JPH0682046B2 - Automatic plate thickness measuring device - Google Patents

Description

Description: TECHNICAL FIELD The present invention relates to an automatic plate thickness measuring device for automatically measuring the plate thickness of an object to be measured transported by a transport line in a non-contact manner by reflecting a light beam.

[Prior Art] Conventionally, there has been known an automatic plate thickness measuring device for automatically measuring a plate thickness of an object to be measured conveyed by a conveying line by an optical displacement meter (for example, Japanese Patent Publication No. 56-10561).

The device used in the past is a one-point measuring device using a so-called C-type frame, and measures an object having a constant width, that is, an object having a fixed width.

In this device, optical displacement meters are arranged above and below the transport line. A light beam, which is a laser beam, is irradiated onto the object to be measured by this optical displacement meter, and the plate thickness of the object to be measured is measured.

Conventionally, such a device has been used to automatically measure the plate thickness of a measured object such as a steel plate.

By the way, generally, calibration is necessary to ensure the accuracy of the automatic plate thickness measuring device.

Calibration is performed every time the device is used, and it is an essential work for operating the device. More specifically, it corrects errors due to aging of the optical displacement meter (electrical correction), and also corrects mechanical distortion (mechanical correction) to maintain reliability and accurately measure plate thickness. It is intended.

[Problems to be Solved by the Invention] However, conventionally, there has been a problem that an error occurs in the plate thickness measurement due to distortion of the gantry, characteristic changes of the optical displacement meter, and the like.

That is, the optical displacement meter is attached to the pedestal on the transfer line, and as long as the pedestal maintains the predetermined position and the predetermined shape, the error caused by the pedestal does not occur. However, in actuality, the pedestal is distorted due to environmental factors such as temperature and humidity and aging. Due to this distortion, the amount of movement of the optical displacement meter changes non-linearly, causing an error in plate thickness measurement.

Further, the detection characteristic of the optical displacement meter also changes due to the same factor. This change also causes an error in the plate thickness measurement.

Further, conventionally, there has been a problem that only the object to be measured having the same surface property can be measured at one time. That is, if the surface properties of the respective objects to be measured are different, accurate measurement becomes difficult with an apparatus calibrated according to one type of surface property. Further, when the surface properties of one measured object are not constant, the measurement cannot be performed.

The present invention has been made to solve such a problem, and it is possible to perform more accurate plate thickness measurement by compensating for pedestal distortion during calibration, characteristic changes of the optical displacement meter, and the like. With the goal. It is another object of the present invention to make it possible to accurately measure an object to be measured having different surface properties at one time, or to measure an object to be measured having an even surface property.

[Means for Solving the Problem] In order to achieve such an object, the present invention forms a pair on a pedestal above and below a transportation line for transporting an object to be measured with a predetermined reference distance. A plurality of pairs of optical displacement gauges that are arranged and determine the distance to the object to be measured based on the reflected light by irradiating the object to be measured with a light beam and measuring the plate thickness of the object to be measured with an L-shaped bend at the tip. Sometimes the tip is placed outside the measurement range of the optical displacement meter and the calibration plate with a predetermined thickness is used. Means, and at the time of measurement, the vertical position of the optical displacement meter is controlled so that the position is determined according to the plate thickness standard of the measured object, and a predetermined trajectory on the measured object is drawn according to the flow of the measured object. Controls the left and right position of the optical displacement meter and moves the optical displacement meter up and down during linearity calibration. Position control means for moving the optical displacement meter at a predetermined interval in the left-right direction during calibration of the gantry, and the output of the optical displacement meter during linearity calibration is associated with the expected vertical position of the optical displacement meter. A reference distance is obtained based on the linearity correction means that creates a linearity correction table, the output of the optical displacement meter during frame calibration, and the plate thickness of the calibration plate, and this reference distance is associated with the left and right positions of the optical displacement meter. Correct the distance between the optical displacement meter and the object to be measured by referring to the gantry correction means that creates the calibration table and the linearity correction table, and correct the reference distance by referring to the calibration table according to the left and right position of the optical displacement meter. A plate thickness calculation means for calculating and averaging the plate thickness of the object to be measured at several points along the locus based on the vertical displacement of the optical displacement meter, the corrected distance, and the reference distance. .

[Operation] In the automatic plate thickness setting device of the present invention, the object to be measured is based on the distance between the optical displacement meter and the object to be measured, the vertical movement amount of the optical displacement meter, and the reference distance between the opposed optical displacement meters. Is required.

Of these, the distance between the optical displacement meter and the object to be measured is corrected by the linearity correction table.

For example, when the characteristics of the optical displacement meter change from the initial characteristics, an error will occur in the plate thickness measurement value unless this change is compensated. Therefore, the linearity calibration is performed in the present invention. The linearity calibration is performed while moving in the vertical direction at a predetermined pitch, and for this calibration, the output of the optical displacement meter is associated with the expected vertical position of the optical displacement meter.

The output of the optical displacement meter at this time indicates the distance between the optical displacement meter and the calibration plate. That is, during calibration, the calibration plate is rotated to a position that blocks the light beam, and reflected light is obtained from this calibration plate. The expected vertical position is the vertical position obtained by position control based on the initial characteristics of the optical displacement meter, for example.

A table showing the correspondence between the output of the optical displacement meter and the vertical position is called a linearity correction table. This linearity correction table is used to correct the output of the optical displacement meter during measurement, that is, the distance between the optical displacement meter and the object to be measured. As a result, the error caused by the above-mentioned characteristic change depending on the vertical position of the optical displacement meter at the time of measurement is compensated.

Further, the distance between the optical displacement meter and the object to be measured is corrected by the calibration table.

For example, when the pedestal is distorted, a measurement error may occur due to this distortion. Therefore, in the present invention, gantry calibration is performed. The gantry calibration is performed based on the output of the optical displacement meter when the optical displacement meter is moved in the left-right direction at a predetermined interval.

More specifically, a calibration table that associates the reference distance obtained from the output of the optical displacement meter with the left and right positions of the optical displacement meter is created. The reference distance in this case is obtained based on the outputs of the upper and lower optical displacement meters and the known plate thickness of the calibration plate.

The calibration table thus obtained is used to correct the reference distance during measurement. As a result, an error that occurs depending on the left and right positions of the optical displacement meter during measurement, for example, an error caused by pedestal distortion is reduced. In addition, it is preferable that the gantry calibration is performed by using the result after the linearity calibration.

Further, at the time of measurement, spatial averaging calculation is performed. At the time of measurement, the left and right positions of the optical displacement meter are controlled so as to draw a predetermined locus on the measured object. In the present invention, a predetermined number of plate thicknesses are obtained along this locus and averaged. Therefore,
In the present invention, the number of points that is the basis of the plate thickness calculation is increased, so that the accuracy of measurement is improved.

[Embodiment] A preferred embodiment of the present invention will be described below with reference to the drawings.

FIG. 1 shows the actual configuration of an automatic plate thickness measuring and measuring device according to an embodiment of the present invention. In particular, FIG. 1 (a) shows the appearance of the apparatus seen from above, and FIG. 1 (b) shows the appearance seen from the side.

In this figure, the object to be measured is in the direction indicated by the arrow in the figure.
A transport line 12 for transporting 10 is shown. The object to be measured 10 in this figure is a steel plate having a different plate thickness, width, etc., and three pieces 10-1, 10-2, 10-3 are shown in the figure. In this example, the measurement object 10 that is the object of plate thickness measurement
Is, for example, plate thickness 4 to 60 mm, width 800 to 4000 mm, length 1500 to 1
It has a standard of 4000 mm, and is arranged at any position on the transfer line 12 in any position.

In addition, a pair of upper and lower gate-shaped stands so that they straddle the transfer line 12.
14 are provided. A line sensor 16 is provided on the upstream side of the transfer line 12 of the gate platform 14, and an optical displacement meter 18 is provided on the downstream side thereof.

The line sensors 16 are a pair of upper and lower gate-shaped mounts so as to form a pair.
It is provided at 14 and detects the left and right end positions of the tip of the object to be measured 10. The detected left and right end positions are used for setting the dead time of the position of the optical displacement meter 18.

Further, three pairs of the optical displacement meters 18 are movably provided on the gate mount 14. The optical displacement meter 18 is a device for measuring the plate thickness of the measured object 10. That is, the optical displacement meter 18 irradiates the measured object 10 with a light beam and captures the reflected light. Furthermore, the distance to the object to be measured 10 is calculated based on the captured reflected light,
It is used for plate thickness calculation based on the principle described later.

FIG. 2 shows a more detailed substance structure of this embodiment as a front view.

In this figure, two upper and lower linear motor rails 20 are shown. The linear motor rail 20 is a rail of a linear motor that drives the six optical displacement gauges 18 in the left-right direction.

The upper three of the optical displacement meters 18 are pulse stages.
It is attached to 22. That is, the three optical displacement meters 18 are vertically driven by the pulse stage 22,
During measurement, the vertical position is set by the control of the pulse stage 22 according to the plate thickness standard of the object to be measured 10.

Further, first and second edge sensors 24 and 26 are attached to two pairs on the left and right sides of the three pairs of optical displacement meters 18. The first edge sensor 24 is used to further finely adjust the position of the optical displacement meter 18 which is initially set according to the output of the line sensor 16. The second edge sensor 26 is used to follow and detect the side edge of the measured object 10.

FIG. 3 shows a device configuration relating to the calibration of the optical displacement meter 18 in this embodiment. In particular, FIG. 3 (a) shows the front surface of the pair of optical displacement meters 18, and FIG. 3 (b) shows the side surfaces thereof.

In this figure, the calibration plate 28 that is pivotally arranged at a position indicated by a broken line during normal plate thickness measurement and a position indicated by a solid line during calibration is shown. The calibration plate 28 has an L-shaped bend, and the plate thickness at the tip is set to a predetermined thickness that has been verified. The rotation of the calibration plate 28 depends on the rotary solenoid.
Made by 30. Further, the calibration plate 28 vibrates in the horizontal direction with an amplitude of, for example, ± 3 mm by a motor (not shown).

FIG. 4 shows the circuit configuration of this embodiment.

In this figure, on the other hand, based on the output of the optical displacement meter 18,
An arithmetic and control unit which obtains the plate thickness of the object to be measured 10 and controls the linear motor 32 and the pulse stage 22 based on the outputs of the line sensor 16 and the first and second edge sensors 24 and 26 on the other hand.
34 is shown. Further, the arithmetic control unit 34 also controls the rotary solenoid 30. In addition, this drawing also shows a memory 36 that stores a reference distance required during calibration and a linearity correction table according to the features of the present invention. In addition,
Optical displacement meter 18, line sensor 16, first edge sensor 24, second edge sensor 26, linear motor 32, pulse stage 22
Although the rotary solenoid 30 is actually plural in number, it is omitted in this figure for simplification of the figure.

Next, the operation of this embodiment will be described.

First, the measured object 10 is placed on the transfer line 12. The measured object 10 placed is conveyed by the conveying line 12 and reaches below the line sensor 16.

Then, the line sensor 16 detects the light-shielding position of the object to be measured 10. That is, the line sensor 16 is
The part where the light beam is blocked by the device under test 10 is detected, and this is supplied to the arithmetic and control unit 34 as the left and right end positions of the device under test 10.

The arithmetic control unit 34 drives and controls the linear motor 32 based on the output of the line sensor 16 to control the position of the optical displacement meter 18. Specifically, one pair of left and right optical displacement gauges 18 are moved to the left and right end positions of the object to be measured 10 which are detected as the light-shielding position, and the pair of optical displacement gauges 18 arranged at the center is moved to the left and right. The optical displacement meter 18 is maintained at the center position. As a result, the position of the optical displacement meter 18 is initialized.

After that, when the measured object 10 is further conveyed and reaches the first edge sensor 24, the position of the optical displacement meter 18 is finely adjusted by the first edge sensor 24. That is, the arithmetic control unit 34 controls the linear motor 32 according to the output of the first edge sensor 24.

Next, the left and right ends of the measured object 10 are captured by the second edge sensor 26. At this time, the arithmetic control unit 34 controls the linear motor 32 by the output of the second edge sensor 26. That is, since the second edge sensor 26 is fixed to the optical displacement meter 18, the second edge sensor 26 continues to capture the right and left ends of the measured object 10 by this control, and the optical displacement meters 18 on both the left and right sides are controlled. Means to detect and scan a locus having a predetermined distance from both left and right ends of the object to be measured 10.

FIG. 5 shows a light beam locus of the optical displacement meter 18, and FIG. 6 shows points (measurement positions) used in the plate thickness calculation on this locus.

In this embodiment, the output of the optical displacement meter 18 relating to the locus indicated by the three arrow lines in FIG. 5 is continuously collected. After this collection, the arithmetic control unit 34 determines the measurement position,
Calculate the plate thickness.

More specifically, the arithmetic and control unit 34 determines the transport speed of the measured object 10 from the time from when the tip of the measured object 10 reaches the line sensor 16 to when it reaches the first edge sensor 24. Since the distance between the line sensor 16 and the first edge sensor 24 is determined by design, the time is measured by using this transport speed.
Can be converted to position coordinates with 10 as the reference. The measurement position is determined based on the conversion result.

The measurement position is determined, for example, from a total of six lines, which are a line of 15 mm from both left and right ends of the object to be measured 10, a line of 15 mm from both front and rear ends, and a center line. That is, the intersection of these lines is measured at the measurement position P ₁
Set to ~P _9.

Next, for the measurement positions P _{1 to} P ₉ set in this way,
The plate thickness calculation based on the output of the optical displacement meter 18 already collected is performed by the calculation control unit 34.

In the case of this embodiment, the data used for the plate thickness calculation is the spatial average of the points in the vicinity of the respective measurement positions P _{1 to} P ₉ .

FIG. 7 shows the calculation contents of the spatial average.

As shown in this figure, the measurement position P _i and each before and after the measurement position P _i
Ten points are considered as primary valid data. Each point is set to 2 mm pitch, and the spatial average is calculated using only the points that meet certain conditions out of these 21 points in total.

For example, out of the 21 points, delete 2 points from the maximum value and 5 points from the minimum value, and also delete the abnormal value, so that the remaining score is 10 points.
When there are more points, the outputs of the optical displacement meter 18 for the remaining points are averaged. If the score does not reach 10 points, it is determined that measurement is impossible.

The plate thickness calculation in this embodiment is executed according to a predetermined principle by using the distance between the optical displacement meter 18 and the measured object 10 thus obtained as the spatial average.

FIG. 8 shows the principle of plate thickness measurement in this embodiment.

In this embodiment, the plate thickness of the object 10 to be measured is obtained based on the distance between the optical displacement gauges 18 facing each other during the plate thickness measurement and the above-mentioned spatial average.

First, it is assumed that the facing distance of the optical displacement meter 18 without the measured object 10, that is, the reference distance L ₀ is determined by design. Further, in the case of the object to be measured 10 having a plate thickness L, the optical displacement meter 18
Let L ₃ be the amount by which the distance between the two is increased, that is, the amount of movement of the optical displacement meter 18.

Then, the plate thickness L can be obtained from the distance L ₁ measured by the upper optical displacement meter 18 and the distance L ₂ measured by the lower optical displacement meter 18 by the following formula.

L = (L ₀ + L ₃ ) − (L ₁ + L ₂ ). Thus, in this embodiment, multipoint measurement of the plate thickness L based on the measurement positions P _{1 to} P ₉ is executed. At this time, since the spatial average is used, a certain degree of accuracy is ensured even when the surface properties of the measured object 10 are nonuniform. That is, the spatial averaging absorbs the nonuniformity of the output of the optical displacement meter 18 due to the surface property. Further, even when the surface properties of the same object to be measured 10 are non-uniform, this is absorbed as well, and therefore measurement becomes possible.

Further, the movement amount L ₁ used for measuring the plate thickness L in this embodiment is a value corrected by the linearity correction table created in each optical displacement meter 18 at the time of calibration.

Next, a calibration operation related to the creation of this linearity correction table will be described.

The optical displacement meter 18 is a device that is accompanied by characteristic changes due to environmental factors, changes over time, and the like. In FIG. 9, the solid line shows the initial characteristics, and the broken line shows the changed characteristics. Such characteristic changes will appear as an error during measurement. Therefore, in the present embodiment, linearity calibration is performed as the calibration.

When the gantry 14 is distorted due to temperature, humidity, aging, etc., this distortion changes the distance between the upper and lower optical displacement meters 18, that is, the reference distance. This change appears as an error in the measured value. Therefore, in this embodiment, the gantry calibration is performed.

Linearity calibration is performed prior to gantry calibration. That is, the gantry calibration is performed on the optical displacement meter 18 after the linearity calibration is performed.

First, at the time of linearity calibration, the calibration plate 28 is rotated by the rotary solenoid 30. As a result of this rotation, the tip is placed at a position between the optical displacement meters 18 facing each other.

The calibration plate 28 is formed of a white ceramic plate having a known plate thickness, and is oscillated in the horizontal direction by the rotary solenoid 30 after the placement. This vibration is a vibration with an amplitude of about ± 3 mm, and is applied to eliminate the influence of the surface properties of the calibration plate 28.

In this state, the optical displacement meter 18 is moved vertically with a predetermined pitch. That is, the pulse stage 22 is controlled by the arithmetic control unit 34, and the vertical position of the upper optical displacement meter 18 changes at a predetermined pitch, for example, 1 mm. An output from the optical displacement meter 18 is obtained for each change. This output is the optical displacement meter 18
And the calibration plate 28. 16 for each pitch
These measurements are performed once, and the vertical displacement of the optical displacement meter 18 is performed for a predetermined number of pitches, for example, a pitch number corresponding to ± 20 mm, and then these outputs are averaged.

The average of the 18 outputs of the optical displacement meter thus obtained (hereinafter,
The output of the optical displacement meter 18) is associated with the expected vertical position of the optical displacement meter 18. That is, the output of the optical displacement meter 18 is associated with the expected vertical position and stored in the memory 36 as a linearity correction table.

FIG. 10 shows an example of the linearity correction table.

As shown in this figure, the linearity correction table includes a control amount (command value) L of the pulse stage 22 by the arithmetic control unit 34.
_3Si is _associated with the actual optical displacement meter 18 output L _3Ai . The command value L _3Si is a value that is issued based on the initial characteristics of the optical displacement meter 18, and is the vertical position that would be obtained if the characteristics of the optical displacement meter 18 were not changed, that is, an ideal value.
Therefore, the linearity correction table associates the ideal value and the actual value with respect to the characteristics of the optical displacement meter 18.

Such a linearity correction table is created for each of the upper optical displacement meters 18 in order to respond to changes in the characteristics of the optical displacement meters 18.

In this way, the gantry calibration is performed after the linearity calibration is performed. In this gantry calibration, the upper and lower optical displacement meters 18 and the calibration plate 28 are horizontally moved in a pair.

That is, as shown in FIG. 11, three optical displacement meters 18
The movable range of 100-1, 100-2, and 100-3 is within a range (for example, about 40 mm), and the entire width 110 of the transfer line 12 is 110.
Covers. The optical displacement meter 18 and the calibration plate 28 are integrally moved at predetermined intervals within their respective movable ranges 100,
A calibration table is created for each optical displacement meter 18.

FIG. 12 shows an example of the calibration table.

As shown in this figure, the calibration table is a table that associates the lateral position x _Ai of the optical displacement meter with the actual reference distance L _{0Ai at} each lateral position x _Ai .

In the frame calibration, the calibration plate 28
Is rotated and horizontally vibrated. The output of the optical displacement meter 18 in this state indicates the distance between the optical displacement meter 18 and the calibration plate 28.

Here, the plate thickness of the calibration plate 28 is l ₀ , and the upper and lower optical displacement meters
Distance from 18 to calibration plate 28 (ie upper and lower optical displacement gauges 18
Of each output) is defined as l ₁ and l ₂ , respectively. In this case, the third
As shown in the figure, the following equation L ₀ = l ₁ + l ₂ + l ₀ holds for the reference distance L ₀ . Therefore, the arithmetic control unit 34 executes the arithmetic operation based on the above equation to obtain the actual reference distance L ₀ . In addition, such calculation is performed a predetermined number of times, for example,
The accuracy of the reference distance L ₀ is further improved by calculating the average 16 times and treating this average value as the reference distance L ₀ .

The reference distance L ₀ is obtained as N pieces of data L _0Ai by moving the upper optical displacement meter 18 left and right at a predetermined interval. The horizontal movement is performed by the linear motor 32 under the control of the arithmetic control unit 34.

The reference distance L _0Ai thus obtained is the optical displacement meter 18
When associated with the left and right positions of, the calibration table as shown in FIG. 11 is created. The calibration table is created for each pair of optical displacement meters 18.

The linearity correction table and the calibration table created as described above are stored in the memory 36.

At the time of measurement, these linearity correction table and calibration table are referred to.

That is, when determining the plate thickness of the object to be measured 10, the calculation control unit 34
Reads the data in the linearity table based on the command value to the pulse stage 22. The data obtained by this reading is, for example, L _3Ai in FIG. Therefore, if the difference between this data and the command value is obtained, the error due to the characteristic change contained in the current output of the optical displacement meter 18 can be obtained. If this error is subtracted from the optical displacement meter 18 output,
The influence of an error caused by the characteristic change of the optical displacement meter 18 is eliminated.

Further, in order to correct the reference distance used in the plate thickness calculation by L ₀ , the calculation control unit 34 reads the data related to the calibration table from the memory 36 based on the lateral position of the optical displacement meter 18. The read data is the reference distance L ₀ related to the left and right positions. Since the reference distance L ₀ is a value that reflects the pedestal distortion as described above, the plate thickness calculation using this reference distance L ₀ prevents the occurrence of an error when the gantry 14 is distorted.

As described above, according to the present embodiment, the calibration plate 28 can collectively perform the electrical correction and the mechanical correction by a simple means. Further, the correction can be performed using the linearity correction table and the calibration table, and the plate thickness L can be calculated more accurately to ensure the accuracy and reliability.

Further, the distance between the optical displacement meter 18 and the measured object 10 is obtained as a spatial average of several points in the vicinity of the measurement point, and as a result, variations in surface properties among the plurality of measured objects 10 and the same measured object 10 are obtained. Even if there is a variation in the surface texture at, the influence of the surface texture can be corrected to measure the plate thickness L more accurately.

Although the pulse stage 22 is provided only on the upper side in the above description, it may be provided on the lower side. in this case,
A linearity correction table is created for the upper and lower optical displacement meters 18 to enable more precise measurement.

As described above, according to the present invention, since the linearity correction table and the calibration table are created and the optical displacement meter output and the reference distance are corrected by the linearity correction table and the calibration table, More accurate plate thickness measurement becomes possible. Further, since the plate thickness is calculated based on the spatial average, the error caused by the surface property is reduced, and the plate thickness can be measured more accurately.

[Brief description of drawings]

FIG. 1 is a schematic external view showing the actual configuration of an automatic plate thickness measuring device according to an embodiment of the present invention. FIG. 1 (a) is a top view, FIG. 1 (b) is a side view, 2 is a front view showing a more detailed substance structure of this embodiment, FIG. 3 is a schematic view showing the structure of the calibration means of this embodiment, and FIG. 3 (a) is a front view and FIG. (B) is a side view, FIG. 4 is a block diagram showing a circuit configuration of this embodiment, FIG. 5 is a view showing a trajectory of a light beam emitted from an optical displacement meter, and FIG. 6 is a plate thickness measurement position. Fig. 7, Fig. 7 is a diagram showing the concept of spatial averaging, Fig. 8 is a diagram showing the thickness measurement principle, Fig. 9 is a diagram showing characteristic changes of the optical displacement meter, and Fig. 10 is an example of a linearity correction table. FIG. 11, FIG. 11 is a diagram showing a moving range of the optical displacement meter, and FIG. 12 is a diagram showing an example of a calibration table. 10: Object to be measured 12: Transport line 18: Optical displacement meter 28: Calibration plate 30: Rotary solenoid 32: Linear motor 34: Arithmetic control unit

 ─────────────────────────────────────────────────── ─── Continuation of the front page (72) Inventor Shuji Naito 1-1, Tobata-cho, Tobata-ku, Kitakyushu-shi, Fukuoka Prefecture Inside Nippon Steel Co., Ltd. Yawata Works (72) Inventor Hisao Fujikawa Tobata, Tohata-ku, Kitakyushu-shi, Fukuoka Town No. 1-1 New Nippon Steel Co., Ltd. Yawata Works (72) Inventor Takashi Mimura 5-1-1 Shimorenjaku, Mitaka City, Tokyo Metropolitan Government (72) Inventor Taichiro Yoneya Shimorenjaku, Mitaka City, Tokyo 5-1-1, Japan Radio Co., Ltd. (72) Koichi Itohara 5-1-1, Shimorenjaku, Mitaka-shi, Tokyo Within 5-1-1 Japan Radio Co., Ltd. (72) Hirotsugu Hashimoto 5-1-1, Shimorenjaku, Mitaka-shi, Tokyo No. 1 in Japan Radio Co., Ltd. (72) Inventor Kazutoshi Fujisaki 5-1-1 Shimorenjaku, Mitaka City, Tokyo Japan Radio Co., Ltd.

Claims (1)

[Claims] 1. A pair of units are arranged on a pedestal above and below a conveyance line for conveying an object to be measured, and are arranged at a predetermined reference distance. A plurality of pairs of optical displacement gages for obtaining the distance to the measurement object, and a tip with an L-shaped bend, of which the tip is placed outside the measurement range of the optical displacement gage when measuring the thickness of the object to be measured. Calibration plate, rotation means for rotating the calibration plate so that the tip is located at a predetermined position that blocks the light beam emitted from the optical displacement meter during calibration, and during measurement, set according to the plate thickness standard of the DUT. The vertical position of the optical displacement meter is controlled so that it will be set to the desired position, and the horizontal position of the optical displacement meter is controlled to draw a predetermined locus on the measured object according to the flow of the measured object. Move the meter up and down at a predetermined pitch, and move the optical displacement meter Position control means to move at a predetermined interval in the direction, linearity correction means to create a linearity correction table that correlates the output of the optical displacement meter during linearity calibration with the expected vertical position of the optical displacement meter, and during pedestal calibration Refer to the linear correction table and the gantry correction means that finds the reference distance based on the output of the optical displacement meter at and the plate thickness of the calibration plate and creates a calibration table that correlates this reference distance to the left and right positions of the optical displacement meter. Then, the distance between the optical displacement meter and the object to be measured is corrected, and the reference distance is corrected by referring to the calibration table according to the horizontal position of the optical displacement meter, and the vertical displacement of the optical displacement meter, the corrected distance and the reference An automatic plate thickness measuring device, comprising: a plate thickness calculating means for calculating and averaging the plate thickness of the object to be measured at several points along the trajectory based on the distance.