JPH03155403A - Method for controlling shape of rolled material by multiple rolling mill - Google Patents

Abstract

PURPOSE:To securely control a high-precision shape by evaluating a plate shape and a plate thickness on the outlet side regarding a specified synthetic evaluation function, requiring a manipulated variable of each actuator to minimize this synthetic evaluation function value and controlling each actuator simultaneously based on this manipulated variable. CONSTITUTION:The shape and thickness of the plate on the outlet side are evaluated synthetically by the synthetic evaluation function, the manipulated variable of each actuator 11 - 13 minimizing the value of this synthetic evaluation function is always required, each actuator 11 - 13 is controlled simultaneously based on the manipulated variable obtained to control the plate shape of the rolled material 1, therefore, the shape of the rolled material need not be identified and, besides, when the actuator 12 for controlling the plate shape is manipulated, the change of the rolling down position of the roll which is made by estimating the change of the plate thickness is prevented from causing a vicious circle such as generation of another change of shape and drastically precision shape can be controlled securely.

Description

[Detailed Description of the Invention] [Industrial Application Field] The present invention relates to a rolling method using a multi-high rolling mill for automatic plate thickness control and automatic plate shape control in thin plate rolling using, for example, a 12-high or 20-high rolling mill. This invention relates to a material shape control method.

[Prior art] In recent years, in rolling thin plates of copper alloys, etc., in order to meet the demand for product thickness accuracy, not only automatic plate thickness control is performed in multi-high rolling mills, but also high precision is applied to the plate shape. As a result, automatic shape control methods have been developed.

For example, in a rolling mill where the thickness of a plate is controlled by the roll reduction position, and the shape is controlled by the push amount of a backup roll or the shift amount of a tapered roll, conventionally, the plate shape in the width direction is controlled based on a signal from a plate shape detector. (elongation of rolled material in the rolling direction) is approximated by a quartic equation, the coefficients of each term are divided into target components and non-target components, shape identification is performed, and plate shape control is performed by operating the plate shape control actuator. (Unexamined Japanese Patent Publication No. 54-151066,
5-19401, Japanese Patent Application Laid-Open No. 55-42144), the plate thickness is calculated by predicting the plate thickness change caused by changing the actuator operation amount for plate shape control and correcting the roll rolling position using a predetermined calculation formula. Efforts have also been made to prevent changes (Japanese Unexamined Patent Publication No. 60-3908,
JP-A-60-3909).

[Problems to be Solved by the Invention] However, in a multi-high rolling mill, since the work rolls have a small diameter, complex composite elongations such as ear wave and medium elongation occur in the plate shape. Therefore, in a multi-high rolling mill, if the shape of the rolled material is approximated and controlled using the above-mentioned quartic equation, sufficiently good shape control cannot be achieved.

Also, when operating the plate shape control actuator,
Even if the roll rolling position is changed in anticipation of changes in the plate thickness, a vicious cycle occurs in which the shape also changes as the roll rolling position changes, resulting in a problem that highly accurate control cannot be performed.

Furthermore, when the shape is severely defective, such as at the beginning of rolling, the signal level output from the shape control device to the shape control actuator increases, and some actuators may not be able to follow the target signal due to constraints due to response characteristics. As a result, there is also the problem that the speed of shape improvement becomes slow.

The present invention aims to solve the above-mentioned problems, and it is an object of the present invention to provide a method for controlling the shape of a rolled material using a multi-high rolling mill, which allows highly accurate shape control to be performed reliably and with good responsiveness. With the goal.

[Means for Solving the Problems] In order to achieve the above object, there is provided a method for controlling the shape of a rolled material using a multi-high rolling mill according to the present invention.

A plate shape detector that detects the elongation of the rolled material in the rolling direction as the exit plate shape; a plate shape control actuator that controls the plate shape of the rolled material; and a plate thickness control actuator that controls the thickness of the rolled material. and a plate shape control device that controls the plate shape control actuator based on the detection result by the plate shape detector, and a plate thickness control device that controls the plate thickness control actuator, and controls these. The device controls the plate shape and plate thickness of the rolled material while correcting the operation amount from the plate thickness control device in consideration of changes in plate thickness caused by changes in the operation amount of the plate shape control actuator. hand.

■ [difference between the plate shape on the exit side of the multi-high rolling mill from the plate shape detector and a preset target plate shape], and [the amount of plate thickness change in response to the change in the operation amount of each of the actuators,
A comprehensive evaluation function for evaluating the outlet side plate shape and plate thickness of the rolled material is defined in advance using the difference between the preset target plate thickness change amount and the change in operation amount of each of the above actuators.
■During the plate shape control of the rolled material, the plate shape of the rolled material is constantly detected by the plate shape detector, and ■Based on the detection results from the plate shape detector, the above comprehensive evaluation function is determined. 1. Calculate the operation amount of each of the above actuators that minimizes the value of . ② Control the above-mentioned plate shape control actuator based on the operation amount calculated by the above-mentioned plate shape control device, and control the above-mentioned plate thickness control actuator. , the control is performed based on the sum of the operation amount from the plate thickness control device and the operation amount from the plate shape control device.

Further, in the method for controlling the shape of a rolling material in a multi-high rolling mill of the present invention according to claim 3, in item and the movement limit of each of the above actuators determined from the upper limit of movement speed, to calculate the operation amount of the plate shape control actuator and the plate thickness control actuator that minimizes the value of the comprehensive evaluation function. It is said that

Furthermore, the method for controlling the shape of rolled material using a multi-stage rolling mill according to claims 2 and 4 of the present invention includes item (1) of claim 1 and 3, respectively.
[difference between the plate shape on the exit side of the multi-high rolling mill detected by the plate shape detector and a preset target plate shape]
is characterized in that the error shape is determined as a weighted sum of the differences between the current error shape and the error shape one point before the current time.

[Function] In the method for controlling the shape of rolled material using a multi-stage rolling mill according to claim 1 described above, the shape of the outlet side plate in the width direction of the plate is detected by the plate shape detector, and the shape of the outlet side plate and the plate thickness are used for the overall evaluation. Comprehensive evaluation using functions.

In other words, the operation amount of the plate shape control actuator and plate thickness control actuator that minimizes the value of this comprehensive evaluation function is constantly determined, and based on the obtained operation amount, each actuator controls the plate shape of the rolled material. controlled at the same time. Therefore, it is no longer necessary to identify the shape of the rolled material as in the past, and when the plate shape control actuator is operated, changes in roll rolling position made in anticipation of a change in plate thickness will lead to further changes in shape, a vicious cycle. does not occur either.

Furthermore, in the method for controlling the shape of rolled material using a multi-high rolling mill according to claim 3, when calculating the operation amount of the actuators, the movement limit of each actuator determined from the current position and the upper limit of the movement speed of each actuator is also taken into consideration. It is possible to prevent actuators from being unable to follow the target signal due to constraints due to response characteristics.

Furthermore, in the methods of claims 1 and 3 described above, the difference between the plate shape on the exit side of the multi-high rolling mill and the target plate shape is the difference between the current error shape and the error shape one point before the current time with respect to the error shape. (Claim 2,
4).

[Embodiments of the Invention] Hereinafter, a method for controlling the shape of a rolling material using a multi-stage rolling mill as an embodiment of the present invention will be explained with reference to the drawings. Fig. 1 is an overall configuration diagram showing an apparatus to which the method of the present invention is applied. , FIG. 2 is a front view of a multi-high rolling mill to which the method of the present invention is applied.6 This embodiment shows a case where the method of the present invention is applied to a 20-high rolling mill.

In FIGS. 1 and 2, 1 is a rolled material that is a thin plate, 2 is a pair of upper and lower work rolls that contact the rolled material 1, 3 is a first intermediate roll that is a tapered roll installed behind the work roll 2, and 4 is the second intermediate roll installed behind the first intermediate roll 3.
The intermediate roll 5 is a backup roll installed further behind the second intermediate roll 4, and these rolls 2 to 5 constitute a 20-high rolling mill.

Further, numeral 6 denotes a plate shape detector located at a downstream position slightly ahead of the 20-high rolling mill to detect the elongation (plate shape) of the rolled material 1 in the rolling direction. In the embodiment, it is configured by arranging n shape sensor elements.

7 and 8 are plate thickness gauges that are placed at appropriate positions on the upstream and downstream sides of the 20-high rolling mill, respectively, to detect the inlet thickness and outlet thickness of the rolled material 1; 9 is the detection by the plate thickness gauges 7 and 8; A plate thickness control device outputs the operation amount as a control signal e to an appropriate number of roll reduction position moving means (actuators for plate thickness control) 11 based on the results and controls the plate thickness control device; This is a plate shape control device that outputs an operation amount to the backup roll pushing means 12 and Taber roll moving means 13 (both actuators for plate shape control) to control them.

In this embodiment, with the apparatus having such a configuration, control of the plate shape of the rolled material 1 by the method of the present invention is performed as follows.

First, the plate thickness control device 9 performs normal feedforward type plate thickness control and feedback type plate thickness control based on detection signals a and b from the plate thickness gauges 7 and 8 and a preset target exit side plate thickness signal C. The operation amount is calculated by thickness control and the control signal e
Output. This control signal e is generated by changing the operation amount of the backup roll pushing means 12 and the Taber roll moving means 13 by adding the control signal d which is the operation amount calculated by the plate shape control device 10 described later. Corrections will be made taking into account changes in plate thickness. After such correction, the control signal is output to the roll reduction position moving means 11, the roll reduction position in the 20-high rolling mill is operated by the instructed operation amount, and the thickness of the rolled material l is controlled. .

On the other hand, the plate shape control device 10 controls the amount of operation of the backup roll pushing means 12 (i.e., increases the amount of pushing of the backup roll 5) based on the detection signal f from the plate shape detector 6 and the preset target plate shape signal g. Quantity) ΔX
Δx4, the operation amount of the Taber roll moving means 13 (that is, the amount of movement of the pair of upper and lower Taber rolls 3, 3) Δxs,
? lΔX, and are output as control signals i, d, respectively. Then, the backup roll pushing means 12 and the tapered roll moving means 13 respectively operate the positions of the backup roll 5 and the tapered rolls 3, 3 by the amount of operation instructed according to the control signal i, and Shape is controlled.

By the way, one characteristic part of the present invention is the plate shape control bag W1.
10 is a calculating means for operating amounts Δx2 to ΔX. The calculation means will be explained in detail below.

That is, the plate shape control device 10 has a comprehensive evaluation function J that evaluates the outlet side plate shape and plate thickness of the rolled material 1 using the following equation (4).
are defined and set in advance.

This comprehensive evaluation function J is the difference between the output side plate shape from the plate shape detector 6 and a preset target plate shape.

and the plate thickness change amount for each actuator 11 to 13 in response to a change in the operation amount and the preset value for each actuator 11.
It is defined using the difference from the target plate thickness change amount when changing the operation amount of .about.13.

Here, the difference between the exit side plate shape and the target plate shape is calculated using the following formula (1).
Error shape a1(k), e 1(k) = f 1'(k) − f 1°(k)
Regarding (i= 1-n) - (1), as shown in the equation (2) below, the difference between the current error shape e 1 (k) and the error shape one point before the current time a1 (k) - at (k-1
) is calculated as the weighted sum of

it(k)=Kx・e t(k)+Kp・[e
t(k) −e x(k-1)) (m=1~n)
(2) Also, the difference between the amount of plate thickness change in response to a change in the operation amount of each actuator 11 to 13 and the preset target plate thickness change amount when changing the operation amount of each actuator 11 to 13 is calculated by the following formula. It is determined by (3).

i m+t(k)=f s+t@(k) −f s+
t''(k)...(3) And the comprehensive evaluation function J
is as shown in equation (4) below.

However, flo (k) (i = 1 to n) is the plate elongation value measured at the time by the i-th shape sensor element constituting the plate shape detector 6, and flo (k) (i = 1 to n) is The target plate elongation value f , , L' (k) at time k for the i-th shape sensor element is
Amount of change in plate thickness with respect to change in operation amount of ~13.

f att” (k) is the target plate thickness change amount when changing the operation amount of each actuator 11 to 13, wl (i=1”n+1)
is the weighting coefficient for the deviation ε1(k), and KIpKP is the difference between the current error shape al(k) and the error shape one point before the current time e z(k)−a t(
k-1).

In addition to introducing such an evaluation function J, an influence coefficient equation of the plate shape and plate thickness of the rolled material 1 due to changes in the operation amount of each actuator 11 to 13 is created as shown in equation (5) below.

However, Δxj(k) (j = 1 to m; in this example, m = 8) is calculated based on each actuator 11 to
13, the amount of change in the manipulated variable, Δf 1(k') (i =
1 to n) represent the operation amount of each actuator 11 to 13 by Δx
The shape change amount, Δfn@, is the amount of shape change detected by the i-th shape sensor element when the part is changed by j(k) (j: 1 to m), and Δfn@ is the amount of shape change detected by the i-th shape sensor element when the corresponding part is changed by Δxj(j= 1 to m), the plate thickness change amount detected by the plate thickness gauge 8 in the relevant part, αj1 (j = 1 to m
, i=1 to n+1) is an influence coefficient of Δxj(k) on Δfx(k').

Then, in equations (2) to (4), flo(k) −f l”(k) =Δft(k)(i
=1~n◆1) ...(6) is substituted, and the board shape detector 6 detects the board shape every moment during the board shape control so that the overall evaluation function J of the board thickness and board shape becomes the minimum every moment. The plate shape detection value f1° (k
Based on L fi'(k-1) (i=l~n), each manipulated variable change amount Δxj(k)(j
= 1 to m), and each actuator 11 to 13
operate.

Now, the deviation signal ti(k) (i=1 to n+1) is expressed as it
(k)=Kr ei(k)+Kp(ex(k)−ex
(k-1)) elck> = f 1″(k) −f
t"(k)el(k-1)=f1°(k-1)-ft"
(k-1) −(7) (i=1~n) ε. When Y(k)=0 and each actuator 11 to 13 is moved by Δx j(k), the following is obtained as the comprehensive evaluation function J. In other words.

Δx(k)=(ATW'A)-'ATV"E(k)...
・(11) It is expressed as i 1 j 1. In order to minimize this comprehensive evaluation function J, it must be, that is, (III) From equation (9), (s-1 to m), and this (
By solving Equation 10) for Δx J(k), the amount of change in the operation amount of each actuator 11 to 13 for minimizing the comprehensive evaluation function J regarding the plate thickness and plate shape can be obtained. However, in the above formula, It T #+ indicates the transposition of the matrix.

By the way, according to the above-mentioned algorithm, when the shape is extremely defective, such as at the initial stage of rolling.

Actuators 11 to 13 whose control target signal level becomes excessive and cannot follow the target signal due to constraints due to response characteristics.
It also comes out. Therefore, in this example, the following steps
By implementing step (2) in the plate shape control device 10, the occurrence of the actuators 11 to 13 not being able to follow the target signal is prevented.

(2) Calculate the movable speed of each actuator 11 to 13 based on a function defined in advance according to rolling conditions (rolling speed, rolling load).

- Calculate the movable limit value, which is constrained by the position limit, from the current position of each of the seven cutter units.

■Each actuator 11 to 13 determined from the movable speed
The movable limit value per control period is calculated.

■Set the smaller of the movable limit values obtained in steps (■) and (2) as the final movable limit value.

(Based on the error shape between the detected shape from the Φ plate shape detector 6 and the target shape, the movement amount target value of each actuator 11 to 13 that minimizes the comprehensive evaluation function J is calculated as described above.

■If there is an actuator for which the target value calculated in the previous step ■ exceeds the movable limit value determined in step Calculate the amount of shape change when moving to the movable limit value, subtract it from the current error shape, exclude the actuator from the usable actuators, and move the remaining actuators to minimize the overall evaluation function J in step ① again. Find the target value and check the movement limit. This process is repeated until there are no more actuators subject to the movement limit restrictions or until all actuators 11 to 13 are no longer usable actuators.

■Multiply the control gain to obtain the final value for each actuator 11
In this embodiment, the operation amount of each actuator 11 to 13 obtained in this way is calculated based on Δxj(k) (j = 1 to 8), and the roll reduction described above is calculated. Position moving means 11. The plate shape of the rolled material 1 is controlled by the backup roll pushing means 12 and the tapered roll moving means 13.

Next, FIGS. 3 and 4 show experimental results obtained by applying the method of the present invention to shape control of actual rolled materials.

Here, plate 1 [630 mm, plate thickness 205 μm] is made of copper alloy.
The experiment was conducted under the conditions of rolled material. Figure 3 shows the plate thickness deviation when the control by this method is turned off and when it is turned on, and Figures 4 (a) and (b) respectively show the rolling thickness deviation when the control by this method is turned off. The elongation of the material in the rolling direction and o
When nL indicates the elongation of the rolled material in the rolling direction. In FIGS. 4(a) and (b), the unit of the vertical axis is II-
unit indicates that the elongation in the rolling direction of a rolled material with a length of 1 m is 104 m longer than the reference value.

As shown in FIGS. 4(a) and 4(b), the plate shape is significantly improved before and after the switching timing of shape control on and off according to the present invention, and at the same time, as shown in FIG. It can be seen that the plate thickness accuracy hardly changes (does not deteriorate) before and after the on/off switching timing.

As described above, according to the pressing material shape control method of this embodiment,
The exit side plate shape and plate thickness are comprehensively evaluated using a comprehensive evaluation function J, and the amount of operation of each actuator 11 to 13 that minimizes the value of this comprehensive evaluation function J is constantly determined, and the obtained operation is Since each of the seven cutting units 11 to 13 is controlled simultaneously to control the plate shape of the rolled material 1 based on the amount, there is no need to identify the shape of the rolled material as in the past, and there is no need to identify the shape of the rolled material as in the past. The roll reduction position is changed by predicting the change in plate thickness when the actuator is operated.
This eliminates the occurrence of a vicious cycle that leads to further shape changes, making it possible to reliably perform highly accurate shape control.

Further, according to the present embodiment, when the above-mentioned steps ■ to ■ are executed and the operation amount of the actuators 11 to 13 is calculated, the movement of each actuator 11 to 13 determined from the current position and the upper limit of the movement speed of each actuator 11 to 13 is performed. By taking the limits into account, the signal level sent from the plate shape control device 1o to each actuator 11 to 13 increases, especially when the shape is extremely defective such as at the beginning of rolling, and it follows the target signal due to constraints due to response characteristics. It is possible to prevent the occurrence of actuators that cannot be used, and it is possible to improve the responsiveness of plate shape control.

In addition, although the said Example demonstrated the case where the method of this invention was applied to a 20-high rolling mill, the method of this invention is not limited to this.

Further, in the above embodiment, as shown in equation (2).

Et(k) was given as the weighted sum of the difference between the current error shape and the error shape one point before the current time, but as shown in the equation (13) below, the weight of the current and past error shapes is May be replaced with the total value.

t 1(k)=: Kl,・e 1(k)+to 1・e
1(k-1) ten, ・e 1(k-2)+...
(i = 1 to n) ... (13) Effect of invention C] As detailed above, according to the method for controlling the shape of rolled material using a multi-high rolling mill of the present invention, the shape and thickness of the outlet side board can be controlled. Evaluation is performed using a predetermined comprehensive evaluation function, the amount of operation for each actuator that minimizes the value of this overall evaluation function is determined, and each actuator is simultaneously controlled based on the obtained amount of operation, ensuring highly accurate shape control. There is an effect that can be done.

In addition, by taking into consideration the movement limit determined from the current position and upper limit of movement speed of each actuator when calculating the operation amount of each actuator, it is possible to prevent some actuators from being unable to follow the target signal due to constraints due to response characteristics. It also has the effect of improving the responsiveness of plate shape control.

[Brief explanation of the drawing]

1 to 4 show a method for controlling the shape of rolled material using a multi-stage rolling mill as an embodiment of the present invention. The figure is a front view of a multi-high rolling mill to which the method of the present invention is applied, and FIGS. 3 and 4 (a) and (b) are graphs for explaining the operation of the above embodiment. In the figure, 1-rolled material, 2-work roll. 3-first intermediate roll, 4-second intermediate roll, 5-backup roll, 6-plate shape detector, 7, 8-plate thickness gauge, 9
- Plate thickness control device, 10- Plate shape control device, 11- Roll reduction position moving means (plate thickness control actuator), 12
- Backup roll pushing means (actuator for plate shape control), 13 - Taper roll moving means (actuator for plate shape control).

Claims (4)

[Claims] (1) A plate shape detector that detects the elongation in the rolling direction of the rolled material on the exit side of the multi-high rolling mill as a plate shape, an actuator for controlling plate shape that controls the plate shape of the rolled material, and a plate thickness of the rolled material. a plate shape control device that outputs and controls an operation amount to the plate shape control actuator based on the detection result of the plate shape detector; and the plate thickness control actuator. The plate thickness control device is equipped with a plate thickness control device that outputs and controls the operation amount to the plate shape control device, and these plate shape control devices and plate thickness control devices take into account plate thickness changes caused by changing the operation amount of the plate shape control actuator. A method for controlling the shape of a rolled material using a multi-stage rolling mill, which controls the shape and thickness of the rolled material while correcting the operation amount from the sheet thickness control device, the method comprising: The difference between the plate shape on the exit side of the multi-high rolling mill and the preset target plate shape, the amount of plate thickness change in response to the change in the operation amount of each of the above actuators, and the change in the preset operation amount of each actuator. A comprehensive evaluation function is defined and set in advance to evaluate the outlet side plate shape and plate thickness of the rolled material using the difference from the target plate thickness change amount, and during the plate shape control of the rolled material, the plate shape detection is performed. The plate shape control actuator and the plate thickness control actuator constantly detect the plate shape of the rolled material using a detector, and minimize the value of the comprehensive evaluation function based on the detection result from the plate shape detector. The plate shape control actuator is controlled based on the operation amount calculated by the plate shape control device, and the plate thickness control actuator is controlled based on the operation amount from the plate thickness control device. A method for controlling the shape of a rolled material using a multi-high rolling mill, characterized in that the control is performed based on the manipulated variable obtained by adding the manipulated variable calculated by the plate shape control device to the above-mentioned sheet shape control device. (2) The difference between the plate shape on the outlet side of the multi-high rolling mill detected by the plate shape detector and the preset target plate shape is the difference between the current error shape and the error one point before the current time. 2. A method for controlling the shape of a rolled material using a multi-high rolling mill according to claim 1, wherein the method is determined as a weighted sum of a difference in shape. (3) a plate shape detector that detects the elongation of the rolled material in the rolling direction on the outlet side of the multi-high rolling mill as a plate shape; a plate shape control actuator that controls the plate shape of the rolled material; and a plate thickness of the rolled material. a plate shape control device that outputs and controls an operation amount to the plate shape control actuator based on the detection result of the plate shape detector; and the plate thickness control actuator. The plate thickness control device is equipped with a plate thickness control device that outputs and controls the operation amount to the plate shape control device, and these plate shape control devices and plate thickness control devices take into account plate thickness changes caused by changing the operation amount of the plate shape control actuator. A method for controlling the shape of a rolled material using a multi-stage rolling mill, which controls the shape and thickness of the rolled material while correcting the operation amount from the sheet thickness control device, the method comprising: The difference between the plate shape on the exit side of the multi-high rolling mill and the preset target plate shape, the amount of plate thickness change in response to the change in the operation amount of each of the above-mentioned actuators, and the change in the preset operation amount of each of the above-mentioned actuators. A comprehensive evaluation function is defined in advance to evaluate the outlet side plate shape and plate thickness of the above-mentioned rolled material using the difference between the target plate thickness change amount and the target plate thickness change amount.
During the control of the plate shape of the rolled material, the plate shape of the rolled material is constantly detected by the plate shape detector, and the detection results from the plate shape detector and the current position and position of each of the actuators are Based on the movement limit of each actuator described above determined from the upper limit of movement speed, the operation amount of the plate shape control actuator and plate thickness control actuator that minimizes the value of the comprehensive evaluation function is calculated, and the plate shape is calculated. The control actuator is controlled based on the operation amount calculated by the plate shape control device, and the plate thickness control actuator is controlled based on the operation amount from the plate thickness control device. A method for controlling the shape of a rolled material using a multi-high rolling mill, characterized in that the control is performed based on the operation amount obtained by adding up the operation amount. (4) The difference between the plate shape on the output side of the multi-high rolling mill detected by the plate shape detector and the preset target plate shape is the difference between the current error shape and the error one point before the current time. 4. The method for controlling the shape of a rolled material using a multi-high rolling mill according to claim 3, wherein the shape is determined as a weighted sum of the shape difference.