JPH0734931B2 - Plate shape and elongation control device for rolling mill - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION <Industrial field of application> The present invention relates to a rolling mill provided with both strip shape control and elongation control of strip steel, and a strip shape and elongation having a non-interference control device for both of these control functions. Rate control device.

<Prior art> In a rolling mill, especially in a skin pass mill or a ramper mill used in a process line, the elongation given to a rolled steel strip is controlled to an appropriate value to improve its material quality. That is, the flatness defects caused by the rolling, such as middle elongation, edge elongation, and partial elongation, are also controlled so as to reach the target plate shape value. FIG. 2 is an example of such a control device, and shows a state in which the strip steel 10 is rolled by the rolling mill 1 composed of main members such as the work roll 2, the backup roll 3, the reduction device 4, and the bending device 5. Shows. In the figure, the pressure reducing device 4 and the bending device 5 are connected to the hydraulic pipes 7 and 9 via the respective servo valves 6 and 8.
Are respectively connected to hydraulic devices (not shown).

The plate shape detector 11 arranged on the strip steel outlet side of the rolling mill ₁ detects the plate shape value λ ₁ of the rolled steel strip 10 and the target transmitted from the plate shape setter 16 by the adder 17 The plate shape variation amount Δλ is calculated by Δλ = λ ₀ −λ ₁ according to the difference from the plate shape value λ ₀ . Then, the bending pressure operation amount ΔF _B calculated by the calculator 18 is output to the servo valve 8 to be operated, and the bending pressure of the work roll 2 is changed by the bending device 5 to control the plate shape of the strip steel 10. The plate shape control means is constituted by the above. On the other hand, the elongation calculator 13
Is an entry side strip speed detector 12a arranged on the strip steel entry side of the rolling mill 1 and an exit side strip speed detector 12b arranged on the strip steel exit side.
The elongation rate ε ₁ of the strip 10 is calculated by ε ₁ = (V _D -V _E ) / V _E according to the difference between the strip running speeds V _E and V _D respectively detected by and According to the difference from the target elongation rate ε ₀ sent from the rate setter 14, the elongation rate variation amount Δε is set to Δε = ε ₀
-Calculate by ε ₁ . Then, the calculator 19 calculates a pressure reduction position operation amount Δs corresponding to this elongation variation amount Δε, outputs it to the servo valve 6 and operates it, and the pressure reduction device 4 changes the gap between the upper and lower work rolls 2. Control the elongation of strip steel 10. The elongation rate control means is constituted by the above.

<Problems to be Solved by the Invention> Thus, although the two control functions of the elongation control means and the plate shape control means exist as independent control loops, the elongation variation amount Δε, which is the controlled object, Since the plate shape variation amount Δλ and the operation amount of the rolling position operation amount Δs and the bending pressure operation amount ΔF _B are interrelated, the controlled object changes when the operation amount is changed, so the following relational expression is established. To do.

However, g _ij (i, j = 1,2) is the influence coefficient that each manipulated variable has on the controlled object.

If this equation (1) is expressed as a matrix, If is used, the following equation is obtained.

However, Is generally not a diagonal matrix, and it is overlooked that the manipulated variables actually interfere with each other and affect the controlled object. That is, the control of the elongation affects the strip shape of the strip steel 10, and conversely, the control of the strip shape affects the strip rate of the strip steel 10. No attention was paid, and therefore, the elongation rate and strip shape control of the strip steel 10 included a large control error, which hindered improvement in quality and yield.

Therefore, the present invention provides a plate shape and elongation control device for a rolling mill which eliminates the control error except the above-mentioned drawbacks.

<Means for Solving Problems> The present invention that achieves the above-described object is to detect a plate shape of a rolled strip steel and detect a plate shape of a rolled roll according to a difference between the detected value and a target plate shape set value. A plate shape control means for calculating the bending operation amount and controlling the bending of the rolling roll according to the bending operation amount, and detecting the elongation rate of the strip steel to determine the detected value as the difference between the target elongation rate setting value. According to the rolling position operation amount of the rolling roll is calculated according to the rolling position operation amount according to the rolling position operation amount and elongation control means for controlling the rolling position of the rolling roll, in the temper rolling mill, the plate shape control means and A non-interference calculation device is provided which is provided on both the elongation control means and which calculates the correction operation amounts ΔF _{B 1} , ΔS ₁ by performing the compensation calculation of the bending operation amount ΔF _B and the rolling position operation amount ΔS by the following formula. Characterized by Here, G ⁻¹ is an inverse matrix of the influence coefficient matrix G.

d = g ₁₁ g ₂₂ -g ₂₁ g ₁₂ Here, the matrix element g _ij represents the influence coefficient, g ₁₁ represents the influence coefficient of the rolling position manipulated variable ΔS on the elongation, and g ₁₂ represents the bending manipulated variable ΔF _B. The coefficient of influence on elongation, g ₂₁ is the coefficient of influence of the rolling position operation amount ΔS on the plate shape, and g ₂₂ is the coefficient of influence of the bending operation amount ΔF _B on the plate shape.

Further, the matrix element G _ij is a _cofactor of g _ij .

<Operation> The bending roll operation amount calculated by the plate shape control unit and the rolling roll reduction position operation amount calculated by the elongation control unit are input to the non-interference calculation device so that both operation amounts are mutually equal. Compensation calculation is performed by the non-interference calculation device so as not to cause interference and reduce the accuracy. The rolling position of the rolling roll and the bending pressure are changed by the corrected bending pressure operation amount and the corrected rolling position operation amount calculated by this compensation calculation, and the strip shape and elongation of the strip steel are controlled more accurately.

<Example> Here, an example of the present invention will be described with reference to FIG. The same members as those in FIG. 2 are designated by the same reference numerals. In FIG. 1, the plate shape detector 11 detects the plate shape value λ ₁ of the rolled steel strip 10 and sends it to the adder 17. The adder 17 uses this plate shape value λ ₁
The plate shape variation amount Δλ is calculated according to the difference between the target plate shape value λ ₀ and the plate shape setting value λ ₀ transmitted from the plate shape setter 16, and the calculated amount is transmitted to the calculator 18. Then, converted by the computing unit 18 to the bending pressure operation amount [Delta] F _B, and inputs the bending pressure operation quantity [Delta] F _B to the non-interference calculation unit 20.

On the other hand, the elongation rate calculator 13 calculates the elongation rate ε ₁ , and the adder 15
Send to. The adder 15 uses the elongation rate ε ₁ and the elongation rate setter 1
The elongation rate variation amount Δε is calculated according to the difference from the target elongation rate ε ₀ transmitted from 4, and is converted by the calculator 19 into the rolling position manipulated variable Δs, which is input to the non-interference calculator 20.

A non-interference computing device 20 is provided on both the transmission path of the bending pressure operation amount ΔF _B of the plate shape control means and the transmission path of the rolling position operation amount Δs of the elongation rate control means. This non-interference computing device 20 is a rolling position operation amount Δ of the elongation control means.
In order to eliminate the interference between s and the bending pressure operation amount ΔF _B of the plate shape control means, compensation calculation is performed, and the corrected rolling position operation amount Δs ₁ is applied to the servo valve 6 of the rolling down device 4 and the corrected bending pressure operation amount ΔF B. _B1 is the servo valve 8 of the bending device 5
To control the elongation and plate shape of the strip steel 10 by changing the gap and bending of the upper and lower work rolls 2, respectively.

Next, the compensation calculation of the non-interference calculation device 20 will be described.

Described in the prior art If is a diagonal matrix, it is clear that the rolling position operation amount Δs and the bending pressure operation amount ΔF _B do not interfere with each other. However, the operation amount obtained as described above Even if given to the controlled object as they are, they interfere with each other as described in the prior art. So this manipulated variable The following compensation calculation is performed by the non-interference calculation device 20, and the correction operation amount is Is calculated by the following formula.

However, the matrix G _ij is a _cofactor of the influence coefficient g _ij .

This correction amount Is given to the controlled object, from equation (2) described in the prior art, Is calculated. (However, Is the identity matrix. ) Is obviously a diagonal matrix, so the manipulated variable It can be seen that each acts on each controlled object without interfering with each other.

In the present embodiment, the bending device is used as the plate shape control device, but this may be another device, for example, by providing a hydraulic chamber in the backup roll and controlling the internal pressure thereof, the roll crown is controlled. Obviously, it is also possible to use a variable crown roll that changes the amount or a device that shifts the intermediate roll in a six-high rolling mill.

<Effects of the Invention> According to the present invention, by providing the non-interference calculating device, the plate shape control means can control the plate shape without affecting the elongation rate of the strip steel, and the elongation rate control means also. The elongation rate can be controlled without affecting the plate shape. This makes it possible to arbitrarily increase the responsiveness without affecting the other control means, and due to mutual interference,
It is possible to significantly improve the control effect as compared with the conventional device in which the control effect could not be obtained sufficiently. The improvement of the control effect can remarkably improve the quality and yield of the steel strip.

[Brief description of drawings]

FIG. 1 is a conceptual diagram showing an embodiment of a plate shape and elongation control device for a rolling mill of the present invention, and FIG. 2 is a conceptual diagram showing an example of a conventional device. In the figure, 1: rolling mill, 4: rolling down device, 5: bending device, 10: strip steel, 11: plate shape detector, 12a: entrance side plate speed detector, 12b: exit side plate speed detector, 13: elongation rate calculator, 14: elongation rate setter, 16: plate shape setter, 18: plate shape calculator, 20: non-interference calculator.

Claims (1)

[Claims] 1. A strip shape of a rolled strip steel is detected, a bending operation amount of a rolling roll is calculated according to a difference between the detected value and a target plate shape setting value, and the rolling operation is performed according to the bending operation amount. The plate shape control means for controlling the bending of the roll and the elongation of the strip steel are detected, and the detected value is used to calculate the rolling position operation amount of the rolling roll according to the difference between the detected elongation set value and this rolling reduction. In a temper rolling mill equipped with an elongation control means for controlling the rolling position of the rolling roll according to a position operation amount, the bending operation amount ΔF _{B provided in} both the plate shape control means and the elongation control means. And the compensation operation of the rolling position manipulated variable ΔS is performed by the following formula to calculate the corrected manipulated variables ΔF _B1 , ΔS ₁ . A plate shape and elongation control device for a rolling mill, comprising a non-interference calculation device. Here, G ⁻¹ is an inverse matrix of the influence coefficient matrix G. d = g ₁₁ g ₂₂ -g ₂₁ g ₁₂ Here, the matrix element g _ij represents the influence coefficient, g ₁₁ represents the influence coefficient of the rolling position manipulated variable ΔS on the elongation, and g ₁₂ represents the bending manipulated variable ΔF _B. The coefficient of influence on elongation, g ₂₁ is the coefficient of influence of the rolling position operation amount ΔS on the plate shape, and g ₂₂ is the coefficient of influence of the bending operation amount ΔF _B on the plate shape. Further, the matrix element G _ij is a _cofactor of g _ij .