enters the optical fiber FB on the output side through the coupling optical element 4C2 of the coupling optical unit 4CA 43 and is input to the multiplexer 130B of the optical multiplexing / demultiplexing optical system 130 through this optical fiber FB on the output side 43

[0124] For example, a birefringent crystal can be used for the coupling optical element 4C2 to perform beam splitting using walk-off

[0125] In addition, for the projection optical system 140A incorporating the coupling optical element, instead of the irradiation coupling optical element 4C2 using the birefringent crystal, a projection optical element 44B configured with a Wollaston prism 4Cb or the like as shown in FIGS. 10(A) and 10(B) can be employed

[0126] FIGS. 10(A) and 10(B) are diagrams showing a configuration example of the projection optical element 44B used in the projection optical system 140A incorporating the coupling optical element. (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] This projection optical element 44B includes a two-core capillary 4C1 and a coupling optical unit 4CB composed of a coupling optical element 4C2' having an optical characteristic of aligning the axes of light beams with orthogonal polarization directions output from the tips of the two-core optical fibers inserted into the two-core capillary 4C1. The input-side optical fiber FB 34 and the output-side optical fiber FB 43 are led out to the outside

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

[0129] ​The above-described combined optical element 4C2’ is formed by disposing a Wollaston prism 4Cb between two collimator lenses 4Ca and 4Cc.

[0130] Also in this projection optical element 44B, the measurement light L 34 input via the above-described optical fiber FB on the input side from the above-described optical wavelength division element 130A S frequency component l S is input to the condenser lens 4A via the above-described combined optical element 4C2’, and the frequency component l S condensed by this condenser lens 4A is irradiated onto the measurement surface of the measurement object 5 via the quarter-wave plate 4B. The reflected light reflected by the above-described measurement surface is the frequency component l S via the above-described quarter-wave plate 4B and has a polarization plane orthogonal to the polarization direction of the frequency component l S ’ and is returned to the above-described condenser lens 4A. Note that the above-described quarter-wave plate 4B may be replaced with a Faraday rotator.

[0131] The frequency component l S and the frequency component l S ’ of the polarization plane orthogonal to the polarization direction are condensed by the above-described condenser lens 4A, and via the above-described combined optical element 4C2’, they are input to the optical fiber FB 43 on the output side, and via this optical fiber FB 43 on the output side, they are input to the multiplexer 130B of the above-described optical multiplexing / demultiplexing optical system 130.

[0132] In the above-described projection optical elements 44A and 44B, as shown in (B) of FIG. 9 and (B) of FIG. 10, the polarization planes input to the above-described combined optical elements 4C2 and 4C2’ from the fiber end faces Port1 and Port2 in the above-described two-core capillary 4C1 arranged such that the stress application portions of the inserted polarization-maintaining (PM) fibers are orthogonal are such that the light input in the direction of the stress application portion passes through the above-described combined optical elements 4C2 and 4C2’ and the optical axes become coaxial and are output in the same direction. The frequency component l S of the above-described measurement light L S with the polarization plane in the same direction as the stress application portion of Port1 is Port1 (optical fiber FB on the input side 34Input from S ’ so that the polarization plane of the frequency component l reflected by the measurement surface is in the same direction as the stress application part of Port2, and it can be received by Port2 (the optical fiber FB on the output side) 43 .

[0133] Here, in the optical multiplexer / demultiplexer head 130 in the multi-point vibration measurement test bench 100 described above, the optical multiplexer / demultiplexer optical system 130 is connected to the projection optical system 4 via the coupling optical system 135. However, in the multi-point vibration measurement test bench 100A, the coupling optical system 135 and the projection optical system 4 in the multi-point vibration measurement test bench 100 are replaced with the projection optical system 140A with a built-in coupling optical element equipped with the function of the coupling optical system 135. As a result, the optical fibers FB that connect the coupling optical system 135 and the projection optical system 140 4311 , FB 4321 , FB 4331 , ···, FB 43m1 , ···, FB 43mn are no longer required, and the optical multiplexer / demultiplexer head 130A can be composed of two optical systems, namely the optical multiplexer / demultiplexer optical system 130 and the projection optical system 140A with a built-in coupling optical element. Not only is the configuration simplified, but also the unnecessary reflected light generated by the end faces of the optical fibers FB 4311 , FB 4321 , FB 4331 , ···, FB 43m1 , ···, FB 43mn is not accompanied.

[0134] That is, when using elements such as coupling optical elements as the coupling optical system 135 like the optical multiplexing / demultiplexing head 130 in the above-described multi-point vibration measurement test bench 100, it will complicate the optical system, and there are problems such as reflections inside the coupling optical element and the extinction ratio of the PM fiber. Also, using a coupling optical element module or the like will increase the number of components. Although reflections due to a plurality of lenses and fiber end faces inside the coupling optical element module also pose a problem, in this multi-point vibration measurement test bench 100A, by providing the coupling optical element built-in projection optical system 140A in the optical multiplexing / demultiplexing head 130A, it is not necessary to separately use the above-described coupling optical element module or the like, and a configuration with a larger directional coupling loss from Port1 to Port2 can be achieved, thus eliminating such problems.

[0135] In the Wollaston prism type coupling optical element built-in projection optical system 140A provided in the above-described optical multiplexing / demultiplexing head 130A, as measured, a directional coupling loss of 80 dB to 90 dB from Port1 to Port2 is obtained.

[0136] Then, in the multiplexing element 130B of the above-described optical multiplexing optical system 130, the measurement light L S reflected at a plurality of measurement points on the measurement surface of the above-described object to be measured 5 and returning through the above-described coupling optical element built-in projection optical system 140A S has each frequency component multiplexed, and the measurement light L 23C ' consisting of the reflected light of each frequency component reflected at a plurality of measurement points on the above-described measurement surface C is input from the above-described multiplexing element 130B to the optical coupler OC

[0137] of the above-described interference optical system 120 through the optical fiber FB C The optical coupler OC S of the above-described interference optical system 120 has the measurement light L 23C ' consisting of the reflected light of each frequency component reflected at a plurality of measurement points on the above-described measurement surface input through the optical fiber FB 12B and the reference light L B input from the second optical comb generator (COMB2) 1B of the above-described light source 1 to the optical coupler OC R through the optical fiber FB2B1 is input via and the measurement light L S ’ and the reference light L R The interference light with is output as measurement interference light. Also, the optical coupler OC D of the interference optical system 120 is from the first optical comb generator (COMB1) 1A of the light source 1 through the optical fiber FB 12A and is input to the optical coupler OC A The measurement light L S is input through the optical fiber FB 2A2 and the reference light L 12B from the second optical comb generator (COMB2) 1B of the light source 1 is input to the optical coupler OC B through the optical fiber FB R is input through the optical fiber FB 2B2 and the interference light between the measurement light L S and the reference light L R is output as reference interference light.

[0138] In the interference light detector 6 of the light detection processing unit 160 into which the measurement interference light and the reference interference light obtained by the interference optical system 120 are input, the optical coupler OC C of the interference optical system 120 is externally connected to two optical fibers FB 26A1 , FB 26A2 and the measurement interference signal S S obtained by detecting the measurement interference light with the measurement photodetector 6A that receives the measurement interference light through is output, and the optical coupler OC D of the interference optical system 120 is externally connected to two optical fibers FB 26B1 , FB 26B2 and the reference interference signal S R obtained by detecting the reference interference light with the interference light detector 6B that receives the reference interference light through is output.

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

[0140] Also 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 therein S The optical path through which the light passes, and the measurement light L provided with the optical multiplexing element 130B that multiplexes the reflected lights of each frequency component reflected at a plurality of measurement points on the measurement surface of the measurement object 5 S ' is input to the interference optical system 120, so the optical path through which the measurement light L irradiating the measurement surface of the measurement object 5 passes through the interference optical system 120 is demultiplexed. S The measurement error caused by the unnecessary reflection component by the optical demultiplexing element 130A provided in the optical path through which the light passes is eliminated from the interference light necessary for multi-point vibration measurement, and multi-point vibration measurement can be performed with high precision.

[0141] And in the signal processing unit 7 of the detection processing unit 160, for the measurement interference signal S S obtained by the interference light detection unit 6 and the reference interference signal S R For each frequency component, the phase is calculated by DFT analysis, and between the measurement interference signal S S and the reference interference signal S R By obtaining the phase difference for each frequency component due to the Doppler shift caused by vibration at a plurality of measurement points on the measurement surface, vibration information such as vibration velocity, moving distance, acceleration, etc. at the plurality of measurement points on the measurement surface is analyzed, and the vibration distribution on the measurement surface is measured.

[0142] Here, for the multi-point vibration measurement units 170A, 170A,... in the multi-point vibration measurement test bench 100, instead of the multi-point vibration measurement unit 170, a multi-point vibration measurement unit 1701 having a configuration as shown in FIG. 11 can be adopted.

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

[0144] This multi-point vibration measurement unit 1701 includes the projection optical element 44 of the projection optical system 140 in the multi-point measurement head 1500 A11 ,44 A21 ,44 A31 ,···,44 Am1 ,···,44 Amn of the (m×n) coupling optical elements 144 A11 ,144 A21 ,144 A31 ,···,144 Am1 ,···,144 Amn modularized into a coupling optical element array 144, the condenser lens 4 of the projection optical system 140 incorporating the coupling optical element A11 ,4 A21 ,4 A31 ,···,4 Am1 ,···,4 Amn i.e., an optical system 4Aab composed of a pair of condenser optical elements 4Aa and 4Ab that function as projection optical elements, and a 1 / 4 wavelength plate 4 B11 ,4 B21 ,4 B31 ,···,4 Bm1 ,···,4 Bmn that functions as a 1 / 4 wavelength plate 4B of the projection optical system 140A incorporating the coupling optical element. Here, the illustrated optical system 4Aab is a simplified two-sided telecentric optical system. Actually, it is composed of a large number of lenses. The two-sided telecentric optical system outputs the measurement light L perpendicularly from the coupling optical element array 144 SIt can be projected vertically onto the horizontal measurement object 5 and condensed. This is the most sensitive projection optical system. For a large measurement object 5, a telecentric optical system may be adopted on only one side, and an fθ optical system may be adopted on the other side. Also, it is not necessary to use a telecentric optical system, and an optical system suitable for the size and shape of the measurement object 5 can be selected.

[0145] In this multi-point vibration measurement unit 1701, the same components as those of the multi-point vibration measurement unit 170 of the multi-point vibration measurement test bench 100 are denoted by the same reference numerals in the figure, and detailed descriptions thereof are omitted.

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

[0147] As shown in FIGS. 12(A) and (B), the coupling optical element built-in projection optical system 1400 employs a coupling optical element array 144 in which a plurality (m×n) of coupling optical elements 144 A11 ,144 A21 ,144 A31 ,···,144 Am1 ,···,144 Amn are two-dimensionally arranged and modularized.

[0148] In the plurality (m×n) of coupling optical elements 144 in the coupling optical element array 144 A11 ,144 A21 ,144 A31 ,···,144 Am1 ,···,144 Amn coupling optical elements 4C2 made of a birefringent crystal or coupling optical elements 4C2' such as Wollaston prisms that use the above-mentioned walk-off to split light rays are used, and the input-side optical fiber and the output-side optical fiber from the two-core capillary are led out to the outside, respectively.

[0149] Note that in this coupling optical element array 144, the input-side optical fiber FB 3411 ,FB3421 , FB 3431 , ···, FB 34m1 , ···, FB 34mn and the optical fiber FB on the output side 4311 , FB 4321 , FB 4331 , ···, FB 43m1 , ···, FB 43mn are each led out to the outside from a two-core capillary. However, without using a two-core capillary, for example, a structure in which a plurality of optical fibers are led out to the outside through a plurality of insertion holes provided in a substrate, or the like, a structure that can accurately install a plurality of optical fibers and control the direction of the PMF may be adopted.

[0150] Also, in the combined optical element built-in projection optical system 1400, the measurement light L S is irradiated to m × n measurement points arranged two-dimensionally in a matrix for each frequency component, and a plurality (m × n) of combined optical elements 144 A11 , 144 A21 , 144 A31 , ···, 144 Am1 , ···, 144 Amn are two-dimensionally arranged and modularized into a combined optical element array 144. However, depending on the measurement object 5, a combined optical element array in which a plurality of combined optical elements 144 A11 , 144 A21 , 144 A31 , ···, 144 Am1 , ···, 144 Amn are two-dimensionally arranged in a fine grid pattern (for example, a hexagonal close-packed grid pattern) and modularized may be adopted.

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

[0152] By adopting the modularized coupling optical element array 144, this projection optical system 1400 with a built-in coupling optical element can collect the plurality of frequency components of the measurement light L 3411 , FB 3421 , FB 3431 , ···, FB 34m1 , ···, FB 34mn input via the plurality of optical fibers FB S using the optical system 4Aab composed of the condenser optical elements 4Aa and 4Ab, and irradiate a plurality of measurement points on the measurement surface of the object to be measured 5 through a quarter-wave plate 4B.

[0153] Then, the reflected light reflected at a plurality of measurement points on the measurement surface of the object to be measured 5 is collected by the optical system 4Aab through the quarter-wave plate 4B as frequency components with a polarization plane orthogonal to the polarization direction of the irradiated frequency components, and is input to the multiplexing element 130B of the optical multiplexing / demultiplexing optical system 130 via the plurality of optical fibers FB 4311 , FB 4321 , FB 4331 , ···, FB 43m1 , ···, FB 43mn on the output side.

[0154] In the multiplexing element 130B of the optical multiplexing / demultiplexing optical system 130, the frequency components of the measurement light L S reflected at a plurality of measurement points on the measurement surface of the object to be measured 5 and returned through the projection optical system 140B are multiplexed, and the measurement light L S' is from the above photosynthetic element 130B to the optical fiber FB 23C and input to the optical coupler OC of the above interference optical system 120 through C it.

[0155] In the above interference optical system 120, the measurement light L composed of the reflected light of each frequency component reflected at a plurality of measurement points on the above measurement surface S ' and the reference light L input to the optical coupler OC through the optical fiber FB from the second optical comb generator (COMB2) 1B of the light source 1 12B are output as the measurement interference light from the optical coupler OC B together with the interference light between the reference light L input to the optical coupler OC R from the optical fiber FB through the optical fiber FB from the first optical comb generator (COMB1) 1A of the light source 1 C and the measurement light L input to the optical coupler OC 12A through the optical fiber FB A is output as the reference interference light from the optical coupler OC S together with the interference light between the reference light L input to the optical coupler OC B from the optical fiber FB through the optical fiber FB from the first optical comb generator (COMB1) 1A of the light source 1 R and the reference light L input to the optical coupler OC D from the optical fiber FB through the optical fiber FB from the first optical comb generator (COMB1) 1A of the light source 1

[0156] In the interference light detector 6 of the measurement detection processing unit 160 to which the measurement interference light and the reference interference light obtained by the above interference optical system 120 are input, two optical fibers FB C externally connected to the optical coupler OC of the above interference optical system 120 26A1 , FB 26A2 The measurement interference signal S obtained by detecting the measurement interference light by the measurement optical detector 6A that receives the measurement interference light through the optical fiber FB and converting it into an electrical signal S is output, and two optical fibers FB D externally connected to the optical coupler OC of the above interference optical system 120 26B1 , FB 26B2 The reference interference signal S obtained by detecting the reference interference light by the interference light detector 6B that receives the reference interference light through the optical fiber FB and converting it into an electrical signal R is output.

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

[0158] Also, in the multi-point vibration measurement unit 1702 shown in FIG. 13, the measurement light L S The measurement light L output from the interference optical system 120 provided with the optical demultiplexing element 130A for demultiplexing a plurality of frequency components included in S The optical path through which passes and the measurement light L provided with the optical multiplexing element 130B for multiplexing the reflected lights of the respective frequency components reflected at a plurality of measurement points on the measurement surface of the measurement object 5 S ' is input to the interference optical system 120 is demultiplexed, so that the unnecessary reflection component by the optical demultiplexing element 130A provided in the optical path through which the measurement light L irradiating the measurement surface of the measurement object 5 passes through the interference optical system 120 is eliminated. The measurement error caused by mixing into the interference light necessary for multi-point vibration measurement can be eliminated, and multi-point vibration measurement can be performed with high precision. S This multi-point vibration measurement unit 1702 can also be adopted for the multi-point vibration measurement units 170A, 170B,... in the multi-point vibration measurement test bench 100A.

[0159] Here, in the interference optical system 120 in the multi-point vibration measurement test benches 100 and 100A, the interference light of the measurement light L

[0160] output from the light source 1 and the reference light L S is output as reference interference light, and the measurement light L R output from the light source 1 is irradiated onto the measurement surface of the measurement object 5 through the multi-point measurement heads 150, 150A, 150B from the interference optical system 120, and the measurement light L S reflected by the measurement surface and returned through the multi-point measurement heads 150, 150A, 150B and the reference light L S ' and the reference light L ROutput the interference light as measurement interference light, and include a measurement photodetector 6A that receives the measurement interference light output from the interference optical system 120, and an interference photodetector 6B that receives the reference interference light output from the interference optical system 120. In the interference light detection unit 6, the measurement interference light is detected by the measurement photodetector 6A and converted into an electrical signal to obtain a measurement interference signal S S And, the reference interference light is detected by the interference photodetector 6B and converted into an electrical signal to obtain a reference interference signal S R In this way.

[0161] And, in the multi-point vibration measurement test benches 100, 100A, in the signal processing unit 7 of the detection processing unit 160, the measurement interference signal S S Obtained from the interference light detection unit 6 and the reference interference signal S R For each frequency component, the phase is calculated by DFT analysis, and the phase difference for each frequency component caused by the Doppler shift due to vibration at a plurality of measurement points on the measurement surface is obtained, so as to analyze the vibration information at a plurality of measurement points on the measurement surface. However, the measurement interference signal S S Is an interference signal obtained by detecting the measurement interference light, which is the interference light of the measurement light L S Reflected back by the measurement surface and the reference light L R Therefore, in the signal processing unit 7, the phase for each frequency component can be calculated by DFT analysis of only the measurement interference signal S S And the phase difference for each frequency component caused by the Doppler shift due to vibration at a plurality of measurement points on the measurement surface can be obtained.

[0162] That is, the multi-point vibration measurement units 170A, 170B, ··· in the multi-point vibration measurement test benches 100, 100A can be composed of an interference optical system 1200 that outputs only measurement interference light, such as the multi-point vibration measurement unit 1702 shown in FIG. 13, the multi-point vibration measurement unit 1703 shown in FIG. 14, and the multi-point vibration measurement unit 1704 shown in FIG. 15, and a detection processing unit 1600 that detects only the measurement interference light output from this interference optical system 1200.

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

[0164] In these multi-point vibration measurement units 1702, 1703, 1704, the components identical to those of the multi-point vibration measurement unit 170 of the multi-point vibration measurement test bench 100 are denoted by the same reference numerals in the figure, and detailed descriptions thereof are omitted.

[0165] Here, FIG. 16 is a schematic diagram showing the software hierarchy of the integration process executed by the integration processing unit 190. This FIG. 16 shows the software hierarchy of the integration process for integrating each vibration information acquired synchronously by the plurality of multi-point vibration measurement units 170A, 170B, ··· into three-dimensional vibration information.

[0166] That is, in the integration processing unit 190, each vibration information acquired synchronously by the plurality of multi-point vibration measurement units 170A, 170B, ··· is collected as vibration information with coordinate information of each head reference local coordinates (x Alocal , y Alocal , z Alocal ), (x Blocal , y Blocal , z Blocal ), ··· added thereto, and is locally integrated for each local coordinate. Each locally integrated vibration information is based on the global coordinates (x Aglobal o Bglobal , ···) of each origin o Aglobal , y Aglobal , z Aglobal ), (x Bglobal , y Bglobal , z Bglobal ) ··· with respect to the attachment orientation of each head and the origin set on the test bench or the origin set on the measurement object 5 installed on the test bench, and the local coordinates (x Alocal , y Alocal , zAlocal ), (x Blocal , y Blocal , z Blocal ), ··· are globally coordinate-transformed in batches every time, and are converted into the global coordinates (X global , Y global , Z global ) of the vibration information given to the three-dimensional space where the test bench is provided. Then, each vibration information that has been globally coordinate-transformed is collected and integrated as the three-dimensional vibration information of the global coordinates (X global , Y global , Z global ). The integrated global coordinates (X global , Y global , Z global ) of the three-dimensional vibration information are subjected to FFT analysis to identify the earthquake source location and display an image of the vibration distribution, etc.

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

[0168] The multi-point vibration measurement test bench 100A shown in this FIG. 17 is obtained by providing a single measurement unit 280 including a plurality (here, two) of single-point vibration measurement units 270A and 270B on the multi-point vibration measurement test bench 100. For the components that are the same as those of the multi-point vibration measurement test bench 100, the same reference numerals are given in the figure, and detailed descriptions thereof are omitted.

[0169] That is, the multi-point vibration measurement test bench 100 is arranged in the three-dimensional space where the measurement object 5 is located, like the multi-point vibration measurement test bench 100A shown in FIG. 17. The measurement light L S distributed to a plurality of optical paths by the optical distributor 110 respectively, and the reference light L RBy using at least one single-point vibration measurement unit 270 (270A, 270B) to synchronously acquire the vibration information of one measurement point on the measurement surface of the measurement object 5, together with the vibration measurements at a plurality of measurement points on the measurement surfaces 5A, 5B, ··· of the measurement object 5 by the plurality of multi-point vibration measurement units 170A, 170B, ···, the vibration measurements at each one measurement point on the measurement surfaces 5A1, 5A2, ···, 5B1, 5B2, ··· of the measurement object 5 by the at least one single-point vibration measurement unit 270 (270A, 270B) are performed synchronously, and each acquired vibration information is integrated by the integration processing unit 190 into three-dimensional vibration information, and the integrated global coordinates (X global , Y global , Z global ) of the three-dimensional vibration information can be subjected to FFT analysis to identify the source position and display an image of the vibration distribution, etc.

[0170] In this multi-point vibration measurement test bench 100A, the single-point vibration measurement units 270A, 270B respectively include an interference optical system 210A, 210B connected to an optical distributor 110 via optical fibers using two sets of PMFs, an optical multiplexing / demultiplexing optical system 220A, 220B connected to the interference optical systems 210A, 210B via optical fibers using two sets of PMFs, a plurality of single-point measurement heads 250A1, 250A2, ···, 250B1, 250B2, ··· connected to the optical multiplexing / demultiplexing optical systems 220A, 220B via optical fibers using two sets of PMFs, and a single-point measurement photodetection processing unit 260A, 260B, ··· connected to the interference optical systems 210A, 210B via optical fibers using four sets of SMFs.

[0171] The single-point vibration measurement units 270A, 270B are internally connected by four optical couplers OC 22A2 , OOC 22B1 , OC 22B2 by optical fibers FB A , OOC B , OC C , OC Dcomprises, and the optical coupler OC is externally connected via the optical fibers FB212A and FB212B of a pair of PMFs used by the optical distributor 110 A , OOC B and is externally connected to the optical coupler OC, and the optical multiplexing / demultiplexing optical system 230 is externally connected to the optical coupler OC 2341 via the optical fibers FB A and the optical coupler OC C and includes an interference optical system 220 externally connected thereto.

[0172] FIG. 18 is a schematic diagram showing a configuration example 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 single-point vibration measurement unit 270, an optical coupler OCA has an optical coupler OC 22A2 internally connected via an optical fiber FB D , and two optical fibers FB B are internally connected to the optical coupler OC 22B1 , FB 22B2 via which two optical couplers OC C , OC D are internally connected.

[0174] And this interference optical system 220 has the measurement light L S distributed to a plurality of optical paths by the optical distributor 110 and the reference light L R input to the optical couplers OC A , OC B via the optical fibers FB212A and FB212B, and the input measurement light L S is input from the optical coupler OC A to the optical demultiplexing element 231A of the optical multiplexing / demultiplexing optical system 230 via the optical fiber FB 2341 .

[0175] The optical multiplexing / demultiplexing optical system 230 is connected to the optical coupler OC A of the interference optical system 220 via an optical fiber FB 2341 , and a plurality of optical fibers FB 4411 , FB 4421 , FB 4431An optical splitter 231A connected to a plurality of single-point measurement heads 2501, 2502, ··· via ···, and a plurality of optical fibers FB 5311 , FB 5321 , FB 5331 , ··· are connected via, and the optical fiber FB 2431 is connected to an optical combiner 231B of the interference optical system 220 via the optical fiber FB C and consists of the optical combiner 231B.

[0176] The optical splitter 231A splits each frequency component included in the measurement light L S input from the optical distributor 110 into each frequency component one by one, and the measurement light for each frequency component is input to the plurality of single-point measurement heads 2501, 2502, ··· via the plurality of optical fibers FB 4411 , FB 4421 , FB 4431 , ···.

[0177] The single-point measurement heads 2501, 2502, ··· irradiate each measurement point in a plurality of measurement regions of the measurement object 5 with the measurement light for each frequency component input from the optical splitter 231A, and the reflected light of each frequency component for each frequency component reflected back at each one measurement point on the measurement surfaces 5A1, 5A2, ···, 5B1, 5B2, ··· is input to the optical combiner 231B via the plurality of optical fibers FB 5311 , FB 5321 , FB 5331 , ···.

[0178] The optical combiner 231B of the optical splitter / combiner optical system 230 combines the reflected light of each frequency component for each frequency component reflected back at each one measurement point on the measurement surfaces 5A1, 5A2, ···, 5B1, 5B2, ··· and returned via the single-point measurement heads 2501, 2502, ···.

[0179] The optical combiner 231B combines the reflected light of each frequency component for each frequency component to obtain the measurement light L S ’ and inputs it to the optical coupler OC of the interference optical system 220 COutput to

[0180] And in the interference optical system 220, the reflected light of each frequency component of each one frequency component reflected and returned at each one measurement point on the measurement surfaces 5A1, 5A2, ···, 5B1, 5B2, ··· is combined by the multiplexing element 231B of the optical multiplexing and demultiplexing system 230 to obtain the measurement light L S ’ and the reference light L input from the optical distributor 110 to the optical coupler OC 212B via the optical fiber FB B The interference light of is output from the optical coupler OC as measurement interference light, and the measurement light L input from the optical distributor 110 to the optical coupler OC R via the optical fibers FB C And the interference light of the reference light L input from the optical distributor 110 to the optical coupler OC 212A , FB 212B via the optical fibers FB A , OC B is output from the optical coupler OC as reference interference light S and the reference light L R The interference light of is output from the optical coupler OC D as reference interference light

[0181] Here, each one frequency component reflected at each one measurement point on the measurement surfaces 5A1, 5A2, ···, 5B1, 5B2, ··· of the measurement object 5 has a phase fluctuation due to the Doppler shift caused by the vibration at each one measurement point on the measurement surfaces 5A1, 5A2, ···, 5B1, 5B2, ···, and the interference light with the one frequency component of the reference light L R That is, the measurement interference light is accompanied by a phase fluctuation due to the Doppler shift. Therefore, as will be described later, in the interference light detection unit 6 of the one-point measurement light detection processing unit 260, an one-point measurement interference signal including vibration information at each one measurement point on the measurement surfaces 5A1, 5A2, ···, 5B1, 5B2, ··· can be obtained

[0182] The measurement interference light output from the optical coupler OC of the interference optical system 220 and the reference interference light output from the optical coupler OOC C are the optical fibers FB using a four-pack of SMF D via 226A1 , FB 226A2 , FB 226B1 , FB226B2 It is input to the interference light detection unit 6 of the single-point measurement optical detection processing unit 260 via

[0183] The single-point measurement optical detection processing unit 260 in the single-point vibration measurement unit 270 can adopt the same configuration as the optical detection processing unit 160 of the multi-point vibration measurement unit 170 respectively. The interference light detection unit 6 of the single-point measurement optical detection processing unit 260, into 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 including vibration information at each one measurement point on the measurement surfaces 5A1, 5A2, ···, 5B1, 5B2, ···. In the signal processing unit 7, for the single-point measurement interference signal and the reference interference signal, the phase for each frequency component is calculated by DFT analysis, and between the single-point measurement interference signal and the reference interference signal, the phase difference for each frequency component caused by the Doppler shift due to vibration at each one measurement point on the measurement surface is obtained, thereby analyzing the vibration information such as vibration velocity, moving distance, acceleration, etc. at each one measurement point on the measurement surfaces 5A1, 5A2, ···, 5B1, 5B2, ···, and measuring the distribution of vibrations at each one measurement point on the measurement surfaces 5A1, 5A2, ···, 5B1, 5B2, ···.

[0184] Here, in the multi-point vibration measurement test bench 100A, in the two single-point vibration measurement units 270A and 270B, the distribution of vibrations at each one measurement point on the measurement surfaces 5A1, 5A2, ···, 5B1, 5B2, ··· is measured by a plurality of single-point measurement heads 250A1, 250A2, ···, 250B1, 250B2, ···. However, it is provided with a single-point measurement unit 280 provided with at least one single-point measurement head 250. For example, vibration information at one measurement point on the measurement surface 5A1 of the measurement object 5 can be acquired by one single-point measurement head 250A1 provided in the single-point vibration measurement unit 270A.

[0185] Here, FIG. 19 is a schematic diagram showing another configuration example 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 above multi-point vibration measurement test bench 100A, as two single-point vibration measurement units 270A and 270B, single-point vibration measurement units 270 with the configurations shown in FIG. 18 are provided respectively. The vibrations at each one measurement point on the measurement surfaces 5A1, 5A2, ···, 5B1, 5B2, ··· are measured by a plurality of single-point measurement heads 250A1, 250A2, ···, 250B1, 250B2, ···. 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 made independent and used as the single-point measurement head 250.

[0187] Also, like the single-point vibration measurement unit 270 shown in FIG. 20, a part of the multi-point optical head 1400 shown in FIG. 15 can be made independent and used as the single-point measurement head 250.

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

[0189] And in this multi-point vibration measurement test bench 100A, a plurality of multi-point measurement heads 150 (150A, 150B, ···) are arranged in the three-dimensional space where the measurement object 5 is located, and vibration information at a plurality of measurement points two-dimensionally distributed on each of the plurality of measurement surfaces of the measurement object 5 is acquired. At the same time, vibration information at each one measurement point on the measurement surfaces 5A1, 5A2, ···, 5B1, 5B2, ··· is 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. In the integration processing unit 190, by a personal computer (PC) 190C, the three-dimensional space where the measurement object 5 installed on the test bench is located is set as the origin O global of the global coordinates (X global , Y global , Z global) is defined as, and each internal origin o of the plurality of multi-point measurement heads 150 (150A, 150B, ···) Aglobal , o Bglobal , ··· are defined respectively based on each origin o Alocal , o Blocal , ··· 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 , ··· global coordinates (x Aglobal , y Aglobal , z Aglobal ), (x Bglobal , y Bglobal , z Bglobal ), ··· are given to the plurality of multi-point vibration measurement units 170A, 170B, ···, and the plurality of multi-point measurement heads 150 (150A, 150B, ···) provided in the plurality of multi-point vibration measurement units 170A, 170B, ··· irradiate measurement light on a plurality of measurement points two-dimensionally distributed on the measurement surface of the measurement object 5. The local coordinates and ray vectors of each irradiation point are the global coordinates (x Aglobal , y Aglobal , z Aglobal ) of the multi-point vibration measurement units 170A, 170B, ···, (x Bglobal , y Bglobal , z Bglobal ), ··· and the attachment angle, Information on the measurement light emission angle Based on this, a global coordinate transformation is performed to collectively transform to the global coordinates (X global , Y global , Z global , Z global ) of the origin O that defines the three-dimensional space, and each internal origin o of the plurality of single-point measurement heads 250A1, 250A2, ···, 250B1, 250B2, ··· provided in the two single-point vibration measurement units 270A, 270B SA1global , o SA2global , ···, o SB1global , o SB2global , ··· are defined respectively based on each origin oSA1local , o SA2local , ···, o SB1local , o SB2 local , ··· of 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 with respect to 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 , ··· of 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 given to the two single-point vibration measurement units 270A and 270B, and the local coordinates and ray vectors of each irradiation point where the plurality of single-point measurement heads 250A1, 250A2, ···, 250B1, 250B2, ··· provided in the two single-point vibration measurement units 270A and 270B irradiate measurement light on the measurement points distributed two-dimensionally on the measurement surface of the measurement object 5 are the global coordinates (x Aglobal , y Aglobal , z Aglobal ), (x Bglobal , y Bglobal , z Bglobal ), ··· and the mounting angles Information on the measurement light emission angle are used to define the origin O of the three-dimensional space global of the global coordinates (X global , Y global , Z global) is converted into, and the vibration information obtained synchronously by the plurality of multi-point vibration measurement units 170A, 170B, ··· and the one-point vibration measurement units 270A, 270B is integrated into the three-dimensional vibration information in the global coordinates (X global , Y global , Z global ). Then, FFT analysis is performed on the integrated three-dimensional vibration information in the global coordinates (X global , Y global , Z global ) to identify the earthquake source location and display an image of the vibration distribution, etc.

[0190] Note that in the integration process of integrating the vibration information obtained synchronously by the one-point vibration measurement units 270A, 270B into three-dimensional vibration information, different from the integration process of integrating the vibration information obtained synchronously by the multi-point vibration measurement units 150A, 150B into three-dimensional vibration information, batch coordinate conversion cannot be performed, and it is necessary to input global coordinates for each head.

[0191] FIG. 22 is a schematic diagram showing the software hierarchy of the integration process of integrating the vibration information obtained synchronously by the plurality of one-point vibration measurement units 270A, 270B executed by the integration processing unit 190 in the multi-point vibration measurement test bench 100A.

[0192] That is, in the integration processing unit 190, the vibration information obtained synchronously by the plurality of one-point measurement heads 250A1, 250A2, ···, 250B1, 250B2, ··· provided in the two one-point vibration measurement units 270A, 270B is, for each head, 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) ··· is collected as coordinate information with an addition, and is locally coordinated for each of the single-point vibration measurement units 270A and 270B. The vibration information for each of the locally coordinated single-point vibration measurement units 270A and 270B is based on the attachment orientation of each head and the origin set on the test bench or the origin set on the measurement object 5 installed on the test bench, and is 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 ). Based on this, it is globally coordinate-transformed for each of the single-point vibration measurement units 270A and 270B, and is transformed into vibration information of global coordinates (Xglobal, Yglobal, Zglobal) given to the three-dimensional space where the test bench is provided. Then, each vibration information obtained by the plurality of single-point measurement heads 250A1, 250A2, ···, 250B1, 250B2, ··· and globally coordinate-transformed is collected and integrated as three-dimensional vibration information of global coordinates (Xglobal, Yglobal, Zglobal), and the integrated global coordinates (X global , Y global , Z global ) of three-dimensional vibration information is subjected to FFT analysis to identify the source position and display an image of the vibration distribution, etc.

[0193] Here, a plurality of 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 object 5 to be measured. However, for example, like the single-point measurement head 250' shown in FIG. 21, it is also conceivable to measure the vibration of the jig 280 that holds the object 5 to be measured. The vibration of the object 5 to be measured and the vibration of the jig 280 can be separately measured, and the jig vibration component included in the vibration information obtained by the multi-point measurement heads 150 (150A, 150B, ···) can be removed using the jig vibration information obtained from the single-point measurement head 250' by the single-point measurement head 250'.

[0194] When a part of the multi-point optical head 140 is made independent 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 each 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 the multi-point optical head and the single-point measurement head are mixed.

[0195] That is, in the integration processing unit 190, coordinate transformation is performed on each vibration information acquired synchronously by the multi-point optical head 140 and the single-point measurement 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 FIG. 16. 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 FIG. 22.

[0197] Even if a multi-point optical head and a single-point measurement head are mixed, after converting them into global coordinates according to the determined procedures respectively, each vibration information can be uniformly handled. In the above integration processing unit 190, each vibration information obtained by the multi-point optical head 140 and converted into global coordinates and the vibration information obtained by the single-point measurement head 250 and converted into global coordinates are collected and integrated, and FFT analysis is performed on the three-dimensional vibration information of the integrated global coordinates, so that the source position can be specified and the vibration distribution can be displayed as an image, 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 element, 4, 240 Projection optical system, 4 A11 , 4 A21 , 4 A31 , ···, 4 Am1 , ···, 4 Amn , 4A Condensing lens, 4 B11 , 4 B21 , 4 B31 , ···, 4 Bm1 , ···, 4 Bmn , 4B Quarter-wave plate, 4Aa, 4Ab Condensing optical elements, 4Aab Set of optical systems, 4C1, 2-core capillary, 4CA, 4CB Coupling optical parts, 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 surfaces, 6, 6’ Interference light detection part, 6A Measurement photodetector, 6B Reference photodetector, 7, 7’ Signal processing part, 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 elements, 44 combined optical element arrays, 100, 100A multi-point vibration measurement test benches, 110 optical distributors, 130 optical multiplexing / demultiplexing optical systems, 130A optical demultiplexing elements, 130B optical multiplexing elements, 135 combined optical systems, 140, 140A, 140B, 1400 projection optical systems with built-in combined optical elements, 144 combined optical element arrays, 150, 150A, 150B, ··· multi-point measurement heads, 160, 160A, 160B, ···, 1600 photodetection processing units, 170, 170A, 170B, ···, 1701, 1702, 1703, 1704 multi-point vibration measurement units, 180 measurement units, 190 integrated processing units, 190A communication boards, 190B DIO boards, 190C PCs, 210A, 210B optical multiplexing / demultiplexers, 250, 250’, 250A1, 250A2, ···, 250B1, 250B2, ··· single-point measurement heads, 260A, 260B, ··· single-point measurement photodetection processing units, 270 single-point measurement units, 270A, 270B single-point vibration measurement units, 1500, 1501, 1502, 1503, 1504 multi-point measurement heads, 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 ’ measurement light, L R reference light, l S , l S ’ frequency component, S R reference interference signal, S S measurement interference signal

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 a coherent measurement light and a reference light, the measurement light and the 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 in which the measurement object installed on the test bench is located, and that synchronously acquire vibration information of a plurality of measurement points that are two-dimensionally distributed on a measurement surface of the measurement object using the measurement light and the reference light that are 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 measuring units into three-dimensional vibration information; Equipped with a multi-point vibration measurement test bench configured to integrate 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 in which the test bench is installed, and a multi-point vibration measurement unit configured to integrate 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 unit configured to integrate 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 multi-point vibration measuring unit includes: a multi-point measurement head including an interference optical system into which the measurement light and the reference light distributed to a plurality of optical paths by the optical distributor are respectively input, an optical branching element that branches each frequency component contained in the measurement light input from the interference optical system, a projection optical system that irradiates a plurality of measurement points on a measurement surface of the measurement object with each frequency component branched by the optical branching element, 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 it to the interference optical system, and a combining 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; a measurement interference light detection unit, in the interference optical system, for receiving measurement interference light obtained by interfering between 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 multi-point measurement head and a reference light output from the light source, and converting 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; 2. The multi-point vibration measurement test bench according to claim 1, further comprising:

3. at least one single-point vibration measuring 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 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 mounting positions and orientations of the plurality of multi-point vibration measuring units in global coordinates based on an origin set on the test bench or an origin set on a measurement object set on the test bench in a three-dimensional space in which the test bench is installed, converts local coordinates and light ray vectors of each irradiation point at which the plurality of multi-point vibration measuring units irradiate a plurality of measurement points distributed two-dimensionally on a 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 on the global coordinates, mounting angles, and measurement light emission angles of the respective multi-point vibration measuring units, and converts the local coordinates and light 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 on the origin set on the test bench or an origin set on the test bench. a mounting position and orientation of the at least one single-point vibration measuring unit in global coordinates based on an origin set on a measurement object installed on a test bench, a local coordinate and a ray vector of an irradiation point at which the at least one single-point vibration measuring unit irradiates one measurement point on the measurement surface of the measurement object with measurement light are converted into global coordinates that define a three-dimensional space in which the test bench is installed based on information on the global coordinates, mounting angle, and measurement light emission angle of the at least one single-point vibration measuring unit, and each vibration information acquired synchronously by the plurality of multi-point vibration measuring units and the at least one single-point vibration measuring unit is integrated into three-dimensional vibration information.

4. The one-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 to which the measurement light is input via the interference optical system; at least one single-point measurement head including a projection optical system which receives one frequency component of a plurality of frequency components contained in the measurement light separated by the optical multiplexing and splitting optical system, irradiates the measurement light of the one frequency component received at one measurement point on the measurement surface of the measurement object, and receives reflected light of the measurement light of the one frequency component reflected and returned from the measurement point on the measurement surface, and receives the reflected light of the measurement light of the one frequency component received at the measurement surface at the optical multiplexing and splitting optical system; a single-point measurement interference light detection processing unit to which the 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 multiplexing, by 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 one-point measurement head, and obtains interference light for one-point measurement by causing interference between the reference light input from the optical distributor and the measurement light consisting of the reflected light of the at least one frequency component; The one-point measurement interference light detection processing section receives the one-point measurement interference light by the one-point measurement interference light detection section and converts it into an electrical signal to obtain a one-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. The multi-point vibration measurement test bench according to claim 2, characterized in that the multi-point measurement head irradiates each frequency component, which is obtained by splitting each frequency component contained in the measurement light by the optical splitting element, 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, which is reflected and returned from the plurality of measurement points on the measurement surface, by an optical combining element.

6. 3. The multi-point vibration measurement test bench according to claim 2, wherein the multi-point measurement head irradiates each frequency component, which is obtained by splitting each frequency component contained in the measurement light into multiple frequency components by the optical splitting element, onto multiple measurement points on the measurement surface of the measurement 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 by an optical combining element.

7. 3. The multi-point vibration measurement test bench according to claim 2, wherein said coupling optical system is built into said projection optical system.

8. The optical splitter element splits each frequency component contained in the measurement light input from the interference optical system through one optical fiber and outputs the splitted signal through a plurality of optical fibers, and the optical combiner element combines each frequency component input through a plurality of optical fibers and outputs the combined signal through a single optical fiber. The multi-point vibration measurement test bench according to claim 7, characterized in that the coupling optical system includes a polarizing optical element that aligns the optical axes of two light beams output from the two optical fibers and having orthogonal polarization directions.

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 combination 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 focusing 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 focusing optical element and input to the polarizing optical element array.

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