JPS5815201B2 - Method for controlling the shape of metal strips - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION The present invention relates to a shape control method in saving rolling of metal strips such as steel plate strips.

Conventional shape control does not use all the information in the shape pattern signal obtained from the detection device, but uses only a few pieces of information as a state variable. It is limited to shape changes that occur symmetrically (monotonous shape defects, compound elongation, etc.), or it is difficult to uniquely give the target shape as a state variable value. It was only possible to control the shape of the strip with low functionality so that the difference between the two values was zero.

Therefore, with conventional shape control methods, ■ it is difficult to achieve good control over complex shape defects such as asymmetric shape changes such as one-sided elongation or compound elongation; ■ strip shape is determined by quality and In terms of productivity, a flat shape may not necessarily be the best shape, and in such cases, it is impossible to control to an arbitrary target shape, ■ It is difficult to select the amount of operation, etc. There are drawbacks.

The purpose of the present invention is to express the plate shape using the minimum number of state variables in order to eliminate the drawbacks of the conventional method as described above, and to have sufficient control ability even for shape defects represented by complex waveforms. The object of the present invention is to provide a shape control method for easily obtaining a strip shape of an arbitrary target pattern.

The present invention expresses a shape pattern signal with four parameters, each of which is related to either a symmetrical component or an asymmetrical component with respect to the center of the board in the width direction, and expresses the shape pattern desired for the product using the parameters. The parameter is given as a target value, and the parameter is recognized by the shape pattern signal from the plate shape detection device placed on the exit side of the rolling stand, and the operating variables for adjusting the asymmetric shape defect with respect to the center of the plate are set in advance. A mathematical model is prepared in which the asymmetric component of the parameters is given as a function of the parameter, and the manipulated variable for adjusting the symmetric shape defect is given as a function of the parameter that is the symmetric component of the above parameters. According to the deviation value between the parameter value and the target parameter, the operation amount to be adjusted for each operating end is determined by the above mathematical model, and the strip shape is controlled to an arbitrary target pattern. It can be controlled to any shape, the symmetrical component and the asymmetrical component with respect to the center of the plate in the width direction can be controlled separately, so it is easy to select the amount of operation in advance, and the mathematical model is simple and easy to create. The control ability can be demonstrated even for complex shape defects and asymmetric shape defects, and the control system can be brought into the optimal state by expressing the relationship between the manipulated variable and the parameter with an adaptive mathematical model. It offers many advantages for achieving a high degree of shape control, such as easy maintenance methods.

Next, an embodiment of the present invention will be described with reference to FIG.

In FIG. 1, 1 is a shape detection device, and 2 is a shape detection device 1.
3 is an arithmetic device that performs function approximation of the shape pattern using a fourth-order power series in the strip width direction X based on the signal from the 3D input signal, and recognizes the shape pattern by displaying the function; 3 is a device that inputs an ideal target pattern that differs depending on the type of strip; , 4 is a device that performs a comparison operation between the detected shape pattern and the target shape pattern, separates it into a symmetrical component and an asymmetrical component, and calculates the deviation value of each component. 5 is a device that selects the operating end of the asymmetrical component and calculates its operating amount. 9 is an IJ Mitsut device for checking the upper and lower limits of the manipulated variable of the asymmetric component; 6 is a gain adjustment device for compensating for the influence of the asymmetric component operation on the symmetric component; 7 is the input from the calculation device 4; A device for adding the symmetrical component deviation output and the influence compensation amount of the asymmetrical component; 8 a device for selecting the manipulated variable of the symmetrical component and calculating the manipulated variable; 10 checking the upper and lower limit values of the manipulated variable for the symmetrical component. A limit device 11 is a device that receives outputs from the calculation devices 5 and 8 and commands set values for various operating terminals.

The shape detection device 1 outputs electrical signals at a maximum of 30 points corresponding to the amount of elongation of the strip from 30 detectors fixedly arranged in the width direction of the strip.

The effective number of detector points varies depending on the width of the material to be rolled, but usually outputs 20 to 30 points.

In response to this electrical signal, the pattern recognition device 2 calculates the difference in the amount of elongation between each point and the center of the plate, approximates the shape pattern in the width direction of the strip with a quartic function as shown in equation (1), and converts the original waveform into Recognizes λ1 to λ4 that best match.

Where, X is the distance from the center of the strip in the width direction of the strip, and λ and λ4 are parameters for pattern recognition.

In equation (1), λ1 and λ3 have information regarding the asymmetric component, and λ2 and λ4 have information regarding the symmetric component.

The state variables used to control the shape pattern are λ1 to λ.
4 may be used directly, or 4 with equivalent information may be used directly.
Control can also be achieved by using, for example, linearly transformed parameters for these parameters.

Note that the function for performing pattern recognition is not necessarily a power series, but can also be expressed by sine and cosine components using a Fourier series or the like.

In this way, the pattern recognition device 2 recognizes and expresses the strip shape pattern using four parameters and outputs it to the block 4.

The deviation detection device in block 4 uses the parameters (
λ01:i=1.2.3.4) and the output value from block 2 (λi:1=112.3°4) are compared, and the symmetrical components (λ2, λ4, λo2, λ.

4) and the asymmetric components (λ3, λo1, λ03), and calculate the deviation (δλi) between the measured value (λi) and the target value (λoi) for each parameter.

That is, calculate the following formula. Asymmetrical component deviationSymmetrical componentdeviationThe asymmetrical component is adjusted by asymmetrical operation, so here, the operating amount of the asymmetrical component is the leveling difference (represented by △S) between the working side and the driving side of the rolling device and the roll pending counter. The difference between the working side and the driving side (expressed as △RBF) was selected.

Since the symmetrical component is adjusted by symmetrically operating the work side and the drive side, the vertical movement amount (S) of the rolling device and the roll venting force operating amount (RBF) were selected here as the operating amounts.

Block 5 is the deviation value (δ
λi: i=1, 2.3.4) is input, and the manipulated variables δΔS and δΔRBF of the asymmetric component are calculated for each δλi using equation (6).

Therefore, the matrix (c?ij) is a shape influence coefficient matrix.

That is, the characteristics of the rolling mill are expressed as equation (6)7.

Here, α'11 is the shape parameter λ when the leveling difference (△S) of the rolling down device is individually changed by a minute unit amount.
1, and a'12 means the amount of change in the shape parameter λ when the difference (△RBF) between the driving side and the working side of the roll pending force is individually changed by a minute unit amount, α′21 means the amount of change in the shape parameter λ3 when S is individually changed by a unit minute amount to the above leveling difference, and α′2□ is the amount of change in the shape parameter λ3 when the above △RBF is individually changed by a unit minute amount These values are given experimentally in advance or calculated using other mathematical models expressing process characteristics from various theta during rolling.

The number matrix [αij] is given in advance.

It is further desirable that these are adjusted according to the rolling conditions at hand.

The manipulated variables δΔS and δΔRBF of the asymmetric components calculated in block 5 are checked by the upper and lower limit checking device 9 to see if they are within a range that does not interfere with actual operation, and are output to the operation command device 11.

If the manipulated variable exceeds the upper or lower limit value, (6
) The manipulated variable calculated by the formula is output to 11 after being either stopped being output to 11 or after being corrected.

According to experiments conducted by the inventors, it has been confirmed that adjusting the amount of manipulation of the asymmetric component affects the symmetric component.

For this purpose, in order to output the manipulated variable of the asymmetric component to the operation command device 11 and at the same time compensate for the influence on the symmetric component, the compensation amount (δλ2, δλ4) is calculated in block 6 using equation (7), and the block Output to 7.

Here, the coefficient matrix [mij] is given in advance.

In other words, mll is the leveling difference (△S) of the lowering device.
The shape parameter λ when is individually changed by a unit minute amount
m12 means the amount of change in the shape parameter λ2 when the difference between the driving side and working side of the roll bending cutter (△RBF) is individually changed by a minute unit amount, and m2□ means the amount of change in the shape parameter λ2 as described above. m22 means the amount of change in the shape parameter λ4 when △S is individually changed by a unit minute amount, and m22 is the amount of change in the shape parameter λ4 when the above △RBF is changed independently by a unit minute amount. , these values are given in advance experimentally or calculated by a mathematical model expressing process characteristics from various data during rolling.

Next, the deviation δλ2 of the symmetrical component calculated in block 4,
δλ4 is added with 7 adder and δ is also added as 1 δ↑4 (
It is output to block 8 as δλ/2 in equation (8) and δλ'4 in equation (9).

δλ12=δλ2+δλ2−・−・・・・・・・・・・・・・
・−・・°(8) δλ′4=δλ4+δ−−・−・−・
(9) Block 8 receives the output from the adder T and calculates the manipulated variables δS and δRBF of the symmetrical component according to equation (11).

Here, the coefficient matrix [β...] is also [αi
j] was given in advance after the same consideration, but
It is more desirable that the rolling conditions be adjusted from time to time.

The manipulated variables δS and δRBF of the symmetrical components calculated in block 8 are outputted to the manipulated variable command device in block 11 through the upper and lower limit checking device in block 10.

The manipulated variable command device of block 11 includes the manipulated variables δ&, δff1BF of the asymmetric component and the manipulated variables δS, δ of the symmetric component.
In response to the RBF, the set value of the manipulated variable of each operating end is output.

In the above embodiment, the amount of correction of the operation amount set value of the drive side rolling down device is δSD = δS + δ△S The amount of correction of the operation amount setting value of the work side rolling down device δSw - δS The amount of correction of the operation amount setting value of the drive side roll bending adjustment device δRBD - δRBF + δ△RBF Amount of correction of operation amount set value of work side roll bending adjustment device δRBw
= δRBF.

In the explanation of the embodiment, a case was described in which a rolling down device and a roll bender adjustment device were selected as the operating end, but the control method according to the present invention allows good shape control to be achieved even when devices other than the above are used alone or simultaneously as the operating end. It is possible to do so.

As described above, the present invention has the effect that the shape of the strip can be easily controlled to any desired pattern, and that controllability can be exerted even for complex shape defects and asymmetric shape defects.

[Brief explanation of drawings]

The drawing is a block diagram showing the configuration of an embodiment according to the present invention. 1: Shape detection device, 2: Arithmetic device, 3: Input device, 4,
5: Calculation device, 6: Gain adjustment device, 7: Addition device, 8
: Calculation device, 9, 10: Limit device, 11: Command device.

Claims (1)

[Claims] 1. In rolling a metal strip, the shape pattern of the metal strip is expressed by four parameters, each of which is related to either a symmetric component or an asymmetric component with respect to the widthwise center of the metal strip, and the shape pattern of the metal strip after rolling is The desired shape pattern of the strip is given as a target value by the above parameters, and the above parameters are recognized by the shape pattern signal outputted by the shape detector that detects the shape of the metal strip after rolling, and the shape pattern of the metal strip is determined in advance. The manipulated variable for correcting a shape defect that is asymmetric with respect to the center in the width direction is given as a function of the parameter indicating the asymmetric component among the above parameters, and the manipulated variable for correcting a symmetric shape defect is given as a function of the symmetric component of the above parameters. A mathematical model is prepared that is given as a function of a parameter indicating the component, and each operating end should be adjusted using the mathematical model based on the deviation between the parameter value outputted and recognized by the shape detector and the target value of the parameter. A method for controlling the shape of a metal strip, characterized in that the shape of the metal strip is controlled to an arbitrary target pattern by determining the amount of operation and operating each operation end.