JP5936738B1 - Measuring system and measuring method - Google Patents

Abstract

It is possible to calculate and acquire pressure and temperature data based on wavelength change data output from a fiber Bragg grating sensor. An FBG sensor having an FBG unit that outputs reflected light having a predetermined wavelength according to an external pressure and an external temperature when incident light from a light source is input, and that outputs a reflected light signal based on the reflected light; Collecting reflected light signals from the FBG sensor, creating a plurality of wavelength value data corresponding to the collected reflected light signals, and changing the wavelength of the reflected light over time, which is composed of the plurality of wavelength value data Waveform analysis means for generating waveform data indicating, temperature value data calculation means for calculating temperature value data relating to a temperature change generated externally based on the wavelength value data, and externally generated based on the waveform data Pressure value data calculating means for calculating pressure value data relating to the pressure change. [Selection] Figure 1

Description

  The present invention relates to a measurement system and a measurement method for measuring a temperature value and a pressure value of a physical phenomenon based on data corresponding to the physical phenomenon.

  A fiber Bragg grating (FBG) sensor has been developed as a sensor for detecting a physical phenomenon, and this FBG sensor has been widely applied in research and industrial fields (for example, JP 2010-286836 A). ).

  The fiber Bragg grating sensor has a grid, and a part of incident light incident on the fiber Bragg grating sensor is reflected by the grid, and the remaining incident light is transmitted through the grid. . The reflection wavelength shifts due to the expansion and contraction of the fiber Bragg grating sensor accompanying the reflection of the incident light, and distortion amount data is acquired based on the shift amount.

JP 2010-286836 A

"Next Generation Sensor Handbook" Baifukan July 8, 2008

  The present inventors have obtained the knowledge that the wavelength change accompanying the reflection of incident light in the fiber Bragg grating sensor is caused based on the change in external pressure and temperature.

  If it becomes possible to separate external pressure / external temperature change information contained in the data acquired by the fiber Bragg grating sensor and extract it as individual data, the application range of the fiber Bragg grating sensor will be further expanded. Is something that can be done.

  An object of the present invention is to provide a measurement system and a measurement method that make it possible to obtain data as separate data by separating data of an external pressure and an external temperature.

In order to achieve the above object, a measurement system according to the present invention has an FBG unit that outputs reflected light of a predetermined wavelength according to external pressure and temperature when incident light from a light source is input, and is based on the reflected light. An FBG sensor that outputs a reflected light signal, an ultrasonic irradiation element that causes a change in the external pressure / external temperature, a reflected light signal collected from the FBG sensor, and a plurality of wavelengths corresponding to the collected reflected light signals Wavelength analysis means for creating value data and creating waveform data that is composed of the plurality of wavelength value data and indicates a change with time of the wavelength of the reflected light, and has occurred outside based on the wavelength value data a temperature value data calculating means for calculating the temperature value data according to a temperature change, the waveform data and spectrum analysis, the spectral strength of the frequency component which oscillates ultrasonic irradiation device , The pressure value data calculating means for calculating a pressure value data from those characterized by having a.

  The temperature value data calculation means is based on the difference between the representative wavelength value data calculated from the plurality of wavelength value data and the initial value of the representative wavelength value data and the wavelength value data in a state where no external change has occurred. The temperature value data is calculated.

  The temperature value data calculating means calculates temperature value data related to the temperature change from a DC component extracted by Fourier transforming the waveform data.

In the measurement method according to the present invention, when incident light from a light source is input, reflected light of a predetermined wavelength corresponding to a change in external pressure / external temperature caused by the ultrasonic irradiation element is output from the FBG unit, and the reflected light is A reflected light signal is output based on the collected reflected light signal in the step, and a plurality of wavelength value data corresponding to the collected reflected light signals are created and configured from the plurality of wavelength value data. Generating waveform data indicating changes over time in the wavelength of the reflected light, calculating temperature value data relating to temperature changes generated outside based on the wavelength value data, and spectrum the waveform data . those analyzed, the ultrasonic irradiation device and executes the steps of: calculating a pressure value data from the spectral intensity of the frequency components of oscillation That.

  In creating the temperature value data, the difference between the representative wavelength value data calculated from the plurality of wavelength value data and the initial value of the representative wavelength value data and the wavelength value data in a state where no external change has occurred. Based on this, the temperature value data is calculated.

  When calculating the temperature value data, the temperature value data relating to the temperature change is calculated from a direct current component extracted by Fourier transform of the waveform data.

  As described above, according to the present invention, the reflected light signals output from the FBG sensor are collected, and a plurality of wavelength value data corresponding to the collected plurality of reflected light signals are created, and the plurality of wavelength value data are used. Waveform data indicating a change with time in the wavelength of the reflected light is generated, temperature value data relating to a temperature change generated outside is calculated based on the wavelength value data, and external data is calculated based on the waveform data. In order to calculate the pressure value data relating to the pressure change generated in the above, the data of the external pressure and the external temperature can be separated and acquired as individual data.

It is a functional block diagram which shows the measurement system which concerns on embodiment of this invention. It is a functional block diagram which shows the specific structure of the FBG sensor shown in FIG. It is a functional block diagram which shows the specific structure of the control means shown in FIG. (A) is the block diagram which applied the measuring system which concerns on embodiment of this invention to the ultrasonic cleaning apparatus, (b) is a characteristic view which shows the FBG wavelength of a fiber Bragg grating sensor. FIG. 2 is a characteristic diagram illustrating the waveform data generated by the wavelength analyzing unit shown in FIG. It is the characteristic view which extracted (enlarged) part of the waveform data which the wavelength analysis means shown in FIG. It is a characteristic view which shows the spectrum intensity | strength (FFT intensity | strength) calculated | required by Fourier-transforming (FFT process) the waveform data which the wavelength analysis means shown in FIG. 1 produced | generated. FIG. 6 is a characteristic diagram illustrating waveform data and amplitude when an ultrasonic frequency is set to 26 kHz on the low frequency side and applied power under the frequency is changed to 5 W, 10 W, 25 W, and 50 W. . FIG. 5 is a characteristic diagram illustrating waveform data and amplitude when an ultrasonic frequency is set to 130 kHz on the intermediate frequency side and applied power under the frequency is changed to 10 W, 25 W, and 50 W. FIG. 6 is a characteristic diagram illustrating waveform data and amplitude when the ultrasonic frequency is set to 200 kHz on the intermediate frequency side and the applied power under the frequency is changed to 10 W, 25 W, 50 W, and 100 W. . Waveform data and amplitude S are shown when the frequency of the ultrasonic wave is set to 430 kHz on the high frequency side and the applied power under the frequency is changed to 10 W, 25 W, 50 W, and 100 W. It is a characteristic view which shows the relationship between electric power, variation | change_quantity RMS, and spectrum intensity | strength (FFT intensity | strength) when the frequency of an ultrasonic wave is set to 26 kHz, 130 kHz, 200 kHz, and 430 kHz, respectively. (A) is the schematic which shows the case where the pressure (sound pressure) of the ultrasonic wave irradiated to a solution with an ultrasonic irradiation element and the temperature of a solution are measured in an ultrasonic cleaning apparatus, (b) is the frequency of an ultrasonic wave Is a characteristic diagram showing a change in the depth direction between the change amount RMS (pm) and the spectrum intensity (FFT intensity) (dB) when the power is 78 kHz and the power is 50 W.

  Hereinafter, embodiments of the present invention will be described in detail with reference to the drawings.

  FIG. 1 is a diagram illustrating an entire measurement system 1 according to an embodiment of the present invention. The measurement system 1 according to the embodiment of the present invention illustrated in FIG. 1 includes a fiber Bragg grating sensor 20 (hereinafter referred to as an FBG sensor 20). And wavelength analyzing means 30 and control means 40. Next, the specific contents of each component for constructing the measurement system shown in FIG.

As shown in FIG. 2, the FBG sensor 20 shown in FIG. 1 has an optical fiber 21 having an FBG portion 21a at an end, a light source 22 that irradiates the optical fiber 21 with incident light L1, and reflected light from the optical fiber 21. It comprises a detector 23 that receives L2, and a duplexer 24 that optically couples the optical fiber 21, the light source 22, and the detector 23. In FIG. 2, the incident light L1 and the reflected light L2 are clearly indicated by arrows.
A known fiber Bragg grating structure is formed in the FBG portion 21a of the optical fiber 21 shown in FIG. 2, and the FBG portion 21a of the optical fiber 21 receives external light pressure / external light when incident light L1 from the light source 22 is input. The reflected light L2 having a predetermined wavelength corresponding to the temperature is output.
The light source 22 shown in FIG. 2 is configured by a semiconductor laser LD (laser diode) that oscillates laser light having a wavelength λ1 near 1500 nm, for example.
The detector 23 shown in FIG. 2 generates an electrical signal (corresponding to the reflected light signal of the present invention) based on the received reflected light L2, such as a CCD, CMOS, or photodiode (PD), and outputs it to the outside. Configured as
A demultiplexer 24 shown in FIG. 2 is, for example, an optical circulator, and makes incident light L1 from the light source 22 enter the optical fiber 21 so that the reflected light L2 reflected by the FBG portion 21a is guided to the detector 23. Configured.

In the FBG sensor 20 described above, when the incident light L1 from the light source 22 is input (incident), the FBG unit 21a outputs reflected light L2 having a predetermined wavelength corresponding to the external pressure / external temperature, and the FBG sensor 20 A reflected light signal based on the reflected light L2 output from the FBG unit 21a is output. The FBG portion 21a reflects a part of the incident light L1 and outputs (emits) reflected light L2, and the reflected light L2 has an FBG wavelength λB (FIG. 4B). .
Here, it has been found that the FBG wavelength λB of the reflected light L2 varies depending on the external force pressure and the external temperature. Specifically, in the FBG sensor 20 used in the measurement system 1 according to the embodiment of the present invention, when the 1 m FBG sensor 20 is extended (expanded) by an external pressure (expanded), It is known that the FBG wavelength λB extends (stretches) by 1 pm, and when the external temperature (strain) rises by 0.1 ° C., the FBG wavelength λB extends by 1 pm (stretches: wavelength increases).

The wavelength analyzing means 30 shown in FIG. 1 is configured by, for example, an FFT analyzer. The wavelength analysis means 30 shown in FIG. 1 collects (samples) the electrical signal (reflected light signal) output from the detector 23 shown in FIG. 2 based on a predetermined rate (sampling rate), and further collects the collected electrical signal. And calculating a wavelength (nm) of each reflected light to create a plurality of wavelength value data corresponding to the collected reflected light signals.
Further, in addition to the above function, the wavelength analyzing means 30 shown in FIG. 1 creates waveform data indicating changes in the wavelength of reflected light over time by plotting the created wavelength value data along the time axis. It has a function.
Further, the wavelength analysis means 30 performs Fourier transform (FFT processing / analysis), performs spectrum analysis on the waveform data displayed in the time domain, and performs a spectrum size (intensity: FFT intensity) for each frequency component. Can be detected.
The waveform data and the result of the Fourier transform (FFT processing) described above can be displayed on a display provided in the wavelength analysis unit 30 shown in FIG. 1, and as will be described later, the control unit shown in FIG. 40 can be displayed.

As shown in FIG. 3, the control means 40 shown in FIG. 1 can be configured by a personal computer (PC), and includes a command unit 41 and an analysis unit 42.
The measuring apparatus used this time includes a light source 22, a demultiplexer 24, a detector 23, and a control means 40, and uses an ultra-fast FBG sensor monitor manufactured by Anritsu (Anritsu).
The command unit 41 shown in FIG. 3 gives a command to the light source 22 of the FBG sensor 2 shown in FIG. 2 or receives data from the wavelength analyzing means 30 shown in FIG. It controls the overall operation of the measurement system 1 shown, and is implemented as software.
The analysis unit 42 shown in FIG. 3 is implemented as software in the same manner as the command unit 41 shown in FIG. 3, and the analysis unit 42 shown in FIG. 3 is the wavelength value created by the wavelength analysis means 30 shown in FIG. Temperature value data calculating means 43 for calculating temperature value data relating to a temperature change generated outside based on the data, and pressure change generated outside based on the waveform data created by the wavelength analyzing means 30 shown in FIG. Pressure value data calculating means 44 for calculating the pressure value data relating to.

FIG. 4A shows an ultrasonic pressure (sound pressure) applied to the solution E (cleaning liquid) by the ultrasonic irradiation element 51 in the ultrasonic cleaning apparatus 50 of the measurement system 1 according to the embodiment of the present invention. The Example applied in order to measure the temperature of the solution E is shown. The ultrasonic cleaning apparatus 50 includes a tank 52 that stores the solution E, and an ultrasonic irradiation element 51 is fixed to the bottom surface of the tank 52.
The ultrasonic cleaning device 50 shown in FIG. 4A generates pressure (that is, sound pressure due to ultrasonic waves) in the solution E by irradiating ultrasonic waves from the ultrasonic irradiation element 51 and the temperature of the solution E. The workpiece R (not shown) immersed in the solution E in the tank 52 is ultrasonically cleaned. In controlling the temperature of the solution E, a heater may be added.

  In the ultrasonic cleaning apparatus 50, as shown in FIG. 4A, the FBG sensor 20 described above has both ends 21b and 21c of the optical fiber 21 held by the fixed body 6 disposed in the tank 52, and the solution In E, the FBG unit 21a is installed at a predetermined position. In FIG. 4, the portion of the FBG sensor 20 excluding the optical fiber 21 is not shown, but actually, the optical fiber 21 is extended and connected to the duplexer 24 installed outside the tank 52. ing.

In the measurement system 1 according to the embodiment of the present invention, whether the pressure (sound pressure) generated in the solution E by the ultrasonic irradiation element 51 in the ultrasonic cleaning device 50 and the liquid temperature of the solution E are as desired. It is used for measuring.
When the ultrasonic irradiation element 51 is driven by a control device (not shown), a pressure change and a temperature change occur in the solution E. Accordingly, in the measurement system 1, the wavelength analysis unit 30 uses the wavelength value data and the waveform data. Will be generated.

FIG. 5 shows the waveform data generated with the horizontal axis as time t and the vertical axis as the wavelength λR of reflected light (that is, FBG wavelength λB). It should be understood that FIG. 6 is extracted (enlarged) by dividing a part of waveform data by a predetermined time (between tx and ty).
As shown in FIG. 6, the waveform data is grasped as waveform data that vibrates up and down (alternating current). However, the embodiment of the present invention is a waveform that shows such a change in wavelength over time. The fact that the data includes data correlating with the pressure value and data correlating with the temperature value is utilized. More specifically, the wavelength value data corresponding to the reflected light L2 correlates with the temperature value, and the signal waveform oscillating up and down (AC-like), that is, the wavelength of the reflected light L2 processed (created) by the wavelength analysis means 30 The waveform data indicating the change over time (the amplitude S of the waveform signal) correlates with the pressure value data.
Hereinafter, a method in which the temperature value data calculating unit 43 calculates (creates) temperature value data related to a temperature change generated outside based on the wavelength value data output from the wavelength analyzing unit 30, and a pressure value data calculating unit 44. Will be described in detail with reference to a method for calculating (creating) pressure value data relating to a pressure change generated outside based on the waveform data output from the wavelength analyzing means 30.
Note that the temperature value data and the change in pressure value data are determined based on the measured wavelength value data and the temperature change because the wavelength value data is a direct current component and the ultrasonic vibration is an alternating current component, for example. Depending on the value of the waveform data, the wavelength analysis means 30 can determine whether the pressure change or temperature change.

First, methods 1 to 3 in which the temperature value data calculating unit 43 calculates temperature value data will be described.
<Method 1: Method of calculating one wavelength value data from initial value>
One of the wavelength value data sampled between the time tx and ty by the wavelength analyzing means 30 is extracted. For example, the nth sampled wavelength value data λn is extracted. Further, a difference D1 (from the wavelength value data λ0 (hereinafter referred to as an initial value) sampled in an initial state in which no ultrasonic wave is applied (and the heater is turned off when a heater is provided) ( (Unit: nm, see FIG. 5). Here, the extracted wavelength value data λn is representative wavelength value data.
Assuming that the difference D1 (nm) is a change in wavelength of the FBG wavelength λB and converting it into a temperature value based on the correlation obtained in advance, as described above, the temperature rise (relative liquid temperature (initial state) From which the temperature rose by X ° C))).
Of course, by measuring the liquid temperature at the time of sampling the initial value λ0 with another temperature sensor or the like, the liquid temperature after rising from the above-mentioned difference D1 (the initial state is P ° C). However, the temperature after the increase may be P + X ° C.).
<Method 2: Method of calculating from representative wavelength value data calculated from a plurality of wavelength value data and initial value>
The actual sampling number of wavelength value data is many. FIG. 6 shows waveform data obtained by plotting about 3200 pieces of wavelength value data representing raw data in the order of sampling. In FIG. 6, the horizontal axis represents the sampling number, and the vertical axis represents the reflected light wavelength (that is, the FBG wavelength λB).
Method 2 statistically manipulates a large number of sampled wavelength values (for example, several tens of thousands) to calculate the representative wavelength value data, in a state where no external change has occurred with the representative wavelength value data. The temperature value data is calculated based on the difference from the initial value of the wavelength value data. In the example shown in FIG. 6, the representative value is λm and the difference is D2.
As a statistical operation, a general arithmetic average value may be used, and known representative values such as a mode value, a median value, a harmonic average value, and a geometric average value may be used. It can be easily understood that this improves the accuracy of the calculated temperature value data.
The initial value λ0 may be calculated from a large number of wavelength value data sampled in the initial state, and the representative value thereof may be used as the initial value.
The temperature value data calculation means 43 according to the above-described methods 1 and 2 includes the representative wavelength value data calculated from a plurality of the wavelength value data, and the wavelength value data in a state in which no external change occurs with the representative wavelength value data. The temperature value data is constructed based on the difference from the initial value.
<Method 3: Method of calculating from DC component value and initial value extracted by Fourier transform (FFT process) of waveform data>
As described above, the waveform data is a signal waveform that vibrates up and down (alternative) as shown in FIG. Therefore, in the method 3, in the required time domain (between tx and ty in the example of FIG. 6), the direct current component value λn calculated by performing Fourier transform (FFT processing) on the waveform data is changed to the wavelength in the time domain. It is considered as value data. In the example shown in FIG. 6, the DC component value λn is set to the same value as the representative value λm of the method 2 for convenience. Here, the extracted DC component value λn is representative wavelength value data.
Subsequent operations are the same as in Method 1 (temperature change is obtained based on the difference from the initial value).
The temperature value data calculating means according to the method 3 described above is constructed as a configuration for calculating a temperature value related to the temperature change from a DC component extracted by Fourier transform (FFT processing) of the waveform data.
The elongation (expansion / contraction) due to the temperature rise of the FBG device used by this measuring apparatus is described in paragraph 0024, and the calculation formula for calculating the temperature change based on this is as follows.
As an example of the calculation formula of temperature change, temperature change ΔT = coefficient k × wavelength change ΔλB
ΔT = 0.1 × ΔλB
A temperature change can be obtained by substituting the difference D into ΔλB.

Next, the pressure value data calculation means 44 outputs from the wavelength analysis means 30, and the pressure change generated outside based on the waveform data that is composed of a plurality of wavelength value data and indicates the change with time of the wavelength of the reflected light L2. A method of creating (calculating) the pressure value data according to will be described in detail.
In the ultrasonic cleaning apparatus 50, the pressure (sound pressure) applied to the solution E can be adjusted by the voltage applied to the ultrasonic irradiation element 51, so that the ultrasonic pressure (sound pressure) on the workpiece R can be adjusted. Yes.
The measurement system 1 according to the embodiment of the present invention confirms whether or not the pressure fluctuation corresponding to the fluctuation of the voltage applied to the ultrasonic irradiation element 51 occurs in the ultrasonic cleaning device 50.

があり、Δλ（Ｓ）が求められるが、上記計算式に限定されるものではない。
図７において、横軸は周波数（ｋＨｚ）、縦軸はスペクトル強度（ＦＦＴ強度）（ｄＢ）を示している。
こうして導出した振幅Ｓ（ｎｍ）をＦＢＧ波長λＢの波長変化分とみなし、上述したように、予め求めておいた相関関係に基づいて振幅Ｓ（圧力値）を換算するのである。
本測定装置が利用するＦＢＧ装置は、非特許文献１の書籍より１Ｐａに対して−３×１０^−１２程度であるので、１５５０ｎｍ帯においては、約−５ｐｍ／Ｍｐａの圧力感度に相当する。
これに基づき、圧力変化を算出する計算式は以下の通りである。
圧力変化の算出式の一例としては
圧力変化＝係数×波長変化
P＝−２．１５×１０^１７×ΔλB
このΔλＢに振幅Ｓを代入すると、圧力変化を得ることができる。 In the example of the waveform data shown in FIG. 6, the amplitude S of the signal waveform that vibrates up and down (alternating current) correlates with the pressure value data, but the actual waveform data is composed of a combination of a plurality of waveforms. Therefore, in practice, it is difficult to uniquely specify the amplitude S.
Therefore, the wavelength analysis means 30 performs Fourier transform (FFT processing) on the waveform data from the wavelength value data sampled between time tx and ty and performs spectrum analysis as shown in FIG. The spectral intensity (FFT intensity) Ia (dB) of the set frequency (fa (kHz)) that is (commanded to irradiate) is obtained, and the effective value is obtained by logarithmically converting the spectral intensity (FFT intensity) Ia. By calculating, the amplitude S is obtained.
As an example of the calculation formula,

Although Δλ (S) is obtained, it is not limited to the above formula.
In FIG. 7, the horizontal axis represents frequency (kHz), and the vertical axis represents spectral intensity (FFT intensity) (dB).
The amplitude S (nm) derived in this way is regarded as the wavelength change of the FBG wavelength λB, and the amplitude S (pressure value) is converted based on the correlation obtained in advance as described above.
Since the FBG apparatus used by this measuring apparatus is about −3 × 10 ⁻¹² to 1 Pa from the book of Non-Patent Document 1, it corresponds to a pressure sensitivity of about −5 pm / Mpa in the 1550 nm band.
Based on this, the calculation formula for calculating the pressure change is as follows.
An example of the pressure change calculation formula is: Pressure change = Coefficient x Wavelength change
P = -2.15 × 10 ¹⁷ × ΔλB
A change in pressure can be obtained by substituting the amplitude S into ΔλB.

Next, the effectiveness of the measurement system according to the above-described embodiment of the present invention will be verified based on FIGS.
8 to 12 show raw data based on actual measurement, where the horizontal axis is time t and the vertical axis is the wavelength λR of reflected light. Further, in FIGS. 8 to 12, waveform data showing the change over time of the wavelength of the reflected light L <b> 2 output from the wavelength analysis unit 30 output from the wavelength analysis unit 30 by the pressure value data calculation unit 44 is shown. . As explained with reference to FIG. 7, the amplitude S of the waveform data is subjected to spectrum analysis by performing Fourier transform (FFT processing) on the waveform data output from the wavelength analyzing means 30, and a specific period ( Frequency) intensity Ia (spectrum intensity) is obtained, and the intensity is converted to pressure data as periodic amplitude S.

  FIG. 8 illustrates waveform data and amplitude S when the ultrasonic frequency is set to 26 kHz on the low frequency side and the applied power under the frequency is changed to 5 W, 10 W, 25 W, and 50 W. Yes. FIG. 9 illustrates the waveform data and the amplitude S when the ultrasonic frequency is set to 130 kHz on the intermediate frequency side and the applied power under the frequency is changed to 10 W, 25 W, and 50 W. FIG. 10 illustrates waveform data and amplitude S when the ultrasonic frequency is set to 200 kHz on the intermediate frequency side and the applied power under the frequency is changed to 10 W, 25 W, 50 W, and 100 W. Yes. FIG. 11 illustrates the waveform data and the amplitude S when the ultrasonic frequency is set to 430 kHz on the high frequency side and the applied power under the frequency is changed to 10 W, 25 W, 50 W, and 100 W. .

FIG. 12 shows the relationship between the power, the change amount RMS, and the spectral intensity (FFT intensity) when the ultrasonic frequency is set to 26 kHz, 130 kHz, 200 kHz, and 430 kHz, respectively. In FIG. 12, the horizontal axis represents power (W), the left vertical axis represents the amount of change RMS (pm), and the right vertical axis represents the spectral intensity (FFT intensity) (dB).
In this graph, the magnitude of the wavelength change corresponding to the pressure is calculated by the change RMS and the spectral intensity (FFT intensity), and it is confirmed whether there is a difference in the calculated wavelength change.
The amount of change RMS (pm) shown in FIG. 12 is a value obtained by subtracting the value of each wavelength measured from the average value of the wavelengths, performing a root mean square, and processing with a square root. Therefore, the change amount RMS (pm) is the magnitude of the wavelength change amount, and this change amount can be converted into a pressure.
FIG. 12 is a diagram illustrating the relationship between the intensity (spectral intensity (FFT intensity), indicated by square marks) of a specific period (frequency) accompanying the change in power and the change amount RMS (shown by rhombus marks). Show.
As apparent from FIG. 12, the spectrum intensity (FFT intensity) and the change amount RMS change relatively in accordance with the change in the power value, and the change amount RMS that allows the entire cleaning region sound field to be examined. It was verified that the magnitude of the wavelength change amount can be calculated by both the above method and the method using Fourier transform (FFT processing).

  From the results shown in FIGS. 8 to 11, the measurement system according to the embodiment of the present invention has linearity in the change of the amplitude S over the frequency range of the ultrasonic wave to be measured from the low frequency side 26 kHz to the high frequency side 430 kHz. It was verified that it had. Further, from the results shown in FIG. 12, it can be verified that there is an approximate linear relationship between the displacement of the change amount RMS and the displacement of the FFT intensity, and these wavelength change amounts are converted into pressure. It was verified that the value was calculated.

Next, the measurement in the depth direction of the solution filled in the tank was verified by applying the measurement system according to the embodiment of the present invention to the ultrasonic cleaning apparatus based on FIGS.
FIG. 13A shows the ultrasonic pressure (sound pressure) applied to the solution E (cleaning liquid) by the ultrasonic irradiation element 51 and the temperature of the solution E in the ultrasonic cleaning apparatus 50 described with reference to FIG. The case of measuring is shown.
FIG. 13B shows the change in the depth direction between the change amount RMS (pm) and the spectral intensity (FFT intensity) (dB) when the frequency of the ultrasonic wave is 78 kHz and the power is 50 W. . In FIG. 13B, the vertical axis is the distance (mm) in the depth direction, the lower horizontal axis is the change amount RMS (pm), and the upper horizontal axis is the spectral intensity (FFT intensity) (dB). .
From the result of FIG. 13B, it can be determined that the measurement data has changed for each half wavelength of the frequency of the ultrasonic irradiation element 51, and the ultrasonic wave is correctly applied to the workpiece R in the liquid depth direction. I can judge.
By measuring the spectral intensity (FFT intensity) in the liquid depth direction, it can be determined whether the ultrasonic oscillator and the ultrasonic irradiation element are oscillating normally.

  From the above verification results, the measurement system according to the embodiment of the present invention has a linearity in the change of the amplitude S from the low frequency side to the high frequency side of the frequency of the ultrasonic wave to be measured, and increases the pressure and temperature. It can be measured. Furthermore, although the measurement in the depth direction of the solution has a certain limitation, the pressure and temperature rise can be measured.

  The present invention can be embodied in many forms without departing from its essential characteristics. Therefore, it is needless to say that the above-described embodiment is exclusively for description and does not limit the present invention.

1 Measurement System 20 Fiber Bragg Grating Sensor 30 Wavelength Analysis Unit 40 Control Unit 42 Analysis Unit 43 Temperature Value Data Calculation Unit 44 Pressure Value Data Calculation Unit

Claims (6)

An FBG sensor that outputs reflected light of a predetermined wavelength according to external pressure and temperature when an incident light from a light source is input, and that outputs a reflected light signal based on the reflected light;
An ultrasonic irradiation element that causes a change in the external pressure and temperature;
The reflected light signal is collected from the FBG sensor, a plurality of wavelength value data corresponding to the collected reflected light signals are created, and the wavelength of the reflected light with time is composed of the plurality of wavelength value data. Wavelength analysis means for creating waveform data indicating changes;
Temperature value data calculating means for calculating temperature value data relating to a temperature change generated outside based on the wavelength value data;
Spectrum analysis of the waveform data , pressure value data calculation means for calculating pressure value data from the spectrum intensity of the frequency component oscillated by the ultrasonic irradiation element ;
A measurement system characterized by comprising:   The temperature value data calculation means is based on the difference between the representative wavelength value data calculated from the plurality of wavelength value data and the initial value of the representative wavelength value data and the wavelength value data in a state where no external change has occurred. 2. The measurement system according to claim 1, wherein temperature value data is calculated.   2. The measurement system according to claim 1, wherein the temperature value data calculation unit calculates temperature value data related to the temperature change from a DC component extracted by Fourier transforming the waveform data. When incident light from a light source is input, a step of outputting reflected light of a predetermined wavelength corresponding to a change in external pressure / external temperature caused by the ultrasonic irradiation element from the FBG unit and outputting a reflected light signal based on the reflected light When,
Collecting the reflected light signals in the step, creating a plurality of wavelength value data corresponding to the collected reflected light signals, and comprising the plurality of wavelength value data, the wavelength of the reflected light over time Creating waveform data indicating changes;
Calculating temperature value data related to a temperature change generated outside based on the wavelength value data;
Spectrally analyzing the waveform data , calculating pressure value data from a spectral intensity of a frequency component oscillated by the ultrasonic irradiation element ;
The measurement method characterized by performing. When calculating the temperature value data, the difference between the representative wavelength value data calculated from the plurality of wavelength value data and the initial value of the representative wavelength value data and the wavelength value data when no external change occurs. The measurement method according to claim 4 , wherein the temperature value data is calculated based on the measurement result. 5. The measurement method according to claim 4 , wherein when calculating the temperature value data, the temperature value data relating to the temperature change is calculated from a direct current component extracted by Fourier transform of the waveform data.

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