JP3080507B2 - Automatic thickness control method for rolling mill - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to an automatic thickness control method for a rolling mill.

[0002]

2. Description of the Related Art In a rolling mill, feed forward AGC, BISRA-AGC, monitor AGC, etc. are used as means for automatically controlling the thickness of a rolled material by adjusting a reduction amount (that is, a roll gap) (hereinafter referred to as a reduction AGC). Is generally known. Conventionally, as illustrated in FIG. 3, two thickness gauges 4 and 5 having different characteristics are arranged between a rolling mill 1 and its inlet and outlet reels 2 and 3, respectively. The thickness deviation signals of the thickness gauges 4 and 5 are input to the reduction AGC 8 via the changeover switches 6 and 7, and the reduction device 9 is operated by the output of the AGC 8 to control the thickness of the rolled material (M). .

The thickness gauge 4 has good responsiveness but poor temperature drift characteristics, and the thickness gauge 5 has poor responsiveness but good temperature characteristics. The selection is made by switching the changeover switches 6 and 7 at the discretion of the operator, and the criterion is the allowable value of the temperature draft. The temperature drift refers to a rolled material (M)
The state in which the zero point of the thickness gauge is out of order due to the influence of the temperature and the accurate thickness deviation signal is not output, and the true thickness deviation signal without temperature drift is as shown in FIG. A false thickness deviation signal having a temperature drift is shown in FIG.

Normally, when temperature drift does not occur, sufficient thickness accuracy can be obtained by inputting the output of the thickness gauge 4 having good response to the AGC 8. However, when the AGC 8 is executed with the thickness gauge 4 having good responsiveness, if the temperature drift occurs, the accuracy of the thickness is deteriorated. Therefore, the operator has switched to the other thickness gauge 5. That is, because the other thickness gauge 5 has good temperature drift characteristics instead of poor response, a more accurate thickness deviation signal can be output than using the good response thickness gauge 4.

[0005]

In the above prior art, the operator is left to determine which one of the thickness gauges 4 and 5 having different characteristics is to be used. , 7 has a problem that a sufficient thickness accuracy cannot be stably obtained.

SUMMARY OF THE INVENTION The present invention has been made in view of the above situation, and its purpose is to utilize the good characteristics of each thickness gauge having different responsiveness without depending on the judgment of an operator. An object of the present invention is to provide an automatic thickness control method for a rolling mill that can correct a thickness deviation signal at the time of a temperature drift to obtain a true signal and ensure sufficient thickness accuracy.

[0007]

According to the present invention, the following technical measures have been taken in order to achieve the above object. That is, the present invention is an automatic thickness control method for a rolling mill, wherein the thickness is controlled based on a deviation signal of two or more thickness gauges having different responsiveness provided on one side of the rolling mill. Among them, the temperature drift of the responsive thickness gauge is detected and its allowable value is determined, and when the temperature drift is within the allowable value, the control means is executed based on the thickness deviation signal of the responsive thickness gauge. When the temperature drift exceeds the allowable value, a signal from which the low frequency component of the thickness deviation signal of the good response thickness gauge is removed and a signal from which the high frequency component of the thickness deviation signal of the other thickness gauge is removed. The thickness is controlled by a correction signal obtained by adding

[0008]

According to the present invention, a temperature drift of a good response thickness gauge is detected, and when the temperature drift is within an allowable value, the thickness is controlled by a thickness deviation signal of the good response thickness gauge. Thereby, sufficient thickness accuracy can be obtained. When the temperature drift exceeds an allowable value, a high-frequency component signal obtained by removing a low-frequency component of the thickness deviation signal of the responsive thickness gauge,
By controlling the sheet thickness with a (corrected) true sheet thickness deviation signal obtained by adding a low-frequency component signal obtained by removing the high-frequency component of the sheet thickness deviation signal of the other sheet thickness meter, Even under a temperature drift state exceeding the value, it is possible to perform rolling with sufficient thickness accuracy.

[0009]

Embodiments of the present invention will be described below with reference to the drawings. Since the basic configuration of the automatic thickness control device of the rolling mill is as shown in the block diagram of FIG. 3, the characteristic portions of the present invention will be described in detail with reference to FIG. 3 and the description thereof.

FIG. 1 shows a thickness deviation signal correction circuit 10 which is a characteristic part of the present invention. Reference numeral 11 denotes a high-pass filter for removing low frequency components from the thickness deviation signal S1 of the thickness gauge 4.
2 is a low-pass filter for removing the high-frequency component of the deviation signal S1, and 13 is the signal S1 and the low-pass filter 1
A low-pass filter for removing high-frequency components from the thickness deviation signal S4 of the thickness gauge 5; and 15 an arithmetic operation of the signal S3 and the output signal S5 of the low-pass filter 14. A determiner for determining temperature drift,
16 is the high frequency component signal S2 and the low frequency component signal S
Adders 5 and 17 and 18 are switches for switching the true deviation output signal S1 of the thickness gauge 4 and the corrected true deviation output signal S6 at the time of temperature drift which is the output of the adder 16.

The temperature drift determiner 15 calculates the signals S3 and S5 of the low frequency components, and when the calculated drift value is within a predetermined allowable value, the changeover switch 1
7 is turned on and the changeover switch 18 is turned off,
When the drift exceeds the allowable value, the changeover switch 17
Is turned off and the changeover switch 18 is turned on.

In the above embodiment, the thickness deviation signal S1 output from the thickness gauge 4 is as shown in FIG. 4A when there is no temperature drift, and is a true signal. As described above, the changeover switch 17 is turned on, and is output to the reduction AGC 8, and the reduction AGC 8 is executed. Further, in the above embodiment, when the thickness gauge 4 causes a temperature drift, the thickness deviation signal S1 is, as shown in FIG. 2 (II), compared to the true signal (FIG. 2 (I)). Drift,
The center is shifted upward. Therefore, the drifted signal S1 passes through the high-pass filter 11 and the high-frequency component signal S2 (see FIG. 2 (III)) from which the low-frequency component has been removed. The signal S3 has a low frequency component (see FIG. 2 (IV)), and the signal S3 is input to the temperature drift determiner 15.

On the other hand, the output thickness deviation signal S4 of the thickness gauge 5
(See FIG. 2 (V)) is a low frequency component signal S5 (FIG. 2 (V
(See I)) and is input to the temperature drift determiner 15. The determiner 15 compares the signal S3 with the signal S5 (i.e., S3-S5 is calculated). As a result, when the drift is within an allowable value, the changeover switch 17 remains ON and the thickness gauge 4 The raw thickness deviation signal S1 is input to the reduction AGC 8.

On the other hand, when the judgment drift in the judgment unit 15 exceeds the allowable value, the changeover switch 17 is turned off by the output of the judgment unit 15 and the changeover switch 18 is turned on at the same time. A correction signal S6 (see FIG. 2 (VII)) obtained by adding the signal S2 of the frequency component and the low frequency component S5 (that is, a true signal) is a reduction A
It is input to the GC 8 and the reduction AGC 8 is executed.

According to the above embodiment, during operation of the rolling mill 1,
Even when temperature drift occurs in the thickness gauges 4 and 5,
The good responsiveness of the thickness gauge 4 is utilized, and a true and accurate thickness deviation signal can be input to the reduction AGC 8 which is a control means and executed, and sufficient thickness accuracy can be secured. is there. The present invention is not limited to the above embodiments,
The design can be changed as appropriate. For example, the present invention can be applied to an automatic sheet thickness control device provided with a reduction AGC and a tension AGC.

[0016]

As described above, the present invention relates to an automatic thickness control method for a rolling mill in which the thickness is controlled based on a deviation signal from two or more responsive thickness gauges provided on one side of the rolling mill. In the thickness gauge, the temperature drift of the responsive thickness gauge is detected and its allowable value is determined, and when the temperature drift is within the allowable value, the thickness deviation of the responsive thickness gauge is determined. The control means is executed by the signal, and when the temperature drift exceeds the allowable value, the signal obtained by removing the low-frequency component of the thickness deviation signal of the responsive thickness gauge and the thickness deviation of the other thickness gauge. The plate thickness is controlled by a correction signal obtained by adding a signal from which the high-frequency component of the signal has been removed, so that even if a temperature drift occurs in the plate thickness gauge, the plate having different characteristics can be obtained. Making use of the good characteristics of thickness gauges to obtain true and accurate thickness deviation signals by signal processing Since the true thickness deviation signal is used to execute the thickness control means, it is possible to stably secure sufficient thickness accuracy, eliminate operator determination errors and operation delays, and reduce operator labor. , Quality and productivity can be improved.

[Brief description of the drawings]

FIG. 1 is a circuit diagram of a board thickness deviation signal correction circuit showing an embodiment of the present invention.

FIGS. 2 (I) to (VII) are graphs showing a thickness deviation signal and a processed signal thereof.

FIG. 3 is a block diagram showing a conventional example of an automatic thickness control device for a rolling mill.

4A is a graph showing a true thickness deviation signal, and FIG. 4B is a graph showing a thickness deviation signal at the time of a temperature drift.

[Explanation of symbols]

 DESCRIPTION OF SYMBOLS 1 Roller 4 Thickness gauge 5 Thickness gauge 8 Thickness control means (reduction AGC) S1 Thickness deviation signal S2 High frequency component signal S3 One low frequency component signal S4 Thickness deviation signal S5 The other low frequency component Signal S6 Correction signal M Rolled material

Claims (1)

(57) [Claims] An automatic thickness control method for a rolling mill for controlling a thickness based on a deviation signal of two or more thickness gauges having different responsibilities provided on one side of a rolling mill. Among them, the temperature drift of the responsive thickness gauge is detected and its allowable value is determined, and when the temperature drift is within the allowable value, the control means is executed by a thickness deviation signal of the responsive thickness gauge, When the temperature drift exceeds the allowable value, a signal from which the low frequency component of the thickness deviation signal of the good response thickness gauge is removed and a signal from which the high frequency component of the thickness deviation signal of the other thickness gauge is removed. And controlling the sheet thickness with a correction signal obtained by adding the above.