JPH0528933U - Laser Doppler instrument calibration equipment - Google Patents

Abstract

(57) [Summary] [Purpose] You can quickly and reliably check the measurement accuracy without moving the detector (optical head) to a calibration position near the measurement site without changing the physical conditions with the DUT. Providing a calibration device for laser Doppler measurement. [Structure] A cylindrical body 4 which is a calibration device 1 is provided at a line proximity position outside the line for the object to be measured 2, and the laser Doppler measuring device 3 is movable from the normal measurement position to the cylindrical body 4 position. Further, with the laser Doppler measuring device 3 moved to the position of the cylindrical body 4, the peripheral surface of the cylindrical body 4 is used as a pseudo measurement surface, and measurement is performed while changing the rotation speed of the cylindrical body 4 according to a command from the computing unit 5, Calibrate. When measuring the plate length by integrating the velocity, the calibration device sets various movement patterns and calibrates them to improve the measurement accuracy.
Maintain at 0.1%.

Description

[Detailed description of the device]

[0001]

[Industrial applications]

 This invention uses the Doppler effect of light to determine the moving speed or moving distance (measured body length) of a measured body such as a steel plate in a manufacturing line for steel and non-ferrous metals (whether hot or cold). The present invention relates to a calibration device for rapidly checking and calibrating the accuracy of a laser Doppler measuring instrument, which makes non-contact measurement.

[0002]

[Problems to be solved by conventional techniques and devices]

When the measured object is irradiated with laser light, the frequency of scattered light shifts from the frequency f _{0 of} incident light due to the Doppler effect. Since the frequency f _d of this scattered light is proportional to the moving speed of the object to be measured, the moving speed V of the object to be measured can be known by measuring f _d , and this speed V can be calculated with time. By integrating, the moving distance of the measured object, that is, the length L of the measured object can be obtained.

In this type of laser Doppler measurement, as shown in FIG. 6, the irradiation angle θ of the laser beam has a great influence. That is, since the Doppler effect is produced even if the irradiation angle is slightly inclined, the measured value changes if this angle shifts. Therefore, it is necessary to confirm and adjust (correct) the setting of this irradiation angle θ with a calibration device.

Conventionally, this type of calibration device is generally not installed in the field where the measuring instrument to be calibrated is used. Even if it is installed, it is an operator's cab or an electric room in a good environment near the line where the measuring instrument is installed. Therefore, the detector (optical head) removed from the measuring instrument on the line was carried into the operator's cab or electric room, carefully positioned and set to the calibration device with a certain degree of accuracy, and then tested, and after the test was completed. In addition, the detector will be installed at the official location of the removed line, and the measurement will be started after connecting the wiring and piping.

A laser Doppler measuring device is disclosed in Japanese Unexamined Patent Publication No. Sho 62-126378 and the like. In Japanese Unexamined Patent Publication No. Sho 62-126378, the measuring point of a moving measured object is the thickness of the measured object. Changes in the height direction due to the change in laser irradiation angle θ, and the thickness meter corrects the measurement error by the Doppler velocimeter, which reduces the measurement error.There is no description about the calibration method at the measurement site. It has not been.

Further, as a calibration device, Japanese Patent Laid-Open Publication No. 1-288706 and Japanese Utility Model Laid-Open No. 64-38501 are known. Here, the former is to measure when the line is stopped by using a device that automatically conveys the reference plate instead of the plate in the line when calibrating the plate width meter. Therefore, it is necessary to insert and remove the reference plates of various sizes, which is labor-saving but not practical, and offline calibration is usually the mainstream. In the latter, various dimensions are combined into one reference plate and the positions are gradually shifted to enable measurement with one reference plate.

As a method for checking the operating status and malfunction of the laser Doppler measuring device, input / output check of the laser transmitter and control panel, that is, electric system check of the system is performed. This is divided into the position check of the mounting angle and distance of the detector (optical head) in the measuring instrument, that is, the optical and mechanical system check of the system. Since each check is performed individually, a great deal of man-hours are required, and it is difficult to make a comprehensive judgment for the man-hours.

Even if the calibration device is on the measurement site side, the detection unit (optical head unit) is removed, and the detection unit (optical head unit) is set in the calibration device to start measurement. The route environment (external noise and cable length) of the optical cable etc. between the optical head part) and the control panel is different, and the optical system cannot be reproduced at all.

The present invention was created in view of the above-mentioned circumstances, and its purpose is to improve a laser Doppler measuring device on a calibration device installed in the vicinity without removing the detection unit (optical head) at the measurement site. The objective is to provide a calibration device that allows anyone to quickly and reliably check the measurement accuracy without changing the physical conditions of the object to be measured by simply moving it to.

[0010]

[Means for Solving the Problems]

 According to this invention, the calibration device is installed near the detection unit (optical head) at the measurement site, for example, the laser Doppler measuring device is installed on the line in the direction perpendicular to the flow of the object to be measured, the installation height of the detection unit, etc. A gate-type mount that can be retracted without changing the position of will be installed. When checking, move the detector of the measuring instrument and bring it directly above the calibration device. Since the environment is the same as formal measurement (both the optical system and the electrical system), calibration under almost the same conditions as online is possible. Be able to do it quickly and reliably.

[0011]

【Example】

 Hereinafter, a calibration apparatus for a laser Doppler measuring device according to the present invention will be described with reference to the illustrated embodiment.

The calibration device 1 (see FIG. 1) for calibrating the measurement value of the laser Doppler measuring device 3 for measuring the moving speed and the moving distance of the object 2 to be measured is used for the object 2 to be measured. The laser Doppler measuring device 3 is provided so as to be movable between the normal measurement position on the line and the line proximity position outside the line, and is provided at the line proximity position where the laser Doppler measurement device 3 moves. A cylindrical body 4 having a peripheral surface that is the same height as the measurement surface of the object to be measured 2 and serves as a pseudo measurement surface, and the rotation speed of the cylindrical body 4 corresponds to the state from the stopped state of the object to be measured 2 to the maximum moving speed state. In order to continuously issue the rotation change command, the actual measurement of the rotational speed and the measurement result of the laser Doppler measuring instrument 3 are recorded, and the actual measurement of the rotational speed of the cylindrical body 4 and the laser Doppler measuring instrument 3 are performed. And a calculator 5 that calculates and stores a measurement error from the measurement result of.

Reference numeral 6 in FIG. 1 is a touch roller type PLG oscillator provided as a backup for the laser Doppler measuring instrument 3. Further, reference numeral 7 is provided in an electric room (not shown), and the measured value from the PLG oscillator (electricity) 6 and the signal from the signal processing unit of the detecting unit 8 which will be described later are transmitted. It is an electric sequencer for controlling the line for the measuring object 2.

The laser Doppler measuring instrument 3 in this embodiment is provided with a detector 8 including a He-Ne laser, an optical detector, and a signal processor, and an optical head (optical probe) 9. The computing unit 5 is composed of a signal processing personal computer provided in an operator's cab (not shown) for an operator, and receives signals from the He-Ne laser of the detection unit 8 and the electric sequencer 7. come.

The calibration of the measurement value by the laser Doppler measuring instrument 3 performed by using the calibration device 1 having such a configuration is performed as described below.

First, in the measurement mode, the electric sequencer 7 reads the measurement value of the laser Doppler measuring device 3 (output from the detecting unit 8 in FIG. 1) and the data from the touch roller type PLG transmitter 6. , Screen display and print output.

Next, in the calibration mode, the laser Doppler measuring instrument 3 is attached to the laser Doppler measuring instrument 3 with the detecting portion 8 and the optical head portion (optical probe) 9 being the detecting portion, and the laser doppler measuring instrument 3 is calibrated at the line proximity position. Move to.

Then, the PLG signal from the calibration device 1 in the cylindrical body 4 and the measurement signal from the laser Doppler measuring device 3 are counted by the calculator 5 for a certain period of time and displayed on the screen and printed out. The data is saved in a RAM disk (not shown) and printed out when necessary.

The method of using these calibration results is mainly for the measured value of PLG, the error of the laser is stored for each of various conditions, and when the measured value at the time of actual production is sent to the control CPU, error correction is performed. Add (calibration value). In order to bring the calibration closer to reality, the rotational speed of the cylindrical body 4 is set to a variable speed from 0 to the maximum plate passing speed. In other words, measurement errors are likely to occur when the moving speed of the device under test 2 changes, so various patterns such as acceleration, deceleration, sudden acceleration, and sudden stop are assumed, and the PLG value is compared with the laser performance.

FIG. 2 is a schematic line diagram showing installation locations of the laser Doppler measuring instrument 3 on the entire line. In addition, Fig. 3 shows that the cylinder 4 is given a Max rotation speed corresponding to the moving speed of the measured object 2 assuming actual operation, acceleration, constant speed, and deceleration are performed, and the total number of rotations (PLG measurement value) and cylinder It is a table which shows the result of having converted into the length of the to-be-measured body 2 from body diameter, and having compared with the length measurement by a laser.

The table of FIG. 4 shows the measurement results of the length-measured coil (calculated from the weight and the plate thickness × width), and the table of FIG. 5 shows the calibration results of the calibration device. In this way, the measurement accuracy check result is the most accurate as compared with PLG / portable measuring, as a result of measurement using a test coil that has been actually measured, and the calibration result by the calibration device, The error was good within ± 0.1%.

[0022]

[Effect of the device]

 In the conventional calibration method, the off-line calibration device was installed farther from the line, and the detector (optical head) of the measuring instrument was removed and moved to the installation location. Since the measuring device is moved to the calibration position with the (optical head) attached, the calibration work of the measuring device can be easily performed.

Also, without having to ask the person in the department specializing in maintenance to check the measurement accuracy of the laser Doppler measuring instrument, the operator of the factory can perform the calibration check work quickly and easily at the chance of a short break in operation. Become. Therefore, the load on the maintenance staff is reduced, and the accuracy of the measuring instrument can be improved, and the measurement can be performed while maintaining high accuracy.

Further, when installed in an existing line, if the conventional method is left and switching is allowed, the operating rate of the measuring instrument can be maintained high.

[Brief description of drawings]

FIG. 1 is a schematic view showing a calibration device of the present invention.

FIG. 2 is a schematic line diagram showing an example of an installation position of a laser Doppler measuring instrument.

FIG. 3 is a comparison table of measurement results of a laser Doppler measuring instrument and a reference PLG in the calibration device of the present invention.

FIG. 4 is a table showing the results of actual measurement tests on measured coils.

FIG. 5 is a table showing a calibration result by the calibration device.

FIG. 6 is a schematic diagram showing the principle of a laser Doppler measuring instrument.

[Explanation of symbols]

1 ... Calibration device, 2 ... Object to be measured, 3 ... Laser Doppler measuring instrument, 4 ... Cylindrical body, 5 ... Arithmetic unit, 6 ... PLG transmitter, 7 ...
Electric sequencer, 8 ... Detection unit, 9 ... Optical head unit (optical probe).

 ─────────────────────────────────────────────────── ─── Continuation of the front page (72) Inventor Toshio Igarashi No. 3 Hikari, Oshima, Kashima-cho, Kashima-gun, Ibaraki Prefecture Kashima Plant Industry Co., Ltd.

Claims (1)

[Scope of utility model registration request] 1. A calibration device for calibrating a measurement value of a laser Doppler measuring device for measuring a moving speed and a moving distance of a measured object by using an optical Doppler effect, and a normal measurement on a line for the measured object. Position and a laser Doppler measuring device provided movably between the line proximity position outside the line, and the laser Doppler measuring device is provided at the line proximity position to move,
A cylindrical body having a peripheral surface which becomes the same height as the measurement surface of the measured object and becomes a pseudo measurement surface, and the rotation speed of this cylindrical object is adjusted from the stopped state of the measured object to the maximum moving speed state. While continuously issuing a rotation change command, record the actual measurement of the number of revolutions and the measurement results of the laser Doppler measuring device, and calculate the measurement error between the actual measurement of the rotational speed of the cylindrical body and the measurement result of the laser Doppler measuring device. A calibration device for a laser Doppler measuring instrument, comprising: an arithmetic unit for storing the information.