JP5557726B2 - Thickness control method and thickness control apparatus for rolling mill - Google Patents

Description

  The present invention relates to a thickness control method and apparatus for a rolling mill.

As is well known, when cold rolling a rolled material such as stainless steel, titanium, special steel, copper, etc., a “cluster type multi-stage rolling mill” in which a group of rolls supporting a work roll expands in a fan shape like a bunch of straw ( Cluster rolling mills ”are generally used.
When rolling the rolled material in the cluster rolling mill, first, the sheet thickness of the rolled material is measured, the roll gap is calculated based on the measured sheet thickness, and the roll gap is controlled by a reduction device. The thickness is controlled.

  As shown in FIG. 5, the roll gap in the cluster rolling mill is a command signal for adjusting the roll gap from the sheet thickness control device to the rolling device, which is output to the servo amplifier of the reduction device, and the servo valve is turned on via the servo amplifier. move. The servo valve operates in response to a command to move the hydraulic cylinder, and adjusts the roll gap by moving a wedge (wedge means) for adjusting the roll gap by expansion and contraction of the hydraulic cylinder.

In such a cluster rolling mill, even if a command signal is output from the plate thickness control device to the reduction device, there is a problem that it is difficult to control the plate thickness properly because servo valves, hydraulic cylinders, etc. have delay elements. .
In view of such a problem, there is a technique in which a command signal is compensated (corrected) in advance in consideration of the attenuation of a delay element such as a servo valve (Patent Document 1).

  In Patent Document 1, when rolling a rolled material, a frequency of a deviation of sheet thickness (referred to as sheet thickness deviation) is detected, a control gain value is calculated using this frequency, and an inverse number of the calculated control gain value is calculated. The calculated roll gap is multiplied and the value obtained by the multiplication is output to the reduction plate thickness control device.

JP-A-6-304629

  In Patent Document 1, a command signal corrected by taking into account a decrease in the control gain by multiplying the roll gap by the reciprocal of the control gain value is output to the reduction device, but the board used for obtaining the control gain value The frequency of the thickness deviation is a fixed value, and even if the command signal is corrected using this technique, the accuracy of the plate thickness may be reduced. In rolling, when the thickness deviation is substantially constant, it is possible to control the thickness using the technique of Patent Document 1, but it is actually difficult to control the thickness properly. is there.

  The present invention has been made in view of the above-described problems, and an object of the present invention is to provide a sheet thickness control method and apparatus for a rolling mill that can perform highly accurate sheet thickness control.

In order to achieve the above-mentioned object, the following technical measures were taken.
The sheet thickness control method of the rolling mill of the present invention measures the sheet thickness of the rolled material, calculates the roll gap of the work roll that rolls the rolled material based on the measured sheet thickness, and according to the calculated roll gap ΔS. A rolling mill thickness control method for controlling a rolling reduction device, wherein a deviation in thickness of the rolled material is decomposed into frequency components, a control gain value for the rolling reduction device is calculated for each frequency component, and the calculated control is calculated The roll gap ΔS obtained by measurement is multiplied by the reciprocal of the gain value, and the value obtained by the multiplication is defined as a roll gap ΔS ′ to which the reduction device is applied, and the plate thickness is controlled based on this roll gap ΔS ′. It is in.

The roll gap ΔS ′ to be applied to the reduction device can be obtained by adding the value obtained by multiplying the roll gap ΔS obtained by measurement by the reciprocal of the calculated control gain value with all frequency components. preferable.
The thickness control device for a rolling mill according to the present invention is a thickness provided in a rolling mill provided with a thickness measuring device for measuring the thickness of a rolled material and a reduction device for changing the roll gap ΔS ′ of the work roll. A control device, the plate thickness control device comprising: frequency resolution means for decomposing a thickness deviation of the rolled material into frequency components; and a control gain for the reduction device for each frequency component decomposed by the frequency resolution means. A control gain value calculating means for calculating a value, a control gain value correction amount calculating means for multiplying the roll gap ΔS by a reciprocal of the calculated control gain value, and calculating a value obtained by multiplication as the roll gap ΔS ′, A reduction control means for controlling the plate thickness based on the roll gap ΔS ′ calculated by the control gain value correction amount calculation means.

Preferably, the control gain value correction amount calculating means calculates a roll gap ΔS ′ to be applied to the reduction device by adding the values obtained by the multiplication with all frequency components.
The most preferable form of the sheet thickness control method of the rolling mill according to the present invention is to measure the sheet thickness of the rolled material, and calculate the roll gap ΔS of the work roll that rolls the rolled material based on the measured sheet thickness. A sheet thickness control method for a rolling mill that controls the reduction device in accordance with the calculated roll gap ΔS, wherein a deviation of the thickness of the rolled material is decomposed into frequency components, and a control gain for the reduction device for each frequency component A value is calculated, and the roll clearance ΔS obtained by measurement is multiplied by the reciprocal of the calculated control gain value, and the value obtained by multiplication is set as a roll clearance ΔS ′ to which the reduction device is applied. The roll thickness ΔS ′ to be applied to the reduction device is based on the value obtained by multiplying the roll gap ΔS obtained by measurement by the reciprocal of the calculated control gain value for all the frequencies. By adding the components Obtained can be characterized.
Moreover, the most preferable form of the plate thickness control device provided in the rolling mill according to the present invention includes a plate thickness measuring device that measures the plate thickness of the rolled material, and a reduction device that changes the roll gap ΔS ′ of the work roll. A sheet thickness control apparatus provided in a rolling mill provided with the sheet thickness control apparatus, wherein the sheet thickness control apparatus is decomposed by a frequency resolution means for decomposing a thickness deviation of the rolled material into frequency components, and the frequency resolution means A control gain value calculating means for calculating a control gain value for the reduction device for each frequency component, and a roll clearance ΔS ′ is calculated by multiplying the roll clearance ΔS by a reciprocal of the calculated control gain value. Control gain value correction amount calculating means, and a reduction control means for controlling the plate thickness based on the roll gap ΔS ′ calculated by the control gain value correction amount calculation means, and calculating the control gain value correction amount Means before Characterized in that it is configured to calculate the roll gap [Delta] S 'to be applied to the pressure device by adding a value obtained by multiplying by all the frequency components.

  According to the present invention, highly accurate plate thickness control can be performed.

It is the schematic of the rolling apparatus provided with the cluster rolling mill. It is the figure which showed the plate | board thickness deviation of the entrance side. It is a flowchart which rolls a rolling material, controlling by a plate | board thickness control apparatus. It is explanatory drawing which calculates | requires roll clearance gap (DELTA) S 'applied to a reduction device. It is a system block diagram of the reduction apparatus with which the cluster rolling mill was equipped.

Hereinafter, embodiments of the present invention will be described with reference to the drawings.
As shown in FIG. 1, a rolling device 1 cold-rolls a rolled material W such as stainless steel, titanium, special steel, and copper, and is a cluster type rolling mill (hereinafter referred to as a cluster) that rolls the rolled material W. 2), an unwinding reel 3 for unwinding the rolled material W, and a take-up reel 4 for winding the rolled material W.

The cluster rolling mill 2 is configured by combining a plurality of upper and lower pairs of work rolls 5, intermediate rolls 7, and backup rolls 8. A pair of upper and lower work rolls 5, an intermediate roll 7, and a backup roll 8 are arranged like a cocoon in side view.
Specifically, in the cluster rolling mill 2 of this embodiment, four intermediate rolls 7 (two vertically) are arranged around a pair of upper and lower work rolls, and six backup rolls 8 are arranged around the intermediate roll 7. (3 pieces on the top and bottom) are arranged. In addition, the number of each roll is not limited to this embodiment. Moreover, the rolling mill 2 is not limited to a cluster type, and may be a normal multi-stage rolling mill.

In such a rolling apparatus 1, the rolled material W having a desired thickness can be rolled by passing the rolled material W between the pair of upper and lower work rolls 5 and changing the roll gap ΔS between the work rolls 5. .
A thickness measuring device 10 for measuring the thickness of the rolled material W is provided on the entry side or the exit side of the cluster rolling mill 2. The cluster rolling machine 2 includes a reduction device 11 that changes the roll gap ΔS according to the plate thickness measured by the plate thickness measuring instrument 10, a calculation that changes the roll gap ΔS, and the like, and a plate that controls the reduction device 11. And a thickness control device 12.

  As shown in FIG. 5, the reduction device 11 operates the wedge 15 that changes the roll gap ΔS by moving each backup roll 8 by pushing up or down, the hydraulic cylinder 16 that moves the wedge 15, and the hydraulic cylinder 16. And a servo valve 17. A command signal from the plate thickness controller 12 is input to the servo valve 17 via a servo amplifier 18, and the hydraulic cylinder 16 is moved by the operation of the servo valve 17. The hydraulic cylinder 16 is provided with a position detector 19 that can detect the expansion / contraction position of the hydraulic cylinder (the position of the wedge 15).

In the present invention, as described above, control attenuation caused by delay elements such as the servo valve 17 and the hydraulic cylinder 16 is corrected.
Hereinafter, a sheet thickness control method and a sheet thickness control apparatus for a rolling mill according to the present invention will be described in detail.
The plate thickness control device of the present invention, that is, the plate thickness control device 12 includes a frequency resolving unit 20, a control gain value calculation unit 21, a control gain value correction amount calculation unit 22, and a reduction control unit 23.

The frequency decomposing means 20 is for decomposing the plate thickness deviation ΔH calculated based on the plate thickness measured by the plate thickness measuring instrument 10 into frequency components.
FIG. 2 shows an example in which the inlet side plate thickness is measured by the plate thickness measuring instrument 10 and the inlet side plate thickness deviation ΔH is obtained by this measurement. The frequency decomposing means 20 decomposes the plate thickness deviation ΔH as shown in FIG. 2 into each frequency as shown in Expression (1) by a frequency analyzer.

The control gain value calculation means 21 calculates a control gain value G (f _n ) for the reduction device 11 (control gain value for a delay element of the reduction device 11) for each frequency component decomposed by the frequency decomposition means 20. . The control gain value calculating means 21 obtains a control gain value for each frequency according to the equation (2).

The control gain value correction amount calculation means 22 obtains the reciprocal of the control gain value G (f _n ) for each frequency calculated by the control gain value calculation means 21 using equation (3).

Then, the control gain value correction amount calculation means 22 multiplies the roll gap ΔS (roll gap obtained by measurement) by the inverse G ′ (f _n ) of the control gain value for each frequency (the roll gap obtained by measurement) ( A roll gap ΔS ′ (corrected roll gap) is calculated based on G ′ (f _n ) × ΔS), and the obtained ΔS ′ is set as a change value of the roll gap to which the reduction device 11 is applied.
Specifically, the control gain value correction amount calculation means 22 calculates the roll gap ΔS from the plate thickness deviation ΔH obtained by measurement with the plate thickness measuring instrument 10. Specifically, it is calculated by the formula (4) based on the concept of feedforward.

Thereafter, the control gain value correction amount calculation means 22 multiplies the obtained ΔS by the reciprocal number G ′ (f _n ) of the control gain value for each frequency obtained by Expression (3). Further, the roll clearance ΔS ′ applied to the reduction device 11 is obtained by adding the values (G ′ (f _n ) × ΔS) obtained by multiplication for all frequency components as shown in the equation (5). .

The reduction control unit 23 controls the plate thickness based on the roll gap ΔS ′ calculated by the control gain value correction amount calculation unit 22. That is, the roll-down control means 23 outputs a command signal to the roll-down apparatus 11 so that the roll gap after the control in the roll-down apparatus 11 becomes the roll gap ΔS ′ obtained by the control gain value correction amount calculation means 22.
As described above, in the plate thickness control device 12 of the present invention, the roll gap ΔS obtained based on the plate thickness deviation ΔH measured by the plate thickness measuring instrument 10 is not directly applied to the reduction device 11, but first the plate thickness. The deviation ΔH is frequency-resolved, and a control gain value G (f _n ) for each frequency subjected to frequency decomposition is obtained. Then, the roll gap ΔS is corrected by multiplying the roll gap ΔS by G ′ (f _n ), which is the reciprocal of the control gain value G (f _n ), and adding the multiplied values for all frequencies. The roll gap ΔS ′ is applied to the reduction device 11.

In other words, the control gain value of the delay element existing in the reduction device 11 is obtained for each frequency component of the plate thickness deviation, and the obtained control gain value for each frequency component is used (for each obtained frequency component). The roll gap ΔS ′ is determined in a manner that cancels the control gain value.
FIG. 3 shows a flowchart for rolling the rolled material W while performing control by the plate thickness controller 12.

As shown in FIG. 3, first, in the first step, the plate thickness measuring instrument 10 measures the plate thickness on the entry side, and the plate thickness deviation ΔH is read.
Next, in the second step, the frequency decomposition means 20 decomposes the entry side thickness deviation ΔH for each frequency.
In the third step, the control gain value G (f _n ) is calculated by approximating the delay element of the reduction device 11 with, for example, a first-order lag system. The transfer function of the first-order lag system can be expressed by Equation (6).

On the other hand, the control gain value | G (jω _n ) | is expressed by Expression (7). Here, while substituting ω _n = 2πf _n (f _n : frequency) and replacing it with G (f _n ) = | G (jω _n ) |, equation (2) for obtaining the control gain value is obtained.
In the fourth step, the reciprocal number G ′ (f _n ) of the obtained control gain value G (f _n ) is obtained using equation (3).

Further, in the fifth step, the roll gap ΔS is obtained by the equation (4) based on the entry side thickness deviation ΔH read in the first step. In this embodiment, the roll gap ΔS is obtained based on feed-forward control, but is not limited to this.
The third to fifth steps are executed by the control gain value correction amount calculation means 22.
In the sixth step, the corrected roll gap to be output to the reduction device 11 by multiplying the inverse number G ′ (f) of the control gain value obtained in the fourth step by the roll gap ΔS obtained in the fifth step. ΔS ′ is obtained using equation (5). That is, in the sixth step, as shown in FIG. 4, a value obtained by multiplying the reciprocal G ′ (f _n ) of the control gain value by the roll gap ΔS is added for all frequency components, and the added value is added to the roll gap ΔS. 'And.

Then, in the seventh step, the roll control unit 23 outputs the roll gap ΔS ′ obtained in the sixth step to the rolling device 11.
In the eighth step, it is determined whether or not to continue the above processing (calculation). When the plate thickness control is continued, the process returns to the first step, and ends when it is stopped.
According to the present invention as described above, the plate thickness deviation ΔH is decomposed into frequency components to obtain the control gain value at each frequency, and the control gain value ( Since the roll gap is corrected, the characteristics of each delay element existing in the reduction device 11 can be reflected with certainty, and the plate thickness can be controlled with high accuracy.

  It should be noted that matters not explicitly disclosed in the embodiment disclosed this time, such as operating conditions and operating conditions, various parameters, dimensions, weights, volumes, and the like of a component, deviate from the range normally practiced by those skilled in the art. However, matters that can be easily assumed by those skilled in the art are employed.

DESCRIPTION OF SYMBOLS 1 Rolling device 2 Cluster rolling mill 3 Unwinding reel 4 Take-up reel 5 Work roll 7 Intermediate roll 8 Backup roll 10 Plate thickness measuring device 11 Sheet reduction device 12 Plate thickness control device 15 Wedge 16 Hydraulic cylinder 17 Servo valve 18 Servo amplifier 20 Frequency Disassembling means 21 Control gain value calculating means 22 Control gain value correction amount calculating means 23 Rolling control means ΔH Sheet thickness deviation W Rolled material

Claims (2)

The thickness of the rolling mill that measures the plate thickness of the rolled material, calculates the roll gap ΔS of the work roll that rolls the rolled material based on the measured plate thickness, and controls the reduction device in accordance with the calculated roll gap ΔS. A control method,
Decomposing the thickness deviation of the rolled material into frequency components,
Calculate a control gain value for the reduction device for each frequency component,
The roll gap ΔS obtained by measurement is multiplied by the reciprocal of the calculated control gain value, and the value obtained by the multiplication is defined as a roll gap ΔS ′ to which the reduction device is applied, and the plate thickness is determined based on this roll gap ΔS ′. It shall control,
The roll gap ΔS ′ applied to the reduction device is obtained by adding the value obtained by multiplying the roll gap ΔS obtained by measurement by the reciprocal of the calculated control gain value by all frequency components. A rolling mill sheet thickness control method. A plate thickness control device provided in a rolling mill provided with a plate thickness measuring device for measuring a plate thickness of a rolled material, and a reduction device for changing a roll gap ΔS ′ of a work roll,
The plate thickness control device
Frequency resolving means for decomposing the deviation of the thickness of the rolled material into frequency components;
Control gain value calculating means for calculating a control gain value for the reduction device for each frequency component decomposed by the frequency decomposing means;
A control gain value correction amount calculating means for multiplying the roll clearance ΔS by a reciprocal of the calculated control gain value and calculating a value obtained by multiplication as the roll clearance ΔS ′;
A reduction control means for controlling the plate thickness based on the roll gap ΔS ′ calculated by the control gain value correction amount calculation means ,
The control gain value correction amount calculating means is configured to calculate a roll gap ΔS ′ to be applied to the reduction device by adding the values obtained by the multiplication with all frequency components. A sheet thickness control device for a rolling mill.

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