JPH07106376B2 - Strip shape control method for multi-stage cluster rolling mill - Google Patents

Description

TECHNICAL FIELD The present invention relates to a strip shape control method in a multi-stage cluster rolling mill.

[Prior Art] Since the multi-stage cluster rolling mill has a large shape correcting ability, if the preset error is large, it causes operating troubles such as defective plate shape and narrowing, and it is necessary to correct the preset error early.

[Problems to be Solved by the Invention] However, in the low speed region of the rolling mill, since it takes a plate transfer time until the plate shape change in the roll bite is detected by the shape detector, If the shape correction device is operated due to the deviation of the target plate shape, the plate shape in the roll bite and the detected plate shape will be different, so in the worst case, the operation will be performed in the opposite direction. It causes operational troubles. For this reason, the current situation is to reduce the gain and operate with low responsiveness.

Incidentally, the plate shape control method in the conventional multi-stage cluster rolling mill is, for example, as shown in JP-A-58-61907, a plate shape detected by a plate shape detector provided on the rolling mill outlet side and a given target. Only the correction amount of the roll crown of the split backup roll, the roll bending force of the work roll and the intermediate roll is calculated according to the plate shape and rolling conditions, and the influence of the transfer time is not taken into consideration.

The present invention is intended to address the above-mentioned problems, and is intended for a wide range of rolling conditions, realizes fast response from a low speed region, and obtains a good strip shape. It is an object to provide a shape control method.

[Means for Solving Problems] In the present invention, the shape of the material to be rolled detected by the shape detecting device is
In the plate shape control method of the multi-stage cluster rolling mill that operates a plurality of shape correction devices to match the target shape and corrects the shape of the material to be rolled, it was calculated based on the current detection signal from the shape detection device. A plurality of shape parameters and the portion of the material to be rolled currently at the position of the shape detection device, calculated based on the operation amount of the shape correction device when it was rolled by the roll of the rolling mill, each shape parameter And the shape parameter estimation value corresponding to each shape parameter calculated based on the current operation amount of the shape correction device is calculated as a value based on the difference. Each shape is added, and each shape correction device is operated so that the added value agrees with each shape target value.

[Operation] According to the present invention, the plurality of shape parameters calculated based on the detection signal from the current shape detection device and the portion of the material to be rolled at the position of the current shape detection device are the rolls of the rolling mill. Calculated based on the amount of operation of the shape correction device when it was rolled at, the difference with the shape parameter estimated value corresponding to each shape parameter is calculated respectively, and the current shape correction to the value based on the error A shape parameter estimated value corresponding to each shape parameter calculated based on the operation amount of the apparatus is added, and each shape correction apparatus is operated so that the added value matches each shape target value. Becomes

Therefore, it is possible to realize a fast responsiveness from a low speed region and obtain a good plate shape in accordance with a wide range of rolling conditions.

[Examples] In the detailed description of the present invention, the shape parameters shown in the invention of Japanese Patent Application No. 60-97980 previously proposed by the present applicant will be used.

First, the method of calculating the shape parameter will be described below. The plate shape is the elongation strain distribution β of the plate at the position X in the plate width direction.
Set each coefficient A _{0 to} A ₄ of the fourth-order orthogonal function corresponding to (x) to (1)
It is calculated by an expression and expressed using A _{0 to} A ₄ .

However, φ _{0 to} φ ₄ are fourth-order orthogonal functions, and are represented by equations (2) to (6), respectively.

φ ₀ (x) = a (2) φ ₁ (x) = bx (3) φ ₂ (x) = cx ² + d (4) φ ₃ (x) = ex ³ + fx (5) φ ₄ (x) = gx ⁴ + hx ² + k (6) Further, the coefficients a to k in the expressions (2) to (6) are obtained by the orthonormal condition of the expression (7).

The elongation strain distribution β (x) of the plate is expressed by the equation (8) using the coefficients A _{0 to} A ₄ of the orthogonal function obtained by the above method.

β (x) A ₀ φ ₀ + A ₁ φ ₁ + A ₂ φ ₂ + A ₃ φ ₃ + A ₄ φ
₄ (8) As can be seen from the equation (8), the coefficient A ₁ represents the magnitude of one-sided elongation and is defined as the first-order mode coefficient. The coefficient A ₂ represents the magnitude of medium elongation and edge elongation, and is defined as the secondary mode coefficient. The coefficient A ₃ represents the magnitude of asymmetric elongation and is defined as the third-order mode coefficient. The coefficient A ₄ represents the size of the middle end elongation and the quarter buckle and is defined as the fourth-order mode coefficient. The coefficient A ₀ has no physical meaning here.

Hereinafter, the present invention will be specifically described.

As described above, in the plate shape control, the shape may be disturbed rather than the control due to the temporal disagreement between the plate shape in the roll bite and the plate shape detected by the shape detector.

Therefore, in the present invention, the shape is represented by each coefficient A _{0 to} A ₄ of the orthogonal function by the equation (1) shown in the above-mentioned Japanese Patent Application No. 60-097980 proposed by the present applicant, and A ₁ , A ₂ , A ₄ are respectively subjected to the following operations by a reduction leveling device, an intermediate roll bending device, and a backup roll crown adjusting device so as to match the target values A ₁ ^* , A ₂ ^* , and A ₄ ^* .

Each operation amount u _{1 of} the reduction leveling device, the intermediate roll bending device and the backup roll crown adjusting device,
for u _2, u _4, deformation resistance, shape estimation model that can estimate the amount of change in plate shape in the roll bite portion of the rolled material conditions and rolling load, such as strip width, rolling conditions such as rolling speed
G ₁ , G ₂ , and G ₄ are obtained by a mathematical model or an experiment, and are expressed as a transfer function as shown in equation (9).

(Here Ki is the shape influence coefficient from each manipulated variable to the shape. Where Ti is a time constant representing the time delay until each shape parameter Ai is represented by the roll bite part from the operation end. ) In addition, the relationship between the material of the material to be rolled, the plate width, the plate thickness, the reduction ratio and the rolling load, and the relationship between the rolling load, the work roll crown amount, the backup roll crown amount, and the intermediate roll bending force are stored. Before the start of rolling, the optimum values of the crown amount of the backup roll and the intermediate roll bending force with respect to the target plate shape are calculated on the basis of the information on the material to be rolled and the above relationship, and each is preset.

FIG. 1 shows an example in which the plate shape control method for a multi-stage cluster rolling mill according to the present invention is applied to A ₂ control by an intermediate roll bending device. In addition, 1 is a rolled material, 2 is a work roll,
3 is an intermediate roll and 4 is a backup roll.

Reference numeral 5 denotes a shape detector that detects the shape of the rolled material 1 and an elongation rate distribution β at the sheet width direction position x (normalized to ± 1 at both ends).
(X) is output to the arithmetic unit 20. The shape calculation unit 21 of the calculation device 20 calculates the elongation rate distribution β (x) by the coefficients A _{0 to} A _{4 of the} orthogonal function.
Convert to.

Reference numeral 10 denotes an intermediate roll bending control device, which sets the intermediate roll bending force to an arbitrary value according to commands from the operation amount calculation unit 22 and the preset calculation unit 26. Although not shown, the backup roll crown is preset based on the information on the rolled material 1, the predicted rolling load, and the work roll crown. Further, the intermediate roll bending force u ₂₀ is preset from the preset calculation unit 26 according to rolling conditions, and the target shape value A ₂ ^* and the shape estimation models K ₂ and T ₂ are set. When rolling is started, the shape detector 5 moves to the shape calculation unit.
The plate shape A ₂ is detected through 21. At the start of control, the shape parameter estimation value is ₂ = ₂ L = 0, so the addition point
The target shape value is passed through 100 and 101 and the correction amount correction calculator 25.
A ₂ ^* is compared with the addition point 102. Correction amount correction calculator
The reference numeral 25 is provided to quickly converge the disturbance applied to the rolling mill. The deviation e ₂ of the addition point 102 is input to the manipulated variable calculation unit 22, PI calculation or the like is performed, and the manipulated variable u ₂ is output to the intermediate roll bending device 10. When the distance from the roll bite to the shape detector 5 is l and the rolling speed is v, the operation amount is
There is a transfer time of 1 / v before the shape detector 5 detects a shape change in the roll bite portion due to u ₂ . Therefore, during this period, the shape is changed by the manipulated variable u _2, but it is not detected by the shape detector 5, so that the deviation e ₂ is output and the u ₂ becomes an excessive manipulated quantity with time. In order to eliminate this phenomenon, the operation amount u ₂ is input to the shape estimation model G ₂ and the shape parameter estimation value ₂ = G ₂
・ The deviation e ₂ is corrected by adding u ₂ to the addition point 100. Further, since the shape detector 5 outputs at a constant time interval, the delay calculating unit 24 causes the transfer time l /
During v, the shape estimation value ₂ is delayed, and the new shape deviation and shape estimation error due to disturbance are corrected by synchronizing with the output interval of the shape detector 5 and comparing with the shape detector at the addition point 101. .

In the figure, 31 and 32 are shape signals, and 33 is a rolling condition signal.

Regarding A ₁ control by the reduction leveling device and A ₄ control by the backup roll crown adjusting device,
Similar to FIG. 1, the intermediate roll lever bending device and the shape estimation model G ₂ may be changed to a reduction leveling device, a backup roll crown adjusting device, and G ₁ and G ₄ , respectively.

Further, the present invention is effective at all rolling speeds, but at high speed rolling, for example, 200 mpm or more, no remarkable effect can be obtained as compared with the prior art. Therefore, at high speed rolling, ki = Alternatively, the shape Ai detected by the shape detector may be directly compared with the shape target value Ai, and the deviation may be used for control.

[Effects of the Invention] As described above, according to the plate shape control method for a multi-stage cluster rolling mill according to the present invention, a high responsiveness is realized from a low speed region in response to a wide range of rolling conditions, and a good plate shape is achieved. Can be obtained.

[Brief description of drawings]

FIG. 1 is a block diagram showing an embodiment of the present invention. 1 ... Rolled material, 5 ... Shape detector, 10 ... Intermediate roll bending control device, 20 ... Calculator, 21 ... Shape calculator, 22 ... Operation amount calculator, 23 ... Shape estimation calculator ,twenty four…
… Delay calculator, 25 …… Correction amount correction calculator, 26 …… Preset calculator.

 ─────────────────────────────────────────────────── ─── Continuation of the front page (72) Inventor Ryoma Kamigori 1 Kawasaki-cho, Chiba-shi, Chiba Kawasaki Steel Co., Ltd. Chiba Steel Works (72) Inventor Satoshi Terado 4-6-22 Kannon-shinmachi, Nishi-ku, Hiroshima-shi Mitsubishi Heavy Industry Co., Ltd. Hiroshima Research Laboratory (72) Inventor Yasunobu 4-6-22 Kannon Shinmachi, Nishi-ku, Hiroshima City, Hiroshima Prefecture Mitsubishi Heavy Industry Co., Ltd. Hiroshima Research Laboratory (56) Reference JP-A-58-61907 (JP, A) Kai 58-116915 (JP, A) JP 58-53319 (JP, A)

Claims (1)

[Claims] 1. A plate shape control for a multi-stage cluster rolling mill that corrects the shape of a material to be rolled by operating a plurality of shape correction devices so that the shape of the material to be rolled detected by a shape detection device matches a target shape. In the method, a plurality of shape parameters calculated based on the detection signal from the current shape detection device, and the portion of the material to be rolled at the position of the current shape detection device, when the roll of the rolling mill was rolled. Calculated based on the operation amount of the shape correction device in, the difference between the shape parameter estimation value corresponding to each shape parameter is calculated, the value based on the difference, the current operation amount of the shape correction device The shape parameter estimation values corresponding to the respective shape parameters calculated based on the respective values are added, and each shape correction device is adjusted so that the added value matches the respective shape target value. A plate shape control method for a multi-stage cluster rolling mill, which is characterized by operating a rolling mill.