JPH10180332A - Shape control method in plate rolling - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a versatile shape control method for plate rolling capable of simultaneously and optimally controlling all shape control mechanisms and moreover easily setting the manipulated variable of a controller difficult to reach an operational limit with a specified control mechanism. SOLUTION: In this control method, shapes of plural places in the width direction of the rolling plate are detected with a shape detector, respective manipulated variables of plural shape control mechanisms are obtained based on the output by the shape detector, respective shape control mechanisms are operated to control the shape of the plate based on the manipulated variable. In this case, a shape deviation of obtained from the difference between the output distribution by the shape detector 7 and a pre-set objective shape distribution with a shape separating device 10, and the shape deviation is separated into plural numbers based on the frequency component. And the manipulated variables of respective shape control mechanisms 13, 14 are obtained based on respective separated shape deviations with optimum manipulated variable arithmetic units 11, 12.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a method for controlling the shape of a sheet in sheet rolling, and more particularly to an automatic shape control method based on the output of a shape detector of a rolling equipment having a plurality of shape control mechanisms.

[0002]

2. Description of the Related Art Conventionally, as automatic control of a sheet shape in sheet rolling, there is known a feedback control method in which arithmetic processing is performed based on an output from a shape detector arranged on the exit side of a rolling mill to operate a shape control mechanism. Have been. In recent years, the requirements for the sheet rolling shape have become more stringent, and a rolling mill having a plurality of shape control mechanisms has been developed, and an automatic shape control arithmetic processing logic for operating the plurality of shape control mechanisms has been proposed.

[0003] The above-mentioned shape control arithmetic processing logic includes, for example, approximating an output of a shape detector to a fourth-order power series or a fourth-order orthogonal function, and calculating a coefficient of the approximate expression or a shape calculated from the coefficient. The logic for calculating the optimal operation amount of the control device having the same number as the number of the evaluation variables by using the evaluation variables is disclosed in, for example, JP-A-54-150066, and
No. 19401, JP-A-55-42144, and the like.

[0004] However, the above control method has the following problems. Problem (1): Unless the number n of control means that can be controlled simultaneously is equal to or less than the number m of shape variables to be controlled, an optimal solution of the operation amount of the control means cannot be obtained. Therefore, in order to solve the above problem, all the control means of the rolling mill can be simultaneously operated effectively without being limited by the number m of control variables and the number n of control means, and a certain shape control device is required. Even if the operating limit is reached, a general-purpose sheet shape control method for sheet rolling capable of calculating the operation amount of the control means using a common optimum operation amount calculation formula is disclosed in Japanese Patent Application Laid-Open No. 6-523. It was proposed by the official gazette.

[0005]

However, a conventional plate shape control method for solving the above problem (1) (Japanese Patent Laid-Open No.
-523) also has the following problems. Problem (2): In many cases, there is a large difference in the dynamic characteristics of the individual shape control devices. A control device having a fast response responds to a sharp shape change, and another control device responds to a slow shape change. It is desirable to correspond. However, Japanese Unexamined Patent Publication No.
In the plate shape control method proposed in Japanese Patent Application Publication No. 523, no consideration is given to the dynamic characteristics, so that a low-response control means responds to a steep shape change, and a high-speed control is hindered. Occurs. That is, the optimum operation including the response of the control means cannot be performed. Problem (3): In order to prevent a specific control device from easily reaching the operation limit, complicated arithmetic processing is required, and esoteric adjustment is required for setting various parameters, which is a problem in practicality. Remains.

SUMMARY OF THE INVENTION The present invention has been made to solve the above-mentioned problems, and it is possible to optimally control all the shape control mechanisms at the same time, and it is difficult for a specific control mechanism to reach the operation limit. It is an object of the present invention to provide a general-purpose sheet rolling shape control method capable of easily setting a control device operation amount.

[0007]

[Means for Solving the Problems]

(1) A sheet shape control method in sheet rolling according to the present invention (claim 1) includes detecting a shape at a plurality of positions in a rolled sheet width direction by a shape detector, and detecting a plurality of shapes based on an output of the shape detector. In the shape control method in sheet rolling in which each operation amount of the control mechanism is obtained and the shape of the plate is controlled by operating each shape control mechanism based on the operation amount, an output distribution of the shape detector and a preset target A shape deviation is obtained from a difference from the shape distribution, the shape deviation is separated into a plurality of components by its frequency component, and an operation amount of each shape control mechanism is obtained based on the separated individual shape deviation. (2) The sheet shape control method in the sheet rolling according to the present invention (Claim 2) is the sheet shape control method according to the above (1), wherein the output distribution of the shape detector and the target shape distribution are each set to the position X in the sheet width direction. The shape deviation is obtained by subtracting the target shape distribution from the output distribution of the shape detector. (3) The plate shape control method in the plate rolling according to the present invention (claim 3) is the plate shape control method according to the above (2), wherein the intermediate roll bender and the work roll bender are a first group of shape control mechanisms; The backup roll crown adjustment mechanism is a second group of shape adjustment mechanisms, and the manipulated variable of the first group of shape control mechanisms is obtained based on the signal extracted by performing high-pass filtering on the shape deviation, and the extracted An operation amount of the second group of shape control mechanisms is obtained based on the remaining signal obtained by subtracting the signal from the shape deviation.

In the present invention, a shape deviation is obtained from a difference between an output distribution of a shape detector and a preset target shape distribution, and the shape deviation is separated according to the frequency characteristics of each shape control mechanism. Can be operated optimally and simultaneously effectively, and the probability that a specific control mechanism reaches the operation limit can be reduced.

[0009]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS FIG. 1 is a block diagram showing a configuration of a control device to which a shape control method in sheet rolling according to an embodiment of the present invention is applied and its related equipment. In the figure, reference numeral 1 denotes a rolling mill. In this example, a 12-high cluster rolling mill has a structure in which a pair of upper and lower work rolls 3, an intermediate roll 4, a backup roll 5, and a small-diameter backup roll 6 are arranged in a cluster. It is. Reference numeral 2 denotes a rolled plate, and 7 denotes a shape detector for detecting the shape of the rolled plate 2 at a plurality of positions in the width direction. Physical quantities detected by the shape detector 7 include, for example, tension and strain. Reference numeral 8 denotes a functioning operation device that performs an operation for converting the output distribution of the shape detector 7 into a function. Reference numeral 9 denotes a target shape setting circuit that sets a target shape distribution of the rolled plate 2. Reference numeral 10 denotes a shape separation device. Device (1). The calculation result by the optimum operation amount calculation device 11 is supplied as an operation command signal to a roll bending mechanism 13 which is a shape control mechanism. Also, 1
Reference numeral 2 denotes an optimum operation amount calculation device (2). The calculation result by the optimum operation amount calculation device 12 is supplied as an operation command signal to a backup roll crown adjustment mechanism 14 which is a shape control mechanism. The roll bending mechanism 13 and the backup roll adjusting mechanism 14 are provided with the optimum operation amount calculating device 1.
The rolling mill 1 is individually controlled based on the operation command signals supplied from 1 and 12, respectively.

FIG. 2 is a diagram showing a roll portion and a shape control mechanism of a rolling mill. In the figure, reference numerals 2 to 5 are the same as those shown in FIG. 15, 16, and 17 are backup roll crown adjustment mechanisms (a) and (b), respectively.
(C), which correspond to the backup roll crown adjusting mechanism 14 in FIG. Reference numeral 18 denotes an intermediate roll bender and reference numeral 19 denotes a work roll bender, which correspond to the roll bending mechanism 13 in FIG. FIG.
, The backup roll 5 is divided into seven,
With respect to the fixed center portion, the other split rolls have a structure that can be independently eccentric in the direction of the intermediate roll, so that any crown pattern can be set,
As symmetrical shape control means, there are a total of five intermediate roll benders 18, work roll benders 19, and backup roll crown adjusting mechanisms (a), (b), (c) 15 to 17.

The characteristics of the five shape control means shown in FIG. 2 can be roughly classified into an intermediate roll bender 18 and a work roll bender 19 (hereinafter, referred to as a first group) capable of high-speed response. Are low-speed backup roll crown adjustment mechanisms (a), (b), (c) (hereinafter, referred to as a second group) 15 to 17. Since the first group of control means is driven by hydraulic pressure, high-speed operation is possible, but the operation range is relatively limited. Further, since the second group of control means is driven by an electric motor, the operation is slower than that of the first group, but the operation range is wide and the shape correction capability is large. If they are used at the same time without considering their characteristics, the following problems occur.

For example, it is assumed that, when a low-frequency shape deviation occurs, the first group of control means is used and the operation limit is reached. At this time, if a high-frequency shape deviation that cannot be dealt with by the second group of control means further occurs, naturally, most or all of the shape deviation remains. In the case of the present embodiment, if the low-frequency shape deviation generated first is dealt with by the second group of control means, the first group of control is performed also on the next high-frequency shape deviation. Correction is possible by means. Generally, the control means corresponding to the second group has a wide operation range as described above, and except for special cases, the probability of reaching the operation limit is extremely low. The operation range is limited and often reaches the operation limit. Also, as a rolling phenomenon, a large shape deviation rarely occurs at a high frequency, and the shape deviation generated at a high frequency is often very small. As described above, the characteristics of the first group of control means and the characteristics of the second group of control means are significantly different, and it is desirable to select according to the shape deviation characteristics. In this embodiment, it is assumed that the responsiveness of the first group of control means is, for example, 10 to 500 times faster than the responsiveness of the second group of control means.

For this reason, in the shape separating device 10 of the present invention, a shape deviation is obtained by subtracting the output of the target shape setting device 9 from the output of the shape functioning operation device 8, and the shape deviation is calculated. By paying attention to the frequency characteristics, only the shape deviation amount that can be dealt with only by the second group of control means is subjected to high-pass filtering by the filter 30 of the processing circuit shown in FIG. Output to the arithmetic unit 11. On the other hand, the amount output to the optimal manipulated variable computing device 11 is subtracted from the total shape deviation amount, and the remaining amount is output to the optimal manipulated variable computing device 12. In the present embodiment, as the high-pass filtering process, a process of obtaining a high-frequency component by subtracting the low-frequency component extracted by the filter 30 from the entire shape deviation is performed. The optimal manipulated variable computing device 1 which has input the respective shape deviation amounts separated by the shape separating device 10 in this way.
1 and 12 calculate the operation amounts of the respective control means, and give operation commands to the respective control means of the roll bending mechanism 13 and the backup roll crown adjusting mechanism 14.

The processing contents of the shape-function-forming calculator 8, the target shape setting device 9, and the optimum manipulated variable calculators 11 and 12 are disclosed in JP-A-6-523 cited as a prior art. The outline is as follows.

The shape functioning operation device 8 expresses the output distribution of the shape detector 7 as a function of the position X in the plate width direction, and the target shape setting device 9 converts the target shape distribution to the position in the plate width direction. Expressed as a function. In the optimum manipulated variable computing devices 11 and 12, as described above, the shape deviation is output to the optimal manipulated variable computing device 11 from the signal extracted by performing the high-pass filtering process on the shape deviation or the total shape deviation thereof. When the residue is input, the following calculation processes (a) to (d) are performed based on the respective shape deviation amounts, so that the control of sheet rolling is limited to the number of shape variables and the number of shape control devices. And the need to add complex multiple control device selection functions and require complex gain setting logic to determine the control amount for each control step. An improvement in shape quality can be expected.

(A) A change in the output of the shape detector (expressed as a function of the position X in the plate width direction) with respect to a unit operation amount of a plurality of shape control mechanisms is subtracted from the shape deviation amount from the shape separating device 10. Then, the first evaluation function is created by integrating the square value of the subtraction value at the position x in the plate width direction. (B) The amount of operation for each control step of each of the plurality of shape control mechanisms includes a coefficient in consideration of the degree of shape change by each control mechanism and each weight coefficient set so that the sum of the respective weight coefficients becomes 1. A second evaluation function is created, which is obtained by multiplying each of them and expressed by the sum of squares of the manipulated variable with a coefficient. (C) setting a first weighting factor and a second weighting factor for determining an arbitrary ratio between the first evaluation function and the second evaluation function, respectively, and setting the first evaluation function, the first weighting factor, And a product obtained by multiplying the second evaluation function by the second weighting coefficient is created. And (d) calculating the operation amounts of the plurality of shape control mechanisms so as to minimize the shape evaluation function of the sum of products.

In this embodiment, an example in which the control means are classified into two groups has been described. However, the present invention can be applied to a case where the dynamic characteristics of the control means are classified into three or more types. Needless to say. For example, in the case of three types, as shown in FIG. 4, a cutoff frequency can be set for each group by two filters 30 and 31.
In this embodiment, only the shape deviation of the symmetric component in the plate width direction has been described, but the present invention can be applied to the shape deviation of the asymmetric component. When only one control unit is provided for each group, the optimal operation amount calculation device for the group is not required.

[0018]

As described above, according to the present invention, a shape deviation is obtained from a difference between an output distribution of a shape detector and a preset target shape distribution, and the shape deviation is separated into a plurality of parts by its frequency component. Based on the separated individual shape deviations, the amount of operation of each shape control mechanism is determined and controlled, so that all the shape control mechanisms can operate effectively at the same time, and the specific control mechanism is limited to the operation limit. An excellent effect that the probability of reaching is reduced is obtained. Further, by applying the shape control method according to the present invention to various rolling mills, it is expected that the shape quality of a product is further improved.

[Brief description of the drawings]

FIG. 1 is a configuration diagram showing a control device to which a plate shape control method is applied to an embodiment of the present invention and related equipment.

FIG. 2 is a diagram showing details of a roll section and a shape control mechanism of the rolling mill of FIG. 1;

FIG. 3 is a block diagram showing an example of a processing circuit built in the shape separation device of FIG.

FIG. 4 is a block diagram showing another example of a processing circuit built in the shape separation device of FIG. 1;

Claims (3)

[Claims] 1. A shape detector for detecting a shape at a plurality of positions in a width direction of a rolled sheet by a shape detector, obtaining respective operation amounts of a plurality of shape control mechanisms based on an output of the shape detector, and obtaining respective operation amounts based on the operation amounts. In a shape control method in strip rolling in which a shape control mechanism is operated to control a shape of a sheet, an output distribution of the shape detector and a shape deviation are obtained from a difference between a preset target shape distribution and the shape deviation. A sheet shape control method in sheet rolling, characterized in that the shape components are separated into a plurality of components by the frequency component, and an operation amount of each shape control mechanism is calculated and controlled based on each separated shape deviation. 2. An output distribution and a target shape distribution of the shape detector are respectively expressed as functions of a position x in a plate width direction, and the shape deviation is obtained by subtracting the target shape distribution from the output distribution of the shape detector. 2. The method according to claim 1, wherein the shape is controlled. 3. An intermediate roll bender and a work roll bender are a first group of shape control mechanisms, a plurality of backup roll crown adjustment mechanisms are a second group of shape adjustment mechanisms, and the shape deviation is extracted by high-pass filtering. Calculating an operation amount of the first group of shape control mechanisms based on the obtained signal, and obtaining an operation amount of the second group of shape control mechanisms based on a remaining signal obtained by subtracting the extracted signal from the shape deviation. 3. The method of controlling the shape of a sheet in sheet rolling according to claim 2, wherein