JP2007192579A - Temperature measuring device and method - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a temperature measurement technique of non-contact method of a molten pool which eliminates the measurement error to be generated in the case of emissivity is made into a fixed value, and capable of temperature measurement of the emitting molten pool. <P>SOLUTION: A temperature measurement device 10 of the molten pool comprises: an infrared radiation detector 12 for detecting the energy intensity of the infrared ray radiated from the measurement point to be an object of temperature measurement; a dichroic radiation thermometer 11 as a radiation rate measurement means for measuring the radiation rate of the measurement point; and an operation processor 13 for calculating the temperature of the measurement point, based on the radiation rate. <P>COPYRIGHT: (C)2007,JPO&INPIT

Description

  The present invention relates to a technique for measuring the temperature of a measurement object such as a molten pool during welding by a non-contact method.

  In the welding process, the temperature of the molten metal being processed (hereinafter referred to as a molten pool) is an important clue for knowing the welding condition such as the quality of welding and the welding range. For this reason, the temperature measurement of a molten pool is performed during welding processing.

Conventionally, as a method for measuring the temperature of a molten pool during welding processing, for example, as described in Patent Document 1, a temperature measurement by a so-called contact method in which a temperature sensor is measured by bringing a detector such as an optical fiber or a thermocouple into contact with the molten pool. The method is adopted. In such a contact-type temperature measurement method, processing for bringing the detector into contact with the measurement target is necessary, and only temperature measurement can be performed experimentally. In other words, the contact-type temperature measurement method has a problem that it is impossible to measure the temperature of the molten pool online.
Further, when the molten pool follows a complicated shape, there is a problem that a mechanism for moving the detector for each measurement region is required and the apparatus becomes complicated. Furthermore, with such a contact-type temperature measurement technique, there is a problem that temperature measurement of the molten pool is possible in arc welding, but temperature measurement is impossible in laser welding.

  Therefore, a non-contact temperature measurement method that solves the above-described problems is desired. Non-contact temperature measurement techniques include infrared radiation thermometers and two-color thermometers.

  An infrared radiation thermometer measures the amount of infrared radiation radiated from an object to be measured, for example, as described in Patent Document 2, and obtains the object temperature. The measurement of the amount of infrared radiation is performed by imaging the measurement area with an infrared camera as an infrared radiation detector and processing the image.

  In the infrared radiation thermometer, the infrared radiation emissivity from the measurement region is calculated as a predetermined fixed value (for example, 1). However, since the emissivity differs depending on the substance, if the emissivity of the measurement area deviates significantly from the predetermined fixed value, the temperature value of the measurement area measured using an infrared radiation thermometer greatly affects the emissivity. As a result, a measurement error occurs, resulting in a problem that the reliability of the measurement value is lowered.

  In addition, for example, as described in Patent Document 3, in a thermometer using the measurement principle of a two-color thermometer, an image is obtained using two mutually different wavelengths selected in advance from light energy radiated from an object. An image of the object can be detected by a sensor, and a ratio of radiation intensity can be obtained for each same part of the detected pair of images, and the surface temperature of the object can be measured based on the ratio of the radiation intensity. Further, as described in Patent Document 4, the emissivity can be calculated from the temperature distribution of the measurement region calculated based on the two-color thermometer, and the emissivity distribution of the measurement region can be known.

The two-color thermometer as described above uses the fact that there is a correlation between the radiation intensity ratio of two different wavelengths and the surface temperature of the measurement region even if the emissivity of the measurement region is unknown. The surface temperature distribution and emissivity distribution in the measurement region can be calculated based on the actual radiation intensity from the relational expression obtained in advance.
However, when measuring the temperature of the molten pool during the welding process using the two-color thermometer as described above, the molten pool emits light and an image of this light emission is detected, so welding is being performed. There was a problem that the temperature of the molten pool could not be detected.
Japanese Patent Laid-Open No. 2005-7451 JP-A-5-34204 JP 2004-45268 A JP 2004-45306 A

  The present invention proposes a non-contact temperature measuring apparatus and method that eliminates measurement errors that occur when the emissivity is a fixed value, and that enables temperature measurement at a light emitting location such as a molten pool.

  The problem to be solved by the present invention is as described above. Next, means for solving the problem will be described.

  That is, in claim 1, an infrared detecting means for detecting a radiation intensity of infrared energy radiated from a measurement point to be measured for temperature, an emissivity measuring means for measuring the emissivity of the measuring point, and a detection It is a temperature measuring device provided with the arithmetic processing means which calculates the temperature of the said measurement point based on the said radiation intensity and the measured said emissivity.

  In claim 2, the intensity of infrared energy radiated from a measurement point that is a target of temperature measurement is detected, and the measurement is performed based on the detected intensity of infrared energy and an emissivity set in advance to a predetermined value. An infrared radiation thermometer that measures the temperature of the point, an emissivity measuring means that measures the emissivity of the measurement point, and an arithmetic process that corrects the measured temperature of the measurement point using the measured emissivity A temperature measuring device.

  According to a third aspect of the present invention, the emissivity measuring means detects at least two wavelengths of radiated light at the same measurement point, and measures the emissivity based on the radiant intensity of the at least two wavelengths of radiated light. .

  In claim 4, the infrared detection means detects the radiant intensity of infrared energy radiated from the measurement point to be temperature measured, the emissivity measurement means measures the emissivity of the measurement point, In this temperature measurement method, the temperature of the measurement point is calculated based on the detected radiation intensity and the measured emissivity.

  In claim 5, an infrared radiation thermometer detects the intensity of infrared energy radiated from a measurement point that is a target of temperature measurement, and the intensity of the detected infrared energy and radiation set to a predetermined value in advance. The temperature of the measurement point is measured based on the rate, the emissivity measurement unit measures the emissivity of the measurement point, and the arithmetic processing unit measures the emissivity using the measured emissivity. It is a temperature measurement method which correct | amends the temperature of the said measurement point.

  In claim 6, the emissivity measuring means detects at least two wavelengths of radiated light at the same measurement point, and measures the emissivity based on the radiant intensity of the at least two wavelengths of radiated light. .

  As effects of the present invention, the following effects can be obtained.

  Based on the measured emissivity and the detected radiation intensity of infrared energy, the temperature distribution in the measurement area is calculated, so it is possible to measure the temperature of the molten pool that emits light, and the temperature of the molten pool that emits light. Can be performed with high accuracy.

  Next, embodiments of the invention will be described.

First, the temperature measuring device 10 according to the first embodiment of the present invention will be described.
FIG. 1 is a diagram illustrating an overall configuration of a temperature measurement device according to the first embodiment, FIG. 2 is a block diagram of the temperature measurement device according to the first embodiment, and FIG. 3 is a flowchart of temperature measurement according to the first embodiment.

As shown in FIGS. 1 and 2, the temperature measuring device 10 includes a two-color radiation thermometer 11, an infrared radiation detector 12, and an arithmetic processing device 13. The two-color radiation thermometer 11 and the infrared radiation detector 12 are electrically connected to the arithmetic processing device 13, and information detected by the two-color radiation thermometer 11 and the infrared radiation detector 12 is transmitted to the arithmetic processing device 13. The
The temperature measurement apparatus 10 according to the first embodiment calculates the temperature distribution in the measurement region D based on the emissivity measured by the two-color radiation thermometer 11 and the radiation intensity of the infrared energy detected by the infrared radiation detector 12. It is characterized by doing.

  In this embodiment, the temperature measuring device 10 measures the temperature of the molten pool of the steel plate being welded. However, the measurement object of the temperature measuring device 10 is not limited to this, and can be widely applied to the temperature measurement of the measurement region, and is particularly suitable for measuring the temperature of the measurement region that emits light. Yes.

[Two-color radiation thermometer 11]
The two-color radiation thermometer 11 is an emissivity measuring means for measuring the emissivity at each measurement point in the measurement region D.
In the two-color radiation thermometer 11 according to the present embodiment, the temperature and emissivity of the measurement point can be measured at a time. Therefore, since the temperature distribution and emissivity distribution of the measurement region D can be obtained, the temperature distribution of the measurement region D detected by the infrared radiation detector 12 described later and the two-color radiation thermometer 11 detected. By collating the image with the emissivity distribution of the measurement region D, each measurement point in the measurement region and the emissivity can be matched.

  However, the emissivity measuring means is not limited to the two-color radiation thermometer 11 that can measure the temperature and the emissivity at a time. For example, the infrared intensity of a black body and a measurement point at the same temperature is measured with a spectroradiometer to calculate the emissivity of the measurement point, or the reflection when the measurement point is irradiated with infrared rays with a known emissivity in advance. The emissivity at the measurement point can be obtained by measuring the intensity with a spectroradiometer and calculating the emissivity at the measurement point. In these cases, it is necessary to measure the emissivity distribution in the measurement region D in advance before welding.

  The two-color radiation thermometer 11 calculates a surface temperature based on a radiation detector 31 that detects light energy of a predetermined wavelength radiated from a measurement point and a ratio of the radiant intensity of the light energy detected for each wavelength. A temperature calculation unit 33 that calculates the emissivity from the calculated temperature of the measurement point.

As the radiation detector 31, a visible light measuring CCD camera is employed.
In this embodiment, the two-color radiation thermometer 11 measures the temperature of the molten pool of the steel plate being welded. Since the temperature at which iron melts is about 1000 to 2000 ° C., judging from this temperature, the peak of the light energy emitted from the measurement region D is estimated to be in the range of visible light to near infrared, It is appropriate to employ a visible light measurement CCD camera as the radiation detector 31.

The radiation detector 31 includes a filter 35, a lens 36, an image sensor 37, and the like.
In the radiation detector 31 configured as described above, the light energy radiated from the measurement point is transmitted through the filter 35, collected by an optical system such as a lens 36, and imaged on the image sensor 37. Only light energy in a predetermined wavelength band is collected by the red filter 35.
In the image sensor 37, the incident light energy is converted into an electrical signal proportional to the radiation intensity of the light energy, and this electrical signal is transmitted to the temperature calculation unit 33 as a detection signal.

The wavelength band detected by the radiation detector 31 is determined by estimating the optimum wavelength band from the temperature of the melting point of the measurement region D.
As an optimal wavelength band estimation method, the wavelength band is calculated based on the relational expression between the peak wavelength and the temperature in Planck's radiation law shown in [Equation 1] below. Based on the calculated wavelength band, the wavelength band detected by the radiation detector 31 is determined.

[Equation 1]
λ × T = 2897.7
λ: Wavelength (μm), T: Absolute temperature (K)

  In the present embodiment in which the temperature of the molten pool of the steel plate being welded is measured with the two-color radiation thermometer 11, the wavelength band calculated based on the above [Equation 1] is almost from the visible light region. The wavelength band that is in the near-infrared region and is detected by the radiation detector 31 is suitably determined to be the 0.8 μm band or the 0.6 μm band. In this embodiment, the band is 0.8 μm, and the wavelengths detected by the radiation detector 31 are determined to be 0.85 μm and 0.75 μm.

In the two-color radiation thermometer 11 having the above-described configuration, first, of the light energy radiated from the measurement region D by the radiation detector 31, one corresponding to a plurality of mutually different wavelengths determined in advance as described above. Is detected.
Subsequently, the temperature calculation unit 33 obtains the ratio of the radiation intensity at each wavelength for each measurement point in the measurement region D, and calculates the surface temperature based on the ratio of the radiation intensity. By calculating the temperature for each measurement point in the measurement region D, the temperature distribution in the measurement region D can be obtained.
Then, the emissivity calculation unit 34 calculates the emissivity of each measurement point from the calculated temperature of each measurement point of the measurement region D. By calculating the emissivity for each measurement point in the measurement region D, the emissivity distribution in the measurement region D can be obtained.
As described above, the temperature distribution and emissivity distribution of the measurement region D measured by the two-color radiation thermometer 11 are transmitted to the arithmetic processing device 13.

[Infrared radiation detector 12]
The infrared radiation detector 12 is infrared detection means for detecting infrared energy radiated from each measurement point in the measurement region D.

An infrared camera is employed as the infrared radiation detector 12.
In addition, as the infrared radiation detector 12, it is desirable to employ one that meets the following conditions (1) to (3).
(Condition 1) A spectroscopic analysis of disturbance factors such as illumination around the measurement region D or sunlight is performed in advance, and sensitivity is obtained in a wavelength band that avoids these disturbance wavelengths.
(Condition 2) Since light is emitted from the molten pool during the welding process, it has sensitivity in a wavelength band that avoids this light emission.
(Condition 3) In consideration of the wavelength dependence of the emissivity of the metal material, the material has sensitivity in a wavelength band as short as possible.

  Moreover, since the infrared camera as the infrared radiation detector 12 has low sensitivity in the high temperature region in the long wavelength band (8 to 13 μm), the sensitivity set in the short wavelength band (for example, 3 to 5 μm) is used. It is desirable to adopt.

The infrared radiation detector 12 includes an infrared filter 42, a lens 43, an infrared sensor 44, and the like.
In the infrared radiation detector 12 having the above-described configuration, the infrared energy radiated from the measurement region D is transmitted through the infrared filter 42, collected by an optical system such as the lens 43, and imaged on the infrared sensor 44. The infrared filter 42 collects only infrared rays in a predetermined wavelength band.
In the infrared sensor 44, the incident infrared energy is converted into an electrical signal proportional to the magnitude of the infrared energy, and this electrical signal is transmitted to the temperature calculation unit 47 as a detection signal.

[Arithmetic processor 13]
The arithmetic processing unit 13 is arithmetic processing means for calculating the temperature distribution in the measurement region D based on the detection signal from the two-color radiation thermometer 11 and the detection signal from the infrared radiation detector 12. .
The arithmetic processing device 13 includes a temperature calculation unit 51 that calculates the temperature of the measurement region D, and an output unit 52 that outputs the calculated temperature distribution of the measurement region D as an image.

  The arithmetic processing unit 13 can be configured as a general-purpose computer including a CPU 25, an input unit 26 such as a keyboard, and an output unit 27 such as a monitor. However, the arithmetic processing unit 13 can also be configured as a dedicated device having the same function.

  The temperature calculation unit 51 receives an electrical signal proportional to the magnitude of the infrared energy transmitted from the infrared radiation detector 12 and corrects the reference temperature and the reflectance, Converted to At this time, the value of the reflectance measured by the two-color radiation thermometer 11 is used as the reflectance value.

  By comparing the temperature distribution of the measurement region D calculated by the infrared radiation detector 12 with the temperature distribution of the measurement region D calculated by the two-color radiation thermometer 11, the infrared radiation detector 12 The temperature distribution of the measurement region D calculated in this way and the emissivity distribution are matched. That is, the emissivity corresponding to each part of the measurement region D calculated by the infrared radiation detector 12 is specified.

  Thus, in the arithmetic processing unit 13, since the temperature conversion is performed using the actually measured emissivity, the temperature in the measurement region D in which the error caused when the emissivity is set to a fixed value is eliminated is measured. be able to. If the temperature is calculated at each measurement point in the measurement region D, the temperature in the measurement region D can be obtained.

  In the output unit 52 of the arithmetic processing unit 13, the temperature distribution of the measurement region D calculated by the temperature calculation unit 51 is converted into an analog signal and displayed and output as an image by the output unit.

  Next, the flow of temperature measurement of the weld pool during welding using the temperature measuring device 10 having the above configuration will be described with reference to the flowchart shown in FIG.

  In the temperature measurement, the radiation detector 31 of the two-color radiation thermometer 11 and the infrared radiation detector 12 are arranged at a position where an image of the same measurement region D included in the measurement object can be simultaneously captured. .

First, the infrared radiation detector 12 as the infrared detecting means detects the intensity of infrared energy radiated from a measurement point that is a target of temperature measurement. On the other hand, the two-color radiation thermometer 11 as emissivity measuring means detects visible light energy emitted from the measurement point, and measures temperature and emissivity (S1).
The measurement point is a part welded immediately before the part being welded in the measurement region D, and the temperature and emissivity measurement by the two-color radiation thermometer 11 and the infrared radiation intensity by the infrared radiation detector 12 are performed. These measurements are performed in parallel.

  Subsequently, upon receiving detection signals from the two-color radiation thermometer 11 and the infrared radiation detector 12, the arithmetic processing unit 13 calculates the temperature distribution in the measurement region D (S2). It is displayed and output as an image on the output means (S3).

According to the above temperature measurement method, since the temperature at the measurement point is calculated based on the actually measured emissivity and the radiant intensity of the infrared energy measured by the infrared radiation detector 12, the difference between the emissivities is calculated. It is possible to obtain a highly reliable measurement value in which an error from the temperature distribution in the actual measurement region D is eliminated.
Moreover, according to said temperature measuring method, the temperature measurement of the non-contact-type molten pool in which the temperature measurement of the molten pool which light-emits is possible is realizable. And since it is a non-contact system, the temperature measurement of the molten pool of the actual product in welding can be performed online.

Next, the temperature measuring device 10 (10B) according to the second embodiment of the present invention will be described.
4 is a diagram illustrating an overall configuration of a temperature measuring device according to the second embodiment, FIG. 5 is a block diagram of the temperature measuring device according to the second embodiment, and FIG. 6 is a block diagram of the temperature measuring device according to the second embodiment. is there.

As shown in FIGS. 4 and 5, the temperature measurement device 10 (10 </ b> B) according to the second embodiment includes a two-color radiation thermometer 11, an infrared radiation thermometer 61, and an arithmetic processing device 62.
The temperature measurement apparatus 10 according to the second embodiment uses the emissivity measured by the two-color radiation thermometer 11 to correct the temperature distribution of the measurement region D measured by the infrared radiation thermometer 61, thereby measuring the temperature. A true temperature distribution in the region D is obtained.

  The configuration of the two-color radiation thermometer 11 included in the temperature measurement device 10 (10B) according to the second embodiment is the same as that of the two-color radiation thermometer 11 included in the temperature measurement device 10 according to the first embodiment. Since it is the same structure, description is abbreviate | omitted.

[Infrared radiation thermometer 61]
The infrared radiation thermometer 61 is a temperature measurement unit that measures the temperature distribution of the measurement region D based on the infrared energy radiated from the measurement region D.
The infrared radiation detector 12 includes an infrared radiation detector 12 that detects infrared energy emitted from the measurement region D, and a temperature calculation unit 63 that calculates a surface temperature based on the radiation intensity of the infrared energy. .

  The configuration of the infrared radiation detector 12 is the same as that of the infrared radiation detector 12 included in the temperature measuring apparatus 10 according to the first embodiment, and a description thereof will be omitted.

In the temperature calculation unit 63, based on the detection signal received from the infrared radiation detector 12, an electrical signal proportional to the magnitude of the infrared energy is corrected and converted into a temperature. Then, the temperature of each measurement point in the measurement region D is calculated. At this time, in the temperature calculation unit 63, the emissivity at each measurement point in the measurement region D is calculated as a fixed value (for example, 1) set in advance according to the type of substance in the measurement region D and the surface state thereof. .
That is, the temperature calculation unit 63 calculates the temperature at each measurement point in the measurement region D based on the detection signal received from the infrared radiation detector 12 and the emissivity set in advance.
The temperature distribution of the measurement region D calculated by the temperature calculation unit 63 is transmitted from the infrared radiation thermometer 61 to the arithmetic processing device 62.

[Arithmetic processing device 62]
The arithmetic processing unit 62 is arithmetic processing means for calculating a true temperature distribution in the measurement region D based on the detection signal from the two-color radiation thermometer 11 and the detection signal from the infrared radiation thermometer 61. is there.
The arithmetic processing unit 62 calculates “true temperature” for the temperature at each measurement point in the measurement region D measured by the infrared radiation thermometer 61 and calculates the true temperature distribution in the measurement region D. And an output unit 66 that outputs the calculated true temperature distribution of the measurement region D as an image.

  The arithmetic processing unit 62 can be configured as a general-purpose computer including a CPU 25, an input unit 26 such as a keyboard, and an output unit 27 such as a monitor. However, the arithmetic processing unit 13 can also be configured as a dedicated device having the same function.

In the temperature calculation unit 65, the temperature at each measurement point in the measurement region D measured by the infrared radiation thermometer 61 is corrected by the emissivity of each measurement point in the measurement region D measured by the two-color radiation thermometer 11. Thus, the true temperature at each measurement point is calculated, and the true temperature distribution in the measurement region D is calculated.
Then, in the output unit 66 of the arithmetic processing unit 62, the true temperature distribution of the measurement region D calculated by the temperature calculation unit 65 is converted into an analog signal and displayed and output as an image by the output unit 27. .

  Next, the flow of temperature measurement using the temperature measurement device 10 (10B) will be described with reference to the flowchart shown in FIG.

First, the infrared radiation thermometer 61 detects the intensity of infrared energy radiated from the measurement point that is the target of temperature measurement, and the detected infrared energy intensity and the emissivity set to a predetermined value in advance. Based on this, the temperature of the measurement point is measured. And the emissivity and temperature of the said measurement point are measured with the two-color radiation thermometer 11 which is an emissivity measurement means (S21).
The measurement point is a part of the measurement region D that is welded immediately before the part being welded. The temperature is measured by the infrared radiation thermometer 61, and the temperature and emissivity are measured by the two-color radiation thermometer 11. Are performed in parallel.

Subsequently, the temperature of the measurement point measured by the infrared radiation thermometer 61 is corrected by using the emissivity measured by the two-color radiation thermometer 11 in the arithmetic processing device 62 which is an arithmetic processing means. (S22).
Finally, the arithmetic processing unit 62 displays and outputs the calculated temperature distribution of the measurement region D (S23).

  As described above, according to the temperature measurement method using the temperature measuring device 10 (10B), the temperature distribution measured by the infrared radiation thermometer 61 is corrected using the actually measured emissivity. It is possible to obtain a highly reliable measurement value that eliminates an error from the actual temperature distribution in the measurement region D that occurs when the value is fixed.

1 is a diagram illustrating an overall configuration of a temperature measurement device according to Embodiment 1. FIG. 1 is a block diagram of a temperature measuring device according to Embodiment 1. FIG. 2 is a flowchart of temperature measurement according to the first embodiment. FIG. 6 is a diagram illustrating an overall configuration of a temperature measurement device according to a second embodiment. FIG. 4 is a block diagram of a temperature measurement device according to a second embodiment. 10 is a flowchart of temperature measurement according to the second embodiment.

Explanation of symbols

DESCRIPTION OF SYMBOLS 10 Temperature measuring device 11 Two-color radiation thermometer 12 Infrared radiation detector 13 Arithmetic processing device 31 Radiation detector 33 Temperature calculation part 34 Emissivity calculation part 35 Filter 36 Lens 37 Image sensor 42 Infrared filter 43 Lens 44 Infrared sensor 47 Temperature calculation Unit 51 Temperature calculation unit 52 Output unit 61 Infrared radiation thermometer 62 Arithmetic processing device 63 Temperature calculation unit

Claims (6)

An infrared detecting means for detecting the radiation intensity of infrared energy emitted from a measurement point to be temperature-measured;
An emissivity measuring means for measuring the emissivity of the measurement point;
An arithmetic processing means for calculating the temperature of the measurement point based on the detected radiation intensity and the measured emissivity,
A temperature measuring device comprising: Detect the intensity of infrared energy radiated from the measurement point that is the target of temperature measurement, and measure the temperature at the measurement point based on the detected intensity of the infrared energy and the emissivity set to a predetermined value in advance. An infrared radiation thermometer,
An emissivity measuring means for measuring the emissivity of the measurement point;
An arithmetic processing means for correcting the measured temperature of the measurement point using the measured emissivity,
A temperature measuring device comprising: The emissivity measuring means detects at least two wavelengths of emitted light at the same measurement point, and measures the emissivity based on the radiation intensity of the at least two wavelengths of emitted light,
The temperature measuring device according to claim 1 or 2. Infrared detection means detects the radiant intensity of infrared energy radiated from the measurement point that is the target of temperature measurement,
The emissivity measuring means measures the emissivity of the measurement point,
A temperature measurement method, wherein the temperature of the measurement point is calculated by the calculation means based on the detected radiation intensity and the measured emissivity. The infrared radiation thermometer detects the intensity of the infrared energy emitted from the measurement point that is the target of the temperature measurement, and based on the detected intensity of the infrared energy and the emissivity set to a predetermined value in advance. Measure the temperature at the measurement point,
The emissivity measuring means measures the emissivity of the measurement point,
A temperature measurement method characterized in that the temperature of the measured measurement point is corrected by using the measured emissivity by an arithmetic processing means. The emissivity measuring means detects at least two wavelengths of emitted light at the same measurement point, and measures the emissivity based on the radiation intensity of the at least two wavelengths of emitted light,
The temperature measurement method according to claim 4 or 5.

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