JPH04237508A - Thickness controller for rolling mill - Google Patents

Abstract

PURPOSE:To correct that the effect of thickness correction in thickness control for a rolling mill is changed by the fluctuating frequency of draft manipulating variable. CONSTITUTION:A thickness controller for the rolling mill is constituted of including a draft correction arithmetic unit 7 with which proper the draft correction in static thickness control is calculated and a frequency characteristic correcting device 8 with which the frequency analysis of the draft correction DELTAS that is calculated with this draft correction arithmetic unit is executed and corrected using correction gain that is preliminarily calculated corresponding to the frequency. Even when the frequency of variation of thickness on the inlet side of rolling mill is higher, a thickness can be sufficiently corrected.

Description

[Detailed description of the invention]

0001

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a plate thickness control device for a rolling mill, and more particularly to a plate thickness control device that takes into account the frequency characteristics of the rolling effect.

0002

[Prior Art] In a conventional plate thickness control device for a rolling mill, a roll gap correction amount (hereinafter referred to as a reduction correction amount) ΔS is basically calculated using the following formula 1 for a detected plate thickness deviation signal Δh. The thickness deviation was corrected by correcting the reduction amount.

0003

[Math 1]

This principle is described, for example, in ``Theory and Practice of Sheet Rolling'' (Iron and Steel Institute of Japan), p. 228.

[0005]

[Problem to be Solved by the Invention] The above-mentioned conventional formula for calculating the rolling reduction correction amount is statically correct, but when applied to an actual rolling mill, it is necessary to It is known that the effect of modifying the plate thickness according to the above-mentioned formula 1 cannot be obtained dynamically due to the interference caused by the fluctuation of . An example of analyzing the plate thickness correction effect due to rolling operation in a single stand.
/ΔS[dB] is shown in FIG. 4. The curve (■) in the figure shows the case when a thin plate material is rolled at high speed, the curve (2) shows the case when a medium thickness plate material is rolled at an intermediate speed, and the curve (■) shows the case when a thick plate material is rolled at a low speed. It can be seen from the figure that the effect of rolling decreases as the line speed increases and the plate becomes thinner. In addition, the effect of plate thickness correction by rolling decreases as the frequency [rad/sec] of fluctuations in the rolling correction amount ΔS increases, and the effect is only effective at high speeds and in the case of thin plates, at the frequency of fluctuations in the rolling correction amount. is 3 to 6 [ra
d/sec]. This characteristic tendency is common to both single-stand rolling mills and tandem rolling mills. Therefore, if the reduction correction amount calculated using Equation 1 has a large amount of variation in a frequency range exceeding 3 to 6 [rad/sec], there is a problem in that the necessary plate thickness correction is not performed. The problem of the present invention is that the operating frequency of the rolling operation required for plate thickness control is within the range of 3 to 6 [rad/sec].
To obtain a sufficient plate thickness control effect even when the thickness varies by more than .

[0006]

[Means for Solving the Problem] The above problem is solved by using information including a plate thickness deviation signal on the entering side of the rolling mill, a plate thickness deviation signal on the exit side of the rolling machine, a rolling pressure signal, and a rolling roll rotation speed signal. A plate thickness control device that calculates a roll gap correction amount for correcting the plate thickness deviation on the exit side of the rolling machine and performs a rolling operation based on the roll gap correction amount is subjected to frequency analysis of fluctuations in the calculated roll gap correction amount. However, this is achieved by providing a frequency characteristic correction device that corrects the frequency-analyzed roll gap correction amount using a correction gain calculated in advance according to frequency components and rolling conditions.

The above object can also be achieved by providing the plate thickness control device for a rolling mill according to claim 1 with a memory that stores a correction gain calculated in advance according to frequency components and rolling conditions. Ru.

The above problem can also be solved by providing the frequency characteristic correction device of the plate thickness control device for a rolling mill according to claim 1 or 2 with means for analyzing the amount of roll gap correction into components in a plurality of frequency regions. is also achieved.

The above-mentioned problem is further solved by using a frequency characteristic correction device of a plate thickness control device for a rolling mill according to any one of claims 1 to 3, which extracts a roll gap correction amount in a preset frequency range. a bandpass filter,
A configuration including a plurality of multipliers that multiply the roll gap correction amount extracted by the bandpass filter by a correction gain corresponding to each frequency domain, and an adder that sums the outputs of the plurality of multipliers. It is also achieved by

The above problem is further solved by using information including a plate thickness deviation signal on the entering side of the rolling mill, a plate thickness deviation signal on the exit side of the rolling machine, a rolling pressure deviation signal, and a rolling roll rotation speed signal.
A plate thickness control method that calculates a roll gap correction amount for correcting the plate thickness deviation at the exit side of a rolling machine and performs a rolling operation based on the roll gap correction amount includes frequency analysis of fluctuations in the calculated roll gap correction amount. and a step of correcting the frequency-analyzed roll gap correction amount using a correction gain calculated in advance according to the frequency component and rolling conditions, and performing a rolling operation based on the corrected roll gap correction amount. It is also achieved by

[0011]

[Effect] First, when the plate thickness correction effect Δh/ΔS when the variation frequency of the reduction correction amount ΔS is zero is ηo, and the plate thickness correction effect Δh/ΔS when it varies in a certain frequency range is ηa, the corresponding frequency The correction gain G in the region is G=ηo/
It is calculated as ηa. The plate thickness control device first calculates the appropriate reduction correction amount ΔS when performing plate thickness control by static operation basically based on the above formula 1, and then calculates the calculated reduction correction amount ΔS based on the frequency. Analyze and obtain ΔSn varying in the frequency domain. The obtained ΔSn is corrected by the correction gain G, and the corrected ΔSn is aggregated for the entire target frequency region to become the roll-down correction amount ΔSo, which is output as the roll-down operation amount.

0012

[Example] The present invention has been made with the focus on the fact that when a dynamic rolling operation has a frequency characteristic, the degree of plate thickness correction effect differs depending on the operating frequency of the rolling operation.
An embodiment of the present invention will be described with reference to FIGS. 1, 2, and 3. FIG. 1 shows an application of the present invention to a plate thickness control device for a single-stand rolling mill, in which an entry-side thickness gauge 1 that detects the entry-side plate thickness of a rolling stand 10 and outputs an entry-side plate thickness deviation signal ΔH, and A pulse generator 5 that outputs a rotational speed signal of the roll drive motor 4, and a tracking processing device 6 that tracks an entry side plate thickness deviation signal outputted from the entry side thickness gauge 1 to the position directly below the rolling stand based on the output of the pulse generator 5. and a rolling pressure detector 2 mounted on the rolling stand 10 to detect the rolling pressure deviation ΔP.
is connected to the rolling pressure detector 2, the exit thickness gauge 3, and the tracking processing device 6. Roll-down correction amount calculation device 7 that outputs the roll-down correction amount ΔS
and a frequency characteristic correction device 8 which is connected to the reduction correction amount calculation device 7 and performs frequency analysis of the reduction correction amount ΔS and performs a correction calculation according to frequency components and rolling conditions (line speed, plate thickness, etc.), and the frequency characteristic correction device 8. The roll reduction control device 9 is connected to the device 8 and controls the roll reduction based on the corrected reduction correction amount ΔSo.

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

Next, the operation of the plate thickness control device having the above structure will be explained. The tracking processing device 6 converts the entry side plate thickness deviation signal ΔH inputted from the entry side thickness gauge 1 into a rotation speed at which the pulse generator 5 outputs the time when the corresponding measurement position of the rolled material 11 reaches the roll gap position of the rolling stand. Calculate based on the signal, and calculate the time required from the obtained time until the rolling roll is rolled down according to the output of the frequency characteristic correction device 8 after the entry side plate thickness deviation signal ΔH is input to the rolling reduction correction amount calculating device 7. At the time obtained by subtraction, the entry side plate thickness deviation signal ΔH is input to the reduction correction amount calculating device 7.

The reduction correction amount calculation device 7 receives the input side sheet thickness deviation signal ΔH, the rolling pressure deviation ΔP inputted from the rolling pressure detector 2, and the output side sheet thickness deviation signal Δh inputted from the exit side thickness gauge 3. Using Equation 2 below, the reduction correction amount ΔS is calculated and output.

[0016]

[Math 2]

The reduction correction amount ΔS is the above-mentioned ΔH, ΔP, Δh
It is a value that fluctuates as the frequency changes, and is a superimposition of values that fluctuate at multiple frequencies. The calculated reduction correction amount ΔS is input to the frequency characteristic correction device 8,
The frequency is divided into three frequency sections by bandpass filters 8A to 8C. In this embodiment, the bandpass filter 8A extracts ΔS (hereinafter referred to as ΔS1) that fluctuates in the frequency domain 0 to 3 rad/sec, and the bandpass filter 8B extracts ΔS (hereinafter referred to as ΔS1) that fluctuates in the frequency domain 3 to 10 rad/sec. Hereinafter referred to as ΔS2), the bandpass filter 8
C extracts ΔS (hereinafter referred to as ΔS3) that varies in the frequency domain from 10 to 20 rad/sec. Figure 3
is an example of extraction of ΔS1 and ΔS2 using a band-pass filter (for the sake of clarity, ΔS3 is assumed to be absent), and the curve ■ is an example of ΔS input to the frequency characteristic correction device 8.
, the curve ■ is ΔS extracted by the bandpass filter 8A.
1, and curve ■ is Δ extracted by band pass filter 8B.
S2 is shown respectively. In other words,

[0018]

[Equation 3] There is a relationship of ΔS=ΔS1+ΔS2+ΔS3.

The extracted ΔS1, ΔS2, and ΔS3 are input to multipliers 8E, 8F, and 8G connected to band pass filters 8A to 8C, respectively, and the rolling conditions (rolled plate thickness, rolling speed) are set in advance for each frequency region. etc.) and is stored in the memory 8D.
G2 and G3 are multiplied. Multiplier 8E, 8F, 8G
Therefore, the output of is ΔS1・G1, ΔS2・G2, ΔS3
・Becomes G3. These outputs are added by an adder 8H, and output as a roll reduction correction amount ΔSo to a roll reduction control device 9 to control the roll reduction amount. That is, the roll reduction correction amount ΔSo output to the roll reduction control device 9 is expressed by the following formula.

[0020]

[Mathematical 4] ΔSo=ΔS1・G1+ΔS2・G2+ΔS3・G3 The curve ■ in Fig. 3 represents the ΔS shown by the curve ■, ΔS3=0,
The reduction correction amount ΔSo obtained by correcting using Equation 4 with G1=1 and G2=2 is shown.

The correction gains G1, G2, and G3 are calculated from the frequency characteristics of the thickness modification effect shown in FIG. 4, and the thickness modification effect in the frequency range exceeding 3 to 6 rad/sec is The fact that the plate thickness correction effect is lower than that when the axis value is 0 is corrected by increasing the reduction correction amount. In this embodiment, the correction gain G1 is the average value of the necessary correction values for each frequency in the frequency region 0 to 3 rad/sec, and the correction gain G2 is the average value of the necessary correction values for each frequency in the frequency region 3 to 1 rad/sec.
The average value at 0 rad/sec and the correction gain G3 are the average value in the frequency region 10 to 20 rad/sec. Instead of the average value of the necessary correction values for each frequency in the corresponding frequency domain, it may be the average value of the necessary correction values at the minimum and maximum frequencies in the corresponding frequency domain. According to this embodiment, a correction gain is set in advance for each rolling condition and each of the frequency domain divisions to increase the rolling operation amount so that the actual plate thickness correction amount becomes the required amount for the reduced plate thickness correction effect. Since the memory 8D for calculating and storing the calculation and the frequency characteristic correction device 8 for extracting the fluctuating reduction correction amount by dividing it into a plurality of frequency regions and correcting it using the correction gain are provided, the plate thickness correction effect is reduced. Even if the reduction correction amount varies depending on the frequency of the region,
We were able to obtain the necessary plate thickness correction amount.

In this embodiment, the frequency region of 0 to 20 rad/sec is divided into three regions, but the frequency region may be further expanded or reduced, and the number of region divisions may be increased or decreased. Further, the reduction correction amount ΔS may be directly reversely corrected by software processing using the frequency characteristic G(s) of the plate thickness correction effect according to the rolling conditions. ΔSo=ΔS/G(s) Furthermore, in this embodiment, the transmitted signal is treated as an analog signal, but in parts other than the bandpass filter,
The signal may be converted into a digital signal and processed as appropriate.

[0023]

Effects of the Invention According to the present invention, the amount of rolling operation is increased in advance for each rolling condition and frequency range division so that the actual plate thickness correction amount becomes the required amount for the reduced plate thickness correction effect. A memory that calculates and stores the correction gain to be applied, and a frequency characteristic correction device that extracts the fluctuating reduction correction amount by dividing it into multiple frequency regions and corrects it using the correction gain are installed. Even if the reduction correction amount (or the plate thickness deviation on the entering side of the rolling mill) changes in the frequency range where the plate thickness decreases, sufficient plate thickness correction can be performed.

[Brief explanation of the drawing]

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

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

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

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

[Explanation of symbols]

1 Entry side thickness gauge 2 Rolling pressure detector 3 Output side thickness gauge 4 Roll drive motor 5 Pulse generator 6 Tracking processing device 7 Rolling correction amount calculation device 8 Frequency characteristic correction device 9 Roll reduction control device 10 Rolling stand

Claims (1)

[Scope of Claims] [Claim 1] Using information including a plate thickness deviation signal on the entering side of the rolling mill, a plate thickness deviation signal on the exit side of the rolling machine, a rolling pressure deviation signal, and a rolling roll rotation speed signal, In a plate thickness control device that calculates a roll gap correction amount for correcting the exit side plate thickness deviation and performs a rolling operation based on the roll gap correction amount, frequency-analyzing fluctuations in the calculated roll gap correction amount, A plate thickness control device for a rolling mill, comprising a frequency characteristic correction device that corrects the frequency-analyzed roll gap correction amount using a correction gain calculated in advance according to frequency components and rolling conditions. 2. The plate thickness control device for a rolling mill according to claim 1, further comprising a memory for storing a correction gain calculated in advance according to frequency components and rolling conditions.Claim 3: Frequency characteristics 4. The plate thickness control device for a rolling mill according to claim 1 or 2, wherein the correction device includes means for analyzing the roll gap correction amount into components in a plurality of frequency regions. The correction device includes a plurality of bandpass filters each extracting a roll gap correction amount in a preset frequency domain, and multiplies the roll gap correction amount extracted by the bandpass filter by a correction gain corresponding to each frequency domain. The plate thickness control device for a rolling mill according to any one of claims 1 to 3, characterized in that the device includes a plurality of multipliers that add up the outputs of the plurality of multipliers, and an adder that adds up the outputs of the plurality of multipliers. 5. Correcting the rolling machine exit side plate thickness deviation using information including a rolling machine entrance side plate thickness deviation signal, a rolling machine exit side plate thickness deviation signal, a rolling pressure deviation signal, and a rolling roll rotation speed signal. In a plate thickness control method in which a roll gap correction amount is calculated for rolling, and a rolling operation is performed based on the roll gap correction amount, fluctuations in the calculated roll gap correction amount are frequency-analyzed, and changes in the frequency components and rolling conditions are performed. Plate thickness control for a rolling mill, characterized in that the frequency-analyzed roll gap correction amount is corrected using a correction gain calculated in advance according to the above, and a rolling operation is performed based on the corrected roll gap correction amount. Method