JPH05312558A - Method of measuring shape of strip-shaped body - Google Patents

Abstract

(57) [Abstract] [Purpose] Non-contact, high-precision measurement of the shape of high-temperature strips such as hot-rolled metal sheets of steel, titanium, aluminum, etc. [Structure] In a band to which tension is applied, vibration excited by excitation or disturbance is detected at a plurality of points in the width direction of the band, and vibration data having amplitude and frequency information extracted therefrom is determined in advance. If the criterion is satisfied, the shape of the strip is measured using the vibration data. If the criterion is not satisfied, tension is further applied until the vibration data satisfies the criterion, and then the shape is detected again. The shape of the strip is measured using the vibration data extracted from the vibration.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a method for measuring a latent shape of a strip, such as a thin metal plate, by measuring a vibration distribution in a width position while applying tension.

[0002]

2. Description of the Related Art Defects in the shape of strips such as thin metal plates are
For example, it means a so-called ear wave shown in FIG. 7 or a state called Nakanobi shown in FIG. 8, which is caused by uneven deformation in the width direction of the strip. Then, when a certain amount of tension is applied in the lengthwise direction, such as during coil winding during rolling of a thin metal sheet, the shape of the band-shaped body apparently becomes flat (becomes latent). The shape in this case is called a latent shape (in contrast, the state as shown in FIGS. 7 and 8 is called a shape defect, and the shape is called a manifest shape).

In this latent state of defective shape, the tensile stress distribution, that is, the tension distribution, at each width position on the surface and inside of the band-shaped body is non-uniform. By measuring this tension distribution, the band-shaped body is measured. The shape of can be estimated.

Conventionally, the measurement of the shape of a belt-shaped body such as a thin metal plate as a tension distribution utilizing vibration is disclosed in, for example, Japanese Patent Publication No. 45-29469, and in this method, a vibrating device is used. The shape is measured by detecting the natural frequency of the excited vibration of a steel sheet called a strip with a vibration detector installed in the width direction.

[0005]

However, in the above-mentioned conventional method, it is assumed that the shape of the strip is completely latent, that is, the natural frequency can be easily measured. When the size becomes large or the applied tension becomes small, the latent shape becomes apparent, and the belt-like body becomes a state similar to buckling and it does not hold as a vibration system,
Alternatively, the shape cannot be measured when the natural vibration cannot be confirmed because the tension is relatively small with respect to the degree of the shape defect without the manifestation. Further, in order to make even a large degree of shape defect latent, applying a large tension to the band in advance causes problems such as an increased risk of breaking the band and an increase in power consumption of the tension applying device. Yes, it is not practical.

It is an object of the present invention to provide a method of accurately measuring the shape of a band-shaped body by utilizing vibration even when the shape becomes apparent.

[0007]

The present invention provides a method for measuring the shape of a strip in a state where tension is applied as a tension distribution for each width position of the strip by utilizing vibration. Vibrations that excite the body or are excited by disturbances are detected at multiple points in the width direction of the strip,
Vibration data having amplitude and frequency information is extracted from the detected vibration, and when the extracted vibration data satisfies a predetermined criterion, the shape of the strip is measured using the vibration data and extracted. If the vibration data does not satisfy the criterion, after further applying tension until the vibration data satisfies the criterion,
It is characterized in that the shape of the strip is measured using the vibration data extracted from the re-detected vibration.

[0008]

In the method of the present invention, vibrations excited by vibration or disturbance are detected at appropriate positions in the length direction of the strip at a plurality of points in the width direction. Excitation is applied for the purpose of exciting the natural vibration in the band, and it is not necessary to excite the natural vibration when the natural vibration is excited. The excitation signal in the present invention includes a sine wave sweep signal, a random signal, an impulse signal, etc., but is not particularly limited thereto. As for the vibration detection position, it is desirable to measure in the vicinity of the central portion where the amplitude is usually considered to have the largest amplitude in the length direction, and in the width direction, a plurality of target positions including the central position are set as the detection points. However, it is desirable to understand the shape of the strip. The vibration detection method in the present invention includes an optical method, an electromagnetic method, and the like.
Any material may be used as long as it does not change the vibration mode of the strip.

As a method of analyzing the detected vibration, a method of directly reading the amplitude or period (reciprocal of frequency) of the vibration waveform in the time domain, or a vibration amplitude in the frequency domain using, for example, Fourier transform or autoregressive model There is also a method to measure the frequency.

Based on the analyzed vibration data, it is determined whether or not the shape of the strip is latent. As a method of judgment, a coefficient of variation (standard deviation / average value) that represents the degree of variation in individual vibration data by performing multiple measurements
Is based on whether or not it is below a predetermined reference value, and the Q value (peak frequency / bandwidth) indicating the degree of sharpness of the peak of the amplitude spectrum in the frequency domain is equal to or smaller than the predetermined reference value. There is a method of judging whether or not it exceeds. In the present invention, when it is determined that the shape of the strip is latent under the tension applied to the strip in advance, the latent shape is measured using the vibration data. If it is determined that the shape of the strip is apparent, vibration is obtained by detecting and analyzing again after applying tension to the strip until the shape becomes latent and making the shape latent. The data is used to measure the latent shape. Hereinafter, the present invention will be described in detail based on examples.

[0011]

【Example】

[Embodiment 1] FIG. 1 schematically shows an embodiment of the present invention.
In FIG. 1, 10 is a vibrating section for vibrating a strip-shaped body (not shown), 20 is a vibration detection section for detecting vibrations at a plurality of points in the width direction of the strip-shaped body, 30 is a vibration analysis section, and 40 is a shape latent shape. A determination unit, 50 is a tension reapplying unit, and 60 is a shape calculation unit.

FIG. 2 shows the vibration unit 10 and the vibration detection unit 2.
An outline of 0 is shown. 2A is a plan view and FIG. 2B is a side view. In FIG. 2, 7 is a band, 8a and 8b
Is a roll-like belt support, 11 is a vibration device of the vibration unit 10, and 21a, 21b and 21c are vibration detection ends of the vibration detection unit 20.

The strip 7 to be measured, to which some tension has been applied in advance, is vibrated by a vibrating section 10 including a vibrating device 11. Then, the vibration of the strip 7 excited by the vibration is detected by the vibration detecting ends 21a, 21b and 21.
The vibration detection unit 20 including c detects at three points in the width direction. With respect to the detected vibration signals at three points, the vibration analysis unit 30 uses, for example, a fast Fourier transform (FFT) algorithm or the like to obtain a plurality of pieces of data for the vibration amplitude spectrum for each point by shifting the time. Further, in the shape hiddenness determination unit 40, which is a feature of the present invention, the value of the variation coefficient indicating the degree of variation of the same spectrum peak value is determined by a predetermined value for a plurality of amplitude spectra obtained for each point. It is determined whether it is smaller (if the variation is smaller, the value of the variation coefficient is also smaller).

When the variation coefficient values are smaller than the predetermined values at all the vibration detection points, the shape calculation unit 60 determines the latent shape corresponding to the tension distribution at each width position of the strip 7. , Calculate based on the amplitude and frequency information of the peak spectrum.

Further, in the shape latent determination unit 40, if even one of the three vibration detection points has a coefficient of variation larger than a predetermined value, the tension reapplying unit 50.
Until the value of the coefficient of variation becomes smaller than a predetermined value at all points of the vibration detection points.
Increase the applied tension to. Then, after the value of the coefficient of variation becomes smaller than a predetermined value at all points due to the increase in the applied tension, the shape calculation unit 60 determines the latent shape corresponding to the tension distribution at each width position of the band-shaped body 7. It is detected again, and calculation is performed based on the amplitude and frequency information of the peak spectrum obtained by analysis.

FIG. 3 shows an example in which the vibration of the steel sheet whose shape is completely hidden is detected and the amplitude spectrum is obtained. Here, (a) of FIG. 3 is a point from one width end of the steel plate to the center of 50 mm width, (b) is a center point of the width of the steel plate, and (c) is a center of 50 mm width from the other width end of the steel plate. The measurement results are at points (the vibration detection positions in the length direction are all central positions). In this figure, the horizontal axis represents the vibration frequency, and the vertical axis represents the amplitude of the vibration displacement at each frequency as 0 dB = 0.4 mm. Frequency is 0H
Although the range from z to 100 Hz is shown, it is not particularly limited to this frequency range. At this time, the steel sheet is a cold rolled steel sheet having a width of 600 mm and a thickness of 0.5 mm in a light selvage state, the distance between the support rolls is 1200 mm, and the applied tension in the length direction of the steel sheet is about 150 N. Also, the vibration is 0
Total power from Hz to 100Hz is about 0.5N
B pulse signal is mechanically applied, and the vibration is detected by an optical vibration displacement detecting end. The peak of the spectrum marked with a dot-dash line in each figure is the first-order vibration mode of the steel sheet obtained by the vibration, and this peak is used for measuring the latent shape of the steel sheet.
In this figure, only this peak is clear in the frequency range within 10 Hz (10% of full scale) before and after the peak spectrum marked with a circle, and the variation coefficient at each vibration detection point is 0. 01 or less (N number =
In 10), the variation is very small, and it can be confirmed that the shape is completely latent.

FIG. 4 shows an example in which the vibration of the steel sheet immediately before the appearance of the shape due to insufficient tension is detected and the amplitude spectrum is obtained. Fig. 4 (a) is 15 mm from one width end of the steel plate
A point from the width center, (b) is a width center point of the steel plate, and (c) is a measurement result at a point 15 mm from the other width end of the steel plate from the width center (the vibration detection position in the length direction is Is also in the central position). Also in this figure, the horizontal axis represents the frequency of vibration, and the vertical axis represents the amplitude of the vibration displacement at each frequency as 0 dB = 0.4 mm. Frequency is 0H
Although the range from z to 200 Hz is shown, it is not particularly limited to this frequency range. At this time, the steel sheet is a lightly stretched cold-rolled steel sheet having a width of 180 mm and a thickness of 0.5 mm, the distance between the support rolls is 600 mm, and the applied tension in the length direction of the steel sheet is about 90 N. Excitation is 0H
By mechanically applying an impulse signal with a total power of about 0.1 N from z to 200 Hz,
Vibration detection was performed using an electromagnetic vibration displacement detection end. The peak of the spectrum marked with a circle from the one-dot chain in each figure,
It is the primary vibration mode of the steel plate obtained by the vibration,
This peak is used to measure the latent shape of the steel sheet. However, particularly in (a) and (c), in the frequency range within 20 Hz (10% of full scale) before and after the peak spectrum, another vibration mode marked with a dot-dash line and not necessary for latent shape measurement is indicated. The peaks corresponding to are also large and become noise during measurement. The variation coefficient at each vibration detection point is 0.1 or more (N number =
In 10), the variation is very large, indicating that the shape is actualized.

FIG. 5 shows a measurement result when a tension of about 90 N is further applied from the state of FIG. All conditions other than tension are the same. From this figure, the peaks marked with Δ are relatively small, and only the desired peak marked with ◯ is clear. The variation coefficient at each vibration detection point is 0.01 or less (N number = 10) at all points, the variation is very small, and the shape is completely latent.

As can be seen from FIGS. 3, 4 and 5,
According to the method of the present invention, the latent shape of the band-shaped body can be accurately measured by making the shape latent when the shape is apparent.

[Embodiment 2] FIG. 6 schematically shows another embodiment of the present invention. In FIG. 6, 20 is a vibration detection unit for detecting vibrations at a plurality of points in the width direction of the strip, 30 is a vibration analysis unit, 40 is a shape latent determination unit, 50 is a tension reapplication unit, and 60 is a shape calculation unit. Is.

A strip (not shown) to be measured, to which some tension has been applied in advance, may be disturbed by some disturbance.
When the natural vibration can be confirmed without vibration, the vibration of the belt at that time is detected by the vibration detection unit 20 at a plurality of points in the width direction. With respect to the detected vibration signals at a plurality of points, the vibration analysis unit 30 uses, for example, a frequency analysis algorithm based on an autoregressive model or the like to obtain an amplitude spectrum of vibration for each point. Further, in the shape latentiation determination unit 40, which is a feature of the present invention, the Q value indicating the degree of sharpness of the peak spectrum is larger than a predetermined value for the obtained amplitude spectrum (Q value when the peak is sharp). Becomes larger).

When the value of the coefficient of variation is smaller than a predetermined value at all of the vibration detection points, the shape calculation unit 60 determines the latent shape corresponding to the tension distribution at each width position of the strip. It is calculated based on the amplitude and frequency information of the peak spectrum.

Further, in the shape latent determination unit 40, even if one of the vibration detection points has a Q value smaller than a predetermined value, the tension re-application unit 50 causes all the vibration detection points to be detected. The tension applied to the strip is increased until the Q value becomes larger than a predetermined value. And due to the increase of applied tension, Q at all points
After the value becomes larger than a predetermined value, the shape calculation unit 60 detects the latent shape corresponding to the tension distribution at each width position of the strip again, and analyzes the amplitude of the peak spectrum obtained by analysis and Calculate based on frequency information.

[0024]

As is apparent from the above description, by using the method of the present invention, it is possible to always measure the shape of the strip in the latent shape state, so that it is possible to measure the shape of the strip using vibration. Become. In particular, since vibration can be detected without contact, it is possible to measure the shape of a high-temperature strip such as a hot-rolled metal thin plate made of steel, titanium, aluminum, etc., which could not be conventionally measured due to problems such as heat resistance.

[Brief description of drawings]

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

FIG. 2 is a vibration unit 10 and a vibration detection unit 20 shown in FIG.
3A and 3B are diagrams showing how the belt-shaped body 7 is vibrated and detected, in which FIG.

FIG. 3 is a graph showing an example of an amplitude spectrum of vibration of the band-shaped body 7, and shows a measured value when the shape of the band-shaped body 7 is latent.

FIG. 4 is a graph showing an example of an amplitude spectrum of vibration of the strip-shaped body 7, and shows a measured value in a state where the shape of the strip-shaped body 7 becomes apparent.

FIG. 5 is a graph showing an example of an amplitude spectrum of vibration of the band-shaped body 7. Measurement after obtaining the measurement value shown in FIG. 3 and further increasing tension to make the shape of the band-shaped body 7 latent Indicates a value.

FIG. 6 is a block diagram showing an outline of another embodiment of the present invention.

FIG. 7 is a perspective view showing an example of a shape defect of a strip.

FIG. 8 is a perspective view showing another example of a shape-defective form of a strip.

[Explanation of symbols]

7: Band 8a, 8b: Band support 10: Excitation part 11: Excitation device 20: Vibration detection part 21a, 21b, 21c: Vibration detection end 30: Vibration analysis part 40: Shape latent determination part 50: Tension re-application unit 60: Shape calculation unit

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[Procedure amendment]

[Submission date] June 19, 1992

[Procedure Amendment 1]

[Document name to be amended] Statement

[Correction target item name] 0016

[Correction method] Change

[Correction content]

FIG. 3 shows an example in which the vibration of the steel sheet whose shape is completely hidden is detected and the amplitude spectrum is obtained. Here, (a) of FIG. 3 is a point from one width end of the steel plate to the center of 50 mm width, (b) is a center point of the width of the steel plate, and (c) is a center of 50 mm width from the other width end of the steel plate. The measurement results are at points (the vibration detection positions in the length direction are all central positions). In this figure, the horizontal axis represents the vibration frequency, and the vertical axis represents the amplitude of the vibration displacement at each frequency as 0 dB = 0.4 mm. Frequency is 0H
Although the range from z to 100 Hz is shown, it is not particularly limited to this frequency range. At this time, the steel sheet is a cold rolled steel sheet having a width of 600 mm and a thickness of 0.5 mm in a light selvage state, the distance between the support rolls is 1200 mm, and the applied tension in the length direction of the steel sheet is about 150 N. Also, the vibration is 0
Total power from Hz to 100Hz is about 0.5N
Performed by applying the impulse signal mechanically vibration detection was performed by the vibration displacement detection end of the optical. The peak of the spectrum marked with a dot-dash line in each figure is the first-order vibration mode of the steel sheet obtained by the vibration, and this peak is used for measuring the latent shape of the steel sheet.
In this figure, only this peak is clear in the frequency range within 10 Hz (10% of full scale) before and after the peak spectrum marked with a circle, and the variation coefficient at each vibration detection point is 0. 01 or less (N number =
In 10), the variation is very small, and it can be confirmed that the shape is completely latent.

[Procedure Amendment 2]

[Document name to be amended] Statement

[Correction target item name] 0017

[Correction method] Change

[Correction content]

FIG. 4 shows an example in which the vibration of the steel sheet immediately before the appearance of the shape due to insufficient tension is detected and the amplitude spectrum is obtained. Fig. 4 (a) is 15 mm from one width end of the steel plate
A point from the width center, (b) is a width center point of the steel plate, and (c) is a measurement result at a point 15 mm from the other width end of the steel plate from the width center (the vibration detection position in the length direction is Is also in the central position). Also in this figure, the horizontal axis represents the frequency of vibration, and the vertical axis represents the amplitude of the vibration displacement at each frequency as 0 dB = 0.4 mm. Frequency is 0H
Although the range from z to 200 Hz is shown, it is not particularly limited to this frequency range. At this time, the steel sheet is a lightly stretched cold-rolled steel sheet having a width of 180 mm and a thickness of 0.5 mm, the distance between the support rolls is 600 mm, and the applied tension in the length direction of the steel sheet is about 90 N. Excitation is 0H
By mechanically applying an impulse signal with a total power of about 0.1 N from z to 200 Hz,
Vibration detection was performed using an electromagnetic vibration displacement detection end. Spectral peaks marked with ○ mark of one point chain line in each figure,
It is the primary vibration mode of the steel plate obtained by the vibration,
This peak is used to measure the latent shape of the steel sheet. However, particularly in (a) and (c), in the frequency range within 20 Hz (10% of full scale) before and after the peak spectrum, another vibration mode not marked for latent shape measurement, marked with a dot-dash line The peaks corresponding to are also large and become noise during measurement. The variation coefficient at each vibration detection point is 0.1 or more (N number =
In 10), the variation is very large, indicating that the shape is actualized.

[Procedure 3]

[Document name to be amended] Statement

[Name of item to be corrected] Brief explanation of the drawing

[Correction method] Change

[Correction content]

[Brief description of drawings]

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

FIG. 2 is a vibration unit 10 and a vibration detection unit 20 shown in FIG.
3A and 3B are diagrams showing how the belt-shaped body 7 is vibrated and detected, in which FIG.

FIG. 3 is a graph showing an example of an amplitude spectrum of vibration of the band-shaped body 7, and shows a measured value when the shape of the band-shaped body 7 is latent.

FIG. 4 is a graph showing an example of an amplitude spectrum of vibration of the strip-shaped body 7, and shows a measured value in a state where the shape of the strip-shaped body 7 becomes apparent.

[Figure 5] is a graph showing an example of the amplitude spectrum of the vibration of the strip 7, after obtaining the measurements shown in FIG. 4, further measured in a state where potential of the high to the shape of the strip 7 tension Indicates a value.

FIG. 6 is a block diagram showing an outline of another embodiment of the present invention.

FIG. 7 is a perspective view showing an example of a shape defect of a strip.

FIG. 8 is a perspective view showing another example of a shape-defective form of a strip.

[Explanation of Codes] 7: Band 8a, 8b: Band support 10: Excitation unit 11: Excitation device 20: Vibration detection unit 21a, 21b, 21c: Vibration detection end 30: Vibration analysis unit 40: Shape latent Deformation determination unit 50: Tension re-application unit 60: Shape calculation unit Patent applicant New Nippon Steel Co., Ltd. agent Attorney Sugi
Trust

Claims (1)

[Claims] 1. A method for measuring the shape of a strip in a state in which a tension is applied as a tension distribution for each width position of the strip by using vibration, or by exciting the strip.
Alternatively, the vibration excited by the disturbance is detected at a plurality of points in the width direction of the strip, and the vibration data having the amplitude and frequency information is extracted from the detected vibration, and the extracted vibration data has a predetermined criterion. If satisfied, the shape of the strip is measured using the vibration data, and if the extracted vibration data does not satisfy the determination standard, tension is further applied until the vibration data satisfies the determination standard. After that, a method for measuring the shape of the strip is characterized in that the shape of the strip is measured using the vibration data extracted from the vibration detected again.