JP2720542B2 - Rolling mill flatness control method - Google Patents

Description

The present invention relates to a method for controlling flatness of a strip mainly in a strip rolling mill or the like.

[Conventional technology]

Method of controlling the flatness of the conventional this type is proposed to measure the tension distribution S _i for each of a plurality of zones, for example set in the width direction of the strip during rolling, superimposed coefficient in this
The optimum parabolic shape (lower-order component, quadratic curve) for shape control is determined based on the sum of the values multiplied by W _i , and based on this, the roll bender is controlled and the residual component (higher-order component, etc.) is determined. Is a method of correcting by using a spot coolant that injects water or other refrigerant into the strip surface in a spot shape (Japanese Patent Publication No. 62-27882), or detecting the shape of the strip during rolling, and There is a method of decomposing it into higher-order function components, and correcting the former by operating a roll shifter, and the latter by operating a work roll bender (JP-A-62-230412).

[Problems to be solved by the invention]

In the former method, low-order components are extracted and positive control is performed by the roll shifter, but high-order components are controlled by spot coolant using the remaining components as residual components. However, there is a limit to the ability to control higher-order components by the spot coolant, and a sufficient flatness cannot be obtained.

In the latter method, the lower-order component and the higher-order component in a strip shape are separated and the lower-order component is controlled by a roll shifter, and the higher-order component is controlled by a work roll bender. Even if the output reaches a saturation state, the roll shifter and the work roll vendor operate independently of each other, so that the roll shifter continues to control only the lower-order components, and the higher-order components are not controlled. Was.

The present invention has been made in view of such circumstances, and a purpose thereof is to extract a low-order single component from a plate shape when the output of a higher-order component control actuator reaches a saturated state, and to reduce a low-order single component based on the extracted component. An object of the present invention is to provide a flatness control method for controlling a next component control actuator.

[Means for solving the problem]

The flatness control method according to the present invention detects a shape in each of a plurality of zones defined in a width direction of a rolled material during rolling, and detects a low-order component extraction factor and a high-order component obtained in advance in a shape detection value of each zone. Multiply the extraction factors, calculate the sum of each, extract the low-order and high-order components of the plate shape, and based on this extract the low-order component control actuator and high-order component control to obtain the target plate shape The actuator is controlled, and when the output of the higher-order component control actuator reaches a saturated state, the shape detection value of each zone is multiplied by a previously obtained low-order single component extraction factor, and the sum thereof is obtained to obtain the low-order single component extraction factor. It is characterized in that a low-order single component having a plate shape in place of the next-order component and the higher-order component is extracted, and the low-order component control actuator is controlled based on this.

[Action]

According to the present invention, when the output of the actuator for controlling a higher-order component reaches a saturated state, the lower-order single component replacing the lower-order component and the higher-order component is obtained by using a previously obtained low-order single component extraction factor. Is extracted, and based on this, flatness control is performed only by the low-order component control actuator.

〔Example〕

Hereinafter, the present invention will be described in detail with reference to the drawings showing the embodiments.

FIG. 1 is a block diagram of an apparatus for implementing a flatness control method for a rolling mill according to the present invention. In the drawing, reference numeral 1 denotes zones Z- _{P to} Z defined in a width direction of a strip ST being rolled. _{P
Shows the} shape sensors A _{-P to} A _P arranged in (2P +
1: Number of shape sensors in the plate width direction). These shape sensors A- _{P to} A
_The detection value detected in _P is output to the low-order component extraction unit 11 and the high-order component extraction unit 21. Low-order component extraction unit 11, the detected value S _-P to S _P of each profile sensor A _-P to A _P for each zone Z _-P to Z _P
Guidance individually to the multiplier E _-P to E _P, superimposition of a low-order component extraction inputted from the detection value S _-P to S _P and a plurality of the setting device in this multiplier E _-P to E _P Factor ▲ W ⁽¹⁾ _-P ▼, ▲ W ⁽¹⁾ _{-P + 1} ▼…
▲ W ⁽¹⁾ _P-1 ▼, ▲ W ⁽¹⁾ _{+ P} ▼
Seeking a low-order component X ⁽¹⁾ of the plate-shaped by adding at summing point 12 is added a multiplication result for each _-P to Z _P, and outputs it to the subtracter 13. The inputs from the setting units connected to the multipliers E _{-P to} E _P include the low-order single component extraction in addition to the above-described superposition factors for low-order component extraction such as ▲ W ⁽¹⁾ _-P ▼. ▲ W ⁽³⁾ _-P ▼, ▲ W ⁽³⁾ _{-P + 1} ▼… ▲ W ⁽³⁾ _P-1 ▼, ▲ W ⁽³⁾ _P
▼ is there, they are each switch SW _1, are inputted selectively to the multiplier E _-P to E _P by _-P to SW _{1, P.} Each switch SW _{1, -P} ~SW _{1, P} is the steady operation of the mill, superposition factor for extracting low-order component, and the output of the work roll bender such as a high-order component control actuator reaches saturation when is adapted to be switched controlled such superposition factors for extraction low-order single component is output to the multiplier E _-P to E _P. The subtractor 13 subtracts the extracted low-order component from the low-order component of the target shape obtained in advance, and calculates the deviation thereof,
That is, the low-order component of the shape deviation is output to the gain setting units 14a and 14b. Gain setting device 14a, the proportional gain K _P in accordance with the rolling speed V in 14b, have set the integral gain K _1, the gain setter 14a is the value multiplied by the proportional gain K _P to the shape deviation low order component and a gain setting unit 14b is a value obtained by multiplying the integral gain K ₁ to the shape deviation low-order component is subjected to integral operation, and outputs to the respective summing point 15, corresponding to values appropriate added thereto at summing point 15 added This signal is output as a control signal to a low-order component control actuator such as a roll shifter to drive and control the actuator.

On the other hand high-order component extractor 21 each zone Z _-P to Z _P each shape sensor A _-P to A detection value of each _P S _-P to S _P individually multiplier F _-P
Leads to to F _P, the detection value in this multiplier F _-P ~F _P S _-P ~S _P
And superposition factors for higher-order component extraction input from a plurality of setting devices ▲ W ⁽²⁾ _-P ▼, ▲ W ⁽²⁾ _{-P + 1} ▼ ... ▲ W ⁽²⁾ _P-1 ▼, ▲ W ^{(2 )}
_{+ P} ▼ and by multiplying the sum of these in each zone Z _-P to Z _P each of the multiplication result to summing point 22, obtains a high order components X ⁽²⁾ of the plate-shaped, which to the subtracter 23 Output. Outside the superposition factor of the multiplier F _-P to F like the above-described input from the setter leading to ^{_{P ▲ W (2) -P ▼}} ... for higher order component extracting such, is "zero" There are two switches SW2 _{, -P}
To SW _2, are input to the selectively multiplier F _-P to F _P by _P. Each switch SW _{2, -P} ~SW _{2, P} is the steady operation of the mill superimposition factor for higher order component extraction, and the output of the work roll bender such as a high-order component control actuator has reached saturation When "zero" is multiplied by F- _P
Is adapted to be switched controlled so as to output the to F _P.
The subtracter 23 subtracts the extracted higher-order component X ⁽²⁾ from the higher-order component of the target shape obtained in advance, and calculates the deviation, that is, the shape-deviation higher-order component through the dead zone setting unit 26 to obtain the shape deviation of the predetermined area. Only the high-order components are output to the gain setting units 24a and 24b. In the gain setting units 24a and 24b, a proportional gain K _P and an integral gain K ₁ according to the rolling speed V are set, and the gain setting unit 24a multiplies the higher order component of the shape deviation by a proportional gain K _P and also gain setter 24b is subjected to integral operation to a value obtained by multiplying the integral gain K ₁ to the shape deviation high-order components, and outputs the respective summing point 25, corresponding to values appropriate added thereto at summing point 25 added This signal is output as a control signal to a higher-order component control actuator such as a work roll bender, and the actuator is driven and controlled. When the output of the higher-order component control actuator reaches a saturated state, the output of the addition point 25 is held unchanged.

The above-mentioned low order component extraction factor ▲ W ⁽¹⁾ _-P ▼… ▲ W ⁽¹⁾ _P
▼ Higher order component extraction factor ▲ W ⁽²⁾ _-P ▼... ▲ W ⁽²⁾ _P ▼ indicates the plate shape detected in each of the detected zones Z _{-P to} Z _P , for example, a quadratic function, an octal function, These correspond to the coefficients of the quadratic function and the octant function, respectively, when expressed by the linear combination of constants with the highest accuracy. That is, for example, if this linear combination expression is represented by the following expression (1), Square error is the sum of (2) the value J ₁ factor of the second order term to minimize alpha, low-order component of the coefficient β is respectively a plate shape of 8-order term at the position of each sensor, each of the high-order component This is a superposition factor for extraction.

The factors α and β are represented by the following equations (3) and (4).

▲ W ⁽¹⁾ _i ▼ and ＷW ⁽²⁾ _i ▼ in equations (3) and (4) are given by the following equations (5) and (6), respectively.

On the other hand low-order component extracting superimposed factor ▲ W ⁽¹⁾ when the output of the high-order actuator reaches a saturated state _i ▼ to place of low-order single-component extraction factor ▲ W used ⁽³⁾ _i ▼ is strip This is a parameter for expressing the detection shape of all zones in the width direction as a quadratic function, and a linear combination expression is represented by the following expression (7). Γ that minimizes the value of the sum of square errors (8) at each sensor position is the extraction factor for low-order single component. This factor γ
Is represented by the following equation (9).

▲ W ⁽³⁾ _i ▼ in the equation (9) is given by the following equation (10).

The values of the factors ＷW ⁽¹⁾ _i ▼, ＷW ⁽²⁾ _i ▼, and ▲ W ⁽³⁾ _i ▼ vary depending on the plate width, and specific numerical values are as shown in Table 1. Table 1 shows board widths of 1400mm, 1100mm, 600m
For each of the three types of strip m, the zones Z _{0 to} Z ₁₃ , Z _{0 to} Z ₁₀ , and Z _{0 to} Z ₅ defined in the width direction (Note that in Table 1, the distance from the center of the strip to one end thereof is shown. It indicates the coefficient value to multiplying the detected value a ₀ to a _P to have) each shows specific numerical values for each zone.

FIG. 2 is a graph showing the results of flatness control by the method of the present invention and the conventional methods 1 and 2, wherein the horizontal axis represents the position of the strip in the width direction, and the vertical axis represents the difference in plate-shaped unevenness. It is.

FIG. 2 (a) shows the case where the method according to the present invention is used and FIG.
Figures (b) and (c) show the results when the conventional methods 1 and 2 are used. As is clear from this graph,
Under a steady operation state in which none of the outputs of the respective actuators for controlling the higher order components are in a saturated state, the method of the present invention and the conventional method 2 except for the conventional method 1 have substantially the same overall flat shape except for the conventional method 1. I have. On the other hand, in a situation where the output of the higher order component control actuator is saturated, the conventional method 2
It can be seen that in the method of the present invention, the shape deformation at both end portions of the strip is suppressed to a small extent.

〔The invention's effect〕

As described above, in the method of the present invention, of course, at the time of steady operation, when the output of the higher-order component control actuator is saturated, the lower-order single component of the plate shape is extracted and only the lower-order shape control actuator is used. Since the control is performed, low-order component control is performed over the entire width of the plate, an uncontrollable state is avoided, and the control accuracy of the flatness is greatly improved. It is.

[Brief description of the drawings]

FIG. 1 is a block diagram of an apparatus for carrying out the method of the present invention, and FIG. 2 is a graph showing a comparison test result between the method of the present invention and a conventional method. 11 low-order component extractor, 13 subtractor, 14a, 14b gain setting unit, 21 higher-order component extractor, 23 subtractor, 24
a, 24b: Gain setting device, 26: Dead zone setting device, S
T: Strip, SW1 _{, -P to} SW1 _{, P} , SW2 _{, -P to} SW2 _{, P} ...
... switch, A _-P ~A _P ...... shape sensor, Z _-P ~Z _P ...... zone, S _-P ~S _P ...... detected value

Claims (1)

(57) [Claims] 1. During rolling, the shape of a rolled material is detected by detecting the tension distribution in the width direction in each of a plurality of zones defined in the width direction of the rolled material, and a low value previously determined as a detected value of each zone. Multiply the next component extraction factor and the high order component extraction factor, respectively, obtain the sum of them, extract the low order component and the high order component of the plate shape, and control the low order component to obtain the target plate shape based on this. Control the actuator for the higher order component control, and when the output of the higher order component control actuator reaches a saturated state, multiply the shape detection value of each zone by a previously obtained low order single component extraction factor, Flatness control of a rolling mill, wherein a sum of the low-order components and a low-order single component of a plate shape in place of the low-order components and the high-order components are extracted, and a low-order component control actuator is controlled based on the extracted components. Method.