JPS62276426A - Shape detector - Google Patents

Abstract

PURPOSE:To detect a shape at a high response speed, in a shape detector applying external force to an object to be measured cyclically to detect the displacement quantity thereof, by removing the irregular vibration noise component of the object to be measured from the detected displacement quantity. CONSTITUTION:External force is cyclically applied to an object 1 to be measured by an external force applying device 4a and the displacement detection signal detected by a displacement detector 4b is inputted to a displacement quantity detection part 100. A first circuit consisting of a polarity change-over device 5, an integrating circuit 6 and a sample holding circuit 7 integrates displacement detection signals detected at every first period applying external force and at every second period applying no external force and subsequently samples the integrated value to detect the displacement quantity of the object to be measured. A second circuit consisting of HPF21, an integrator 22 and a sampling circuit 23 detects the irregular noise component of the object 1 to be measured. A device 24 of finite differences subtracts said noise component from the above mentioned displacement quantity. By this method, because the shape of the object to be measured can be obtained two times at every first and second periods, said shape can be detected at a high response speed.

Description

[Detailed Description of the Invention] 3. Detailed Description of the Invention [Field of Industrial Application] This invention is a method for detecting the shape (flatness) of a strip-shaped object such as a thin steel plate by knowing its tension distribution in the width direction. This invention relates to a detection device.

[Conventional technology]

In general, when cold rolling a strip, the shape (also called flatness) is important as well as the thickness accuracy. However, in cold rolling, high tension is applied during rolling, so
Due to the elastic elongation of the rolled material, i.e. the strip, even if a flatness defect such as medium elongation or ear waves occurs in this strip, the displacement (unevenness) is reduced or disappears and is usually undetectable. .

Therefore, while it is not possible to directly detect the flatness defects of the strip under high tension as described above, it is especially possible to indirectly detect the shape by knowing the tension distribution in the width direction of the strip. It is well known as shown in Publication No. 53-17071.

In other words, the tension is weak in areas with poor flatness (this is why the shape can be determined from the tension distribution).

FIG. 3 is a block diagram showing an example of this type of conventional shape detection device.

Reference numeral 1 denotes an object to be measured, that is, a strip-shaped body, and 2 denotes a support roll, such as a deflector roll, for applying tension to the strip-shaped body 1. 3 is a rectangular wave oscillator as an example of a drive signal generator, and 3a is an amplifier.

Reference numeral 4 denotes a detection head, which is provided along the width direction of the strip-shaped body 1 and spaced apart from the surface of the strip-shaped body 1 at appropriate intervals by appropriate locking means. This detection controller 4 is an external force applying device 4a.
and a displacement detector 4b. The external force applying device 4a is
It consists of an electromagnet in which an excitation coil B is provided on a magnetic pole A having a U-shaped cross section along the width direction of the strip 1, and a displacement detector 4b is provided at a base portion C along the width direction of the strip 1 for measuring the displacement of multiple tubes. The electrodes are provided facing the surface of the strip 1, and are provided integrally with the external force applying device 4a.

Note that the displacement detector 4b may be provided separately from the external force applying device 4a, and the external force applying device is not limited to an electromagnet as described above, but may be a device capable of applying force without contact, such as compressed air. Any means may be adopted as long as it does not depart from the purpose of the present application. 4C is a displacement converter such as a capacitance-to-voltage converter, and 9 is a signal processing circuit. and a polarity switch 5, an integrating circuit 6, a sample hold circuit 7, and each of the above-mentioned devices 5, 6.
It is composed of a timing generation circuit 8 connected in series to ゜7,
The timing generating circuit 8 is connected to each of the devices 5, 6, 7 and the square wave oscillator 3, respectively. The signal processing circuit 9 is connected to a display device 11, such as a CRT monitor, via a display control device 10. Further, the signal processing circuit 9 can also be connected to the roll crown adjustment device 13 via the roll crown control circuit 12.

Next, the operation will be explained. First, the rectangular wave oscillator 3 generates a rectangular wave with a period Tc as a drive signal. Next, this drive signal is amplified in the amplifier 3a, and this amplified signal is applied as an external force to the surface of the strip 1 through the external force applying device 4a, thereby causing the strip 1 to generate a displacement P (x - t). Displacement P (x − t) generated on the surface of the strip 1
The displacement is detected as capacitance by the displacement detection electrode provided in the displacement detector 4b, and the signal converter, that is, the capacitance
It is converted into a voltage signal by a displacement converter 4C which is a voltage converter.

The plurality of displacement detection electrodes provided along the width direction of the strip 1 detect the displacement of each part of the strip 1 in the same way, and the signal converted into a voltage signal after detection is subjected to signal processing. It is input to circuit 9.

After the polarity of the displacement detection signal is switched by a polarity switch 5, the signal is input to an integrating circuit 6, where it is integrated for each rectangular wave period. As a result, noise other than the tension signal is removed, only the portions related to the tension of each part of the strip 1 are calculated, and the integral value thereof is input to the sample and hold circuit 7 and sampled and held. Timing generation circuit 8
Based on the reference signal from the rectangular wave oscillator 3, controls each timing such as the polarity switching timing of the polarity switch 5, the resent timing of the integrating circuit 6, and the sample hold timing of the sample hold circuit 7. The output of the sample and hold circuit 7 is displayed on a display device 11 such as a CRT monitor via a display control circuit 10, for monitoring by an operator, and used as data for shape adjustment.

In addition, when performing automatic shape control of the object to be measured, that is, the strip-like object 1, the output of the sample hold circuit 7 is sent via an automatic control system, that is, a roll crown control circuit 12, separately from the display system.
The purpose can be achieved by providing input to the roll crown adjustment device 13.

In the above description, a case has been described in which a rectangular wave signal is used as the drive signal, but the drive signal is not limited to a rectangular wave signal, and signal waveforms such as an M-sequence signal, an undam signal, or a sine wave signal may also be used. If this is possible and these signal waveforms are employed, a multiplication circuit may be provided in place of the polarity switch 5 in the signal processing circuit 9.

Furthermore, to explain using a mathematical formula, in Fig. 3, T(x): Tension L per unit width at x: 1 for the span between the rolls: A coefficient in the force balance, and considering the force balance for the band width (hereinafter simply referred to as plate width) ΔX, approximately Displacement P (x-
t) is expressed as. Further, assuming that equation (1) is the displacement detection signal, the output C(x-nTc) of the sample-and-hold circuit 7 is expressed as follows.

Tc: Period of the rectangular wave n: Number of cycles of the rectangular wave Furthermore, the external force per unit width f(t) is a rectangular wave with an amplitude a, and can be expressed as follows.

Therefore, the output value C (x-nTc) from the sample-and-hold circuit 7 is the above (
1), (2) and (3). Here (4)
The second term in the equation is the effect of disturbance, but if the rectangular wave period Tc becomes large, it can be considered that it becomes sufficiently smaller than the stationarity of the irregular vibration d(t) of the strip 1, so the above equation (4) is expressed as follows, and further, from this equation (5), the width direction coordinate
The tension per unit width T (x) at can be expressed as and the tension is measured.

Next, the content of equation (4) above is realized. The signal waveforms of each signal processing section in the circuit of FIG. 3 will be explained with reference to FIG. 4.

(a) of FIG. 4 shows a rectangular wave signal generated by the rectangular wave signal generator 3, where n is a positive integer, ..., m
-2,...2m+1... are each position that n takes.

(b) of FIG. 4 shows the period Tc of O by the external force applying device 4a.
The AC waveform of the displacement signal component at point 2 is shown when the strip 1 is displaced by applied external forces of N and OFF.

(C) in FIG.
The noise signal caused by this vibration is the waveform of the displacement detection signal shown in FIG. 4(d) that is superimposed on the displacement signal of (bl) in FIG.
This is a 0 point displacement detection signal indicating the output of , and when the signal processing circuit 9 switches the polarity of the displacement detection signal and the detection signal, a signal (point ■ signal) having the waveform of (e) in FIG. 4 is obtained.

When this is integrated by the integrating circuit 6 for a period from nTc to (n+1)TC, the signal (f) in FIG. 4 (0 fish signal) is obtained.

When the sample-and-hold circuit 7 samples and holds the signal shown in FIG. 4 (f) at the time point (n+1)Tc, the signal shown in FIG. 4 (g) (0 fish signal) is obtained.

As is clear from the above equation (4) and the signal processing waveform in FIG. 4, the output of the shape detection device [(g) in FIG. 4] is obtained every rectangular wave period Tc.

[Problem that the invention seeks to solve]

Since the conventional shape detection device is configured as described above, the output response is determined by the rectangular wave period Tc for periodically applying external force to the object to be measured, and by shortening the rectangular wave period Tc. The response must be fast, but
Due to the effect of eliminating noise caused by irregular vibrations of the object to be measured by increasing the rectangular wave period Tc, the lower limit of the period Tc is also limited, and there are problems such as the inability to further increase the response speed.

This invention was made in order to solve the above-mentioned problems, and it is possible to obtain a shape signal by removing noise caused by irregular vibrations of the object to be measured every period shorter than one period in each period of a periodic wave. The purpose of this study is to obtain a shape detection device with high responsiveness.

[Means for solving problems]

The shape detection device according to the present invention detects the shape of the object to be measured by applying an external force to the object to be measured in each periodic first period, in which one period consists of a first period and a second period. In a shape detection device that detects the displacement of the body by a displacement detection means to generate a displacement detection signal, and outputs a shape signal representing the shape of the measured object based on the displacement detection signal, A first integral amount of the absolute value of the displacement detection signal outputted by the first integral processing means and included in the displacement detection signal outputted by the second integral processing means for each period of at least one of the first and second periods. The differential means outputs a shape signal that is the difference between the second integrated amount of the noise component due to irregular vibrations of the object to be measured, and the difference between the first and second integrals is determined based on the reference signal of the external force applying means that applies an external force to the object to be measured. The timing of the operation of the integral processing means and the difference means is controlled by the timing generating means.

[Effect]

In the shape detection device according to the present invention, the first integral amount output by the first integral processing means includes the integral amount due to the displacement signal component generated by the application of external force and the integral amount due to the noise component. By subtracting the second integral amount of the noise component produced by the second integral processing means from the first integral amount in at least one of the first and second periods, The integral amount of only the displacement signal component is output as a shape signal from the difference means every two times per period, that is, every first and second period.

〔Example〕

An embodiment of the present invention will be described below with reference to the drawings.

In FIG. 1, the same reference numerals as those in FIG.
It is a bypass filter that only allows the passage of Reference numeral 22 has the same configuration as the integration circuit 6, and is an integration circuit after the bypass filter 21. Reference numeral 23 has the same configuration as the sample and hold circuit 7, and a sample and hold circuit after the integration circuit 22.
is a differentiator that calculates the difference between the integration results of the integration circuits 7 and 22. Reference numeral 25 denotes a sample-and-hold circuit having the same configuration as the sample-and-hold circuit 7, which is interposed between the output side of the subtractor 24 and the input side of the display control circuit 10 and/or the input end of the roll crown control device 12. . Reference numeral 26 denotes a timing generation circuit, which operates a polarity switch 5 based on a reference signal from a rectangular wave generator 3 as an example of a drive signal generator.
．． Integrating circuits 6, 22. A timing signal is generated to determine the operation timing of the sample and hold circuits 7, 23.degree. 25 and the differentiator 24.

FIG. 2 is a diagram showing signal waveforms at various parts of the device shown in FIG. 1 in one embodiment of the present invention, with the vertical axis representing the voltage value and the
(a) to (e) in the figure are exactly the same as (al to (e)) in FIG.

4c, 5 to 7. Each part in double brackets 21 to 25 is composed of a plurality of cylinders (for example, each N cylinders), and for example, the head 4
for each number of displacement detection electrodes and displacement detector 4b inside (
For example, if there are N locations, they are arranged in series in correspondence with each other.

Next, the operation of this embodiment will be explained. The nth is a positive integer and takes the value m-2,..., m+l,...)
is applied to the strip 1 as a rectangular wave with an amplitude a for a period of . Due to this external force f(t), the strip l is displaced, and the above (
1) The amount of displacement shown in the first term of the equation occurs.

On the other hand, irregular vibrations are occurring in the strip 1, which is the source of the disturbance signal as shown in (C) in FIG. 2, and naturally the external force r (t
This irregular vibration d(t) is superimposed on the amount of displacement of the strip 1 due to ), and this noise component is expressed as the second term of equation (11) above.

Displacement 1tP(χ・t
) is converted into an electrical signal by the displacement converter 4c via the displacement detector 4b, and the displacement detection signal shown in (dl) in FIG. 2 is integrated by the integrating circuit 6 in FIG. The result is released from the sample holding position in the sample hold circuit 7 at the time of nTc + - and returns to the position before displacement.
) Tc, the band 1 is displaced by the timing signal from the timing generation circuit 26, and the waveform of the displacement detection signal inverted by the polarity switch 5 of the displacement converter 4c in FIG. Point 0, which is the output side of the switch 5, is shown in FIG. 2(e). Further, the value integrated by the integrating circuit 6 is indicated by ff) in FIG.

At the time point (n+1)Tc, the output of the integrating circuit 6 is sampled and held by the sample and hold circuit 7.

By repeating the above operation, the output side of the integrating circuit 6 is 0.
The signal at the point is T c/2, as shown in FIG. 2(f).
For each time, the integral value of the displacement amount P (x-t) of the above equation (1) is obtained, and the sample-and-hold circuit 7 receives 31, 32, . The integral value of the displacement amount P(x·t) in S3... is sampled and held.

On the other hand, the disturbance signal component at the zero point due to the irregular vibration of the strip body 1 has a frequency sufficiently higher than the rectangular wave period Tc, as shown in (C) in FIG. A case will be described in which the amounts of disturbance signals due to irregular vibrations in the disturbance signals due to vibrations are approximately equal to X.

The disturbance signal component due to the irregular vibration of the band-shaped body 1 shown in FIG. 2(C) is input to a bypass filter 21 that passes only a frequency band sufficiently higher than the rectangular wave period Tc, and is extracted. The output of the bypass filter 21 is sent to the integrating circuit 22.
Only the disturbance signal due to the irregular vibration of C1 in FIG. 2 is integrated.

(n+1)Tc, and the integration circuit 2
The signal at point [F], which is the output side of 2, is as shown in (g) in FIG.

Then, the disturbance signal due to the integrated random vibration is (n+
1) At the time Tc, the sample and hold circuit 23 samples and holds, and as shown in (gl) in FIG.
N2. For example, the integral value of the disturbance signal due to irregular vibration of N4 is (m-2) Tc, (m-1) Tc.

mTc, which can be obtained at the timing of (m+1)Tc.

Sample hold values SL, S2 . which are integral values of displacement amounts already obtained. S3..., sample hold value No. which is the integral value of the disturbance signal due to irregular vibration, N2. N4・
. . , are sequentially determined by the subtractor 24 every Tc/2.

The difference between the integral value S6 of the integral displacement amount of the disturbance signal due to the irregular vibration during the period mTc and the integral value N6 of the disturbance signal due to the irregular vibration during the same period is determined by the subtractor 24. (f), (g), and (h) in FIG. 2 show the waveforms of the above difference calculation, and the difference signal obtained by the difference device 24 is sampled and held by the sample and hold circuit 25 every Tc/2. , the waveform of the shape signal at point [F], which is the output side of the sample and hold circuit 25, is shown in (h) in FIG.
) are shown as C1, C2, C3... A signal that changes every Tc/2 from the sample hold circuit 25 is applied to the display device 11 via the display control circuit 1o or to the roll crown adjustment device 13 via the roll crown control device 12.

Note that the timing generation circuit 26 determines the polarity switching timing of the polarity switch 5, the recent timing of the integrating circuits 6 and 22, and the sample and hold circuit based on the reference signal from the square wave oscillator 3. , 23°25 sample hold timing, etc.

In the above embodiment, the disturbance signal due to the irregular vibration of the strip 1 was integrated only during the period when the external force f(t) was O. However, when the external force f(t) outputs an amplitude of a and the strip 1 is For the period of displacement, the disturbance signal due to irregular vibration may be integrated in the same manner, and the difference between the integral value of the absolute value of the displacement detection signal and the integral value of the disturbance signal due to irregular vibration during the same period may be obtained. .

Further, in the above embodiment, each part of the double brackets is made of a plurality of cylinders, but it goes without saying that each part of the double bracket may be made of one cylinder.

〔Effect of the invention〕

As described above, according to the present invention, the displacement of the object to be measured is detected, and the polarity of the displacement detection signal is switched for each of the first period in which an external force is applied to the object to be measured and the second period in which no external force is applied. The amount of displacement is obtained by integrating the first and second periods alternately and then holding them, and only the disturbance signal due to the irregular vibration of the measured object is extracted every at least one of the first and second periods. By integrating and retaining the displacement amount to obtain the noise amount, and calculating the difference between the displacement amount and the noise amount, the irregular vibration noise component of the measured object is removed for each of the first and second periods. Since the structure is configured so that a displacement signal of the object to be measured can be obtained, the shape of the object to be measured can be obtained twice per cycle in each of the first and second periods, and the shape can be detected with a fast response speed. It has the effect of

[Brief explanation of drawings]

FIG. 1 is a block diagram showing a shape detection device according to an embodiment of the present invention, FIG. 2 is a waveform diagram of signal processing in each part of the circuit in FIG. 1, and FIG. 3 is a block diagram showing a conventional shape detection device. , FIG. 4 is a waveform diagram of signal processing of the conventional device. In the figure, 1 is a band-shaped body, 4a is an external force applying device, 4b is a displacement detector, 4c is a displacement converter, 5 is a polarity switch, 6,
22 is an integrator circuit, 7, 23, 25 are sample and hold circuits, 21 is a bypass filter, and 24 is a differentiator. In addition, in the figures, the same reference numerals indicate the same or corresponding parts. Figure 2: 5)-9

Claims (1)

[Claims] Tension is applied to the object to be measured in a direction that intersects with the width direction of the surface of the object to be measured. an external force applying means for applying an external force along the axis; and a displacement detecting means for detecting the displacement of the object to be measured due to the application of the external force and generating a displacement detection signal. In the shape detection device that outputs a shape signal indicating the shape of the object to be measured based on a first integral processing means for generating a first integral amount of a value; and a noise component due to irregular vibrations of the object to be measured, which is included in the displacement detection signal for each of at least one of the first and second periods. a second integral processing means for outputting a second integral quantity; a difference means for taking the difference between the first and second integral quantities and outputting the difference as the shape signal; A shape detection device comprising: timing generation means for controlling operational timing of the first and second integral processing means and the difference means based on a reference signal indicating a second period.