JPH0571948A - Strip shape measurement method - Google Patents

Abstract

(57) [Summary] [Purpose] Effectively using a limited number of non-contact rangefinders,
The shape defect of the running strip is measured more accurately in real time. [Structure] An edge part measuring instrument 10 for measuring the shape of the edge part of the strip 1 detects the position of the edge 1a and is positioned accordingly. Therefore, a limited number of non-contact rangefinders can be effectively used. Further, the respective outputs of the non-contact distance meter 5 of the edge measuring instrument 10 are input to the arithmetic unit A after passing through the filter 22 and the peak hold circuit 24 which are the features of the present invention. Therefore, more accurate shape measurement can be performed in real time.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a strip shape measuring method for detecting a defective shape of a strip during traveling, and more particularly,
The present invention relates to a strip shape measuring method capable of effectively measuring a defective strip shape during traveling in real time more effectively by effectively using a limited number of non-contact distance meters.

[0002]

2. Description of the Related Art For example, in a hot or cold continuous rolling mill, the material to be rolled must be rolled flat.

However, the shape may be distorted due to a difference in rolling conditions between the central portion and the edge portion in the width direction of the material to be rolled.

For example, due to the difference in the rolling conditions in the width direction of the material to be rolled, the central portion of the material to be rolled stretches as compared with the edge portion, so-called "medium elongation (or belly elongation)", On the contrary, it is a distortion (defective shape) such as so-called “edge extension” in which the edge portion extends.

At present, various sensors based on various measuring principles and methods and various methods are used to detect the shape defect of the strip such as the material to be rolled.

For example, by utilizing the vibration of the string, the amplitude or frequency distribution at a certain point in the longitudinal direction of the strip is measured,
There is a method of obtaining the tension distribution in the width direction of the strip to detect the shape of the strip.

Further, by utilizing magnetostriction, the internal stress of a strip plate which is a magnetic material such as a steel plate or a conductor is detected by a magnetic sensor, and the tension distribution is obtained from the stress distribution in the width direction of the strip plate.
There is a method of detecting the shape (for example, Japanese Patent Publication No. 51
-3259).

It is also said that the rolls divided in the width direction of the strip are used, the load applied to the roll bearing of each of the divided rolls is measured, the tension distribution is obtained, and the shape of the strip is measured. There is a way.

There is also a method in which an ultrasonic sensor is used and the propagation time of ultrasonic waves from the ultrasonic sensor to the strip plate is measured to measure the shape of the strip plate.

There is also a method of measuring the shape of the strip plate using a light beam or a laser beam (see, for example, JP-A-61-161).
254809).

In the method using the above-mentioned magnetic sensor and the method for measuring the shape of the strip using this light beam or laser optical rangefinder, generally, a plurality of rangefinders are arranged in the width direction of the strip. Defects in the shape of the strip are detected by the outputs of these distance meters.

On the other hand, in the above-mentioned Japanese Patent Laid-Open No. 61-254809, while irradiating a laser beam as a scanning beam in the width direction of the strip plate, the positional displacement of each part in the strip plate width direction is detected to detect the strip plate. The shape is being measured.

Further, in Japanese Patent Laid-Open No. 62-235516, a displacement gauge is arranged on each of a plurality of carriages traveling in the widthwise direction of the strip (rolled material), and the strip is produced by combining the output signals of the displacement gauge. There is disclosed a technique of measuring the flatness of the.

Further, JP-A-61-86013 and JP-A-61-86014 disclose a technique relating to the evaluation method of the shape measurement result of the strip as described above.

That is, in this Japanese Patent Laid-Open No. 61-86013,
That the flatness of the strip is evaluated by the magnitude of the integrated value of the difference between the strip flatness detection value in a predetermined area in the width direction of the rolled strip and the predetermined strip flatness reference value, A technique related to a method for evaluating flatness of a strip is disclosed.
Further, in Japanese Patent Laid-Open No. 61-86014, the strip is determined by the difference between the flatness detection value of the strip at a predetermined position in the width direction of the rolled strip and a predetermined flatness reference value of the strip. A technique relating to a method for evaluating flatness of a strip, which is to evaluate flatness of a plate, is disclosed.

[0016]

However, in the conventional method for measuring the shape of a strip plate, in which a plurality of sensors and rangefinders are arranged in the width direction of the strip plate to be measured,
Considering the meandering of the running strip, an extra number of sensors and rangefinders must be installed, which requires many sensors and rangefinders as a whole, which is a cost problem. is there.

Further, in the above-mentioned Japanese Patent Laid-Open No. 61-254809, since the shape measurement of the strip plate scans the laser beam in the width direction of the strip to be measured, a large amount of the strip plate is formed in the width direction of the strip plate. On the other hand, it has a merit that the measured value can be obtained, but on the other hand, it takes a long processing time to obtain the measured value by scanning, or the amount of information becomes huge and the processing time becomes long as the measured value increases.

In particular, using such a large amount of measured values
Since it takes a very long processing time to directly measure a dimensional shape, online measurement is extremely difficult.

Further, the mechanism for scanning the laser beam in the width direction of the strip to be measured as in Japanese Patent Laid-Open No. 61-254809 is complicated and has a problem in cost. Particularly, in the rotating mirror and the like of the embodiment of JP-A-61-254809, particularly high precision is required when the width of the strip to be measured is long, and adverse effects such as vibration are caused. There is also a technical or cost problem in this respect.

Further, the above-mentioned Japanese Patent Laid-Open No. 62-235516,
When the running strip meanders, the displacement gauge cannot follow this meandering, and it cannot follow the measuring location at a certain distance in the plate width direction from the plate edge, so there is an error in the measured flatness. Will occur.

Further, the above-mentioned JP-A-61-86013 and JP-A-61-86014 are strip plate flatness evaluation methods, in which the strip plate flatness is measured (that is, the strip plate shape measuring method).
It's not about itself.

The present invention has been made to solve the above-mentioned conventional problems, and in a method for measuring the shape of a strip for detecting a shape defect of the strip during traveling, a limited number of non-contact distances are used. Effectively using the meter, it is possible to remove the defective shape of the running strip.
It is an object of the present invention to provide a method for measuring the shape of a strip that enables more accurate real-time measurement.

[0023]

According to the present invention, there is provided a strip shape measuring method for detecting a defective shape of a strip during traveling. Among the plurality of non-contact distance meters that are detected and arranged in the width direction of the strip, at least the non-contact distance meters at both ends are positioned in the width direction of the strip according to the position detection of the both edges in the width direction. , A frequency characteristic for extracting a component of a change in the output signal due to a change in the shape of the strip due to the travel of the strip, among changes in the output signal of the non-contact distance meter due to the travel of the strip. An electrical filter having the respective outputs of the plurality of non-contact distance meters, corresponding to each of the plurality of non-contact distance meters, for each output of the electrical filter, etc., the strip only has a predetermined length. Hold the peak value for each period From these peak values, by detecting a defective shape of the strip is obtained by achieving the above objects.

Further, the plurality of non-contact distance meters are divided into at least three groups, ie, both edge groups and a central portion group, according to the respective array positions, and according to the position detection of the both edges in the width direction, At the time of the positioning in the width direction of the strip, the both edge portion groups,
By positioning the non-contact distance meter for each group,
Similarly, the above-mentioned object is achieved.

Further, the edge extension range of the strip is detected from each of the peak values corresponding to the plurality of non-contact distance meters for each of the both edge portion groups, so that the same problem can be solved. It has been achieved.

[0026]

The present invention not only improves the accuracy of the method for measuring the shape of a strip by arranging a plurality of non-contact distance meters in the width direction of the strip to be measured, but also organically achieves multiple effects such as cost. It is a work done to find a procedure to improve.

The running strip is meandering to some extent.

Therefore, in the present invention, the positions in the width direction of both edges of the running strip, which is the object of shape measurement, are respectively detected, and a plurality of non-aligned strips arranged in the width direction of the strip are detected in accordance with the position detection. Among the contact distance meters, at least the non-contact distance meters at both ends are positioned in the width direction of the strip plate.

When the strip is a material to be rolled, etc.,
The width dimension of the strip to be shape-measured may not be constant. Therefore, in the present invention, the detection of the positions in the width direction of both edges of the running strip that is the object to be measured is performed independently for each edge.

Therefore, according to the present invention, the number of non-contact distance meters to be used does not need to be extra with respect to the width of the strip whose shape is to be measured, and a limited number of non-contact distances can be used. The measurement can be performed effectively using a meter. Therefore,
The cost can be reduced by reducing the number of generally expensive non-contact distance meters used.

The present invention does not limit the non-contact distance meter used. For example, the above-mentioned one using a magnetic sensor, one using a light beam, a laser beam, or an ultrasonic wave, or a non-contact distance meter based on another measuring principle or method may be used.

Further, the present invention does not limit the method for detecting the widthwise positions of both edges of the running strip.
For example, a back light type or a forward light type optical detection method may be used, and for example, a video camera may be used as in an embodiment described later. Alternatively, a contact-type detection method using a touch sensor or the like may be used.

Further, the present invention does not limit the positioning mechanism or control system of the non-contact distance meter according to the position detection in the width direction of both edges of the running strip.

Further, according to the position detection of both edges of the strip in the width direction, the number and position of the non-contact distance meters positioned in the width direction of the strip are not limited, and both edges of the strip are supported. It is only necessary to position at least the non-contact distance meters at both ends. Further, when positioning a plurality of non-contact distance meters, it is not limited to positioning these non-contact distance meters in conjunction with each other, and these non-contact distance meters may be positioned independently of each other.

The procedure of the method for measuring the shape of a strip according to the present invention further comprises the step of changing the output signal of the non-contact distance meter due to the running of the strip which is the object of shape measurement. An electric filter having a frequency characteristic for extracting a change component of an output signal due to a shape change is made to pass each output of a plurality of non-contact distance meters arranged in the width direction of the strip. ing.

Such a frequency characteristic of such an electric filter may be obtained, for example, by previously performing a frequency analysis such as FFT (fast Fourier transform) on the output signal of the non-contact distance meter to be passed.

Further, the present invention is not limited to the frequency characteristics of the respective electric filters that pass the output signals of the plurality of non-contact distance meters independently of each other.

Among the non-contact distance meters of the present invention, at least the non-contact distance meters arranged at both ends are positioned in the width direction of the running strip according to the position detection of both edges of the strip in the width direction. Therefore, even if the running strip meanders or the width of the running strip changes, such a non-contact distance meter can be positioned at a predetermined position on the strip. can do. Therefore, for example, when the frequency characteristic of each electric filter corresponding to such a positioned non-contact distance meter is a frequency characteristic corresponding to the measurement portion of the strip plate of each non-contact distance meter, The accuracy of measuring the shape of the strip can be further improved.

That is, when the frequency characteristics of the electric filter are thus determined independently of each other, the non-contact distance according to the detection of the positions in the width direction of both edges of the running strip according to the present invention. The accuracy of shape measurement can be further improved in combination with the positioning of the meter.

In the strip plate shape measuring method of the present invention, the strip plate to be measured has a predetermined length for each output of the electric filter corresponding to each of the plurality of non-contact distance meters. The peak value is held for each period advanced. That is, the maximum absolute value is sequentially held as the peak value in each period when the strip advances by a predetermined length for each output of the electric filter as described above, which corresponds to each of the plurality of non-contact distance meters. Then, the peak value is reset at the end of each of the periods.

In this way, when the peak value corresponding to each of the plurality of non-contact distance meters is obtained, it is possible to detect the shape defect of the strip more accurately according to the peak value. Further, according to the present invention, the electric filter and the means for holding the peak value can be configured by hardware, and can be processed in real time as a whole.

The shape defect may be detected based on the obtained peak value, for example, the peak value itself may be used as the measured value of the shape of the strip, or the peak value thus obtained is used. Other strip plate shape evaluation methods may be performed.

As described above, according to the present invention, it is possible to effectively use the limited number of non-contact distance meters and to measure the shape defect of the running strip more accurately in real time.

[0044]

Embodiments of the present invention will be described in detail below with reference to the drawings.

FIG. 1 is a block diagram of an embodiment of the present invention.

The method for measuring the shape of a strip shown in the block diagram of FIG. 1 is carried out immediately after a continuous rolling machine for rolling steel sheets with various strip widths from 850 mm to 1250 mm at a strip speed of around 140 m / min. There is. Further, the strip plate shape measuring method of the present embodiment is carried out when feedback control of the continuous rolling mill is performed in order to flatten the shape of the strip plate 1 to be rolled.

In FIG. 1, the strip 1 which is a steel plate
However, in FIG. 1, the cross section is such that the left and right sides are edges 1a, respectively. That is, the traveling direction of the strip 1 in FIG. 1 is the side facing from the front side in FIG.
Alternatively, the direction is from the opposite side to the front side.

A total of 15 non-contact distance meters 5 are arranged in the width direction of the running strip 1.

The non-contact distance meter 5 of this embodiment is used.
Is a laser range finder, but the present invention does not limit the type of the range finder, and may be a non-contact type range finder.

The total of 15 non-contact distance meters 5 are divided into a total of 3 groups including both edge groups and a central portion group. That is, in FIG. 1, a total of three non-contact distance meters 5 are used for the left edge group, and a total of nine non-contact distance meters 5 are used for the central group. A total of three non-contact distance meters 5 are used for the edge group.

The edge measuring instrument 10 above the edge of the strip 1 mainly accommodates a total of three non-contact distance meters 5 of the aforementioned edge group and a video camera 12a. The output signals of a total of three non-contact distance meters 5 housed in the edge measuring instrument 10 are independently input to the arithmetic unit A through the filter 22 and the peak hold circuit 24.

On the other hand, the output signals of a total of nine non-contact distance meters 5 of the above-mentioned central group are independently input to the arithmetic unit B.

The output of the video camera 12a is input to the arithmetic unit A.

Reference numeral 12b in FIG. 1 denotes a rod-shaped light source when the shape of the strip 1 is photographed by the above-mentioned video camera 12a.

To position the edge measuring instrument 10 in the width direction of the strip 1, the servo motor 14m for moving the edge measuring instrument 10 has a pulse for detecting the position of the edge measuring instrument 10. A generator 14p is attached.

The servo control device 14s follows the rotation command of the arithmetic unit A indicated by the coordinates of the strip 1 in the width direction, and rotates the servo motor 14m in accordance with the rotation command of the pulse generator 1.
The servo signal 14m is driven while performing feedback control of a semi-closed loop for positioning by the pulse signal output from 4p.

The edge measuring instrument 10 containing the non-contact distance meter 5 of the edge group detects the position of the edge of the strip 1 in the width direction of the strip 1 by using the video camera 12a and the rod-shaped light source 12b. While using the servo motor 14m, the pulse generator 14p, and the servo controller 14s, the strip 1
Is positioned at a predetermined position in the width direction with reference to the edge 1a.

The positioning of the edge measuring instrument 10 in the width direction is performed by moving the edge measuring instrument 10 with the servomotor 14m so that the edge 1a of the strip comes to a fixed position within the visual field of the video camera 12a. Positioning control is performed.

The operation of the embodiment of the present invention will be described below.

FIG. 2 is a plan view of the strip for explaining the method for measuring the shape of the strip according to the embodiment of the present invention.

In FIG. 2, the width dimension is W (= 8).
The strip 1 of 50 mm to 1250 mm) runs from right to left. Also, while the strip 1 is running, the total of 15 non-contact distance meters 5 described above with reference to FIG.
Each time the strip 1 travels the predetermined length La, the shape of the strip 1 is measured.

The predetermined length La corresponds to a predetermined length that the strip 1 advances in correspondence with a peak hold period, which will be described later. Hereinafter, such a predetermined length La will also be referred to as a peak hold length La.

In FIG. 2, the base point is (1,1).
Points, or (150,1) points, (1,15) points,
(150,15) point and many other points indicated by other black dots,
And many points (not shown) (150 x 15
= 2250) are the measurement points of the strip 1 that are performed by the non-contact distance meter 5 described above with reference to FIG. 1 at each predetermined sample time t 1.

FIG. 3 is a side view of the strip for explaining the method for measuring the shape of the strip according to the embodiment of the present invention.

In FIG. 3, the strip 1 is running from right to left.

While the strip 1 is running, a total of 15 non-contact distance meters 5 are arranged in the width direction of the strip 1.
Thus, the wave heights ΔHa and ΔHb due to the shape deformation of the strip 1 are measured by measuring the distance h from each range finder to the surface of the strip 1 at each predetermined sample time t 1.

Hereinafter, the operation of the edge shape defect detection method and the ear extension range detection method using the plurality of non-contact distance meters 5 arranged in this manner and outputting a signal according to the distance to the strip plate 1 will be described. The action of and the action of the method for detecting the central portion shape defect will be described in order.

First, the method for detecting the edge shape defect according to the embodiment of the present invention mainly includes the arithmetic unit A, the non-contact distance meter 5 arranged on the most edge side, the filter 22, and the peak hold circuit 24. , Servo motor 14m, pulse generator 14p, and servo controller 14s.

The outputs of a total of three non-contact distance meters 5 built in the edge measuring device 10 are independently input to the filter 22.

This filter 22 is a component of the change in the output signal of the non-contact distance meter due to the traveling of the strip 1 due to the change in the shape of the strip 1 due to the traveling of the strip 1. Is an electric filter having a frequency characteristic for extracting

Output from each of the non-contact distance meters 5,
The signal according to the distance from each of the non-contact distance meters 5 to the strip 1 is passed through the filter 22 to obtain a signal according to the height H of the strip 1 at each measurement point of the non-contact distance meter 5. Become.

The filter 22 of this embodiment is a high-pass filter having a cutoff frequency of 12 Hz.

The outputs from the filters 22 that are independently output corresponding to the respective non-contact distance meters 5 are independently input to the peak hold circuit 24.

The peak hold circuit 24 holds the peak value for each output of the filter 22 corresponding to each of the non-contact distance meters 5 and for each period when the strip 1 advances by the predetermined length La. That is, the peak hold circuit 24
When a larger peak value is input for each output of the filter 22 described above, the value is sequentially held and the strip 1
At the end of the period that advances by the predetermined length La of, the held peak value is reset.

FIG. 4 is a graph showing the operation of the peak hold circuit used in the embodiment of the present invention.

In the graph of FIG. 4, the horizontal axis represents the running distance L (n) of the strip 1 in the longitudinal direction (running direction).
Also, the vertical axis is output from the non-contact distance meter 5, and the filter 2
The height H of the strip passed through 2.

The section from the traveling distance Ls to the traveling distance Le is the peak hold section, which is the section corresponding to the above-mentioned predetermined length La (peak hold length) of the strip 1 traveling.

In FIG. 4, the output of the peak hold circuit 24 is reset to "0" at the time of the traveling distance Ls, and sequentially increases from the traveling distance Ls to the traveling distance L1, ΔH1 at mileage L1
Becomes Also, between the traveling distance L1 and the traveling distance L2,
When the amount of decrease in the value of the distance h becomes larger than ΔH1, the output of the peak hold circuit 24 gradually increases and becomes ΔH2 at the traveling distance L2. As described above, the output of the peak hold circuit 24 is Δ at the traveling distance L3.
It becomes H3, and becomes ΔH4 at the traveling distance L4. After this traveling distance L4, the amount of change in the distance h does not become larger than ΔH4 (ΔH4>ΔH5> ΔH6).
The final peak value in the peak hold circuit shown in FIG. 4 is ΔH4, and this peak value is output from the peak hold circuit 24.

Although ΔH1 to ΔH6 are obtained from the strip plate height H, they are almost values according to the wave height of the strip plate 1.

The output of the peak hold circuit 24 is input to the arithmetic unit A as a total of three independent signals corresponding to each non-contact distance meter.

The arithmetic unit A receives a defect in the shape of the edge portion due to the signal corresponding to the non-contact distance meter 5 arranged on the most edge side of the strip 1 out of a total of three signals input from the peak hold circuit 24. Is detected.

As described above, according to the edge defect detecting method of the present embodiment, the non-contact distance meter 5 output from the non-contact distance meter 5 arranged on the most edge side is transmitted from the non-contact distance meter 5 to the strip plate 1. A signal according to the height H of the strip 1 can be obtained from the signal according to the distance h, and a signal according to the wave height ΔH of the strip 1 can be obtained. Therefore, according to the present embodiment, the edge shape defect can be detected more accurately. Furthermore, according to the present embodiment, the wave height ΔH can be peak-held and the edge shape defect can be effectively detected.

In this embodiment, the non-contact distance meter 5 arranged on the most edge side is used for the method of detecting such an edge portion shape defect. As long as it is a non-contact distance meter arranged, it can be used in almost the same manner.

Next, according to the method for detecting the ear extension range of the present embodiment, a total of three output from the above-mentioned peak hold circuit 24 corresponding to a total of three non-contact distance meters 5 of the edge measuring instrument 10 is performed. According to the output of.

The arithmetic unit A is substantially continuous in the width direction of the edge portion of the strip 1 by the outputs of the three peak hold circuits 24 corresponding to the three non-contact distance meters 5 of the edge portion measuring device 10. The typical strain height can be measured.

Therefore, in this arithmetic unit A, the total three outputs of the peak hold circuits 24 corresponding to the three non-contact distance meters 5 arranged in order from the edge 1a of the strip 1 are the reference wave heights. The ear extension range is also detected depending on which non-contact distance meter 5 the output of the peak hold circuit 24 that is smaller than h corresponds to.

The arithmetic unit A outputs to the arithmetic unit B the respective positioning positions of the edge measuring instruments 10 for both edges and the plate width W of the strip 1 obtained from these positioning positions.

The method of detecting the central shape defect of this embodiment will be described below.

The method of detecting the central shape defect of this embodiment is as follows.
A total of 15 collected as described above using FIG.
Of the total (150 × 15 = 2250) data input from each non-contact distance meter 5 at a predetermined sampling time t 1, a total of 9 data stored in the central measuring instrument 30 of FIG.
Using a total of (150 x 9 = 1350) data input from each non-contact distance meter 5 at a predetermined sampling time t, the change in distance in the longitudinal direction (running direction) and width direction of the strip 1 is minimized. An n-th order (fourth-order in this embodiment) approximation is obtained by the square method to obtain an approximate expression, and the wave height of the shape defect of the strip 1 and the wavelength of the shape defect and the steepness of the wave of the shape defect are obtained from this approximation expression. Based on these, the shape defect of the strip 1 is determined.

For example, FIG. 5 is a graph showing an example of an approximate expression of the shape in the longitudinal direction of a certain portion of the central portion of the strip 1 thus obtained.

The method of detecting the central shape defect of this embodiment will be described in detail below with reference to the flow charts of the processes for detecting the defective shape of the central part of the strip shown in FIGS.

The processes shown in the flowcharts of FIGS. 6 to 8 are executed mainly by the arithmetic unit B shown in FIG.

The processing shown in the flow charts of FIGS. 6 to 8 is started every time the strip 1 travels by the predetermined length La, as described above with reference to FIG. That is, when the processes shown in the flowcharts of FIGS. 6 to 8 are executed, a total of nine non-contact distance meters 5 built in the central measuring instrument 30 are used 150 times at a predetermined sampling time t. Total input (150 × 9 = 13
50) pieces of data are input to and stored in the arithmetic unit B.

The approximate expression of the shape of the strip 1 obtained by the processing shown in the flow charts of FIGS. 6 to 8 is a fourth-order approximate expression, but may be an approximate expression of another order.

When the processes shown in the series of flowcharts in FIGS. 6 to 8 are started, first, step 10
2, the measurement point number variable i in the width direction of the strip 1 and the strip 1
Write "0" in each of the measurement point number variables j in the longitudinal direction (traveling direction) of.

With respect to such variables i and j, variables Yij, variables Lij, and variables Wij are as follows.

Yij: Distance h at measurement point number i in the longitudinal direction (traveling direction) of strip 1 and measurement point number j in the width direction
Measured value of (mm).

Lij: measurement point number i in the longitudinal direction of the strip 1
And the position in the longitudinal direction at the measurement point number j in the width direction (m
m).

Wij: measurement point number i in the longitudinal direction of the strip 1
And the position (m in the width direction at the measurement point number j in the width direction
m).

In step 104 following step 102, the variable i is incremented (the value is incremented by "1").

In steps 106 to 110, the variables Yi1 to Yi9, the variables Li1 to Li9, and the variables Wi1 to Wi9 are read.

That is, in step 106, the variable j is incremented. In step 108, the variables Yij, Lij, and Wij are read. In step 110, it is determined whether or not the value of the variable j is "9" or less. If the value of the variable j is "9" or less, the process branches to the front of step 106. Go to step 112.

In step 112, the distance h in the longitudinal direction and the width direction of the strip 1 is quartically approximated by the least square method to obtain an approximate expression.

Here, such a fourth-order approximation formula can be expressed in the determinant form as follows.

[Matrix Y] = [Matrix W] · [Matrix A] (1a)

The determinant of the above equation (1a) is as follows.

[0107]

[Equation 1]

Here, by obtaining [matrix A],
This fourth-order approximation formula is obtained. It is known that this [matrix A] is obtained as follows.

[Matrix A] = ([Matrix Wt] · [Matrix W]) ⁻¹ · [Matrix Wt] · [Matrix Y] (2)

The [matrix Wt] is a transposed matrix of the [matrix W].

Therefore, the approximate expression thus obtained is as follows.

[0112] Y = a0 + a1 · W + a2 · W 2 + a3 · W 3 + a4 · W 4 ... (3)

After step 112 in the flowchart of FIG. 6, in step 114, the maximum point and the minimum point of the approximate expression obtained as described above are obtained.

In step 114, the above equation (3) is first differentiated as follows.

[0115] d Y / d W = a1 + 2 · a2 · W + 3 · a3 · W 2 +4 · a4 · W 3 ... (4a)

Therefore, the maximum point and the minimum point in the obtained approximate expression can be obtained by solving the following equation.

[0117] a1 + 2 · a2 · W + 3 · a3 · W 2 +4 · a4 · W 3 = 0 ... (4b)

The maximum point and the minimum point obtained by the equation (5) are defined as Wt (n) and Wb (n), respectively. The maximum point Wt (n) and the minimum point Wb (n) are as shown in the graph of FIG. 5, for example.

After step 114 of the flowchart of FIG. 6, the process proceeds to step 120 of the flowchart of FIG.

Steps 120, 122, 124 of FIG.
At 126 and 128, the positions it (n) of the maximum point Wt (n) and the minimum point Wb (n) obtained in the above-mentioned step 114 are obtained.
), Jt (n), ib (n), jb (n), and the displacement value Y
(Wt (n)) and Y (Wb (n)) are obtained.

That is, at step 120, the maximum point Wt
Write "0" in the variable n of (n) and the minimum point Wb (n).

At step 122, the variable n is incremented.

In step 124, the position it (n) in the longitudinal direction and the position jt (n) in the width direction of the maximum point Wt (n) are obtained from the maximum point Wt (n). Also, this step 1
At 24, from the minimum point Wb (n) to the minimum point Wb (n)
The position ib (n) in the longitudinal direction and the position jb (n) in the width direction are obtained.

In step 126, the above-mentioned step 12 is executed.
From the respective positions of the maximum point Wt (n) and the minimum point Wb (n) obtained in step 4 and the above equation (3), the maximum point Wt (n)
(N) and the minimum value Wb (n) of each displacement value Y (W
t (n)) and Y (Wb (n)) are obtained.

That is, the displacement values Y (Wt (n)) and Y (Wb (n) of the maximum point Wt (n) and the minimum point Wb (n).
)) Is as follows.

Y (Wt (n)) = a0 + a1.Wt (n) + a2.Wt (n) ² + a3.Wt (n) ³ + a4.Wt (n) ⁴ (5a) Y (Wb (n)) = a0 + a1 · Wb (n) + a2 · Wb (n) ² + a3 · Wb (n) ³ + a4 · Wb (n) ⁴ … (5b)

In step 128, it is determined whether the variable n is smaller than "3". If the variable n is smaller than "3", the process branches to the front of step 122. Otherwise, the process proceeds to the next step 130. move on.

At step 130, the wave height is calculated by the following equation.
From hw (1) to wave height hw (5).

Hw (1) = Y (Wt (1))-Y (Wb (1)) (6a) hw (2) = Y (Wt (2))-Y (Wb (1)) (6b) ) Hw (3) = Y (Wt (2))-Y (Wb (2)) (6c) hw (4) = Y (Wt (3))-Y (Wb (2)) (6d) hw (5) = Y (Wt (3))-Y (Wb (3)) (6e)

Then, in step 132, the wavelength S (i) is obtained by the following equation.

S (i) = Wt (i) -Wb (i) (7)

Then, in step 134, the above (6
Among the wave heights hw (1) to hw (5) obtained from the equations (a) to (6e), the one with the largest value is defined as hw maX (i), and the corresponding maximum point W
t (i) and the minimum point Wb (i), and these maximum points Wt
The respective positions of (i) and the minimum point Wb (i) are obtained.
Further, in this step 134, the steepness λ (i) is calculated from the hw max (i), Wt (i) and Wb (i) thus calculated and the following equation.

Λw (i) = (hwmax (i) / S (i)) × 100 [%] (8)

After step 134 in the flowchart of FIG. 7, the process proceeds to step 140 in the flowchart of FIG.

At step 140, the maximum wave height hw max (i) thus obtained and the maximum wave height hw max are obtained.
The wavelength S (i) corresponding to (i) and the steepness λw (i) are
Output as calculation result.

Subsequently, in step 142, it is determined whether or not the value of the variable i is smaller than 150, and if the value of the variable i is smaller than 150, the process branches to the front of step 104 of the flowchart of FIG. On the other hand, this step 142
If it is determined that the variable i is "150" or more, all the processes shown in the flowcharts of FIGS. 6 to 8 described above are ended.

FIG. 9 is a graph of the distribution of defective height measurement accuracy of this embodiment. Further, FIG. 10 is a graph of the distribution of the accuracy of defective height measurement according to the conventional method.

In these FIGS. 9 and 10, the horizontal plate wave height measurement accuracy is the wave height measured more accurately by hand from the wave height measurement values of this embodiment or the conventional method. It is the value obtained by subtracting the value. or,
The conventional method of the graph of FIG. 10 is a divided roll method, that is, a roll divided in the width direction of the strip is used and the load applied to the roll bearing of each divided portion of the roll is measured to obtain the tension distribution. It is a method of detecting the shape of the strip plate.

As is clear from the comparison between the distribution graph of this embodiment shown in FIG. 9 and the distribution graph of the conventional method shown in FIG.
According to this embodiment, the accuracy of measuring the wave height of the strip plate can be improved. That is, the distribution of variations in the strip wave height measurement accuracy in this embodiment is a distribution centered on the strip wave height measurement accuracy "0 mm". On the other hand, the distribution of variations in the strip wave height measurement accuracy of the conventional method is centered on the strip wave height measurement accuracy of approximately "-3 mm".
Further, the spread of the variation of the strip wave height measurement accuracy of the present embodiment is narrower than the spread of the variation of the strip wave height measurement accuracy of the conventional method.

According to this embodiment, it is possible to obtain the effect that the edge extension range of the edge portion of the strip can be measured in real time.

Further, in this embodiment, the influence of the meandering of the running strip and the change of the strip width is reduced.

In the present embodiment, the total of 15 non-contact distance meters 5 are grouped into a total of 3 groups including both edge groups and the central edge group.
The present invention is not limited to this. That is, the number of non-contact distance meters used and the grouping method are not limited.

For example, in shape measurement after rolling a thin steel plate or after rolling a wide steel plate, there is a so-called 1/4 elongation, in which elongation strain occurs at any one of the positions in the width direction of the steel plate. Therefore, the number of the non-contact distance meters 5 used and the grouping method may be determined according to the nature of the occurrence of such strain in the width direction.

For example, in the shape measurement after rolling such a thin steel plate or after rolling a wide steel plate, a plurality of non-contact distance meters arranged in the width direction of the steel plate (strip plate) are grouped into a total of 5 groups. You may divide. Further, at this time, not only the both edge group but also the adjacent inner group of both the edge groups independently of the other groups (with a different movement amount from the other groups) in the width direction of the steel sheet. You may position with.

In the present embodiment, the non-contact distance meter 5
Installation interval, number of uses, wavelength division point, peak hold length L
“A” and the like are set in accordance with the form of the defective shape appearing on the strip and the plate speed, and the capabilities (processing speed, storage capacity, etc.) of the arithmetic units A and B.

[0146]

As described above, according to the present invention, it is possible to effectively use a limited number of non-contact distance meters to accurately measure the shape defect of a running strip in real time. It is possible to obtain an excellent effect.

[Brief description of drawings]

FIG. 1 is a block diagram of an embodiment of the present invention.

FIG. 2 is a plan view of a strip for explaining the method for measuring the shape of the strip according to the embodiment.

FIG. 3 is a side view of the strip for explaining the method for measuring the shape of the strip according to the embodiment.

FIG. 4 is a graph showing the operation of the peak hold circuit used in the above embodiment.

FIG. 5 is a graph of an example of an approximate expression of the shape of the central portion of the strip in the longitudinal direction of the embodiment.

FIG. 6 is a first part of a flowchart of a process of detecting a shape defect in the central portion of the strip according to the embodiment.

FIG. 7 is a second flowchart of a part of the flowchart of the process for detecting the defective shape of the central portion of the strip according to the embodiment.

FIG. 8 is a third flowchart of a part of the flowchart of the process for detecting the defective shape of the central portion of the strip according to the embodiment.

FIG. 9 is a graph of distribution of strip plate wave height measurement accuracy in the above-described embodiment.

FIG. 10 is a graph of the distribution of the strip plate wave height measurement accuracy of the conventional method.

[Explanation of symbols]

DESCRIPTION OF SYMBOLS 1 ... Strip plate (rolled material such as steel plate), 5 ... Non-contact distance meter, 10 ... Edge measuring instrument, 12a ... Video camera, 12b ... Rod light source, 14m ... Servo motor, 14p ... Pulse generator, 14s ... pulse control device, 22 ... filter, 24 ... peak hold circuit, 30 ... central measuring instrument, A ... arithmetic unit, B ... arithmetic unit, h ... distance from non-contact distance meter to strip, H ... strip Height of strip due to shape deformation, ΔHa, ΔHb, ΔH1 to ΔH6 ... Wave height due to shape deformation of strip, i ... Measurement point number in longitudinal direction (running direction) of strip, j ... Measurement in width direction of strip Point number, La ... A predetermined length (peak hold length) that the strip travels, which is a unit period for measuring the shape of the strip, W ... Strip width of the strip.

 ─────────────────────────────────────────────────── ─── Continuation of the front page (72) Inventor Hitoshi Aizawa 1-chome, Mizushima Kawasaki-dori, Kurashiki City, Okayama Prefecture (no address) Inside the Mizushima Works, Kawasaki Steel Co., Ltd. (72) Akira Katamine, Mizushima Kawasaki-dori, Kurashiki City, Okayama Prefecture 1-chome (no street number) Kawasaki Steel Co., Ltd. Mizushima Works

Claims (3)

[Claims] 1. A strip shape measuring method for detecting a defective shape of a strip during traveling, wherein the widthwise positions of both edges of the strip during traveling are respectively detected. Among a plurality of non-contact distance meters arranged in the direction, at least the non-contact distance meters at both ends are positioned in the width direction of the strip according to the position detection in the width direction of the both edges, and the traveling of the strip plate Among the changes of the output signal of the non-contact distance meter, the electrical filter having a frequency characteristic for extracting the component of the change of the output signal caused by the change of the shape of the strip due to the running of the strip is Through each output of the non-contact range finder, corresponding to each of the plurality of non-contact range finder, for each output of the electric filter, etc., hold a peak value for each period when the strip advances by a predetermined length. From these peak values Shape measuring method of the strip, characterized in that detecting a defective shape of the strip. 2. The at least three non-contact distance meters are divided into at least three groups, that is, both edge groups and a central portion group, according to their respective arrangement positions, and the positions of both edges in the width direction. A method for measuring the shape of a strip, characterized in that when performing the positioning in the width direction of the strip according to the detection, a non-contact distance meter is positioned for each of the edge groups. 3. The edge extension range of the strip according to claim 2, wherein the edge extension range of the strip is detected from each of the peak values corresponding to the plurality of non-contact distance meters for each of the two edge group groups. Characteristic measuring method of strip shape.