JPS63215928A - Shape detector - Google Patents

Abstract

PURPOSE:To enable quantitative determination of deficiency level of shape with a high response and accuracy, by a method wherein displacement of a body to be measured is integrated by switching the polarity for each of first and second periods depending on the application of an external force to obtain a displacement value and a disturbance signal of the object being measured is passed for each one of the first and second periods to obtain the amount of noise by integration. CONSTITUTION:With the application 4a of a periodical external force to a strip body 1 as object to be measured,a displacement is detected 4b at a point N along the width thereof to generate a signal. Then, displacement detection signals with the polarity thereof inverted for each first period during which an external force is applied 4a to the strip body 1 and for each second period during which no external force is applied are integrated 6 or a signal with the polarity inverted for each second period delayed by 1/2 cycle phase and a signal for each next first period are integrated 32 while noise components in signals for each of the first and second periods are integrated 22. An external force is computed 27 to obtain a desired S/N from the integration values while a drive signal is generated 28. In addition, elongation percentage indicating flatness is determined with an elongation percentage signal processing circuit 42.

Description

DETAILED DESCRIPTION OF THE INVENTION [Field of Industrial Application] The present invention relates to a shape detection device that detects the shape (flatness) of a strip-shaped object such as a thin steel plate by knowing the tension distribution in the width direction of the strip.

[Conventional technology]

In general, when cold rolling a strip, the shape (also called flatness) is as important 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. This is well known as shown in Publication No. 58-17071.

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

FIG. 4 is a block diagram showing an example of a conventional shape detection device of this kind.

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. 8 is a rectangular wave oscillator as an example of a drive signal generator, and 8a is an amplifier. 4 is a detection head;
They are provided along the width direction of the band-shaped body 1 at appropriate intervals on the surface of the band-shaped body 1 by appropriate engagement means. This detection head 4 is composed of an external force applying device 4a and a displacement detector 4b. The external force applying device 4a is an electromagnet with an excitation coil B provided on a magnetic pole A having a U-shaped cross section along the width direction of the strip 10, and the displacement detector 4b is a basic portion C extending in the width direction of the strip 10.
A plurality of displacement measuring w1 poles are provided facing the surface of the strip 1, and are also 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 used without departing from the purpose of the present application. 4c is a displacement converter such as a capacitance-to-voltage converter. 9 is a signal processing circuit, and a polarity switch 5. Integrating circuit 6゜sample hold circuit 7 and each of the above-mentioned devices 6.
The timing generating circuit 8 is connected to each of the devices 5, 6.7 and the rectangular wave oscillator 8, respectively.

The signal processing circuit 9 is connected to a display device 11 such as a CR monitor, for example, via a display device control device IO. Further, the signal processing circuit 9 can also be connected to the roll crown adjustment device 18 via the roll crown control circuit 12. Next, the operation will be explained. First, the rectangular wave oscillator 8 generates a rectangular wave with a period of TC as a drive signal. Next, this drive signal is amplified in the amplifier 8a, and this amplified signal is applied to the surface of the strip body 1 via the external force applying device 4a. It is applied as an external force to generate a displacement P(xt) in the band-shaped body 1. The displacement P(x-t) generated on the surface of the strip 1 is detected as a capacitance by a displacement detection electrode provided in the displacement detector 4b, and the displacement is detected as a capacitance by a signal converter, that is, a capacitance-voltage converter. It is converted into a voltage signal by a displacement converter 4C. The plurality of displacement detection electrodes provided along the radial direction of the strip 1 detect the displacement of each part of the corresponding strip 1 in the same way, and these detected values are converted into voltage signals and then output as signals. The signal is input to the processing 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 object to be measured are calculated, and the integral value thereof is input to the sample and hold circuit 7 and sampled and held. The timing generation circuit 8 performs polarity switching 8! based on the reference signal from the square wave oscillator 8. Each timing such as the polarity switching timing of I5, the reset timing of the integrating circuit 6, and the sample hold timing of the sample hold circuit 7 is controlled. 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.
This objective can be achieved by providing input to the roll crown adjustment device 18.

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, a random signal, or a sine wave signal may also be used. , and when 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. 4, T(x): Tension L per unit width at x: 1 for the span between rolls: A coefficient in the force balance, and considering the force balance for the strip width (hereinafter simply referred to as plate width) ΔX, approximately Displacement P(x-t
) is represented by . 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 n of the rectangular wave: Number of cycles of the rectangular wave, and the external force per unit width f (t) is the amplitude III! It is a rectangular wave of a, and can be expressed as.

Therefore, af:f! ! ! Assuming that the air volume is the same, the output value C (x-nTc) from the sample and hold circuit 7 is as shown in (1) above.
, from equations (2) and (3). Here, the second term in equation (4) is the effect of disturbance, but it can be considered that if the rectangular wave period TC becomes large, it will be sufficiently smaller than the stationarity of the irregular vibration d (t) of the band-shaped body 1. The above equation (4) is expressed as follows, and further, from this equation (5), the width direction coordinate
The tension per unit width Tfx) can be expressed as, and the tension is measured.

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

FIG. 5(a) shows a rectangular wave signal generated by a rectangular wave signal generator, where n is a positive integer and ゛tm −2
+...+m+1 is each position taken by fin.

(b) of FIG. 5 shows the period TC of O by the external force applying device 4a.
The alternating current waveform of the displacement signal when the strip 1 is displaced by an applied external force of N.OFF is shown.

(C) in Figure 5 is the disturbance signal component at the zero point due to irregular vibrations of the band-shaped body, and the noise signal due to this vibration is superimposed on the displacement signal in Figure 5 (a) above. Figure 5 (
dl, which is a 0-point signal waveform indicating the output of the displacement converter 4C, is input to the signal processing circuit 9. By the polarity switch 5, during the period from C nTc +- to (n+1)Tc, (d
When the polarity of the input signal 1 is switched, a signal having the waveform (e) in FIG. 5 is obtained from the output of the polarity switch 6 (point signal . The integration circuit 6 converts this from nTc to (n+1)T
When integrated over the period c, the output in Figure 5 is
A signal with the waveform (◎ point signal) is obtained. (n+1)Tc
When the sample-and-hold circuit 7 samples and holds the signal shown in FIG.
The signal (g) in FIG. 5 (point ■ signal) which is the output of is detected.

As is clear from the above equation (4) and the signal processing waveform in FIG.
obtained every time.

[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 an external force to the object to be measured, and it is possible to shorten the rectangular wave period TC. We need to improve responsiveness, 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 is a problem that it is not possible to increase the response speed. , the ratio between the first and second terms in equation (4) above can be expressed as an S/N ratio (signal-to-noise ratio), and the magnitude of this 8/N ratio is a major factor that affects detection accuracy. In general, the irregular vibration d(tl) of the object to be measured is considered to have its amplitude and frequency determined by the magnitude of the tension applied to the object to be measured.Therefore, The S/N ratio of the output of the signal processing circuit changes depending on the tension value applied to the object to be measured, and the S/N ratio is influenced by the tension value applied to the object to be measured, and irregular vibrations Even if the amount of disturbance due to It is inversely proportional to the vibration caused by the applied external force, so even if the flatness of the measured object is the same, the tension and external force applied to the measured object will
Since the output changes, this is extremely inconvenient when the purpose is to control the flatness of a strip-shaped object. There were some problems, such as the output being distorted.

This invention was made to solve the above-mentioned problems, and it is possible to obtain an output in which noise caused by irregular vibrations of the object to be measured is removed for each period of the periodic wave that is shorter than one period. High accuracy can be achieved by achieving high responsiveness, measuring the noise level due to irregular vibrations of the measured object, and controlling the applied external force so as to ensure a sufficiently high displacement signal of the measured object compared to the noise level. We developed a shape detection device that can convert the output for shape detection into the elongation rate of the object to be measured, and obtain the same elongation rate even if the tension or applied external force changes as long as the flatness of the object to be measured is the same. The purpose is to obtain.

[Failure to solve the problem]

The shape detection device according to the present invention uses a displacement detection means to detect displacements at N locations along the width direction of the object to be measured due to periodic external force application to the object by the external force application means. A displacement detection signal for each first period in which an external force is applied to the object to be measured and a displacement detection signal with inverted polarity for each second period in which no external force is applied to the object to be measured are generated. 1 of each displacement detection signal by the integral processing means of 1.
The integral amount is output, and the second integral processing means delays the phase by 1/2 period from the first integral processing means, and the polarity of the displacement detection signal is inverted for each second period in which no external force is applied to the object to be measured. , and the displacement detection signal for each first period of the next cycle of applying an external force to the object to be measured, the second integral processing means outputs the second integral amount of each displacement signal, and the second integral processing means outputs the second integral amount of each displacement signal, and the second integral processing means outputs the second integral amount of each displacement signal. Then, each third integral amount of the noise component in each displacement detection signal is calculated for at least one of the first and second periods, and the applied external force calculating means calculates the third integral amount of the noise component in each displacement detection signal. Based on the S/N ratio calculated from the second and third yt quantities, an external force to obtain the desired S/N ratio is calculated, and the drive signal generating means generates a drive signal according to the calculation result. to drive the external force applying means, and generate a shape signal indicating the elongation rate representing the flatness of the measured object at the displacement detection point of the measured object based on the N first and second integral quantities and a preset calculation formula. The elongation rate calculating means calculates the value of , and the timing generating means controls the operational timing of the first + second and third integral processing means based on the reference signal of the driving signal. be.

[Effect]

The shape detection device according to the present invention cancels out the integrated amount of noise components due to irregular vibrations of the object to be measured between the first period and the $2 period, and detects only the displacement signal component generated by the periodic application of external force. is outputted by the first integral processing means, the phase is delayed by 1/2 period from the above-mentioned period, and in the same way, only the displacement signal component is outputted to the second integral processing means, and the third integral processing is performed. The third integrated amount of the noise component is calculated by the means, and the first integrated amount is calculated by the applied external force calculation means. Determine the ratio of the second and third integral quantities as approximately equal to the true 8/N ratio7
'Calculate an external force to obtain a desired S/N ratio based on the i-8/N ratio, apply an external force according to the calculation result to the object to be measured by an external force applying means via a drive signal generating means, N first and second integral quantities obtained at a desired S/N ratio are output every 92 times per period, and the elongation rate calculating means calculates these N integral quantities and a preset calculation formula. Based on this, the elongation rate indicating the flatness of the measured object at the displacement detection point of the measured object is 1/
Calculate and output every two cycles.

〔Example〕

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

In FIG. 1, the same symbols as those in FIG. It is a no-pass filter that allows the light to pass through. 22 has the same configuration as the integrating circuit 6, and the integrating circuit after the bypass filter 21. The phantom has the same configuration as the sample and hold circuit 7, and the sample and hold circuit after the integrating circuit 22. 81 has the same polarity as 6. The switch 82 has the same configuration as 6, and the integration circuit 88 after the polarity switch 81 has the same configuration as the sample and hold circuit 7, and the sample and hold circuit after the integration circuit 82. .7 constitutes a first integral processing means, and 81, 82, and 88 constitute a second integral processing means. Reference numeral 26 is a timing generation circuit, and a polarity switch 5. Integrating circuit 6.22. A ninth timing signal is generated for timing each operation of the sample and hold circuits 7 and 2g. 34 is also a timing generation circuit similar to 26, but with a 1/2 cycle phase delay compared to 26, and a polarity switch 81. Integrating circuit 82. A timing signal for timing the sample and hold circuit 88 is generated. Furthermore, 27 is a sample hold circuit? , 28 , and 88 are input, and SIN
An applied external force calculator 28 is a rectangular wave generator as an example of a drive signal generator; A rectangular wave signal, for example, the level of which is changed according to the calculation result of step 27, is generated in the amplifier 8a. Reference numeral 29 denotes a displacement average value calculator which inputs the displacement integral amounts of the sample and hold circuits 7 and 28 and calculates the average value of displacement in elongation rate calculation, and 80 denotes a displacement average value inputted from the displacement average value calculator 29. This is an elongation rate calculator that calculates the elongation rate according to a preset arithmetic expression. 41 is code 5-7.21-27
42 is an extension wheel signal processing circuit composed of components indicated by reference numerals 29e and 8Q. Code 4c, 5~
7, 21 to 25, and 81 to 84 are each composed of a plurality of cylinders (for example, each N cylinders), for example, the head 4
For each number of displacement detection m poles and displacement detector 4b inside (
For example, if there are N locations, they are arranged in series in correspondence with each other.

Fig. 2 is a diagram showing signal waveforms at various parts of the device shown in Fig. 1, with voltage values plotted on the vertical axis.
e) is the same as (at to (e)) in FIG.

In the MB diagram, the width of the strip 1 is plotted on the horizontal axis, and the elongation rate β (X
) is a diagram showing the relationship between

Next, the operation of this embodiment will be explained. In FIG. 2, the external force f (t) is determined by the timing C shown in (a) of FIG. is applied to the strip l as a rectangular wave of amplitude a during a period of time (takes a value of ). Due to this external force f (t), the strip 1 is displaced,
The amount of displacement shown in the first term of equation (1) above occurs.

On the other hand, irregular vibrations, which are the source of disturbance signals such as fc) in Fig. 2, occur in the band l, and naturally the applied external force f
This irregular vibration d (
t) will be superimposed, and this noise component will be the above (1
) is expressed as the second term of the equation.

Displacement MP (X-t) of the strip l shown by the above equation (1)
The displacement detection signal shown in FIG. 2(d), which is converted into an electric signal by the displacement converter 4C via the displacement detector 4b, is generated by the integrating circuit 6 of FIG. 1C during the period from nTc to n'I'c +-. integrated over.

TC Next, the external force f (t) is set to 0 over a period from nTC+7 to (n+1)Tc. Therefore, the band IC is released from the position where it was displaced in the previous period nTc+7 and returns to the position before displacement. In other words, in between
The strip 1 is displaced.

TC Therefore, at the time of nTc+7, the polarity switch 5 is operated by the timing signal ° from the timing generation circuit 26, and the polarity of the displacement detection signal at the 0 point on the output side of the displacement converter 4c in FIG. 1 is reversed. The inverted signal at T is converted from nTc +- to (n+
1) Integrated over a period of Tc.

The linearity of the displacement detection signal inverted by the polarity switch 5 is as shown in (e) in FIG. 2 at the 0 point, which is the output side of the polarity switch 5.
It is indicated by. Further, the value integrated by the integrating circuit 6 is shown by (f) 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, and the amount of displacement integration during the period from nTC to (n+1)Tc is held.

By repeating the above operation, the output side of the integrating circuit 6 is 0.
As shown in FIG. 2, the integral value of the displacement P(x-t) in equation (1) above is obtained for each Tc, and the sample and hold circuit 7 receives the integral value of the displacement P(x-t) for each Tc. 5l-82, 8
The integral value of the displacement amount P(xt) of g... is sampled and held.

On the other hand, the disturbance signal component at the 0 point due to the irregular vibration of the strip l is explained for the case where the amount of the disturbance signal due to the regular vibration of the rectangular wave is approximately equal to , as shown in FIG. 2(c). do.

The integral amount from n'l'c to n'I'c +-, which is the seventh period of TC, includes a disturbance signal shown in FIG. 2(C).

TC On the other hand, in the second period, from nTc +- to (n+1)Tc, the A point high power signal is inverted and integrated by the polarity switch 6, so in this second period. The disturbance signal is integrated with opposite polarity to the disturbance in the first period. 2
When the disturbance amounts in two periods are approximately equal to y, the integral amounts of the first and second disturbance amounts cancel each other out, and from n'I'c of the displacement detection signal to (n+1)TC Only the integral amount during the period is held by the sample and hold circuit 7.

This is shown by the second term of equation (4), and is the operation of the first integral processing means which has the same effect as the conventional device.

Next, the operation of the second integral processing means will be explained.

The second integral processing means includes the polarity switch 31 and the integral circuit 82.
゜Sample hold circuit 88. Timing generation circuit 84
The timing generation circuit 34 operates the polarity switch 81, the integration circuit 82 and the sample hold circuit 88 with a delay of 1 or 2 cycles with respect to the timing generation circuit 26 in the first integral processing means. The point large force displacement detection signal in the second integral processing means that generates the timing signal is as follows:
This is shown in Figure 2 fh). Further, the integrating circuit 82 is shown in FIG.
), the sample and hold is performed by the first integration processing means and the first sample and hold circuit.

The results of the first and second integral processing means are as follows every 1!2 cycles:
It is output as shown in Fig. 2 fk).

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 sufficiently high frequency band with a 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 irregular vibration shown in FIG. 2(C) is integrated.

The integration period of the disturbance signal due to irregular vibration is the period when the external force C f (t) is 0, that is, from nTc +- to (n+
1) The signal at point 0, which is the output side of the integrating circuit 22, is carried out over the period up to TC, and becomes like ill in FIG.

Then, the disturbance signal due to the integrated random vibration is (n+
x) At time Tc0, the sample and hold circuit 28 holds the sample, and as shown in (m) in FIG.
O・N2. For example, the integral value of the disturbance signal due to irregular vibration of N4 is (m-2)Tc + (m-1)Tc, m
It can be obtained at the timing of Tc + (m+1)Tc.

On the other hand, regarding the displacement detection signal at point 2 in FIG. 11, referring to the above equation (1), by increasing the external force f (t), the first term can be made large and the 8/N ratio can also be made large. Therefore, if the irregular vibration d (t) of the strip 1 is large, the disturbance signal shown in (c) of FIG. 2 also becomes large, and the integral value of (11) in FIG.
) is increased to increase the level of (b) in Figure 2, and the integral values of (i) and (i) of Figure 2 are increased to obtain the required S/
A good N ratio can be ensured.

A value obtained by holding the integral value of the disturbance signal due to irregular vibration is output from the sample-hold circuit 28, and the ratio of this integral value to the output of the sample-hold circuits 7 and 28, which is the integral value output of the displacement amount, is S/ By approximating the N ratio υ, these two signals are sampled and held by circuits 7, 8!3,
The applied external force calculation unit 27 inputted from 28 calculates the ratio of the two human force signals, outputs the current S/N ratio, and calculates the required 8/
The external force f (t) necessary to ensure the N ratio is calculated and instructed to the square wave generator 28 .

In response to this instruction, the rectangular wave generator 28 changes the rectangular wave signal, for example its level, and applies a required external force f (t) to the strip 1 via the amplifier 8a and the external force applying device 4a. In addition, the calculation for the external force applying device 4a can specifically calculate the current external force from the amount of displacement, and the calculated S
The calculation can be performed by functional calculation using the /N ratio and a desired S/N ratio set in advance, or it can be easily calculated by using a well-known interpolation formula.

The irregular vibrations of the strip 1 have stationarity over a relatively long period, and the tension T (x
) also does not fluctuate rapidly, so the external force f (
The calculation period of t) does not need to be every rectangular wave period TC;
For each M-TC that is longer than C, the external force applying device 4a applies an external force f.
ft), where M may be set according to the irregular vibrations of the band-shaped body 1 and the state of tension.

Note that in the above embodiment, the disturbance signal caused by the irregular vibration of the strip 1 is integrated only during the period when the external force f (t) is O, but when the external force f (t) outputs the amplitude of a and Similarly, the disturbance signal due to irregular vibrations may be integrated during the period of displacement, and the difference between the displacement amount and the integral value of the irregular vibrations during the same period may be determined.

Furthermore, it goes without saying that a plurality of electromagnets (for example, N pieces) of the external force calculator 27, the drive signal generator 28, the amplifier 8a, and the external force applying device 4a may be provided.

Next, to express the degree of shape defect (flatness) of the strip 1,
Consider the elongation rate β(X). This elongation rate β(X) is defined as the amount of elongation of the defective portion expressed as a ratio of the average portion of the defective shape to the length of the strip 1. The following equation (8) holds between the tension distribution T (x) of the defective shape portion and the average tension T, and FIG. 3 illustrates this relationship. Where E is the elastic modulus of the strip l, T(x) = '1'±β(X)・E ・・・・・・・・・
・・・・・・・・・・・・・・・・・・(8) This is β
When (X) is determined, the following equation (9) is obtained.

±β(xl= (T-T(xi)・i・・・・・・・
・・・・・・・・・ (9) Similarly, the average tension T is obtained by the following formula (113).

A plurality of cylinders (N pieces) of displacement measuring electrodes corresponding to the amount of displacement and arranged at appropriate intervals in the width direction of the strip l, and N
The displacement average value calculator 29 can calculate the average value of the outputs of the N sample and hold circuits 26 obtained from the N displacement signals detected by the displacement detectors 4b.

By substituting T (x) and below into the above equation (9), the following equation 69 is obtained.

The first page output every period. The second integral amount is shown.

As is clear from the above formula, the elongation rate βfX) of the strip 1
can be calculated using the above αυ formula.

Therefore, the elongation book adder 80 to which the displacement average value C determined by the displacement average value calculator 29 is inputted can obtain an output of the elongation rate β(X) by executing the above-mentioned on-type calculation. Can be done. Note that L, a, and E are values set in advance on the stretchable book meter, and f at position X within the displacement measuring electrode. sample and hold circuit 2
It becomes possible to calculate the above αυ equation using the difference signal C(x) and the average difference signal C which are given as they are through the 5-displacement average value calculator 29. The elongation rate β(X) calculated by the elongation calculator 80 is displayed on the display device 11 via the display device control circuit 10 for monitoring by the operator and also as data for shape adjustment. used as.

In addition, when automatically controlling the strip l, the elongation rate β(X
) is input to the roll crown adjustment device 18 via the roll crown control circuit 12 to achieve the purpose.

〔Effect of the invention〕

As described above, according to the present invention, the amount of displacement is calculated by integrating and holding the displacement of the object to be measured by switching the polarity for each of the first period in which an external force is applied and the second period in which no external force is applied. Gain,
Further, a disturbance signal due to irregular vibration of the object to be measured is passed through at least one of the first and second periods, and the noise amount is obtained by integrating and holding the signal, and the first and second integrated amounts are obtained. By calculating the 8/N ratio from the noise amount, the external force f(t) is specified to adjust the external force f (t), which should always ensure the expected S/N ratio, and the corresponding displacement Since the elongation rate is calculated using the amount, the shape of the object to be measured can be periodically obtained in the first period and the second period, and the shape can be detected with a fast response speed. By adjusting the external force, it is possible to detect the shape with high precision.Furthermore, by obtaining the elongation rate of the object to be measured, the shape of the object to be measured can be quantitatively understood as the degree of physical shape defect. .

[Brief explanation of the drawing]

Figure 1 is a block diagram showing a shape detection device according to an embodiment of the present invention, Figure 2 is a signal waveform diagram of signal processing of each part of the device in Figure 1, and Figure 3 shows the relationship between tension distribution and elongation rate. A tension distribution diagram, FIG. 4 is a block diagram showing a conventional shape detection device, and FIG. 5 is a signal waveform diagram of signal processing of the conventional device. In the figure, 1 is a strip, 4a is an external force applying device, and 4b#
- is a displacement detector, 4C is a displacement converter, 5.81 is a polarity switcher, 6, 22, 82 is an integrating circuit, 7, 2i9
, 88 is a sample and hold circuit, 21 is a bypass filter, 26, 34 is a timing generation circuit, 27 is an applied external force calculator, an opening drive signal generator, 29 is a displacement average value calculator, and 30 is an elongated book adder. In addition, in the figures, the same reference numerals indicate the same or corresponding parts.

Claims (2)

[Claims] (1) A drive signal whose one period consists of a first period and a second period is input, and tension is applied to the object to be measured in a direction crossing the width direction of the surface of the object to be measured along the width direction. Said first
an external force applying means that applies an external force every period of time; and a displacement detecting means that detects displacements at N locations along the width direction of the object to be measured due to the application of the external force and generates N displacement detection signals. and a shape detection device that outputs a shape signal indicating the shape of the object to be measured based on the displacement detection signal, wherein the displacement detection signal for each first period and the shape signal in which the external force is not applied to the object to be measured are provided. a first integral processing means that integrates a displacement detection signal whose polarity is inverted for each second period; and a second integral processing means that does not apply the external force to the object to be measured at a period that is 1/2 period behind the integral processing means. a second integral processing means that integrates the displacement detection signal whose polarity has been inverted for each period and the displacement detection signal for each first period of the next period in which the external force is applied;
a third integral that calculates a third integral amount of each noise component due to irregular vibrations of the object to be measured, which is included in each of the displacement detection signals for at least one of the first and second periods; a processing means and S from the first, second and third integral quantities;
/N ratio, and an applied external force calculating means for calculating an external force that the external force applying means should generate in order to obtain a desired S/N ratio based on this S/N ratio, and a calculation result of the applied external force calculating means. drive signal generating means for generating the drive signal according to
elongation rate calculating means for calculating an elongation rate representing the flatness of the measured object at a displacement detection location of the measured object as a value of the shape signal based on an integral amount and a preset calculation formula; and the driving signal. The first and second
and timing generating means for controlling the operational timing of the third integral processing means. (2) The above N difference signals are converted to C(X_1), C(X_2
), . x), the value corresponding to the span applying the tension to the object to be measured is L, and the amplitude of the object to be measured corresponds to the external force per unit width applied to the object to be measured. When the value is a, the value corresponding to the coefficient for force balance is K, the value corresponding to the elastic modulus of the object to be measured is E, and the elongation rate is β(x), the calculation formula is β (x)=(L・a)/(2・K・E)([1/@C@
]-[1/C(x)]) However, @C@=1/N[C(x
＿1)+C(x_2)+・・・・・・+C(X_N)]
A shape detection device according to claim 1, characterized in that it is given by: