JPH0698365B2 - Shape control device for cluster rolling mill - Google Patents

Description

The present invention relates to a shape control device for a cluster rolling mill.

<Prior art> In the cluster rolling mill, the backup roll crown can be set in any pattern and amount, and the bending force can be applied to the intermediate roll by the roll bender. By combining with, shape control can be performed under a wide range of rolling conditions. On the other hand, when each coefficient of the fourth-order orthogonal function corresponding to the strain distribution of the sheet shape is calculated from the detected sheet shape after rolling, the first-order coefficient represents the magnitude of unilateral elongation, and the second-order coefficient represents the medium elongation and Indicates the amount of edge extension.
Further, the reduction leveling (having a roll gap between the driving side and the working side) affects the magnitude of one-sided elongation, and the bending force affects the middle and end elongations.

From the above, in the conventional shape control method of the cluster rolling mill (for example, Japanese Patent Application No. 60-97980), the pattern and amount of the backup roll crown are calculated and preset to one suitable for the rolling condition. Perform feedback control of the reduction leveling so that the next coefficient reaches the target value, and
The roll vendor was feedback-controlled so that the following coefficient also reached the target value. As a result, during steady rolling, a desired strip shape with high productivity was obtained under a wide range of rolling conditions.

<Problems to be solved by the invention> However, according to the conventional control method described above, since it is a method of feeding back the signal of the shape detector installed 2 to 3 m behind the rolling mill, during acceleration / deceleration and welding. When a sudden load change occurs, such as when passing a point, the detection and correction operations may be delayed and a satisfactory plate shape may not always be obtained.

SUMMARY OF THE INVENTION It is an object of the present invention to provide a shape control device for a cluster rolling mill capable of eliminating the above-mentioned inconvenience by improving responsiveness.

<Means for Solving Problems> The configuration of the present invention that achieves such an object is a means for calculating and presetting a pattern and amount of a backup roll crown suitable for the rolling condition in response to input of the rolling condition, and after rolling. Means for detecting the plate shape, means for calculating each coefficient of the quaternary orthogonal function corresponding to the plate shape strain distribution from the detected value of the plate shape, and the first-order coefficient of the coefficients of the quaternary orthogonal function is the target. Means for controlling the reduction leveling to match the value,
In a cluster rolling mill equipped with means for controlling a roll bender so that a quadratic coefficient of a quaternary orthogonal function matches a target value, a load cell for detecting a rolling load is provided in the cluster rolling mill and the load cell is used. The present invention is characterized in that a correction calculation circuit is provided to correct the roll bender control according to the difference between the detected rolling load at the present time and the rolling load when a desired good plate shape is obtained. .

<Operation> According to the method of the present invention, it is possible to prevent a defective shape due to a rapid change in rolling load during acceleration / deceleration, passing through a welding point, or the like, and therefore product quality is improved.

<Example> Hereinafter, an example of the present invention will be described in detail with reference to the drawings.

FIG. 1 is a block diagram showing a configuration of an apparatus according to an embodiment of the present invention, in which 1 is a cluster rolling mill and 2 is a rolled material. First, the cluster rolling mill will be explained.
The intermediate roll 4, the work roll 5 and the small diameter backup roll 6 are arranged in a cluster as shown in the figure,
The backup roll 3 has a divided structure as shown in FIG. Further, the divided backup rolls can be extruded in the direction of the arrow shown in FIG. 1 by a driving device (not shown), and the backup roll crown can be set in an arbitrary pattern and amount. Further, the bending force can be applied to the intermediate roll 4 by the roll benders 21 and 22 shown in FIG. 2, and in combination with the backup roll crown adjustment, the structure can be controlled in a wide range of rolling conditions. ing.

In FIG. 1, 7 is a backup roll crown adjusting servo system, which sets a crown of the backup roll 3 in an arbitrary pattern and amount by a command from a preset arithmetic unit 14. The preset arithmetic unit 14 calculates the pattern and amount of the backup roll crown suitable for the rolling condition in response to the input of the rolling condition. A roll bender servo system 8 sets a bending force of the roll benders 21 and 22 to an arbitrary value according to a command from the controller 13 and the correction calculation device 16. Further, 9 is a reduction leveling servo system, which performs leveling of a reduction device (not shown) in response to a command from the controller 12. Further, 10 is a shape detector, which detects the shape of the rolled material 2,
The elongation strain distribution β (x) at the position x in the plate width direction (normalized to ± 1 at both ends) is output.

Further, the orthogonal function calculation device 11 calculates each coefficient A _{0 to} A ₄ of the orthogonal function by the following equation (1).

Here, i is 0 to 4, and φ ₀ to φ ₄ are fourth-order orthogonal functions, which are expressed by the following equations. φ ₀ (x) = a… (1.0) φ ₁ (x) = bx… (1.1) φ ₂ (x) = Cx ² + d… (1.2) φ ₃ (x) = ex ³ + fx… (1.3) φ ₄ (X) = gx ⁴ + hx ² + k (1.4) Further, the coefficients a to k in the equations (1.0) to (1.4) are obtained by the orthonormal condition of the following equation.

The elongation strain distribution β (x) represents the distribution of the elongation rate β in the width direction when the position in the plate width direction is x.

Here, the elongation rate β is expressed as follows.

Here, 1 is the length of a certain section, and Δl is the difference in elongation between the central portion of the plate width and the position x in the plate width direction.

When the shape is expressed by the formula (1), A ₁ is _one- sided elongation, A ₂ is medium elongation and edge elongation, A ₃ is asymmetrical elongation, and A ₄ is middle edge elongation and _quarter elongation.

A load cell 15 is provided in the cluster rolling mill 1 and detects a rolling load. Reference numeral 16 is a correction calculation device which is the center of the present invention. This device calculates the roll bender correction amount ΔF by the following equation (2).

In the equation (2), P is the current rolling load, P ₀ is the rolling load when the desired good rolling shape is obtained, and k is the gain.

Is a reduction effect coefficient and represents the magnitude of medium elongation (edge elongation) per unit rolling load change. Also Is a vendor influence coefficient, which represents the magnitude of medium elongation (edge elongation) with respect to a unit bender force change. The rolling influence coefficient and the vendor influence coefficient can be obtained by calculation or experiment as a function of the strip width for each material of the rolled material. Therefore, the roll bender force for correcting the defective shape caused by the fluctuation of the rolling load can be obtained by the equation (2). The gain k is for adjusting the correction amount in consideration of the error of the influence coefficient.

Next, the operation of the embodiment apparatus shown in FIG. 1 will be described. First, before the start of rolling, the preset calculation device 14 inputs the rolling conditions such as the rolling load target value and the strip width to calculate the optimum pattern and amount of the backup roll crown, and the result is used to adjust the backup roll crown adjusting servo system 7 Command to preset the backup roll crown.

Next, if the rolling speed after the start of rolling becomes a predetermined value or more and the detection signal of the shape detector 10 can be stably used,
Shape feedback control is started.

The shape feedback control uses an orthogonal function calculation device to calculate the elongation strain distribution β (x) in the plate width x direction obtained from the shape detector 10.
11 and input the first-order mode coefficient A ₁ according to the above equation (1).
And the second-order mode coefficient A ₂ are calculated to calculate the first-order mode and the second-order mode
Obtain the detected value of the next mode coefficient. In the primary mode, the difference between A ^* ₁ given as the target value and the detected value A ₁ is input to the controller 12, PI calculation processing is performed and the leveling command value of the reduction servo system 9 is input. Perform feedback control so that ₁ ^* = A ₁ . Similarly, for the secondary mode, the controller 13 calculates the difference between the target value A ₂ ^* and the detected value A _2.
It is input to the roll bender servo system 8 via and feedback control is performed so that A ₂ ^* = A ₂ . Normally, A ₁ ^* = A ₂ ^* = 0 is set to obtain a flat shape.

Next, the feedback control outputs a lock-on command at the time when the shape becomes stable, obtains the rolling load P ₀ , and starts the correction calculation by the equation (1). As mentioned above,
According to the equation (1), it is possible to obtain the roll bender correction amount ΔF for correcting the shape defect caused by the difference between the current value P of the rolling force and the rolling load P _0. Even if there is a sudden change in rolling force when passing the point,
It is possible to immediately calculate and output the roll bender correction amount ΔF and prevent the occurrence of shape defects. That is, while performing highly accurate shape control by feedback control, responsiveness is improved by this method, and a shape defect due to a sudden load change that cannot be followed by feedback control is corrected.

<Effects of the Invention> According to the present invention, it is possible to prevent a defective shape due to a sudden load change at the time of acceleration / deceleration and at the time of passing through a welding point. Therefore, when used in combination with feedback control, highly accurate and highly responsive shape control becomes possible.

[Brief description of drawings]

FIG. 1 is a block diagram showing an embodiment of the present invention, and FIG. 2 is a schematic diagram of a roll part of a cluster rolling mill. In the drawing, 1 ... Cluster rolling mill, 2 ... Rolled material, 3 ... Backup roll, 4 ... Intermediate roll, 5 ... Work roll, 6 ... Small diameter backup roll, 7 ... Backup roll crown adjustment servo system , 8 ... Roll bender servo system, 9 ... Rolling down leveling servo system, 10 ... Shape detector, 11 ... Orthogonal function computing device, 12 ... Controller, 13 ... Controller, 14 ... Preset computing device, 15 ...... Load cell, 16 …… Correction calculation device, 21 …… Roll vendor, 22 …… Roll vendor.

 ─────────────────────────────────────────────────── ─── Continuation of the front page (72) Inventor Goro Fukuyama 4-6-22 Kannon Shinmachi, Nishi-ku, Hiroshima City, Hiroshima Prefecture Mitsubishi Heavy Industries Ltd. Hiroshima Plant (72) Inventor Takayuki Kaji 1 Kawasaki-cho, Chiba-shi Chiba Prefecture Kawasaki (72) Inventor Masanori Kitahama, 1 Kawasaki-cho, Chiba-shi, Chiba Kawasaki Steel Co., Ltd. (72) Inventor Akihiko Fukuhara, 1 Kawasaki-cho, Chiba, Chiba Kawasaki Steel Co., Ltd. Chiba Inside a steel mill (56) References JP-A-61-255710 (JP, A)

Claims (1)

[Claims] 1. A means for calculating and presetting a pattern and an amount of a backup roll crown suitable for the rolling condition in response to the input of the rolling condition, a means for detecting the rolled plate shape, and a plate from the detected value of the plate shape. 4 corresponding to the strain distribution of the shape
A means for calculating each coefficient of the quadratic orthogonal function, a means for controlling the reduction leveling so that the first-order coefficient of the coefficients of the quaternary orthogonal function matches the target value, and the quadratic coefficient of the quaternary orthogonal function In a cluster rolling mill having a means for controlling a roll bender so as to match a target value, and a rolling load at the present time detected by the load cell while providing a load cell for detecting a rolling load in the cluster rolling mill, A shape control device for a cluster rolling mill, comprising a correction arithmetic circuit for correcting the control of a roll bender as needed according to a difference from a rolling load when a desired good plate shape is obtained.