JPH0218922B2 - - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION The present invention provides a metal strip rolling mill such as a hot rolling mill, cold rolling mill or thick plate rolling mill equipped with a gauge meter type plate thickness control device and a roll bending device. Plate thickness control and crown control by bending operation do not interfere with each other.
The present invention relates to a control device for achieving good control effects.

In recent years, gauge meter-based plate thickness control has become widely used as automatic plate thickness control in rolling mills.
It has a high control effect. On the other hand, although roll bending has been carried out for a long time, the method of use is to set the optimum roll bending amount based on the rolling schedule before rolling, and to hardly change the bending amount during rolling. Ta. Recently, the problem of the shape of rolled materials has been widely discussed, and various control methods and devices for this purpose have been developed. The main method is to use a bending device and vary the bending amount during rolling in accordance with the variation in the crown amount of the sheet, thereby producing a sheet with an excellent shape and a target crown.

FIG. 1 shows an example of a control system that uses such a gauge meter type automatic plate thickness control device in combination with a shape control device using a bending operation. In this figure, when the rolled material is bitten by the roll, a rolling reaction force is generated, which is detected by the rolling force detector 6, and in order to keep the exit side thickness of the rolled material constant, the difference from the standard rolling reaction force is detected. The corresponding operation amount is calculated by the calculation device 10.
is calculated and output to the servo valve 9a.

As a result, oil flows, the cylinder moves, and the pressure position changes. This is the plate thickness control system.

In addition, the bending pressure control system detects the internal pressure of the bender with the pressure detector 5, calculates the bending pressure operation amount with the arithmetic unit 11, and outputs it to the servo valve 9b.

In a control system that uses both plate thickness control and shape control by bending, a phenomenon occurs in which the two interfere with each other.

That is, bending pressure fluctuations caused by the bending operation are transmitted to the rolling force detector 6, and automatic plate thickness control is activated in response to the rolling force fluctuations.

On the other hand, automatic sheet thickness control causes rolling reaction force to fluctuate, and if the rolling reaction force fluctuates, the amount of crown of the rolled material changes, making it necessary to perform further bending operations.

In this way, a phenomenon occurs in which one manipulated variable (bending pressure or bending position) affects two objects to be controlled, the crown deviation and the plate thickness deviation.

The control device proposed in the present invention solves these problems and performs so-called non-interference control to separate mutual interference and cancel the interference in order to effectively control both the plate thickness and shape of the rolled material. It is something.

To this end, the plate thickness and shape control device for a rolling mill according to the present invention detects the rolling reaction force and operates the rolling position according to the difference between the detected value and the rolling reaction force reference value. In a rolling mill equipped with a control device and a roll bending device that operates the roll bending pressure according to the shape and crown amount of the rolled material, signals from a rolling force detector and a signal from a bender internal pressure detector are used. In response to this, the rolling position operation amount △S is the plate thickness variation △h and the crown amount variation △
Effects on Cr and roll bending pressure operation amount △r on plate thickness variation △h and crown amount variation △Cr
control variable matrix (△
h, △Cr) and the manipulated variable matrix (△s△r), and multiply it by the manipulated variable matrix to calculate a new manipulated variable matrix (△s ^* △r ^* ). , the gist is that a compensation calculation device is provided which outputs this △s ^* as a roll bending position manipulated variable to a roll bending position manipulation calculation device, and outputs △r ^* as a roll bending pressure manipulated variable to a bending pressure manipulated variable calculation device. It is something to do.

The method will be explained based on an example (see FIG. 2). Between the control targets, which are the outlet side plate thickness variation △h and the outlet side crown amount variation △Cr, and the operation amounts, which are the rolling position operation amount △s and the bending pressure operation amount △r, changing one operation amount will cause both changes. Since the controlled object changes, the following relationship is established.

Δh=g ₁₁ Δs+g ₁₂ Δr ΔCr=g ₂₁ Δs+g ₂₂ Δr However, g ₁₁ , g ₁₂ , g ₂₁ , and g ₂₂ are influence coefficients that the respective manipulated variables have on the controlled object.

If expressed as a matrix, it becomes as follows.

(△h △Cr) = (g ₁₁ g ₁₂ g ₂₁ g ₂₂ ) (△s △r) = G (△s △r) − (where G = (g ₁₁ g ₁₂ g ₂₁ g ₂₂ )) Influence coefficient matrix G is generally not a diagonal matrix, so the manipulated variables interfere with each other and affect the controlled object.

If G is a diagonal matrix, it is clear that △s and △r do not interfere with each other. Now, from the output of the detector or the output of the host computer caused by various disturbances, the operation amount (△s △r) is calculated by the reduction position operation amount calculation device 10 and the bending pressure operation amount calculation device 11.
Suppose that we find

However, even if this is directly applied to the controlled object, the manipulated variables will interfere with each other according to the equation.

Therefore, this operation amount (△s △r) is calculated by the compensation calculation device 12
The following compensation calculation is performed and a new manipulated variable (△s ^* △r ^* ) is output.

Compensation calculation example 1 (△s ^* △r ^* ) = G ^-1 (△s △r) - However, G ^-1 = 1/g ₁₁・g ₂₂ −g ₂₁・g ₁₂ (g ₂₂ −g ₁₂ −g ₂₁ g ₁₁ ) When this new manipulated variable (△s ^* △r ^* ) is given to the target,
From the formula (△h △Cr) = G (△s ^* △r ^* ) = G・G ^-1 (△s △r) (from the formula) = E (△s △r) (E is the identity matrix) E Since is clearly a diagonal matrix, it can be seen that the manipulated variables (Δs Δr) act on the controlled object without mutual interference.

Compensation calculation example 2 (△s ^* △r ^* )=G′ (△s △r) − 2′ where G′=1/g ₁₁・g ₂₂ −g ₂₁・g ₁₂ (−g ₁₂ g ₂₂ g ₁₁ − g ₂₁ ) When this new manipulated variable (△s ^* △r ^* ) is given to the controlled object, (△h △Cr) = G (△s ^* △r ^* ) = G・G′ (△s △r ) (From 2') = E' (△s △r) (However, E' = (01 10)) = (△s △r) In other words, the manipulated variables (△s △r) can be controlled without mutual interference. It can be seen that it acts on the target.

As explained above, according to the present invention, the plate thickness control system can achieve a control effect on the exit side plate thickness without affecting the crown amount, and from the viewpoint of the bending pressure control system, It is possible to improve the control effect of the plate crown without affecting the plate thickness.

This makes it possible to increase the responsiveness arbitrarily without affecting the other control system even in a device that uses both thickness control and shape control, and because of mutual interference, it is possible to obtain sufficient control effects. Compared to conventional devices, which were unable to do so, significant improvements in control effects can be expected.

[Brief explanation of drawings]

FIG. 1 shows a conventional control system that combines automatic plate thickness control and shape control, and FIG. 2 shows a plate thickness-shape control system according to an embodiment of the present invention. 1 is a rolled material, 2 is a work roll, 3 is a back-up roll, 4 is a reduction cylinder, 5 is a roll bender, 6 is a reduction force detector, 7 is a reduction position detector,
8 is a bender internal pressure detector, 9a and 9b are servo valves, 10 is a reduction position operation amount calculation device, 11 is a bending pressure operation amount calculation device, and 12 is a compensation calculation device.

Claims (1)

[Claims] 1. A gauge meter type automatic plate thickness control device that detects rolling reaction force and operates the rolling position according to the difference between the detected value and the rolling reaction force reference value, the shape of the rolled material,
In a rolling mill equipped with a roll bending device that operates the roll bending pressure according to the amount of crown, the reduction position operation amount △
A control variable matrix (△ h△
Cr) and the manipulated variable matrix (△s△r), and multiply it by the manipulated variable matrix to calculate a new manipulated variable matrix (△s ^* △r ^* ). A rolling mill characterized in that it is provided with a compensation calculation device that outputs s ^* as a rolling position operation amount to a rolling position operation calculation device and outputs △r ^* as a roll bending pressure operation amount to a bending pressure operation amount calculation device. Plate thickness and shape control device.