JPH04116410A - Automatic plate-thickness measuring apparatus - Google Patents

Abstract

PURPOSE:To improve the uniformity of the reflection pattern of a calibration plate apparently and to make it possible to perform accurate measurement by providing a horizontal oscillating means for oscillating the calibration plate in the right and left directions at the time of calibration. CONSTITUTION:A horizontal oscillating means for oscillating a calibration plate 34 in the right and left directions in calibration is provided in this apparatus. The calibration plate 34 is oscillated in the right and left direction when linearity is calibrated. Namely, the measuring accuracy, when the optical displacement gage 18 emits a light beam on the calibration plate 34 and receives the reflected light, is affected by the reflection pattern which is determined by the property of the surface of the calibration plate 34. The nonuniformity of the surface of the calibration plate 34 deteriorates the measuring accuracy. Therefore, the calibration plate 34 is horizontally oscillated, and the apparent uniformity is improved. When a frame is calibrated, the calibration plate 34 is horizontally oscillated as in the linearity calibration. The calibration table obtained in this way is used for correcting a reference distance in measurement. Thus, errors which occur in response to the right and left positions of the optical displacement gage 18 in measurement, e.g. the error caused by the strain in the frame, can be decreased.

Description

DETAILED DESCRIPTION OF THE INVENTION [Field of Industrial Application] The present invention relates to an automatic plate thickness measuring device that automatically determines 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, automatic plate thickness measuring devices have been known that automatically measure the plate thickness of an object to be measured transported by a transport line using an optical displacement meter such as a PSD.

The conventionally used device is a one-point measurement device using a so-called C-shaped frame, and is used to measure an object having a constant width, that is, a fixed width object.

In this device, optical displacement gauges are placed above and below the conveyance line. This optical displacement meter irradiates the object to be measured with a light beam, which is a laser beam, and measures the thickness of the object. Conventionally, such a device has been used to automatically measure the thickness of an object to be measured such as a steel plate.

By the way, in general, calibration is required to ensure the accuracy of automatic plate thickness measuring devices. Calibration is performed each time the device is used, and is an essential task for device operation. More specifically, we correct errors caused by aging of the optical displacement meter (electrical correction), and correct mechanical distortion (mechanical correction) to maintain reliability and ensure accurate plate thickness &111. It is expected that the

Furthermore, as a calibration method, a method is known in which a reference distance between optical displacement meters is determined by using a calibration plate having a predetermined thickness and measuring the distance between the optical displacement meter and the calibration plate.

[Problems to be Solved by the Invention] However, in the past, the surface properties of the calibration plate were not uniform, which caused problems in measurement accuracy.

For example, a ceramic plate is used as the calibration plate due to its relatively uniform surface texture, but in the plate thickness/l1ll determination device, it is necessary to capture the reflected light from the optical displacement meter or the calibration plate. For example, even with a calibration plate using a ceramic plate, the uniformity of the reflection pattern is not sufficient.

The present invention aims to solve such problems (
The purpose of this invention is to improve the apparent uniformity of the reflection pattern of the calibration plate to enable accurate measurements, and to construct a compact calibration means having such a function. .

[Means for Solving the Problems] In order to achieve such an object, the present invention provides a pair of mounts on the upper and lower mounts of the conveyance line that conveys the object to be measured, and which are spaced apart by a predetermined reference distance. A plurality of pairs of optical displacement meters are placed in the same position and have an L-shaped bend at the tip and measure the distance to the object to be measured based on the reflected light by irradiating a light beam to the object to be measured. When measuring plate thickness, the tip is the a of the optical displacement meter.
a calibration plate having a predetermined thickness and arranged externally; a rotating means for rotating the calibration plate so that the tip thereof is located at a predetermined position that blocks the light beam emitted from the luminous intensity position 1 during calibration;
During calibration, a horizontal vibration means vibrates the calibration plate in the left-right direction, and during measurement, the horizontal position of the optical displacement meter is controlled so as to draw a predetermined trajectory on the object to be measured, and is determined according to the plate thickness standard of the object to be measured. The vertical position of the optical displacement meter is controlled so that it is in the position shown in FIG. a linearity correction means for creating a linearity correction table that associates the output of the optical displacement sensor at the time of linearity calibration with the expected vertical position of the optical displacement sensor; A reference distance is determined based on the output and the thickness of the calibration plate, and a mount correction means is used to create a calibration table that corresponds to the left and right positions of the optical displacement meter, and a linearity correction table is referenced. Correct the distance between the optical displacement meter and the object to be measured (1), refer to the calibration table according to the left and right positions of the optical displacement meter, correct the reference distance, and calculate the vertical movement amount of the optical displacement meter, the corrected distance and The present invention is characterized by comprising plate thickness calculating means for calculating and averaging the plate thickness of the object to be measured based on the reference distance.

[Function] In the automatic plate thickness measuring device of the present invention, based on the distance between the optical displacement meter and the object to be measured, the -L downward movement amount of the optical displacement meter, and the reference distance between the opposing optical displacement meters, The thickness of the board for regular holidays is required.

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

For example, if the characteristics of the optical displacement meter change from the initial characteristics, an error will occur in the plate thickness measurement unless this change is compensated for. Therefore, in the present invention, linearity calibration is performed. Linearity calibration is performed while moving the optical displacement meter at a predetermined pitch in the vertical direction, and in 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 where it blocks the light beam, and reflected light is obtained from this calibration plate. Further, the expected vertical position is, for example, a vertical position obtained by position control based on the initial characteristics of the optical displacement meter.

Further, the calibration plate is vibrated in the left-right direction during calibration. That is, the reflection pattern determined by the surface quality of the calibration plate influences the measurement accuracy when the optical displacement meter irradiates the calibration plate with a light beam and receives the reflected light. More specifically, non-uniformity on the surface of the calibration plate degrades measurement accuracy. Therefore, a major feature of the present invention is that the calibration plate is horizontally vibrated to improve the apparent uniformity.

The table showing the correspondence between the output of the optical displacement meter and the vertical position will be referred to as 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.

This compensates for the error caused by the above-mentioned change in characteristics depending on the vertical position of the optical displacement meter during measurement.

Further, the reference distance is corrected using a calibration table.

For example, if the pedestal is distorted, this distortion may cause a measurement error. Therefore, in the present invention, pedestal calibration is performed. The gantry calibration is performed by moving the optical displacement meter in the left-right direction at predetermined intervals and based on the output of the optical displacement meter at that time.

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

During frame calibration, the calibration plate is vibrated in the horizontal direction in the same way as during linearity calibration.

The calibration table obtained in this way is used to correct the reference distance during measurement. This reduces errors that occur depending on the left and right positions of the optical displacement meter during measurement, such as errors caused by frame distortion. Note that it is preferable to perform the gantry calibration using the results after the linearity calibration.

Therefore, in the present invention, the reflection pattern of the calibration plate is made uniform in appearance by the horizontal vibration of the calibration plate, and the measurement accuracy by the optical displacement meter is improved by the horizontal vibration of the calibration plate, which is a simple and compact means.

[Examples] Hereinafter, preferred embodiments of the present invention will be described based on the drawings.

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

This figure shows a conveyance line 12 that conveys the object to be measured 10 in the direction indicated by the arrow in the figure. The nj constant bodies IO in this figure are steel plates having different thicknesses, widths, etc., and three of them, 10-1, 10-2, and 10-3, are shown in the figure.

In this embodiment, the measuring object 10 to be measured has a thickness of 4 to 60 mm, a width of 800 to 4000 mm,
It has a standard length of 1,500 to 14,000 mm, and is placed at any position on the conveyance line 12 in any orientation.

Further, a pair of upper and lower gate-shaped frames 14 are provided so as to straddle the transport line 12 . Conveyance line 1 of gate-shaped dye table 14
2, a line sensor 16 is provided on the upstream side, and an optical displacement meter 18 is provided on the downstream side.

A pair of line sensors 16 are provided on both the upper and lower concave mounts 14, and detect the positions of both left and right ends of the tip of the object 10 to be measured. The detected left and right end positions are used for initial setting of the position of the optical displacement meter 18.

Further, three pairs of optical displacement meters 18 are provided on the concave pedestal 14. This optical displacement meter 18 is a device that measures the thickness of the object 10 to be measured. That is, the optical displacement meter] 8 is the object to be measured 10
A light beam is irradiated onto the object and the reflected light is captured. moreover,
Based on the captured reflected light, the distance to the object to be measured] 0 is determined and used to calculate the plate thickness according to the principle described later.

FIG. 2 shows a more detailed actual configuration of this embodiment as a front view.

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

Further, the upper three of the optical displacement meters 18 are attached to the pulse stage 22. That is, these three optical displacement meters 18 are driven in the vertical direction by the pulse stage 22.

Further, first and second edge sensors 24 and 26 (=j) are provided in two pairs on the left and right sides of the three pairs of optical displacement meters 18.The first edge sensor 24 is connected to the line sensor 16
It is used to further finely adjust the position of the optical displacement [8] which is initially set according to the output of the optical displacement. 2nd edge sensor 2
6 is used to follow and detect the side edge of the object 10 to be measured.

FIG. 3 shows the configuration of the calibration means of the apparatus of this embodiment. FIG. 3(a) shows its two sides, FIG. 3(b) shows its front view, and FIG. 3(c) shows its longitudinal section.

The calibration means shown in this figure supports the entire calibration means and
The lower optical displacement meter 18 is installed in the tray (=1 unit 28), the tray placed horizontally above the mounting base 28 (=J plate 30, and the tray (=1 plate 30) Calibration plate unit 32
It is equipped with.

The calibration plate unit 32 includes a calibration plate 34, which is a white ceramic plate with an L-shaped bent end, and a rotary solenoid 36 that rotates the calibration plate 34 as shown by an arrow in the figure. That is, an arithmetic control unit (described later) controls the rotary solenoid 36 to rotate the calibration plate 34. The position of the calibration plate 34 is set at a position where its bending blocks the light beam from the optical displacement meter 18 during calibration, as shown by the solid line in the figure.
During measurement, it is removed from the optical beam path as shown by the broken line in the figure.

Further, in this embodiment, a motor 38, an eccentric cam 40, and a cam follower 42 according to the features of the present invention are provided.

The motor 38 is attached to the front surface of the mount 38 and rotated by the arithmetic control unit during calibration.

The eccentric cam 40 is connected to the motor 38, and the rotation of the motor 38 via the cam follower 42 causes the mounting plate 30 to vibrate horizontally (for example, horizontally in FIG. 3(c)) at a constant speed. Note that the mounting plate 30 is attached to the mounting base 28 via a linear motion base 44. The orthogonal accuracy of the linear motion table 44 is below the resolution of the optical displacement unit 18 (several microns or less)
In order to ensure straightness, the straightness is set to several microns or less.

FIG. 4 shows the circuit configuration of this embodiment.

In this figure, the detection outputs of the line sensor 16, the first edge sensor 24, and the second edge sensor 26 are taken in, and the thickness of the object ff111 is determined based on the output of the optical displacement meter 18. stage 22,
A calculation control unit 48 that controls the rotary solenoid 36 and the motor 38 is shown. Also shown in this figure is a memory 50 that stores a linearity correction table and a calibration table that are obtained during calibration. Note that in this figure, only one optical displacement meter 18 and the like is shown for the sake of simplification.

Next, the operation of this embodiment will be explained.

In this embodiment, first, the object to be measured]0 is placed on the transport line 12. The mounted object 10 is
2 and reaches below the line sensor 16.

Then, the line sensor 16 detects the light-blocking position due to the object to be measured]0. That is, line sensor 1
6 detects the portion where the light beam is blocked by the object to be measured 10, and supplies this to the arithmetic control section 48 as the left and right end positions of the object to be measured 10.

The calculation control unit 48 drives and controls the linear motor 46 based on the output of the line sensor 16 to control the position of the optical displacement meter 18 . Specifically, one pair of optical displacement meters 18 on both the left and right sides
A pair of optical displacement meters 1 located in the center are moved to both left and right end positions of the object to be measured 10, which are detected as light shielding positions.
8 is maintained at the center position of the left and right optical displacement meters 18. This initializes the position of the optical displacement meter 18.

Thereafter, when the object to be measured 10 is further transported 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 calculation control unit 48 controls the near motor 46 according to the output of the first edge sensor 24 .

Next, both left and right ends of the object to be measured 10 are captured by the second edge sensor 26 . At this time, the calculation control section 48 controls the linear motor 46 based on the output of the second edge sensor 26. That is, since the second edge sensor 26 is fixed to the optical displacement meter 18, this control allows the second edge sensor 26 to continue tracking and capturing both the left and right ends of the object to be measured 10.
The optical displacement meters 18 on both the left and right sides detect and scan a locus at a predetermined distance from both the left and right ends of the object 10 to be measured.

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

In this embodiment, the output of the optical displacement meter 18 related to the trajectory indicated by the three arrow lines in FIG. 5 is continuously collected. After this collection, the calculation control unit 48 determines the measurement position and calculates the plate thickness.

More specifically, the calculation control unit 48 controls the first edge sensor 2 after the tip of the object 10 reaches the line sensor 16.
The conveyance speed of the object to be measured 10 is determined from the time taken to reach the speed of 4. Since the distance between the line sensor 16 and the first edge sensor 24 is determined by design, using this conveyance speed,
The time can be converted into position coordinates with respect to the object to be measured 10. Based on this conversion result, the measurement position is determined.

The measurement position is, for example, 15 m from both left and right ends of the object to be measured 10.
m line, 15mm line from both front and back ends, and center line total 6
Determine from the line of the book. That is, the intersection of these lines is I
l+++ set to regular positions P1 to P.

Next, for the measurement positions P1 to P9 set in this way, the calculation control unit 48 performs plate thickness calculation based on the output of the optical displacement meter 18 that has already been collected.

FIG. 7 shows the principle of plate thickness measurement in this embodiment.

In this embodiment, the distance between the opposing optical displacement gauges 18 and the upper and lower optical displacements 18 when measuring the plate thickness,
The thickness of the object to be measured 10 is determined based on the distance from 0.

First, it is assumed that the facing distance of the optical displacement meter 18 in the absence of the object to be measured 10, that is, the reference distance Lo, is determined by design. Further, in the case of the measured object 10 having a thick plate, the amount by which the distance between the optical displacement meters 18 is increased, that is, the amount of movement of the optical displacement meters 18 is defined as L3.

Then, the distance L measured by the upper optical displacement meter 18
□ and the distance L2 measured by the lower optical displacement meter 18
Therefore, the plate thickness can be calculated using the following formula.

L=(Lo+L3)-(L1+L2) Furthermore, in this embodiment, the plate thicknesses are determined and averaged at several points in the vicinity of the measurement positions P1 to P9. For example, find the plate thickness at 21 points before and after the measurement positions P□ to P9 along the trajectory shown in Figure 5, and average only the effective values excluding the maximum value, minimum value, abnormal value, etc. do. The averaged value is defined as the plate thickness at the measurement position Pi.

In this way, in this example, the measurement positions P□-P,
The multi-point measurement of plate thickness based on this method is performed more accurately using an averaging method.

In addition, the distances L and L2 used for measuring plate thickness in this example are values corrected by the linearity correction table created during linearity calibration, and the reference distance is created during frame calibration. This is the correction value obtained by referring to the calibration table.

Next, the calibration operation in this embodiment will be explained.

In this embodiment, linearity calibration and pedestal calibration are performed as calibrations. As for the order of implementation, linearity calibration is performed first, and then mount calibration is performed.

In the device of this embodiment, if the initial characteristics of the optical displacement meter 18 are sufficiently maintained, the outputs of the optical displacement meter 18 may be used as they are as the distances L and L2. However, in reality, the characteristics of the optical displacement meter 18 change due to temperature, humidity, aging, etc. As a result, an error occurs in the output of the optical displacement meter 18.

For example, as shown in FIG. 8, when the initial characteristic shown by the solid line changes to the characteristic shown by the broken line, a difference occurs between the actual displacement of the optical displacement meter 18 and the detection output of the optical displacement meter 18, and this This results in a measurement error of the thickness Lo.

Furthermore, if the pedestal 14 is not distorted, the designed reference pressure #Lo may be used as is. but,
In reality, the pedestal 14 is distorted due to temperature, humidity, aging, etc., and as a result, the reference distance T-.

Errors also occur.

Therefore, in order to prevent errors from occurring due to these changes,
Calibration using the calibration plate 34 is required.

First, a description will be given of the calibration related to the distance L□, that is, the operation related to the creation of the linearity correction table.

In this embodiment, since only the optical displacement meter 18 on the second side is driven in the downward direction, linearity calibration related to the distance L1, which is likely to cause errors, is performed.

In this case, the calibration plate 34 is rotated by the rotary solenoid 36. 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 34 is formed from a white ceramic plate of known thickness, and is vibrated in the horizontal direction after placement. This vibration has an amplitude of approximately ±3 mm, and the calibration plate 34
This is done to eliminate the influence of surface properties.

That is, the motor 38 is controlled by the arithmetic control section 48, and when the motor 38 rotates, the mounting plate 30 is moved linearly by the eccentric cam 40 and the cam follower 42. Tori (-J plate 30
When the calibration plate 34 is moved in a straight line, the calibration plate 34 vibrates in the horizontal direction.

Since the calibration plate 34 is a ceramic plate, it is possible to realize a relatively good reflection pattern. In this embodiment, it is further vibrated in the horizontal direction, and as a result, the apparent non-uniformity of the surface can be reduced and an even better reflection pattern can be obtained.

In this state, the upper light displacement guide 18 is moved up and down. That is, the pulse stage 22 is controlled by the calculation control unit 48, 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 indicates the distance between the optical displacement meter 18 and the calibration plate 34. For example, 16 measurements are taken at the same pitch position and averaged. Further, the optical displacement meter 18 is moved in the vertical direction by a predetermined number of pitches, for example, a number of pitches corresponding to ±20 mm.

Output of the optical displacement meter 18 obtained in this way (average value)
is associated with the command value sent from the calculation control unit 48 to the pulse stage 22. That is, a linearity correction table as shown in FIG. 9 is created and developed on the memory 50.

The linearity correction table shown in this figure is based on the command value L
This is a table that corresponds to the output of the optical displacement meter 18 and 3A□.

The linearity correction table is a table showing changes in characteristics of the optical displacement meter 18. That is, the command value L38 issued from the calculation control unit 48 to the pulse stage 22 is the amount of movement expected for the optical displacement meter 18, and in this embodiment, it is initially set to match the operation of the actual machine. It is a value. The linearity correction table is created using this command value L3si.
and the value resulting from the characteristic change, that is, the current optical displacement meter 18
This corresponds to setting the output "3Ai" as a corresponding example. This linearity correction table has a total of 3 for each upper optical displacement meter 18.
pieces are created.

Using the linearity correction table obtained in this way,
Mount calibration is performed. For frame calibration, optical displacement meter 18
And the calibration plate 34 is moved integrally in the left and right direction. That is, as shown in FIG. 10, three optical displacement meters 18
The movable range is 1001, 100-2 and 100-3 (for example, about 40 mm), and the transport line 1
It covers the entire width 110 of 2. 3 pairs of optical displacement meters 18
and the calibration plate 34 are set within this range 100-1.100-2 by controlling the linear motor 46 by the arithmetic control unit 48.
and 100-3, it is driven left and right, and gantry calibration is performed for each.

In the pedestal calibration, a total of three calibration tables as shown in FIG.
1 and stored in the memory 50. As shown in this figure, the calibration table is based on the left and right position x of the optical displacement meter]8.
A1 and the reference distance at that position. Correlate with Ai.

The operation of this gantry calibration will be explained in more detail.

In the case of gantry calibration, as in the case of linearity calibration, first, the calibration plate 34 is rotated by the rotary solenoid 36 and placed at a position between the opposing optical displacement meters 18 . Further, horizontal vibration of the calibration plate 34 is also performed in the same manner.

Here, the thickness of the calibration plate 34 is Ω. , the distances from the upper and lower optical displacement meters 18 to the calibration plate 34 are p and ρ2, respectively. The distances ρ□ and ρ2 are obtained as the output of the optical displacement meter 18, while, as shown in FIG.
Regarding the reference distance Lo, the following formula % formula % holds true.

Therefore, the actual reference distance is determined by the calculation control unit 48 executing calculations based on the above formula. or will be required. Further, such calculations are repeated a predetermined number of times, for example, 16 times, and the average value is obtained, and this average value is used as the reference distance. If you treat it together, the standard distance will be further increased. accuracy will be improved.

The reference distance Lo obtained in this way is the optical displacement meter 1
8 and stored in the memory 50 as a calibration table.

The linearity correction table and calibration table obtained in this way are referred to when calculating the plate thickness.

That is, the linearity correction table is referred to when correcting the output L□ of the optical displacement meter 18, and the calibration table is referred to when correcting the reference distance Lo.

Specifically, the calculation control unit 48 controls the current pulse stage 2.
2, the linearity correction table is referred to, and data related to the table is read from the memory 50. The data read is the amount by which the optical displacement meter 18 is actually displaced with respect to the command value.

Therefore, using the difference between this data and the command value, the optical displacement meter 1
By correcting the output error of 8, errors caused by changes in the characteristics of the optical displacement meter 18 can be eliminated.

Further, the calculation control unit 48 refers to the calibration table using the current left and right positions of the optical displacement meter 18, and reads data related to the table from the memory 50.

The read data is the actual reference distance L at the position, and if the plate thickness is calculated based on this reference distance Lo, errors caused by distortion of the pedestal 14 can be prevented.

As described above, according to the present embodiment, the electrical correction and mechanical correction can be performed at once using simple means using the calibration plate 34, and accuracy and reliability can be ensured.

Furthermore, in this embodiment, the horizontal vibration of the calibration plate 34 can improve the apparent uniformity of the surface of the calibration plate 34, making the reflection pattern even better and allowing for more accurate plate thickness measurements. becomes possible. Furthermore, this horizontal vibration is achieved by simple means using the eccentric cam 40 and the like through the rotation of the motor 38, and the above-mentioned effects can be achieved with a compact device configuration.

In this embodiment, the pulse stage 22 is provided only on the upper optical displacement meter 18, but it may also be provided on the lower side to create a linearity correction table related to the distance L2. In this way, even more accurate plate thickness measurement becomes possible.

[Effects of the Invention] As explained below, according to the present invention, the reflection pattern of the calibration plate can be improved by horizontal vibration of the calibration plate, and more accurate plate thickness measurement can be carried out by simple and compact means. realizable.

[Brief explanation of drawings]

FIG. 1 is a ring road 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 two-side view, and FIG. 1(b) is a side view. 2 is a front view showing a more detailed actual configuration of this embodiment, FIG. 3 is a schematic diagram showing the configuration of the calibration means of this embodiment, and FIG. 3(a) is a top view. , FIG. 3(b) is a front view,
FIG. 3(c) is a longitudinal sectional view, FIG. 4 is a block diagram showing the circuit configuration of this embodiment, FIG. 5 is a diagram showing the trajectory of the light beam emitted from the optical displacement meter, and FIG. 6 is a diagram showing the trajectory of the light beam emitted from the optical displacement meter. , FIG. 7 is a diagram showing the plate thickness measurement principle, FIG. 8 is a diagram showing changes in characteristics of the optical displacement meter, FIG. 9 is a diagram showing a linearity correction table, Fig. 10 is a diagram showing the movement range of the optical displacement meter, Fig. 11 is a diagram showing the calibration table, and Fig. 12 is a diagram showing the calibration principle.
is a front view, and FIG. 12(b) is a side view. 10... Object to be measured 12... Transport line 18... Optical displacement meter 34... Calibration plate 36... Rotary solenoid 38... Motor 40... Eccentric cam 42... Cam follower 44... Direct acting Base 48... Arithmetic control unit

Claims (1)

[Claims] A light beam is arranged above and below the conveyance line for conveying the object to be measured, in pairs and separated by a predetermined reference distance, and irradiates the object to be measured with a light beam and converts it into reflected light. a plurality of pairs of optical displacement meters that calculate the distance to the object to be measured, and a predetermined plate whose tip has an L-shaped bend and whose tip is placed outside the measurement area of the optical displacement meter when measuring the thickness of the object to be measured. a thickness calibration plate; a rotating means for rotating the calibration plate so that its tip is positioned at a predetermined position that blocks the light beam emitted from the optical displacement meter during calibration; and a horizontal mechanism for vibrating the calibration plate in the left-right direction during calibration. During measurement, the horizontal position of the optical displacement meter is controlled so as to draw a predetermined trajectory on the object to be measured, and the vertical position of the optical displacement meter is controlled to be at the position determined according to the plate thickness standard of the object to be measured. position control means that moves the optical displacement meter vertically at a predetermined pitch during linearity calibration, and moves the optical displacement meter horizontally at a predetermined interval during mount calibration; linearity correction means for creating a linearity correction table that associates the output of the optical displacement meter with the expected vertical position of the optical displacement meter; and a mount correction means that creates a calibration table that associates this reference distance with the left and right positions of the optical displacement meter, and a linearity correction table that corrects the distance between the optical displacement meter and the object to be measured. Plate thickness calculating means for correcting a reference distance by referring to a calibration table based on the left and right positions, and calculating and averaging the plate thickness of the object to be measured based on the vertical movement amount of the optical displacement meter, the corrected distance, and the reference distance; An automatic plate thickness measuring device comprising: