JPH0792384B2 - Steel plate flatness measurement method - Google Patents

Description

TECHNICAL FIELD The present invention relates to a method for measuring flatness of a steel sheet, and particularly to 1 m strain and
The present invention relates to a flatness measuring method that introduces a calculation step that can obtain a value close to a manual measurement of 2 m.

[Prior Art] The present applicant has previously proposed a flatness measuring device for a steel plate using a non-contact distance meter (Japanese Patent Application No. 2-162719).
The configuration of the device according to this application is shown in FIG. In the figure, 1 is a transport table for a steel plate 10, 2a and 2b are transport rolls constituting the transport table 1, 5a, 5b and 5c are idle rollers arranged between the transport rolls, and 6 is a plate between adjacent transport rolls. A plurality of non-contact distance meters arranged at equal intervals in the width direction, 8
Is a controller, 11 is a low-pass filter that removes the influence component of the vibration of the steel plate from the output signal waveform of the non-contact distance meter 6, 12 is an amplifier, 13 is the non-contact distance meter 6 that influences the fluctuation component of the pass line of the steel plate The first calculator 16 in the controller 8 for removing from the output signal waveform of 10 calculates various strains such as longitudinal strain and widthwise strain related to the flatness of the steel sheet based on the output of the first calculator 13. Second calculators 14 and 15 in the controller 8 are a pulse generator and a pulse counter for obtaining the roll cycle necessary for calculating the distortion of the steel sheet. Then, the obtained distortion is output to the CRT 19, the printer 20, and the like. Reference numeral 21 is a plate passing detector for detecting the passage of the steel plate.

In the above device, the output of the non-contact distance meter 6 is first input to the low-pass filter 11 to remove the influence component of the vibration of the steel sheet 10 from the output signal waveform thereof, and the first calculator 13 further determines the pass line of the steel sheet. An actual distortion signal waveform is obtained by removing the influence component of the fluctuation, and the distortion signal waveform thus obtained is input to the second computing unit 16, and the steel plate is based on this distortion signal waveform.
Various distortions for flatness of 10 are calculated. The distortion calculated at this time was the following five items.

(1) Longitudinal strain (see FIG. 7 (a)) The longitudinal strain is the difference between the maximum strain value and the minimum strain value of each channel. That is, longitudinal strain = | strain maximum value−strain minimum value |, and the maximum value between the channels is also calculated.

(2) Strain in the width direction (see FIG. 7 (b)) The strain in the width direction is the maximum value over the entire length of the difference between the maximum strain value and the minimum strain value in each cross section in the width direction.

Strain in width direction = | maximum strain value-minimum strain value | (3) Maximum steepness (see Fig. 7 (c)) The maximum steepness is the value obtained by dividing the height of a mountain by the pitch of the mountain in all mountains. It is the maximum value.

Maximum steepness = [h _i / l _i ] Maximum of all mountains (4) Warp of the tip or tail (see Fig. 7 (d)) The warp of the tip or tail is excluding the dead zone at the tip / tail. The amount of warpage. Since warping may occur at the tip and tail of the steel plate, this part is excluded from the measurement target as a dead zone.

Warp = Δh (5) 1m strain, 2m strain (see Fig. 7 (f) and (e)) 1m strain and 2m strain are line segments between the two highest peaks in the 1m and 2m sections, respectively. Is the distance between the lowest valley and the line segment. Find the maximum value for the total length.

1m strain, 2m strain = [h _i ] maximum total length On the other hand, the conventional strain measurement method without using the flatness measuring device described above is as follows.
This is a manual measurement method in which the gap 31 between the steel plate 10 and the upper surface of the steel plate 10 is measured with a taper gauge (not shown), and the strain management value is determined by the measurement value by this method.

[Problems to be Solved by the Invention] However, although the conventional manual measurement method is the simplest method for knowing the flatness of the steel sheet, it is inefficient and has a problem in measurement accuracy. Moreover, when the longitudinal strain value and the widthwise strain value output by the flatness measuring device are used for management, the measurement principle is different from the manual measurement method. However, the control accuracy becomes too strict and the re-correction rate of the steel sheet increases. Therefore, there is a demand for a method of obtaining a strain value that is closer to the conventional manual measurement by using the flatness measuring device. It should be noted that the above-mentioned prior application merely outlines how to obtain the 1m / 2m strain, and does not describe the specific calculation method.

It is an object of the present invention to provide a flatness measuring method in which the 1 m · 2 m strain can be obtained with a value close to that by manual measurement.

[Means for Solving the Problems] In order to achieve the above object, a flatness measuring method for a steel sheet according to the present invention uses a flatness measuring device equipped with a non-contact distance meter to measure a strain signal relating to the flatness of the steel sheet. A waveform is obtained, and a predetermined length (1 m
Or take a measurement span of 2m), select the highest mountain in the measurement span as the second mountain, connect the two mountain tops with a straight line, and extend from the deepest valley in the measurement span to the straight line. The distance is calculated, then the same as above is repeated starting from the second mountain, and the maximum value of the distances thus obtained is taken as the distortion in the measurement span.

If there are multiple second peaks with the same height in the measurement span, select the peak farther from the starting point, and measure the height from the reference line (corrected pass line) to the valley bottom in the measurement span. When there are a plurality of valleys with the same value, the valley closer to the higher one of the two peaks is selected.

When there is no second peak in the measurement span, the starting peak and the end of the measurement span are connected by a straight line, the distance from the deepest valley in the measurement span to the straight line is calculated, and when there is no valley, The distance from the position of the midpoint of the measurement span to the straight line is calculated, and the position of the midpoint is used as the next starting point.

Furthermore, in the case where the position of the midpoint is the starting point,
When there are no peaks in the measurement span, the end of the measurement span and the midpoint should be connected by a straight line, and when the end of the measurement span is the starting point and there are peaks in the measurement span, The re-verification is performed starting from the end of the measurement span, which is the position returned by a predetermined length from the mountain.

[Operation] By using the flatness measuring device as shown in FIG. 6, the strain signal waveform h relating to the flatness of the steel sheet is described above.
Since (i) is obtained, 1 m strain and 2 m strain close to manual measurement can be obtained by introducing the calculation step having the above configuration into this distortion signal waveform h (i). It is confirmed that the measured value by the method of the present invention and the actual measured value by the manual measurement method are extremely close to each other as described later. Therefore, of the strain items related to the flatness of the steel sheet, 1 m strain and 2 m strain can be automatically measured online by a method similar to the manual measurement method, and the strain pass / fail judgment can be managed accurately and easily.

[Embodiment] FIG. 1 is a schematic diagram showing a flatness measuring method of the present invention. FIG. 1 (a) shows a method for obtaining 2m distortion on a normal distortion signal waveform, and FIG. 1 (b) shows a special distortion. It shows the method to obtain 2m distortion on the signal waveform. Further, FIG. 7C shows the case of obtaining 1m strain.

In these distortion signal waveforms h (i), the pass line (PL) which is the reference line 100 is, of course, the one after the fluctuation component is corrected.

Distorted signal waveform h obtained by the flatness measuring device of FIG.
(I) is a wavy waveform that usually has peaks and valleys (first
There is a special case in which the figure (a) does not have the peaks and valleys or is not detected as shown in the figure (b). Therefore, in the case of 2m strain, the measurement span is long, so it is necessary to consider separately in the normal case and the special case. It is not necessary for 1m strain because the measurement span is short. This will be described below.

A.2m Distortion method The distance h _i obtained by the following method is calculated by the non-contact distance meter 6 (6th
The maximum value is calculated for each channel shown in the figure), and the maximum value is calculated for each steel plate. The x and y coordinates are taken as shown in the figure.

(1) Normal case (see FIG. 1 (a)) The first mountain 1 is used as a starting point.

The distance from the mountain 1 in the longitudinal direction (measurement span l ₂ ) is 2 m or less,
Find the highest mountain. In this case, mountain 2 corresponds.

A straight line 101 connects the tops of the starting mountain 1 and the mountain 2.

Find the deepest valley between Mountain 1 and Mountain 2. In this case it is valley 1.

The length h ₁ of the vertical line drawn from the valley 1 to the straight line 101 is calculated by the following formula.

h ₁ = y ₁ + (y ₃ -y ₁ ) * x ₁ / x ₂ -y ₂ where y _{1 is} the height from the pass line of mountain 1 y _{2 is} the height from the pass line at the bottom of valley 1. Height y ₃ : Height from pass line of mountain 2 x ₁ : Horizontal distance between mountain 1 and valley 1 x ₂ : Horizontal distance between mountain 1 and mountain 2.

Next, start from mountain 2.

 Repeat from mountain 2 as the starting point.

However, if there are multiple deepest valleys (those with the same valley bottom height) (for example, valley 2 and valley 3), if y ₃ > y _5, then valley 2 If y ₃ > y _5, then valley 3 is the deepest A valley and a distance h ₂ to the straight line 102 are obtained. In the case where if the valley is not, or not detected obtains the distance between the straight line 102 at the midpoint (x _4/2).

h ₂ = y ₃ + (y ₅ -y ₃ ) * x ₃ / x ₄ -y ₄ where y _{4 is} the height from the pass line at the bottom of valley 3 y _{5 is} the height from the pass line at mountain 4. It is x _3: horizontal distance between peaks 2 and valleys 3 x _4: horizontal distance between peaks 2 and mountain 4 next to the starting point mountain 4.

 Repeat from mountain 4 as the starting point.

However, when there are a plurality of highest mountains (having the same mountain height) (for example, mountains 5 and 6), the farthest one is selected. The distance h ₃ to the straight line 103 is calculated by the following equation.

h ₃ = y ₅ + (y ₇ -y ₅ ) * x ₅ / x ₆ -y ₆ where y ₆ : Height from the bottom pass line of valley 5 y ₇ : Height from the pass line of mountain 6 Length x ₅ : Horizontal distance between crest 4 and valley 5 x ₆ : Horizontal distance between crest 4 and crest 6 (2) Special case (see Fig. 1 (b)) Measurement span l ₂ = 2m from starting crest 1 If there is no mountain inside, consider point A (the end of the measurement span) 2 m from mountain 1 as a temporary mountain and connect mountain 1 and point A with a straight line 104.

If there is a valley between the mountain 1 and point A, find the deepest valley and find the distance h ₁ to the straight line 104 from the following formula.

h ₁ = y ₁ + (y ₃ -y ₁ ) * x ₁ / 2m-y ₂ If there is no valley between peak 1 and point A, find the distance h _1B to the straight line 104 at the midpoint B of the measurement span. .

h _1B = y ₁ + (y ₃ -y ₁ ) / 2-y ₄ where y _{3 is} the height of the temporary mountain A point y _{4 is} the height of the midpoint B The final point is the temporary mountain A point In this case, the next starting point is the midpoint B.

When there is no mountain within the measurement span l ₂ = 2m from the starting point B, consider the point C (end of the measurement span) of 2m as a temporary mountain and connect BC with the straight line 105.

The valley between BC is searched, but when there is no valley, the distance h ₂ to the straight line 105 at the midpoint A is calculated.

h ₂ = y ₄ + (y ₅ -y ₄ ) / 2-y ₃ where y ₅ : Height of temporary mountain C point When the temporary mountain C point is the end point, the next starting point is the midpoint A And

Search for the highest mountain within the measurement span l ₂ = 2 m from the starting point A. In this case it is mountain 2.

Reverse from mountain 2 to the left, and set the point E (the end of the measurement span) of 2m as the starting point.

Find the deepest valley between point E and mountain 2.

If there is no valley, the distance h ₃ to the straight line 106 at the midpoint D is calculated.

_{h 3 = y 8 + (y} 7 -y 8) / 2-y 6 here, y _6: Height of the middle point D y _7: mountain 2 height y _8: height following origin of point E Mountain 2

This process is performed only when the starting point is a temporary mountain and the ending point is a mountain.

B. How to obtain 1 m strain Similar to the case of 2 m strain, the maximum value of the distance h _i is obtained in channel units, and further in steel plate units (see FIG. 1 (c)).

Find the highest mountain whose longitudinal distance (measurement span l ₁ ) is less than 1 m from mountain 1. In this case it is mountain 2.

A straight line 107 connects the vertices of the starting mountain 1 and the mountain 2.

Find the deepest valley between Mountain 1 and Mountain 2. In this case it is valley 1.

A vertical line length h ₁ drawn from the valley 1 to the straight line 107 is obtained from the following equation.

h ₁ = y ₁ + (y ₃ -y ₁ ) * x ₁ / x ₂ -y _2nd order starts at mountain 2.

 Repeat from mountain 2 as the starting point.

If there is no peak within the measuring span l ₂ = 1m, move the starting point to the next peak. In this case it is mountain 3.

 Repeat from mountain 3 as the starting point.

If there are multiple highest mountains, select the highest mountain from the starting point.

If there are multiple deepest valleys, if the height of the starting point is greater than the height of the ending point, select a valley that is close to the starting point.

If the height of the starting point <the height of the ending point, select a valley far from the starting point.

If there is no valley or it is not detected, the distance h is not calculated and the process moves to the next mountain.

FIG. 2 is a flowchart of how to obtain the 2m strain. 2m
Strain or 1m strain (see Fig. 3) is to calculate the above distance h _i by using a total of 3 channels of the range finder located at each edge and the center of the steel plate among the multiple range finders. (Step S1).

In step S2, the first mountain is set as the starting mountain 1. From starting point 1
Find the highest mountain 2 within 2m (step S3), step
If there is a mountain 2 in the judgment of S4, it is judged whether or not there are a plurality of mountains 2 (step S5). If there is no mountain 2, the process for a special case starts. If there is only one mountain 2, the peaks of mountain 1 and mountain 2 are connected by a straight line (step S6), and if there are multiple mountains 2, the farther mountain 2 is selected (step S7).

Next, find the deepest valley between Mountain 1 and Mountain 2,
S8), it is determined whether there are a plurality of deepest valleys (step S9). If there is one deepest valley, find the distance h ₁ between that valley and a straight line (step S10), and if there are multiple deepest valleys, go to the straight line from the valley closest to the higher of mountain 1 and mountain 2. The distance h ₁ is calculated (step S11).

Then, in step S12, it is determined whether or not the mountain 2 is the last. If not, the mountain 2 is used as a starting point (step S13), the process returns to step S3 and the same operation as above is repeated.

H ₁ determined in this manner, h _2, ... h _i maximum value of
(Step S14), and finally, h _i takes the maximum value among the above three channels (step S15).

When there is no mountain 2 in the above step S4, a point 2 m from the mountain 1 is set as a temporary mountain A (step S16), and the mountain 1 and the point A are connected by a straight line (step S17). Then, the deepest valley between the mountain 1 and the point A is searched (step S18), and if there is a valley (step S).
19) Find the distance h ₁ between the deepest valley and the straight line (step
S20). If there is no valley (step S19), mountain 1 and A
Find the distance h ₁ between the midpoint B of the point and the straight line (step S2
1). Then, the next starting point is moved to the middle point B (step S2
2) Find the mountain 2 within 2 m from the starting point B (step S23).
If there is no mountain 2 (step S24), the point C of 2 m is used as a temporary mountain and BC is connected by a straight line (step S25). Next, search for the deepest valley between BC (step S26), and if there is a valley (step S2)
7) Find the distance h ₂ between the deepest valley and the straight line (step S
28). If there is no valley (step S27), the distance h ₂ between the midpoint A and the straight line is calculated (step S29). And midpoint A
As the next starting point (step S30), and the above step S23.
Return to and repeat the same as above.

Next, if there is a mountain 2 in the above step S24, the point E of 2 m returning to the left from the mountain 2 is reset as a starting point and connected by a straight line (step S31). Then, search for the deepest valley between point E and mountain 2 (step S32), and if there is a valley (step S33),
Find the distance h ₃ from the valley to the straight line (step S34),
If there is no valley (step S33), the middle point D between point E and mountain 2
And the distance h ₃ between the line and the straight line is obtained (step S35). After that, the process returns to the above step S12 and is processed in the same manner as above.

Next, in the case of 1m strain, as shown in FIG. 3, it is processed almost in the same way as in the case of 2m strain, but only in step S4
If there is not, it is skipped, and step S1
Find the next mountain at 6 and mark it as Mountain 2.

FIG. 4 shows an example of the cross-sectional shape of the center and both edges of the steel plate, that is, a distortion signal waveform.
This is a calculation of 2m distortion. FIG. 4 (a) shows a 2m distortion calculation section that gives a maximum value, and FIG. 4 (b) shows a 1m distortion calculation section that gives a maximum value. The number 2 or 1 in the broken straight line in the figure is the calculation section of each measurement span.

In addition, FIG. 5 shows a comparison between the 1 m strain value and the 2 m strain value of the same steel sheet according to the method of the present invention and the actual measurement value by the manual measurement method using steel meters of 1 m and 2 m. As is clear from this accuracy test, a very good approximation is shown between both measured values, indicating that the method of the present invention can be sufficiently substituted for the manual measurement method.

[Effects of the Invention] According to the present invention as described above, since the flatness measuring device including the non-contact distance meter is used to obtain the 1 m strain and the 2 m strain close to those of the manual measurement, the online measurement is possible. Therefore, there is an effect that the pass / fail judgment of steel plate strain and management can be performed more accurately and easily.

[Brief description of drawings]

FIG. 1 is a schematic diagram for explaining the method of the present invention. FIGS. 1 (a) and 1 (b) show a case where 2 m strain is obtained, and FIG. 1 (c) shows a case where 1 m strain is obtained. Fig. 2 is a flow chart for 2m strain, Fig. 3 is a flow chart for 1m strain,
FIG. 4 (a) is a diagram showing a distortion signal waveform at the center of the steel sheet and both edges and a 2 m strain calculation section in the embodiment, and FIG. 4 (b) is a distortion signal waveform at the center of the steel sheet and both edges and 1 m in the embodiment.
5 is a diagram showing a distortion calculation section, FIGS. 5 (a) and 5 (b) are diagrams showing the results of an accuracy test by the method of the present invention and a manual measurement method, and FIG. 6 is a configuration of a flatness measuring device according to the previous application. FIGS. 7 (a) to 7 (f) are explanatory diagrams showing definitions of various strains, and FIG. 8 is an explanatory diagram showing a conventional manual measurement method. 100 …… Reference line 101 to 107 …… Straight line h (i) …… Distorted signal waveform l ₁ , l ₂ …… Measurement span h ₁ , h ₂ , h ₃ …… Distance

 ─────────────────────────────────────────────────── ─── Continuation of the front page (72) Inventor Atsushi Takekoshi 1-2-1, Marunouchi, Chiyoda-ku, Tokyo Nihon Kokan Co., Ltd. (56) Reference JP-A-58-193414 (JP, A) JP-A-SHO 59-30010 (JP, A) JP-A-2-251716 (JP, A)

Claims (6)

[Claims] 1. A strain signal waveform relating to the flatness of a steel sheet is obtained using a flatness measuring device equipped with a non-contact distance meter, and a predetermined length from the peak is measured starting from the first peak on the strain signal waveform. Take a span, select the highest peak in the measurement span as the second peak and connect a straight line between the crests of these two peaks to determine the distance from the deepest valley in the measurement span to the straight line. A method of measuring the flatness of a steel sheet, which is calculated, and then the same as above is repeated starting from the second crest, and the maximum value of the distances thus obtained is the strain in the measurement span. 2. The flatness measuring method for a steel sheet according to claim 1, wherein when there are a plurality of second peaks having the same height in the measurement span, the peak farther from the starting point is selected. 3. A valley close to a higher one of the two peaks is selected when there are a plurality of valleys having the same height from the reference line to the valley bottom in the measurement span. Method for measuring flatness of steel sheet. 4. When the second peak does not exist in the measurement span, the peak of the starting point and the end of the measurement span are connected by a straight line, and the distance from the deepest valley in the measurement span to the straight line is calculated. If there is no valley, the distance from the position of the midpoint of the measurement span to the straight line is calculated, and the position of the midpoint is used as the next starting point. Degree measuring method. 5. A case where the position of the middle point is used as a starting point, and when there are no peaks in the measurement span, the end of the measurement span and the middle point are connected by a straight line. Four
The method for measuring the flatness of the steel sheet described. 6. When the end of the measurement span is used as a starting point, and when there is a crest in the measurement span, the end of the measurement span, which is a position returned by a predetermined length from the crest, is reset as a starting point. The method for measuring flatness of a steel sheet according to claim 4, wherein.