JPS59202109A - Device for controlling sheet thickness and shape of strip in rolling mill - Google Patents

Abstract

PURPOSE:To obtain a titled device capable of rolling a strip excellent in sheet thickness and shape by compensatingly operating a shape control by a roll bending operation and a sheet thickness control, in a rolling mill, for preventing the mutual interference between said controls and controlling a strip tension to a fixed value. CONSTITUTION:In a rolling mill for rolling a strip 1 by rolling rolls 2, 3, the tension values detected by strip tension detectors 10, 10' provided to the inlet and outlet sides of the mill are outputted to an arithmetic device 11 to control a strip tension to a fixed value through a driving device 14, and are also outputted to a compensating arithmetic device 15. Further, an output of a rolling down force detector 4 is outputted to an arithmetic device 12 to control a rolling down force through a servovalve 7 and a rolling reduction cylinder 8, and is also outputted to a compensating arithmetic decide 15. Moreover, an output of a pressure detector 6 in a roll bender 5 is outputted to an arithmetic device 13 to control the bending quantity through a servovalve 7', and also is outputted to the device 15. The device 15 outputs a compensation value operated basing on three inputs to the arithmetic device 12 of draft position operating quantity and the arithmetic device 13 of bending pressure operating quantity to compensate the control quantity.

Description

DETAILED DESCRIPTION OF THE INVENTION The present invention provides a rolling mill equipped with a gauge meter type plate thickness control device and a roll bending device, in which plate thickness control and shape control by roll bending operations can be performed by strip material without interfering with each other. The present invention relates to a control device for controlling tension to a constant value.

Recently, the problem of the shape of rolling mills has become a focus of attention, and various control devices have been developed for this purpose. Roll bending equipment has been used for a long time, but the equipment sets the optimal amount of roll bending based on the rolling schedule before rolling, and changes the amount of roll bending during rolling to produce plates with excellent shapes. A control device is being considered.

On the other hand, since the strip tension value has a large influence on the strip thickness accuracy, strip width, strip shape, etc., it is necessary to maintain it at a constant value even if there are two kinds of disturbances.

For this reason, in a rolling mill, the entrance and exit sides of the rolling mill are
It is necessary to detect the IJ knob tension value and correct the strip tension value according to the difference between the detected value and the strip tension reference value. An example of a conventional control device that also uses such a shape control device is shown in FIG.

In this figure, when the strip is bitten by the roll, the rolling pressure increases, which is detected by the total pressure lower detector 4, and in order to keep the thickness of the strip at the exit side constant, the operating amount corresponds to the differential pressure with the standard rolling reaction force. is calculated by the arithmetic unit 12 and output to the servo valve 7. As a result, oil flows and the cylinder 7 operates to change the pressure position. This is the plate thickness control system. In addition, the bending pressure control system detects the internal pressure of the bender using a pressure detector 6.
The bending pressure operation amount is calculated by the arithmetic unit 13 and output to the servo valve 7'.

On the other hand, the tension control system detects the strip tension on the inlet and outlet sides of the rolling mill using strip tension detectors 10 and 10', and calculates the detected values in an arithmetic unit 11 to determine the strip tension value in the drive control system 14 ( Outputs to the input/output side of the rolling mill, the rotation speed control between the rolling mills, the looper, etc.).

In a control system that uses such a board thickness control system, a shape control system based on a bending operation amount, and a strip tension control system in combination, a phenomenon occurs in which the three systems interfere with each other.

That is, bending pressure fluctuations due to bending operations affect the rolling force detector 41C, and automatic plate thickness control is activated by the fluctuations in the rolling blade.

Additionally, rolling reaction force fluctuates due to automatic plate thickness control.

As a result, the shape of the strip changes, requiring additional bending operations. On top of that,
The tension of the systrip changes due to the variation in rolling force due to bending operation and the variation in rolling force due to automatic plate thickness control.

In this way, a phenomenon occurs in which the manipulated variables (rolling position, bending pressure) affect the control objects of the plate thickness deviation, shape deviation, and strip tension value.

The control device proposed in the present invention solves these problems,
(b) In order to sufficiently control the thickness and shape of the IJ tube, control is performed that allows mutual interference to be separated and corrected independently.

Next, this invention will be explained based on one embodiment (FIG. 2). The outlet side plate thickness variation Δh is the control target.

There is a mutual relationship between the IJ knob tension variation ΔT, the operating amount of the reduction position ΔS, the bending pressure operating amount ΔFB, and the drive system fluctuation risk Δδ. Since the controlled object changes when the manipulated variable changes, the following relational expression holds true.

However, -gij (L, j=1 to 3) is an influence coefficient that each manipulated variable has on the controlled object.

Expression (1) is expressed as a matrix as shown below.

The influence coefficient matrix G is generally not a diagonal column, so the manipulated variables interfere with each other and influence the controlled object. If 9 matrix G
If is a diagonal matrix, ΔS, ΔFB.

It is clear that Δδ do not interfere with each other.

Now, the direction of the output of the detector due to various disturbances or the output of the host computer, etc., is determined by the lower position operation amount calculation unit 12. Assuming that the inverse matrix eG' of the matrix G in the bending pressure amount calculation device 13 (2) is expressed as eG'.

However, the 9 matrix GIJ is all the factors of the influence coefficient gij.

(ij=1~3) d=g++gz2gz3+g+
2g23g3+”g+3g2+ga2-gIIg23g
It can be seen from equation 32-gI2g21g33-g13g22g31 that they act on the controlled object without mutual interference.

As explained above, according to the present invention, the plate thickness control system can control the exit side plate thickness without affecting the shape effect and the strip tension value, and
Regarding the bending pressure control system, it is possible to increase the effect of controlling the IJ tube shape without affecting the plate thickness control system and strip tension value. As a result, in a device that uses both a plate thickness control system and a shape control system (bending pressure control system and strip tension control system), it is possible to arbitrarily increase the responsiveness without affecting the other control system. It is expected that the control effect will be significantly improved compared to conventional devices, which have not been able to obtain sufficient pressure control effects due to mutual interference.

Strip tension detection is possible by installing load detectors on the inlet and outlet sides of the rolling mill.

It can also be estimated by measuring itching.

[Brief explanation of drawings]

FIG. 1 shows a conventional control device that combines automatic plate thickness control and shape control. FIG. 2 shows a plate thickness control and shape control device according to an embodiment of the present invention. l... Strip, 2, 3... Rolling mill roll, 4...
... Reduction force detector, 5. Roll bender, 6-Bender internal pressure detector, 7.7'... Servo valve, 8. Reduction cylinder, 9. Reduction position detector, 10. 10'・
. . . Strip tension detector, 11 . . . Strip tension calculation device, 12 . . . Down position operation amount calculation device. 13... Bending pressure operation amount calculation device, 14...
Drive system control device, 15...compensation calculation device. Continued from page 1 0 Inventor Yoshimi Tasaka No. 4-31 Minamikannon 6-chome, Nishi-ku, Hiroshima City Ryosen Engineering Co., Ltd. Applicant Ryofune Engineering Co., Ltd. 6-4-31 Minamikannon, Nishi-ku, Hiroshima 51-

Claims (1)

[Claims] A gauge meter type automatic plate thickness control device detects rolling reaction force and controls the rolling position according to the difference between the detected value and the rolling reaction force reference value, and the roll bending pressure is adjusted according to the shape of the strip material. In a rolling mill equipped with an operating roll bending device and a device capable of detecting the strip tension on the entry and exit sides of the rolling mill, the rolling position is compensated for so that the strip tension reference value does not fluctuate. The roll bending pressure is compensated for so that the strip tension standard value does not fluctuate, and the strip thickness and strip tension value do not fluctuate according to the number of roll bending pressure adjustments. 1. A plate thickness and shape control device for a rolling mill, characterized in that a compensation calculation device is provided which performs an operation of compensating the rolling position.