JP3069001B2 - Feedback control method of sheet crown / shape model - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a feedback control method for a crown / shape model of a rolled material in a continuous rolling mill.

[0002]

2. Description of the Related Art In general, accurate control of the crown and shape of a rolled material such as a steel plate in continuous rolling is important not only for maintaining the quality of the rolled material but also for avoiding trouble during rolling. For this reason, a roll bending device or a variable crown roll is provided in each stand of a continuous rolling mill, and in each stand, the amount of operation is adjusted to control the crown and the shape to target values.

For example, as disclosed in Japanese Patent Publication No. 5-85245, a preset roll bending force preset value is calculated to obtain a plate shape control method which can obtain a proper plate crown and a good plate shape. In order to achieve the target crown and shape based on the predicted rolling force, plate thickness, tension, etc. given by the schedule calculation, the hardware control of the roll bending force and the shape constraint between each stand The sum of squares of the difference between the final stand target crown and shape and the crown and shape predicted by the mathematical model, the roll bending force preset value to be obtained, and the square sum of the difference between the predetermined bending force and the predetermined bending force. Is set as the evaluation function, and the roll bending force preset value of each stand is obtained by the quadratic programming method. The have been disclosed.

[0004]

However, in presetting the crown and shape control of the multi-high rolling mill, the accuracy of the prediction model of the crown and shape is important, but the maximum error factor in the prediction model is the plasticity of the plate. This is a roll profile change due to roll wear and thermal expansion during deformation and rolling, and there is a problem that it is difficult to separate and control these effects from the sheet crown and shape error. Therefore, conventionally, all errors of the plastic deformation of the sheet and the change of the roll profile during the rolling are corrected by correcting the plastic deformation of the sheet and the change of the roll profile during the rolling. Therefore, at the time of schedule-free rolling, there is a problem that the error in this feedback method increases because the error between the two greatly changes for each plate.

On the other hand, Japanese Patent Publication No. 5-85245 discloses a secondary programming method using hardware control of a plate shape and a roll bending force in each stand based on a plate crown model and a plate shape model. The purpose of this method is to determine the preset value of the roll bending force, which becomes an unknown value.However, the operation correction amount of the roll bending force by this method can be used when the rolling conditions such as the sheet thickness and the sheet width change. There is no problem.

[0006]

Means for Solving the Problems In order to solve the above problems, the present invention has conducted intensive studies, and as a result, it has been found that plastic deformation and plate deformation, which are the largest factors of a plate crown / shape prediction error in sheet rolling, are considered. The purpose of the present invention is to provide a method of separating and controlling the roll profile change during rolling and performing feedback control, and the gist of the invention is to measure the sheet crown of the rolled material at the exit side of the final stand and perform these measurements. Next setting control based on sheet crown prediction model by feedback control based on values and sheet crown prediction model
In the strip crown / shape control method in a continuous rolling mill in which the operation amount of the crown control device at the time is corrected and the crown / shape on the exit side of the final stand is controlled to a target value, the sheet on the edge side of the final stand at the exit side of the final stand pre crown Found
The error for measurement values is separated into <br/> difference and plastic deformation prediction model for errors erroneous roll profile prediction model, respectively,
Roll profile prediction model and plastic deformation prediction model where a component of the strip crown prediction model Nitsu
The effect of errors for roll profile prediction models
Appropriate distribution to the roll profile prediction model for each stand
To correct the model,
Using the difference to correct the plastic deformation prediction model of the rolled material,
In the non-edge part of the plate, only the error for the roll profile prediction model is regarded as the total error and the
Allotment to the profile prediction model as needed
More specifically, the present invention provides a feedback control method for a sheet crown / shape model, wherein the sheet crown / sheet shape at the next setting is corrected to a target value .

[0007]

Embodiments of the present invention will be described below in detail with reference to the drawings. FIG. 1 is a system configuration diagram for explaining an embodiment according to the present invention. In FIG. 1, hot rolling mill group 1
Is a continuous rolling mill for a steel plate having six stands with four rolls, and the rolled material 2 is composed of a work roll 3 to be directly rolled, and a backup roll 4 that contacts and reinforces the work roll 3. The work roll 3 is reduced by the control device 5 and the work roll 3 is mounted on the work roll 3.
An operation amount of a crown control device such as a bending device is controlled. Numeral 6 denotes an arithmetic unit of the control unit 5. This arithmetic unit calculates the shape change coefficient of the stand by the control amount arithmetic unit 10 from the rolling condition data of the roll profile estimating unit 7 and the sheet deformation estimating unit 8 and the like. The coefficient is compared with the set index value. On the other hand, a crown detector 9 is provided on the exit side of the final stand, and a detection signal from this detector is inputted to the arithmetic unit 6 and is corrected.

FIG. 2 is an explanatory view showing a sheet crown error in the sheet width direction according to the present invention. As shown in FIG. 2, the plate edge is deformed three-dimensionally at the edge thereof, so that the plastic deformation error increases. Therefore, the sheet crown error (the actual sheet
Down the difference between the predicted value by the plate crown prediction model) errors and plastic deformation prediction for roll profile prediction model
On isolated model for errors, respectively, upstream each Stan
To correct roll profile prediction model and plastic deformation prediction model constants of the rolled material in the de. On the other hand, in the non-edge portion of the plate, the plate is deformed two-dimensionally, and the crown ratio before and after rolling is reduced.
Since the rate is also inherited , the change of the plastic deformation prediction model can be considered to be small, so that all the sheet crown errors are treated as errors for the roll profile prediction model . In other words, feedback is also available at each upstream stand
This is performed only for the role profile prediction model .

Therefore, the error ΔC _R for the roll profile prediction model in the non-edge portion is corrected as _{ΔC R} = C _aq −C _cal . Here, C _{aq is} measured by the crown detector 9 in FIG.
Plate crown actual measurement value C _cal : Final stand exit side plate crown prediction value Also, roll profile prediction model at the edge part
The use error _{△ C RP, △ C RP =} (C aq -C cal) × β β: As a model error distribution correction value, △ C _R, △ C _RP low <br/> Le impact upstream of each stand The model is corrected by appropriately allocating it to the profile prediction model . Note that △ C _R , △ C _RP , C _aq , and C _{cal ask} for errors.
It is given for each point in the width direction as the subject. Also, β
Is the roll of the total error of the plate crown of C _aq -C _cal
Figure 2 shows the proportion of the error for the profile prediction model.
It is a coefficient for allocating as described above. More specifically β
Becomes 1 at the base point of the edge and decreases as approaching the extreme edge.
It is expressed by a function in the width direction of the sheet to be reduced.

Further, the error ΔC ^P for the plastic deformation prediction model
_{R ^{is, △ C P R.New = C aq}} -C cal - △ C RP △ C P R = α · △ C P R.New + (1-α) △ C P R.Old However, △ C ^P _{R .New} : Corrected plastic deformation prediction model error _ΔC ^P _R.Old : Corrected plastic deformation prediction model error α: Calculated as relaxation coefficient to correct the plastic deformation prediction model constant of the rolled material . Again, △ C ^P _R , △ C ^P _R.New , △ C ^P
_R.Old is for each point in the plate width direction where error is a problem.
give. In this way, the error with respect to the calculated value of the actual value of the sheet crown at the exit of the final stand at the sheet edge is calculated by using the error for the roll profile prediction model and the plastic deformation prediction model.
Separating Le for error, respectively, as well as modify the roll profile prediction model and plastic deformation model constants upstream each stand, the roll profile predicted by the non-edge portion
Low upstream each stand the only model for the error as the total error
This is a modification of the profile prediction model . Like this
Roll profile model error and plastic deformation model
Crown prediction model with improved accuracy by eliminating
Is used to calculate the next setting of the operation amount of the crown control device.
Correct the plate crown and plate shape to target values.

[0011]

As described above, according to the present invention, the roll is divided into a plate edge portion and a non-edge portion. At the plate edge portion, the plastic deformation error of the plate and the roll during rolling caused by the roll wear and thermal expansion. After separating the profile error, the roll profile and the plastic deformation model constants are corrected, while the non-edge portion of the plate is corrected only by the roll profile error. The precision of strip crown and shape control over the entire length of the rolled material is greatly improved, and strips with good strip crown and shape quality can be manufactured.
This is an extremely excellent effect of improving the yield.

[Brief description of the drawings]

FIG. 1 is a system configuration diagram for explaining an embodiment according to the present invention;

FIG. 2 is an explanatory view showing a sheet crown error in a sheet width direction according to the present invention.

[Explanation of symbols]

 REFERENCE SIGNS LIST 1 hot rolling mill group 2 rolled material 3 work roll 4 backup roll 5 control device 6 arithmetic unit 7 roll profiling prediction unit 8 plate deformation prediction unit 9 crown detector 10 control amount calculation unit

Claims (1)

(57) [Claims] 1. A sheet crown of a rolled material is measured on the exit side of a final stand, and the measured values are compared with a sheet crown prediction model.
By feedback control based on the Le, strip crown prediction
Operation of Crown Control Device at Next Setting Control Based on Model
In the strip crown / shape control method for a continuous rolling mill that corrects the amount and controls the strip crown / shape on the exit side of the final stand to the target value, the predicted value of the measured value of the sheet crown on the exit side of the final stand at the edge of the strip is determined. the error was separated into a roll profile prediction model for errors and <br/> error for plastic deformation prediction model, respectively, configuration of the strip crown prediction model
Roll profile prediction model of the place is an element Hoyo
Roll profile predicted for fine plastic deformation prediction model
The effect of model errors is evaluated by the roll profile of each upstream stand.
Allocation to the model for forecasting
In addition, the error for the plastic deformation prediction model is used to predict the plastic deformation of the rolled material.
Used to model modification, further, its shadow only error roll profile prediction model in the plate non-edge portion as a total error
Hibiki into roll profile prediction model for each upstream stand
By appropriately distributing and modifying, the board
A feedback control method for a sheet crown / shape model, wherein the sheet / shape shape is corrected to a target value .