JP3013049B2 - Rolling mill thickness control device - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a thickness control device for a rolling mill, and more particularly to a thickness control device taking into consideration the frequency characteristic of a rolling effect.

[0002]

2. Description of the Related Art In a conventional thickness control device for a rolling mill, a roll gap correction amount (hereinafter referred to as a rolling reduction amount) ΔS basically calculated by the following equation 1 is applied to a detected thickness deviation signal Δh. Only the reduction amount was corrected to correct the thickness deviation.

[0003]

(Equation 1)

This principle is described, for example, in "Theory and Practice of Sheet Rolling" (Iron and Steel Institute of Japan), p.

[0005]

The conventional formula for calculating the reduction amount of the rolling reduction is a statically correct expression, but when applied to an actual rolling mill, the tension of the rolled material on the front and rear surfaces of the rolling mill due to the reduction operation is required. It is known that the sheet thickness correction effect as shown in the above equation 1 cannot be obtained dynamically. In the example of analyzing the sheet thickness correction effect by the rolling operation in the single stand, the horizontal axis represents the frequency [rad / sec] of fluctuation of the reduction amount ΔS, and the vertical axis represents the thickness correction effect Δh / ΔS.
FIG. 4 shows [dB]. The curve in the figure shows the case where the thin plate is rolled at a high speed, the curve shows the case where the intermediate plate is rolled at an intermediate speed, and the curve shows the case where the thick plate is rolled at a low speed. From the figure, it can be seen that the effect of the reduction becomes smaller as the line speed becomes higher and the sheet becomes thinner. In addition, the effect of the thickness reduction by the reduction decreases as the frequency [rad / sec] of the variation of the reduction amount ΔS increases, and is effective only in the case of a high-speed, thin plate material, the frequency of the variation of the reduction amount. Is an area from 3 to 6 [rad / sec]. This characteristic tendency is common to both single-stand rolling mills and tandem rolling mills. For this reason, in the rolling reduction amount calculated by the above equation 1, 3 to 6 [rad / se
If there are many portions that fluctuate in a frequency region exceeding c], there is a problem that necessary thickness correction is not performed. It is an object of the present invention to provide a sufficient thickness control effect even when the operating frequency of the rolling operation required for controlling the thickness varies from 3 to 6 [rad / sec].

[0006]

SUMMARY OF THE INVENTION The above object is achieved by using information including a rolling mill entry side sheet thickness deviation signal, a rolling mill exit side sheet thickness deviation signal, a rolling pressure signal, and a rolling roll rotation speed signal. Calculate the roll gap correction amount for correcting the roll thickness at the exit side of the rolling mill, and perform a frequency analysis on the fluctuation of the calculated roll gap correction amount to a sheet thickness control device that performs a rolling operation based on the roll gap correction amount. This is achieved by providing a frequency characteristic correction device that corrects the roll gap correction amount subjected to the frequency analysis using a correction gain calculated in advance according to the frequency component and the rolling conditions.

[0007] The above object is also achieved by providing a thickness control device for a rolling mill according to claim 1 with a memory for storing a correction gain calculated in advance according to a frequency component and rolling conditions. You.

[0008] The above object is also achieved by providing a frequency characteristic correction device of a plate thickness control device for a rolling mill according to claim 1 or 2 comprising means for analyzing a roll gap correction amount into a plurality of frequency domain components. Is also achieved.

The above object is further achieved by providing a frequency characteristic correction device for a thickness control device of a rolling mill according to any one of claims 1 to 3 for extracting a roll gap correction amount in a preset frequency region. And a bandpass filter of
A plurality of multipliers for multiplying the roll gap correction amount extracted by the band-pass filter by correction gains corresponding to respective frequency domains, and an adder for summing outputs of the plurality of multipliers. Is also achieved by

[0010] The above object is further achieved by using information including a rolling mill entering side thickness deviation signal, a rolling mill exit side thickness deviation signal, a rolling pressure deviation signal, and a rolling roll rotation speed signal.
A thickness control method for calculating a roll gap correction amount for correcting the roll thickness deviation on the rolling-out side of the rolling mill and performing a rolling-down operation based on the roll gap correction amount includes a frequency analysis of the fluctuation of the calculated roll gap correction amount. And correcting the frequency-analyzed roll gap correction amount using a correction gain calculated in advance according to the frequency component and the rolling condition, and performing a rolling-down operation based on the corrected roll gap correction amount. It is also achieved by:

[0011]

First, the thickness correction effect Δh / ΔS when the variation frequency of the rolling reduction amount ΔS is zero is ηo, and the thickness correction effect Δh / ΔS when the variation frequency in a certain frequency region is ηa, The correction gain G in the region is G = ηo /
It is calculated as ηa. The sheet thickness control device first calculates an appropriate rolling reduction amount ΔS when performing the sheet thickness control by a static operation based on the above-described equation 1, and then calculates the calculated rolling reduction amount ΔS as a frequency. Analysis to obtain ΔSn that varies in the frequency domain. The obtained .DELTA.Sn is corrected by the correction gain G, and the corrected .DELTA.Sn is totaled for the entire frequency range of interest, and becomes a reduction correction amount .DELTA.So, which is output as a roll reduction operation amount.

[0012]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS The present invention has been made by paying attention to the fact that if the dynamic rolling operation has a frequency characteristic, the degree of the thickness correction effect varies depending on the operating frequency of the rolling operation.
One embodiment of the present invention will be described with reference to FIGS. FIG. 1 shows a single-stand rolling mill in which the present invention is applied to a thickness control device. The thickness gauge 1 detects the thickness of the entry side of a rolling stand 10 and outputs an entry-side thickness deviation signal ΔH. A pulse generator 5 for outputting a rotation speed signal of a roll drive motor 4, and a tracking processing device 6 for tracking an incoming side plate thickness deviation signal output from the incoming side thickness meter 1 to immediately below a rolling stand based on an output of the pulse generator 5. And a rolling pressure detector 2 mounted on a rolling stand 10 and detecting a rolling pressure deviation ΔP.
And an output thickness gauge 3 that detects the output thickness of the rolling stand 10 and outputs an output thickness deviation signal Δh, and is connected to the rolling pressure detector 2, the output thickness gauge 3, and the tracking processing device 6. Reduction amount calculating device 7 for outputting reduction amount ΔS
A frequency characteristic correction device 8 connected to the rolling correction amount calculating device 7 for frequency-analyzing the rolling correction amount ΔS and performing correction calculation according to frequency components and rolling conditions (line speed, plate thickness, etc.); A roll reduction control device 9 is connected to the device 8 and controls the roll reduction based on the corrected reduction amount ΔSo.

FIG. 2 shows an example of the configuration of the frequency characteristic correction device 8, in which band-pass filters 8A, 8B, 8C connected in parallel to input terminals, and the band-pass filters 8A, 8A,
8B, 8C connected to multipliers 8E, 8F,
8G, an adder 8H connected to each output side of the multipliers 8E, 8F and 8G, and a memory 8D for storing rolling conditions and frequency characteristics connected to the input sides of the multipliers 8E, 8F and 8G. It is comprised including.

Next, the operation of the plate thickness control device having the above configuration will be described. The tracking processor 6 converts the entry side thickness deviation signal ΔH input from the entry side thickness gauge 1 into a rotation speed at which the pulse generator 5 outputs a time at which the corresponding measurement position of the rolled material 11 reaches the roll gap position of the rolling stand. From the obtained time, the time required from when the entry side sheet thickness deviation signal ΔH is input to the reduction correction amount calculation device 7 to when the rolling roll is reduced according to the output of the frequency characteristic correction device 8 is calculated. At the time obtained by subtraction, the entry side plate thickness deviation signal ΔH is input to the rolling reduction amount calculation device 7.

The rolling correction amount calculating device 7 receives the input side thickness deviation signal ΔH, the rolling pressure deviation ΔP input from the rolling pressure detector 2, and the output side thickness deviation signal Δh input from the output thickness gauge 3. The rolling reduction amount ΔS is calculated by the following equation 2 using the method described above and output.

[0016]

(Equation 2)

The rolling reduction amount ΔS is determined by the above ΔH, ΔP, Δh
Is a value that fluctuates in accordance with the fluctuation of the frequency, and a value that fluctuates at a plurality of frequencies is superimposed. The calculated rolling reduction amount ΔS is input to the frequency characteristic correction device 8,
It is divided into three frequency divisions by the band pass filters 8A to 8C. In the present embodiment, the bandpass filter 8A extracts ΔS (hereinafter referred to as ΔS1) that fluctuates in a frequency range of 0 to 3 rad / sec.
ΔS fluctuating in the frequency range of 3 to 10 rad / sec (hereinafter ΔS2
), The band-pass filter 8C
ΔS fluctuating at 0 to 20 rad / sec (hereinafter referred to as ΔS3)
Are respectively extracted. FIG. 3 shows an example of extracting ΔS1 and ΔS2 by a band-pass filter (for easy understanding,
S3 was the case where there was none. ), A curve indicates ΔS input to the frequency characteristic correction device 8, a curve indicates ΔS1 extracted by the bandpass filter 8A, and a curve indicates ΔS2 extracted by the bandpass filter 8B.
That is,

[0018]

## EQU3 ## There is a relation of ΔS = ΔS1 + ΔS2 + ΔS3.

The extracted .DELTA.S1, .DELTA.S2, and .DELTA.S3 are input to multipliers 8E, 8F and 8G connected to the band-pass filters 8A to 8C, respectively, and the rolling conditions (rolling thickness, rolling speed) are determined in advance for each frequency region. Correction gains G1 and G calculated in accordance with
2, G3 is multiplied. The outputs of the multipliers 8E, 8F, 8G are therefore: ΔS1 · G1, ΔS2 · G2, ΔS3 ·
G3. These outputs are added by an adder 8H.
The roll reduction amount is output to the roll reduction controller 9 as the reduction amount ΔSo, and the roll reduction amount is controlled. That is, the reduction amount ΔSo output to the roll reduction control device 9 is expressed by the following equation.

[0020]

ΔSo = ΔS1 · G1 + ΔS2 · G2 + ΔS3 · G3 In the curve of FIG. 3, ΔS shown by the curve is represented by ΔS3 =
The roll-down correction amount ΔSo obtained by performing correction according to Equation 4 with 0, G1 = 1, and G2 = 2 is shown.

The correction gains G1, G2, and G3 are calculated from the frequency characteristics of the sheet thickness correction effect shown in FIG. 4, and the sheet thickness correction effect in the frequency region exceeding 3 to 6 rad / sec is not shown in FIG. The value lower than the plate thickness correction effect when the value of the axis is 0 is corrected by increasing the rolling reduction amount. In this embodiment, the correction gain G1 is the average value of the necessary correction values for each frequency in the frequency range of 0 to 3 rad / sec, and the correction gain G2 is the frequency range of 3 to 10 rad / sec.
And the correction gain G3 in the frequency range of 10 to 20 ra
It is the average value in d / sec. Instead of the average value of the necessary correction values for each frequency in the corresponding frequency region, the average value of the required correction values at the lowest and maximum frequencies in the corresponding frequency region may be used. According to the present embodiment, a correction gain for increasing the rolling operation amount so that the actual thickness correction amount becomes a necessary amount with respect to the reduced thickness correction effect in advance for each rolling condition or the frequency region section. Memory 8D for calculating and storing
And the frequency characteristic correction device 8 for extracting the fluctuating rolling correction amount divided into a plurality of frequency regions and performing correction using the correction gain is provided. , The required thickness correction amount could be obtained.

In this embodiment, the frequency range of 0 to 20 rad / sec is divided into three. However, the frequency range may be further enlarged or reduced to increase or decrease the number of divisions. In addition, the frequency characteristic G (s) of the thickness correction effect according to the rolling conditions
May be used to directly and inversely correct the rolling reduction amount ΔS by software processing. ΔSo = ΔS / G (s) In this embodiment, the transmitted signal is treated as an analog signal.
The signal may be appropriately converted into a digital signal and processed.

[0023]

According to the present invention, the rolling operation amount is increased in advance so that the actual thickness correction amount becomes the necessary amount with respect to the reduced thickness correction effect for each rolling condition and the frequency domain division. Since a memory for calculating and storing a correction gain to be calculated and a fluctuating reduction correction amount are divided into a plurality of frequency regions and extracted, and a frequency characteristic correction device for correcting using the correction gain is provided, the plate thickness correction effect is reduced. Even if the amount of draft reduction (or the thickness deviation on the rolling mill side) fluctuates at the frequency of the lower region,
Sufficient plate thickness correction can be performed.

[Brief description of the drawings]

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

FIG. 2 is a block diagram showing details of a part of the embodiment shown in FIG. 1;

FIG. 3 is a conceptual diagram illustrating the principle of the present invention.

FIG. 4 is a graph showing an example of frequency characteristics in sheet thickness control.

[Explanation of symbols]

 DESCRIPTION OF SYMBOLS 1 Inlet thickness gauge 2 Rolling pressure detector 3 Outlet thickness gauge 4 Rolling roll drive motor 5 Pulse generator 6 Tracking processing device 7 Reduction correction amount calculation device 8 Frequency characteristic correction device 9 Roll reduction control device 10 Rolling stand

Claims (5)

(57) [Claims] 1. A method for correcting a thickness deviation on a rolling mill exit side using information including a thickness deviation signal on a rolling mill entering side, a thickness deviation signal on a rolling mill exit side, a rolling pressure deviation signal, and a rolling roll rotation speed signal. In the sheet thickness control device that calculates the roll gap correction amount for performing, and performs the rolling operation based on the roll gap correction amount, the fluctuation of the calculated roll gap correction amount is frequency-analyzed, and the frequency component and the rolling condition are calculated. A thickness control device for a rolling mill, comprising a frequency characteristic correction device for correcting the roll gap correction amount subjected to the frequency analysis using a correction gain calculated in advance in accordance with the frequency characteristic. 2. The apparatus according to claim 1, further comprising a memory for storing a correction gain calculated in advance according to the frequency component and the rolling conditions. 3. The thickness control device for a rolling mill according to claim 1, wherein the frequency characteristic correction device includes a means for analyzing a roll gap correction amount into a plurality of frequency domain components. 4. A frequency characteristic correction apparatus comprising: a plurality of band-pass filters each extracting a roll gap correction amount in a preset frequency region; 4. The apparatus according to claim 1, further comprising: a plurality of multipliers for multiplying the correction gains corresponding to (a), and an adder for summing outputs of the plurality of multipliers. Rolling mill thickness control device 5. A rolling mill exit thickness deviation is corrected using information including a rolling mill entry side thickness deviation signal, a rolling mill exit side thickness deviation signal, a rolling pressure deviation signal, and a rolling roll rotation speed signal. In the sheet thickness control method of performing a rolling operation based on the roll gap correction amount, a frequency analysis is performed on the fluctuation of the calculated roll gap correction amount, and a frequency component and a rolling condition are calculated. The thickness control of a rolling mill, wherein the roll gap correction amount subjected to the frequency analysis is corrected using a correction gain calculated in advance in accordance with the roll gap, and a rolling operation is performed based on the corrected roll gap correction amount. Method