JPH0452017A - Method for controlling sheet thickness on rolling mill - Google Patents

Abstract

PURPOSE:To exactly and precisely remove the phase deviation or the amplitude error of the high frequency part including in the sheet thickness deviation and to realize the good control by controlling the sheet thickness with the target value of the value adding the sheet thickness deviation without including the range of high frequency to the preliminary set value. CONSTITUTION:The inlet side material of the steel sheet, etc., delivered out from the delivering out machine 2 is rolled with the rolling mill 1, and wound with the winding machine 3. On the equipment of the rolling mill as like this, the sheet thickness deviation of the material of the inlet side of the rolling mill 1 against the standard sheet thickness is detected with the sheet thickness deviation detector 10, as the means to remove the part of the sheet thickness deviation of high frequency being unable to be detected accurately for example, the low pass digital filter 11 is set, and the output from the sheet thickness deviation detector 10 is stored in the data-file 12 through this low pass digital filter 11. By reading the data of the sheet thickness deviation equivalent to the position of just under rolling reduction of the rolling mill out from the data-file 12, and it is inputted to the coefficient element 9. The output of the coefficient element 9 is given to the adding machine 13 as the compensating value to compensate the diviation of sheet thickness by adding it to the position setting value of the rolling reduction given on the other way from the rolling reduction position setting device 15, and the rolling reduction target position value S* is made.

Description

DETAILED DESCRIPTION OF THE INVENTION [Field of Industrial Application] The present invention relates to a method for controlling the thickness of a steel plate or the like in rolling mill equipment.

[Conventional technology]

Conventionally, in this type of rolling mill equipment, a thickness deviation of the material on the input side in the rolling direction is detected using a plate thickness deviation detector, and automatic plate thickness control is performed to remove the thickness deviation of the input side material.

[Problem to be solved by the invention]

The plate thickness deviation detector used in this type of control is as follows:
For example, in many cases, the actual plate thickness is determined from the amount of attenuation of the T-line, and the deviation between this and the standard plate thickness is determined.

However, since such plate thickness deviation detectors generally have a delay, the phase of the plate thickness deviation at high frequencies may shift due to this delay, or the amplitude may become small, making it difficult to accurately capture deviations at high frequency components. The problem is that it becomes difficult.

For this reason, for example, if a normal analog filter is used, it has poor frequency characteristics and is difficult to remove high frequencies reliably and accurately, and it is also difficult to remove high frequencies other than high frequencies that are necessary for plate thickness control. A phase lag (delay in the output relative to the filter input) occurs, making it impossible to accurately detect plate thickness deviations and deteriorating the accuracy of plate thickness control. In addition,
It has been found that when plate thickness control is performed using the detected inlet plate thickness deviation value, which includes deviations that are out of phase or have a small amplitude, the plate thickness deviation of the material increases.

Therefore, an object of the present invention is to accurately and accurately remove phase shifts and amplitude errors of high frequency components included in plate thickness deviations, and to enable good control.

[Means to solve the problem]

High frequency removal means for removing phase shift and amplitude error of high frequency included in plate thickness deviation output with respect to standard plate thickness of entry side member detected by plate thickness deviation detector installed in rolling mill equipment. is provided, and the plate thickness is controlled using a value obtained by adding the plate thickness deviation that does not include this high frequency component to a predetermined set value as a target value.

[Effect]

By providing a high frequency removal means, phase shifts and amplitude errors of high frequency components included in plate thickness deviation can be removed.
Enables highly accurate control.

〔Example〕

FIG. 1 is a configuration diagram showing an embodiment of the present invention, in which 1 is a tanobe machine, 2 is a payout machine, 3 is a winder, 4 is a servo valve, 5 is a servo amplifier, 6 is a positioning control section, and 7 is a winder. Oil field equipment, 8 is a reduction position detector, 9 is a coefficient element, 10 is a plate thickness deviation detector, 11 is a low-pass digital filter as a high frequency removal means, 12 is a data file, 13 is an adder, 1
4 is a subtracter, and 15 is a lowering position setter.

Incoming materials such as steel plates discharged from the unloading machine 2 are transferred to the rolling mill 1.
It is rolled by a winder 3 and wound up by a winder 3. In such rolling mill equipment, a plate thickness deviation detector 10 detects the plate thickness deviation of the material at the entrance of the rolling mill 1 with respect to a standard plate thickness, and removes plate thickness deviations at high frequencies that cannot be accurately detected. For example, a known low-pass digital filter 11 as shown in FIG. Plate thickness deviation data corresponding to the position immediately below the rolling mill rolling position is read from the data file 12 and is given to the coefficient element 9. Coefficient element 9
The output is sent to the adder 13 as a correction value for correcting the plate thickness deviation.
and a roll-down position setting device 15 provided separately to this.
This value is added to the set value of the rolling position from , and becomes the target rolling position S2 of the rolling mill 1.

The positioning control unit 6 performs a predetermined adjustment calculation to make the actual value of the roll position detected by the roll position detector 8 coincide with the target roll position value S9, and outputs the result to the servo amplifier 5.
is applied, and the rolling position of the rolling @1 is controlled via the servo valve 4 and the hydraulic device 7 so that it reaches the target position.

FIG. 2 is a block diagram showing an example of a low-pass digital filter.

In the figure, 21 is a delay element, 22 is an addition element, 23
is a proportional gain element, and the broken line frame constitutes a known moving average filter. This is a digital filter with good frequency characteristics and small delay by incorporating a moving average filter as shown by the broken line in the gain section of a conventionally known discrete-order low-pass filter. be.

In other words, a discrete-order low-pass filter is a digital filter obtained by discretizing an analog filter, and in particular, in order to remove noise from a signal X(i) containing periodic noise, the time constant must be large. Must be. However, increasing the time constant increases signal delay, which deteriorates frequency characteristics. On the other hand, the moving average filter uses the order (n) of the moving average.
Although its noise removal ability is determined by the amount of noise it takes, it can at least reduce or eliminate periodic noise.

From these facts, as shown in Fig. 2, the signal VJ (i
) is input to the discrete-order low-pass filter to reduce the time constant of the discrete-order low-pass filter, reduce signal delay, and improve frequency characteristics.

Note that the high frequency removal means is not limited to the above, and a similar low-pass digital filter can be used.

〔Effect of the invention〕

According to the present invention, since a high-frequency removal means including a low-pass digital filter is provided, it is possible to accurately and reliably remove phase shifts and amplitude errors of high-frequency sheet thickness deviations caused by delays in the sheet thickness deviation detector. As a result,
It is possible to eliminate unnecessary corrections in plate thickness control and prevent a decrease in the accuracy of plate thickness control.

[Brief explanation of the drawing]

FIG. 1 is a block diagram showing an embodiment of the present invention, and FIG. 2 is a block diagram showing an example of a low-pass digital filter. 1... Rolling machine, 2... Payout machine, 3... Winding machine, 4
...Servo valve, 5...Servo amplifier, 6...
Positioning control unit, 7... Hydraulic device, 8... Drop position detector, 9... Coefficient element, 10... Plate thickness deviation detector, 11... Low pass digital filter, 12...
Data file, 13...Adder, 14...Subtractor, 15...Down position setter, 21...Delay element, 2
2... Addition element, 23... Proportional gain element. Figure 1

Claims (1)

[Claims] 1) A high frequency that removes the phase shift and amplitude error of the high frequency included in the plate thickness deviation output with respect to the reference plate thickness of the entry side member, which is detected by the plate thickness deviation detector installed in the rolling mill equipment. A method for controlling plate thickness using a rolling mill, comprising removing means, and controlling the plate thickness using a value obtained by adding the plate thickness deviation not including the high frequency component to a predetermined set value as a target value.