JP2003305510A - Method for controlling continuous rolling mill - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a method for controlling a continuous rolling mill to control both a plate crown of a rolling material and the flatness of the plate to a desired value. <P>SOLUTION: A plate crown gauge is installed at the outlet side of an intermediate rolling machine among a plurality of rolling machines having actuators which are disposed in tandem to control plate crowns. When deviations between measured values of the plate crowns by the plate crown gauge and calculated target values of the plate crowns are made to approach zero, the deviations of the plate crowns are divided by a product of an influence coefficient of a control input to the actuator to the plate crown and a transfer rate thereof for the respective rolling machines on the upstream side more of the rolling machine having the plate crown gauge at the outlet side, and thus the control input to the actuator proportional to the obtained value is determined to control the corresponding actuator. <P>COPYRIGHT: (C)2004,JPO

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a continuous rolling mill for rolling metal or the like, and more particularly, to a plate thickness distribution in the width direction of a rolled material, that is, a plate crown, and a wave in the longitudinal direction, that is, a plate flatness. The present invention relates to a control method of a continuous rolling mill for controlling the value.

[0002]

2. Description of the Related Art An apparatus for controlling the strip crown and strip flatness in a hot finish rolling mill is disclosed in, for example, the Iron and Steel Institute of Japan 100th Memorial Symposium Rolling Theory Section (1994). June 1996), pages 81 to 90, entitled "High-precision rolling technology in hot strip mills" (Yasuyuki Nishiyama et al.). In particular,
On page 87 of the magazine, the hot finish rolling mill consisting of 6 stands and the roll bender as the control end during rolling based on the outputs of the strip crown gauge and strip flatness meter installed on the exit side of the final stand. A crown / shape control system is shown. In this case, the roll bender is operated only in the three stands in the rear stage, and the feedback operation is not performed for the stands in the front stage. Therefore, it is not sufficient to control the plate crown and the plate flatness to desired values, and moreover, there is no specific explanation about the operation of the roll bender, which makes it difficult to carry out easily.

Further, "The Development of Shape / Crown Control Theory in Thin Sheet Rolling" by Hiromi Matsumoto, pp. 155 to 176, pp. 155-176, Journal of Rolling Theory Section (March 1985), 30th anniversary of Japan Iron and Steel Institute. ) Is a detailed description of the relationship between the virtual plate crown (hereinafter referred to as mechanical plate crown) when the rolling load distribution is uniform in the width direction, the transfer rate, the genetic coefficient of the input side plate crown to the output side plate crown, etc. It is explained.

However, there is no description in this section magazine about controlling the plate crown and the plate flatness to desired values, and it has been difficult to carry out these controls easily.

The present invention has been made in consideration of the above circumstances, and an object of the present invention is to provide a control method for a continuous rolling mill which controls the plate crown and the flatness of a rolled material in a continuous rolling mill to desired values. And

[0006]

A method for controlling a continuous rolling mill according to a first aspect of the present invention is one of a plurality of rolling mills which are arranged in tandem and each of which has an actuator for controlling a strip crown. A strip crown meter is installed on the exit side, and when approaching the deviation between the actual value of the strip crown measured by this strip crown meter and the target value of the strip crown calculated in advance to zero, a rolling mill with a strip crown gauge on the exit side is used. For each rolling mill upstream, the deviation of the strip crown is divided by the product of the coefficient of influence of the actuator control amount on the strip crown and the transfer rate for each rolling mill, and the actuator control amount proportional to the obtained value is obtained. Then, the corresponding actuator is controlled.

The control method for a continuous rolling mill according to a second aspect of the present invention further includes a first actuator and a second actuator for controlling the strip crown of each of the plurality of rolling mills. When the control amount exceeds the facility allowable limit, the control amount for the second actuator corresponding to the amount exceeding the facility allowable limit is calculated, and the first
The control amount of the actuator is held at the equipment permissible limit value, and the second actuator is controlled according to the control amount corresponding to the amount exceeding the equipment permissible limit.

According to a third aspect of the present invention, in the method for controlling a continuous rolling mill according to the first or second aspect, a plate flatness meter is installed between stands where a plate crown gauge is installed, and the plate flatness meter is installed. When the measured value of the plate flatness due to the value exceeds the allowable range, the control based on the measured value of the plate crown meter is stopped, and the work of the rolling mill that has the plate flatness meter on the output side based on the measured value of the plate flatness meter. Either or both of the roll bending force and the leveling are controlled.

According to a fourth aspect of the present invention, in the control method for a continuous rolling mill according to the third aspect, in controlling the bending force of the work rolls, the flatness on the operator side by the flatness meter and the flatness on the drive side are controlled. Measure the plate flatness and the plate flatness at the center in the plate width direction, and find the difference between the average value of the plate flatness on the operator side and the drive side and the plate flatness at the center in the plate width direction. The PI calculation is executed for the deviation from the plate flatness command value, and the plate thickness is inversely proportional to the transfer rate, the influence coefficient of the bending force on the mechanical plate crown, and the shape change coefficient determined by the rolling mill and the rolling schedule. Find the proportional bending force control amount.

According to a fifth aspect of the present invention, in the control method for a continuous rolling mill according to the third aspect, in controlling the leveling of the work rolls, the flatness on the operator side by the flatness meter and the flatness on the drive side are measured. While measuring the degree
The difference between the plate flatness on the operator side and the plate side on the drive side is calculated, and the PI calculation is executed for the deviation between this difference and the plate flatness command value, and at the same time the coefficient of influence of the transfer rate and bending force on the mechanical plate crown and rolling A leveling control amount that is inversely proportional to the shape change coefficient determined by the mill and rolling schedule and that is proportional to the plate thickness is obtained.

[0011]

In the control method for the continuous rolling mill according to the first aspect of the present invention, the actuator of the upstream rolling mill is operated so as to bring the deviation between the measured value and the target value of the strip crown close to zero. Various combinations with and are possible.

In the control method for a continuous rolling mill according to a second aspect of the present invention, when the control amount of the actuator is large, the control amount of the first actuator is held at the equipment allowable limit value, and the second actuator is also held. Is controlled according to the control amount corresponding to the amount exceeding the equipment allowable limit, so that reliable and safe control can be performed.

In the control method for a continuous rolling mill according to a third aspect, when the measured value of the plate flatness measured by the plate flatness meter exceeds an allowable range, the control based on the measured value of the plate crown gauge is stopped, Based on the measurement value of the plate flatness meter, the bending force and leveling of the work roll of the rolling mill having the plate flatness meter on the outlet side are controlled so that either or both of them are controlled. It is possible to prevent the situation where the plate flatness deteriorates.

In a control method for a continuous rolling mill according to a fourth aspect of the present invention, when controlling the bending force of the work roll, the flatness on the operator side by the flatness meter, the flatness on the drive side and the strip width direction are used. While measuring the plate flatness of the central portion, the difference between the average value of the plate flatness of each of the operator side and the drive side and the plate flatness of the central portion in the plate width direction is calculated, and this difference and the plate flatness command value By performing the PI calculation on the deviation and determining the bending force control amount that is inversely proportional to the transfer rate, the influence coefficient, and the shape change coefficient, and is proportional to the plate thickness, it is possible to perform reliable plate flatness control.

In the method for controlling a continuous rolling mill according to a fifth aspect of the present invention, the PI calculation is executed for the difference between the flatness on the operator side and the flatness on the drive side by the flatness meter, and the transfer rate is obtained. Since the leveling control amount that is inversely proportional to the influence coefficient and the shape change coefficient and proportional to the plate thickness is obtained, reliable plate flatness control can be performed.

[0016]

The present invention will be described in detail below with reference to the embodiments shown in the drawings. FIG. 1 is a block diagram showing the configuration of the first embodiment of the present invention together with an applicable rolling mill. 1 in the figure
To 7 are stand rolling mills arranged in tandem (hereinafter,
1st stand to 7th stand). Each stand is provided with an actuator (not shown) for controlling the plate crown and the plate flatness. As the actuator, the upper work roll and the upper backup roll are integrated, and the lower work roll and the lower backup roll are integrated, and a cross angle control device called a pair cross for crossing in the rolling direction, bending to the work roll. There are a work roll bender that applies a force, a work roll shifter that shifts the work roll in the axial direction, an intermediate roll shifter that shifts the intermediate roll in the axial direction, and the like. Here, the work roll bender and the cross angle control device are used as actuators for simplification of description.
The present invention is not limited to this and can be applied to rolling mills equipped with other actuators.

The rolled material 8 is sequentially rolled in the direction of arrow 9 by the first to seventh stands. Of these stands, the plate crown meter 10 and the plate flatness meter 13 are installed on the exit side of the fourth stand, and the plate crown meter 11 and the plate flatness meter 14 are installed on the exit side of the fifth stand. Furthermore, the seventh
A plate crown gauge 12 and a plate flatness gauge 15 are installed on the exit side of the stand. Then, based on the outputs of the plate crown meter 10 and the plate flatness meter 13 installed on the exit side of the fourth stand,
Plate crown controllers 21 to 24 are provided which output the control amounts for the work roll benders of the first to fourth stands, respectively, and also output the control amounts to the cross angle control device when the control amounts exceed the allowable range. . Further, based on the outputs of the plate crown gauge 11 and the plate flatness gauge 14 installed on the exit side of the fifth stand, the same control amount is output to the work roll bender and the cross angle control device of the fifth stand. A plate crown control device 25 is provided, and further, a seventh
A plate crown that outputs the same control amount to the work roll bender and the cross angle controller of the sixth and seventh stands based on the outputs of the plate crown meter 12 and the plate flatness meter 15 installed on the exit side of the stand. Control devices 26 and 27 are provided.

The operation of the present embodiment configured as described above will be described below together with the related rolling theory.

The mechanical plate crown of the i-stand, that is, the plate crown C _mi when the rolling load distribution is uniform in the width direction, is expressed by the following equation. C _mi = A _i · P _i + B _i · θ _i ² + D _i · F _Bi + E _i · C _WRi + M _i (1) where P _i : rolling load of the i stand θ _i : cross angle of the i stand F _Bi : i-stand work roll bending force C _WRi : i-stand work roll crown A _i , B _i , D _i , E _i , M _i : a constant determined by the rolling schedule. Of these, the constant is generally called an influence coefficient for the mechanical plate crown. Further, the plate crown C _i on the i stand stand-out side is expressed by the following equation. C _i = α _i · C _mi + β _i · C _i-1 (2) where α _{i is} the transcription rate of the i stand β _{i is} the genetic coefficient of the i stand C _i-1 is the plate crown on the i stand entry side. .

Further, there is a relation of the following equation among the entrance side thickness, the exit side thickness, the transfer rate and the genetic coefficient in the i stand.

[0021]

[Equation 1] However, H _{ci is} the plate thickness in the center of the plate width direction on the i stand entry side, and h _{ci is} the plate thickness in the plate width direction center of the i stand exit side.

The plate flatness δ _i of the i-stand is expressed by the following equation using the entrance side plate crown, the exit side plate crown, the entrance side plate thickness and the exit side plate thickness.

[0023]

[Equation 2] Where ξ _i is a shape change coefficient determined by the rolling mill and rolling schedule.

The operation of the first embodiment will be described below in accordance with the above rolling theory. In the tandem rolling mill illustrated in FIG. 1, the material is generally hot-rolled in units of several tons to tens of tons, and the rolled material is called one coil. At this time, the plate width and plate thickness are determined for each coil. Also,
The cross angle of the first stand to the seventh stand and the work roll bending force are calculated in advance by a host computer (not shown), and the settings are made before rolling. If there is an error in the set value, an error will occur in the output side plate crown and plate flatness of each stand, and the desired product cannot be obtained. Also,
The hardness, temperature, plate thickness, etc. of the rolled plate are not constant in the rolling direction and the plate width direction, so the output side plate crown and plate flatness of each stand fluctuate, and the desired product cannot be obtained. become.

This embodiment is intended to control the plate crown and plate flatness to desired values even under such conditions.
i stand deviation [Delta] C _i and strip flatness deviation .DELTA..delta _i of the strip crown is defined as follows.

[0026]

[Equation 3] However, C _i ^REF : Target value of ^output side plate crown of i stand C _i ^MEAS : Measured value of output side plate crown of i stand δ _i ^REF : Target value of ^output side plate flatness of i stand δ _i ^MEAS : Measurement of ^output side plate flatness of i stand Value h _ci : Plate thickness at the center of plate width on the stand side of the i stand h _{DR, i} ^Xc : X _c from the end of the plate width on the drive side on the stand side of the i stand
Plate thickness h _{OP, i} ^Xc : X from the operator side plate width end of the i stand
It is the plate thickness of _c .

Generally, the target value and the measured value of the plate crown and the plate flatness are obtained for each point in the plate width direction, but in the present embodiment, the plate crown is controlled at a position inside the plate width end by X _c. However, we are trying to control the plate flatness at a position inside by X _F from the plate width edge. In this case, the case of X _c = X _F is also included. Therefore, the values of X _c and X _F are used as the respective values in the above equations (1) to (4).

Now, the plate crown meter 10 in FIG. 1 measures the plate crown on the delivery side of the fourth stand, and the plate crown controller 21
24 to 24 output the control amount for the roll bender and the cross angle control device of the corresponding stand using the measured value. In this case, the plate crown control devices 21 to 23 corresponding to the stand having no plate crown meter on the output side, and the plate crown control device 24 having the plate crown meter on the output side calculate the plate crown in exactly the same manner, and further, , And calculates a control amount for the work roll bender and the cross angle control device based on the calculation result. Therefore, the method of obtaining the plate crown will be described.

Here, the target value of the plate crown on the outgoing side of the i-stand in the setting calculation of the plate crown and the plate flatness is C
_i ^REF (i = 1 to 4). Along with this, the target value of the rolling load of each stand is P _i ^REF and the target value of the cross angle is θ _i.
^REF , the target value of the work roll bending force is F _Bi ^REF , and the target value of the work roll crown is C _WRi ^REF . Also,
The measured value of the rolling load of the i stand corresponding to this is P _i
^{Let MEAS be} the measured value of the cross angle be θ _i ^MEAS , be the measured value of the work roll bending force be F _Bi ^MEAS , and be the measured value of the work roll crown be C _WRi ^MEAS .

By using these target value and actual measurement value and the equation (1), the first to
The output side plate crown C _i ^CAL of four stands is calculated by the following formula. C _i ^CAL = C _i ^REF + α _i [A _i (P _i ^MEAS −P _i ^REF ) + B _i {(θ _i ^MEAS ) ² − (θ _i ^REF ) ² } + D _i (F _Bi ^MEAS −F _Bi ^REF ) + E _i (C _WRi ^MEAS −C _WRi ^REF )] + β _i (C _i-1 ^CAL −C _i-1 ^REF ) (7) At this time, in the first stand, C _i-1 ^CAL = C _i-1
^Since it is ^REF , first, the output side plate crown C ₁ ^{CAL of} the first stand is required, and subsequently, the output side plate crown C ₂ ^{CAL of} the second stand and the output side plate crown C ₃ of the third stand.
^CAL and the ^output side plate crown of the fourth stand C ₄ ^CAL are used to sequentially calculate the output side plate crown of the downstream side stand by using the output side plate crown of the upstream side stand. Distinguishing ^{_{Here, C 1 CA L, C 2}} CAL, C 3 CAL, C 4 CAL and referred to as the strip crown calculating measurements, the strip crown correction calculation, the following measured values.

The plate crown on the delivery side of the fourth stand is measured by a plate crown meter 10, and its measured value C ₄
Deviation between ^MEAS and calculated value C ₄ ^CAL can be ^adjusted to 1 to 3 depending on the plate thickness.
If the distribution is distributed to the stands, the final correction calculation value C _i ^MEAS of the plate crowns of the first to third stands is obtained by the following equation.

[0032]

[Equation 4] However, i = 1, 2, 3, and j = 4.

In the same manner as above, the sixth stand without a plate crown meter is determined from the deviation between the measured value C ₇ ^MEAS of the plate crown meter 12 provided on the exit side of the seventh stand and the calculated value C ₇ ^CAL. The board crown on the exit side can be obtained.

2 and 3 show a host computer and plate crown control devices 21 to 24 corresponding to the above-described plate crown measuring method.
5 is a flowchart showing a specific processing procedure of. In this case, the target value of the plate crown of each stand is set in step S1, and the rolling load of each stand, the cross angle of the pair-crossed rolls, the work roll bend force (hereinafter, the roll cross angle and the work roll are set in step S2. the bend force abbreviated as state amount of the actuator) and predicts a work roll crown, each value to the actual measurement corresponding to the prediction value of step S3, step S4 rolling load of each stand, the state amount of the actuator and For the work roll crown, the deviation between the predicted value and the measured value is calculated.

Subsequently, in step S5, these deviations are multiplied by the respective influence coefficients for the mechanical plate crown, and in step S6 the values obtained by the multiplication are added according to the equation (1) to obtain the deviation of the mechanical plate crown. Is calculated. In the next step S7, the counter that counts the number of the stand that executed the calculation is set to "1", and in step S8, the deviation of the mechanical plate crown of the first stand is multiplied by the transfer rate to add it to the plate crown target value. Calculate the exit plate crown of the first stand. Next, in step S9, the value of the stand number counter is set to "2", and in step S10, the egress plate crown of the second stand is calculated by also taking into account the genetic coefficient using equation (7), and in step S11. It is determined whether or not the value of the stand number counting counter has reached the target "4". If it is not "4", the value of the stand number counting counter is incremented by "1" in step S12, and the calculation in step S10 is performed. Execute and obtain the exit side plate crown up to the 4th stand.

Next, in the processing procedure collectively represented as step S13, in step S13A, the plate crown on the delivery side of the fourth stand is measured by the plate crown meter 10, and step 13
In B, a deviation from the calculated value of the plate crown on the delivery side of the fourth stand obtained in step S10 is calculated, and in step S13C, the deviation is distributed to the first to third stands, and further, in step S13D. These deviations are added to the calculated values of the plate crowns of the first to third stands to obtain the final correction calculation values of the plate crowns of the first to third stands.

Thus, the sheet crown can be calculated and measured from the difference between the target value and the actual measured value of the rolling load, cross angle, work roll bending force, and work roll crown of the i stand, regardless of the presence or absence of the sheet crown meter. And in addition,
By correcting the calculated value of each stand upstream of this from the deviation between the measured value and the calculated value of the plate crown meter installed on the downstream side stand, the same measured value as when installing the plate crown meter on each stand was obtained. can get. Further, if the plate crown controller corrects the work roll bending force and / or the cross angle according to the measured value, the plate crown can be controlled for each stand.

The above formula (7) is ignored because the plate crown by the backup roll is very small. However, when this plate crown cannot be ignored, the plate crown caused by the backup roll is neglected. An expression including the item may be used.

By the way, when the plate crown is controlled by each of a plurality of continuous stands, for example, in correcting the difference between the measured value and the target value of the plate crown meter 10 installed on the exit side of the fourth stand, the first Or, simultaneous control of the fourth stand can be considered. The simultaneous control is to control the work roll bend force and / or the cross angle of the first to fourth stands at substantially the same time, as shown in the time chart of FIG. In order to carry out this control, the plate crown control device 21 ~
For 24, the control amount for the roll bender or the cross angle control device is obtained as follows.

First, the case where the work roll bending force is simultaneously controlled for the first to fourth stands will be described.
The following two methods can be arbitrarily selected for this.

One of them is a case where the work roll bend force control amounts of the first to fourth stands are the same or are set to a given ratio, and the other one is a ratio crown of the first to fourth stands. This is the case where the control amount of (plate crown / plate thickness) is the same or is set to a given ratio.

Therefore, first, the case where the work roll bend force control amounts of the first to fourth stands are the same or set to a given ratio will be described.

From equation (1) above, the work load of the i stand
Rubend force F_BiMinute change ΔF_BiMechanical against
Board crown C_miMinute change ΔC_miIs calculated by
It ΔC_mi= D_i・ ΔF_Bi                      … (9) In addition, from formula (2), the mechanical plate crown of the i-stand is
C_miMinute change ΔC _miAnd plate claw on the i-stand entry side
C_i-1Minute change ΔC_i-1For i stand plate
Crown c_iMinute change ΔC_iIs calculated by the following equation. ΔC_i= Α_i・ ΔC_mi+ Β_i・ ΔC_i-1     …(Ten) ΔC in equation (9)_miSubstituting into equation (10) yields ΔC_i= Α_i・ D_i・ ΔF_Bi+ Β_i・ ΔC_i-1… (11) Therefore, each plate club of the first to fourth stands
The minute change in Eun can be expanded as follows. ΔC₁= Α₁・ D₁・ ΔF_B1+ Β₁・ ΔC₀ ΔC₂= Α₂・ D₂・ ΔF_B2+ Β₂・ ΔC₁ ΔC₃= Α₃・ D₃・ ΔF_B3+ Β₃・ ΔC₂ ΔC_Four= Α_Four・ D_Four・ ΔF_B4+ Β_Four・ ΔC₃ … (12) ΔC in equation (12)₀= 0. Therefore, α_i・ D_i= Γ_i                       …(13) In addition, the minute change in work roll bending force ΔF
_BIn contrast, the work roll bend force F of each stand_Biof
Small change ΔF_BiAre each W_iΔF multiplied by_Bi=
W_i・ ΔF_B, Then equation (12) can be rewritten as
Get (ΔC₀= 0).

[0044] _{ΔC 1 = γ 1 · W 1} · ΔF B ΔC 2 = γ 2 · W 2 · ΔF B + β 2 · ΔC 1 ΔC 3 = γ 3 · W 3 · ΔF B + β 3 · ΔC 2 ΔC 4 = γ ₄ · W ₄ · ΔF _B + β ₄ · ΔC ₃ (14A) Therefore, solving for ΔC ₄ gives ΔC ₄ = γ ₄ · W ₄ · ΔF _B + β ₄ · (γ ₃ · W ₃ · ΔF _B + β ₃ · ΔC ₂ ) = γ ₄ · W ₄ · ΔF _B + β ₄ · (γ ₃ · W ₃ · ΔF _B + β ₃ · (γ ₂ · W ₂ · ΔF _B + β ₂ · ΔC ₁ )) = γ ₄ · W ₄ · ΔF _B + β ₄ · (γ ₃ · W ₃ · ΔF _B + β ₃ · (γ ₂ · W ₂ · ΔF _B + β ₂ · γ ₁ · W ₁ · ΔF _B )) = γ ₄ · W ₄ · ΔF _B + β ₄・ Γ ₃・ W ₃・ ΔF _B + β ₄・ β ₃・ γ ₂・ W ₂・ ΔF _B + β ₄・ β ₃・ β ₂・ γ ₁・ W ₁・ ΔF _B = ΔF _B (γ ₄・ W ₄ + β the _{4 · γ 3 · W 3 +} β 4 · β 3 · γ 2 · W 2 + β 4 · β 3 · β 2 · γ 1 · W 1) ... (14B) this equation (16) and solving for [Delta] F _B following The formula is obtained.

[0045]

[Equation 5] U = W ₁・ γ ₁・ β ₂・ β ₃・ β ₄ + W ₂・ γ ₂・ β ₃
Β ₄ + W ₃ · γ ₃ · β ₄ + W ₄ · γ _{4 where} W _{i is a} given ratio (0 to 1.0).

Here, that the work roll bend force control amount is the same means W ₁ = W ₂ = W ₃ = W ₄ , and a certain ratio of the work roll bend force control amount is W ₁ : W
_{2: W 3: W 4 =} a 1: a 2: a 3: a 4 (a 1,
a ₂ , a ₃ , a ₄ are predetermined values).

Therefore, the control amount ΔF _Bi of the work roll bending force of the first to fourth stands may be calculated by the following equation. ΔF _Bi = W _i · ΔF _B (16) Thus, it is possible to perform control while giving an even load, paying attention to the bending force of the work roll bender of the rolling mill.

Next, a case will be described in which the ratio crown control amounts of the first to fourth stands are the same or are set to a given ratio.

I (= 1,2,3)
h_i, The deviation of the plate crown is ΔC_iAnd the 4th stand out
Side plate thickness h_Four, The deviation of the plate crown is ΔC_FourAnd the fourth
Stand ratio Ratio of i stand to crown control amount
Rate crown control rate W _iThen the following equation holds
It

[0050]

[Equation 6] By solving this equation (17) for ΔC _i and substituting it in equation (11), the following equation is obtained.

[0051]

[Equation 7] Further, the following equation is obtained by modifying the above equation (3). β _i · h _ci-1 = h _ci −α _i · h _ci (20) Substituting this equation (20) into equation (18) and solving for ΔF _Bi ,
The following equation is obtained.

[0052]

[Equation 8] The work roll bend force control amount of the second to fourth stands is obtained according to this equation (21). Since the plate crown on the entrance side of the first stand is zero, the work roll bending force control amount of the first stand is calculated using the following equation.

[0053]

[Equation 9] Thus, focusing on the ratio crown, it is possible to perform control while applying a uniform load to the roll bender of the rolling mill, that is, control that does not disturb the shape.

As described above, when the control amounts of the work roll bending forces of the first to fourth stands are obtained and the simultaneous control is performed, the leading end of the plate passes through the fourth stand and the plate crown gauge 10
The first simultaneous control was performed at the time when the plate crown was measured by, and the rolled material part subjected to the simultaneous control by the first stand passed through the fourth stand and the plate crown was measured by the plate crown meter 10. At the time point, the second simultaneous control is performed, and thereafter, the same control as this is repeated.

The case where the control amount of the work roll bending force of the first to fourth stand rolling mills is obtained by the equation (16) or the equations (21) and (22) and simultaneously controlled is explained above. It is necessary to confirm how much the plate crown control amount by the correction of 1 is, or whether the plate flatness is within the allowable range for the plate crown control. If it is not within the allowable range, the work roll bend force control amount must be changed. The plate crown control devices 21 to 24 also have these functions. The derivation of the plate crown control amount and the change of the work roll bend force control amount will be described below.

In this case, the control amount ΔC _i ^CTL of the plate crown with respect to the control amount ΔF _Bi of the work roll bending force is calculated as follows using the transfer rate α _i and the coefficient of influence D _i on the mechanical plate crown with respect to the bending force. expressed. ΔC _i ^CTL = α _i · D _i · ΔF _Bi (23) Therefore, the value after the control of the strip crown on the delivery side of each rolling mill with respect to the correction of the work roll bend force of the first to fourth stand rolling mills C ₁ ^CTL ~ C ₄ ^CTL can be ^calculated by the following equation. C ₁ ^CTL = C ₁ ^MEAS + ΔC ₁ ^CTL (24) C ₂ ^CTL = C ₂ ^MEAS + β ₂ · ΔC ₁ ^CTL + ΔC ₂ ^CTL ... (25) C ₃ ^CTL = C ₃ ^MEAS + β ₃ · β ₂ · ΔC ₁ ^CTL + Β ₃ · ΔC ₂ ^CTL + ΔC ₃ ^CTL (26) C ₄ ^CTL = C ₄ ^MEAS + β ₄ · β ₃ · β ₂ · ΔC ₁ ^CTL + β ₄ · β ₃ · ΔC ₂ ^CTL + β ₄ · ΔC ₃ ^CTL + ΔC ₄ ^CTL (27) However, C _i ^{MEAS is} a plate crown correction calculation measurement value obtained by the above equation (8).

By correcting the control amount of the work roll bending force according to the value after controlling the plate crown,
The control accuracy of the plate crown is improved.

Here, in the plate crown control, it is essential to control the plate flatness while keeping the plate flatness within an allowable range.
To keep the plate flatness within the allowable range is to keep δ _i calculated by the equation (4) within the upper and lower limit values. This can be expressed by a mathematical expression as follows.

[0059]

[Equation 10] However, a _i : the lower limit of the i stand b _i : the upper limit of the i stand. Note that H _i = h _i−1 by definition.

Therefore, the values C ₁ ^{CTL to} C ₄ ^{CT L} of the plate crown after control, which are obtained by the equations (24) to (27), are converted into C _i ,
As C _i-1 , it can be checked whether or not the plate flatness is kept within an allowable range. Here, if the allowable range is exceeded, the output side plate crown control amount ΔC _{i is set in} the order of the fourth stand, the third stand, the second stand, and the first stand so that the lower limit value a _i or the upper limit value b _i is reached. ^CTL , that is, the control amount ΔF _Bi of the work roll bending force is changed. As a result, it becomes possible to perform plate crown control in consideration of plate flatness without installing a plate flatness meter.

Next, if the work roll bending force thus obtained is within the allowable limit of the work roll bending equipment, no problem will occur. However, since the allowable limit may be exceeded, in this embodiment, the cross angle is corrected by the amount of protrusion. The correction of the cross angle will be described below.

[0062] From equations (1) and (2), the minute change amount [Delta] C _i of the strip crown for small variation [Delta] F _Bi of minute change amount [Delta] [theta] _i and the work roll bending force of the cross angle theta _i is determined by the following equation .

ΔC _i = (B _i · 2θ _i · Δθ _i + D _i · ΔF _Bi ) · α _i (29) Here, under the condition that does not affect the plate crown (ΔC _i = 0), There is the following relationship between the minute change Δθ _i of the cross angle and the minute change ΔF _Bi of the work roll bending force.

[0064]

[Equation 11] Therefore, the amount of work roll bend force protruding is ΔF _Bi.
^{If OVER} , the cross angle correction amount Δθ _i to compensate for this
Can be calculated by the following equation.

[0065]

[Equation 12] In the embodiment shown in FIG. 1, the plate crown control devices 21 to 24 are
If the measured value of the plate flatness by the plate flatness meter 13 is within the allowable range, the measured value of the plate crown gauge 10 is used to calculate the work roll bend force according to the equations (16) or (21) and (22). Calculate the control amount and add it to the work roll bender control system (not shown) via adders 41-44.If the work roll bend force is not within the allowable limit, control the cross angle according to equation (31). The amount is obtained and added to a cross angle control system (not shown) via the adders 41 to 44.

Even if the above-described cross angle correction is performed, if the value measured by the plate flatness meter 13 exceeds the allowable range, the work roll bender and the cross angle control system are not controlled and will be described later. As described above, the plate flatness control is performed on the fourth stand.

As a result, even if the control amount for the plate crown is large, the control can be performed reliably and safely.

FIG. 5, FIG. 6 and FIG. 7 are flow charts showing a concrete processing procedure for the plate crown controller for the above control. That is, in step S21, the fourth
Set the target value of the plate crown of the stand, and step S22
Then, measure the plate crown on the exit side of the 4th stand, and step
After calculating these deviations in S23, in step S24, the work roll bend force ΔF _Bi of the first to fourth stands is calculated according to the given ratio W _{i from} the work roll bender control amounts by the equations (16) to each other. It is calculated using the transcription rate and the genetic coefficient so as to be the same or a predetermined ratio.

Next, in step S25A of the two steps collectively shown as step S25, (23)
Calculate the control amount of the plate crown according to the formula, step S25B
At the calculated value of the control amount of the plate crown of the stand,
4)-(27) is used to calculate the total controlled variable by adding the value obtained by multiplying the controlled variable of the plate crown on the upstream side of the stand by the genetic coefficient.

Next, of the eight processing steps expressed collectively as step S26, in step S26A, the ratio plate crown, that is, the process of dividing the control amount of the plate crown by the total control amount by the outlet plate thickness, is performed. Execute and step S26B
Then, the plate flatness is calculated using the equation (28), and in the next step S26C, the value of the counter indicating the stand number is set to 4, and subsequently, in step S26D, this plate flatness is an allowable value. If it is within the allowable value, it is determined whether or not the value of the counter is "1" indicating the first stand in step S26E, and it must be "1". For example, in step S26F, the counter value is decremented by "1", and in step S26D it is determined whether or not the plate flatness of the third stand is within the allowable value.
Repeat the same operation up to the stand. If the allowable range of formula (28) is deviated in the process of step S26D, the range within the lower limit of the formula (28) is corrected in step S26G, and the work roll bend force is lost in step S26H. The cross angle correction amount for compensating for the protrusion amount is calculated, and after the correction is performed, the processes in and after step S25B described above are executed.

On the other hand, when it is determined by the determination in step S26E that only the first stand, that is, all of the first to fourth stands, can be dealt with only by controlling the work roll bending force, they are put together as step S27. 6 processing steps represented by That is, in step S27A, the control of the plate crown is performed only by the roll bending force, the counter value indicating the stand number is set to "4" in step S27B, and the roll bending force of the roll bending force is set in the next step S27C. It is determined whether the controlled variable is within the allowable limit of the equipment. If it is within the allowable limit of the equipment, step S2
In 7D, it is determined whether or not the counter value is "1" indicating the first stand, and if it is not "1", the counter value is decremented by "1" in step S27E and step S27D. It is determined whether or not the plate flatness of the third stand is within the allowable value, and thereafter, the same operation is repeated up to the first stand as long as it is within the allowable limit of the equipment.

If the result of determination in step S27C is not within the limit of the equipment, in step S27F, the cross angle correction amount is calculated in the same manner as when the roll bend force exceeds the limit, and the processing of step S27D is performed. Move on to. The correction of the calculated cross angle is added to the cross angle control device.

Note that FIG. 5, FIG. 6, and FIG. 7 show the processing procedure corresponding to the control while giving equal load by paying attention to the bending force to the roll bender of the rolling mill. 8, 9 and 10 show processing procedures for controlling the same or a given ratio.
Although these flowcharts have step numbers in the 20's and 30's, they are exactly the same except for the difference between step S24 and step S34.
Therefore, step S34 will be described. This step
In S34, the control amount of the roll bender bending force is controlled by using the transfer rate and the genetic coefficient so that the control amounts of the ratio crowns are equal to each other or the predetermined ratio is obtained by using the formulas (21) and (22). calculate.

By the way, the processes shown in FIGS. 5 to 7 and 8 to 10 are conditioned on whether or not the plate flatness is within the allowable range. However, it is certain that the plate flatness is within the allowable range. In some cases, omit these processes, determine whether the control amount of the bending force of the roll bender exceeds the allowable limit of the equipment, and control the roll cross angle only for rolling mills that exceed it. Good.

FIG. 11 and FIG. 12 are flowcharts showing these processing procedures. In this case, it is detected in step S41 that the tip of the plate has reached the plate crown meter, and the step
In S42, the deviation between the calculated value and the measured value is calculated as described above. Then, in step S43, the control amount of the bending force of each roll bender of the first to fourth stands is calculated, and step
In S44, set the counter value indicating the stand number to "4". Next, in step S45, it is determined whether or not the control amount of the bending force of the fourth stand is within the allowable limit of the equipment. if,
If it is within the allowable limit, it is determined in step S46 whether or not the value of the counter indicating the stand number is "1". If it is not "1", the value is decremented by "1".
When the process of S45 is performed and the control amount of the bending force is within the allowable limit of the equipment for all stands, the process proceeds to step S48.

However, if it is determined that the equipment is not within the allowable limit in step S45, the control amount of the cross angle is obtained in step S45A, and the process returns to step S46. Then, in step S46, when the value of the counter indicating the stand number becomes "1", in step S48, if the stand is within the allowable limit of the equipment, only the control amount of the bending force is changed to the allowable limit of the equipment. If the stand exceeds the limit, the control amount of the bending force and the control amount of the roll angle are output at the same time. And step
In S49, it is determined whether or not the rolling of the rolled material currently being rolled is finished, and if it is not finished, it is determined in step S50 that the control position, that is, the time when the tip of the rolled material reaches the plate crown gauge. Every time the position bitten by the first stand reaches the plate crown meter, the processing of step S41 and thereafter is executed, and the arrival at the plate crown meter is not detected, and the step
The control operation ends when it is determined in S49 that the rolling has ended.

Although the simultaneous control of the first to fourth stands has been described above, the simultaneous control of the fifth to seventh stands is also performed. Therefore, a plate crown meter installed on the exit side of the fifth stand
11 and the plate flatness meter 14 measure the same points as the measurement points by the plate crown meter 10 and the plate flatness meter 13 installed on the exit side of the fourth stand, and similarly are installed on the exit side of the seventh stand. The plate crown meter 12 and the plate flatness meter 15 measure the same points as those measured by the plate crown meter 10 and the plate flatness meter 13 installed on the exit side of the fourth stand.

Then, the plate crown control device 25 provided corresponding to the fifth stand calculates the plate crown deviation ΔC ₅ according to the measurement value of the plate crown meter 11, and at the same time, the work roll bend force of the fifth stand is calculated by the following equation. Control amount ΔF
Calculate _B5 .

[0079]

[Equation 13] That is, the plate crown controller 25 subtracts the value obtained by multiplying the controlled variable at the upstream stand by the genetic coefficient from the plate crown deviation ΔC ₅ of the fifth stand, and the obtained value is used to influence the transfer rate and the mechanical plate crown. Divide by the product of the coefficient and the work roll bend force control amount ΔF _B5 . Further, in addition to a work roll bender control system (not shown) via the adder 45, if the work roll bend force is not within the allowable limit, the plate crown control device 25 (31)
The control amount of the cross angle is calculated according to the formula and is added to the cross angle control system (not shown) via the adder 45.

Further, the plate crown control devices 26 and 27 provided corresponding to the sixth and seventh stands also use the respective measured values of the plate crown meter 12 and the plate flatness meter 15 and perform the same operation as described above. The control amount of the work roll bending force of the 6th and 7th stand is obtained, and it is added to the control system of the work roll bender (not shown) via the adders 46 and 47. If the work roll bending force is not within the allowable limit, Plate crown controller 2
Reference numerals 6 and 27 determine the control amount of the cross angle according to the equation (31), and add it to the cross angle control system (not shown) via adders 46 and 47. As a result, the plate crown of the rolled material on the upstream side as viewed from the measurement position can be quickly controlled by all the rolling mills on the upstream side.

The case where the plate crown controllers 21 to 27 simultaneously control the plate crowns has been described above.
When the control point of the strip crown in the upstream rolling mill reaches the downstream rolling mill, the strip crown controllers 21 to 27 may have a delay control function for compensating for the control amount in the downstream rolling mill. With respect to the delay control, the plate crown control for the first to fourth stands will be described below, as described above.

When the work roll bend force control amount is the same in each rolling mill or at a certain ratio, the work roll bend force control amount is obtained according to the equations (15) and (16) as in the case of simultaneous control. . Further, when the ratio crown control amount is the same or a certain ratio in each rolling mill, the control amount of the work roll bending force is obtained according to the equations (21) and (22) as in the simultaneous control. In addition, the controlled plate crown amount (2
4) to (27), when the allowable range shown in Eq. (28) is exceeded, change the work roll bend force control amount, or (31)
Obtaining the correction amount of the roll cross angle by the formula is similar to the case of the simultaneous control.

There are two possible methods for executing the delay control according to these control amounts.

The first method is, as shown in FIG. 13, in addition to the above control amount, the plate crown deviation ΔC is obtained only by the fourth stand.
Work roll bend force control amount ΔF to make ₄ zero
_B4 is calculated by the following formula.

[0085]

[Equation 14] Also for this work roll bend force control amount ΔF _B4 , it is checked whether the flatness limit is exceeded by the above formula (28). If it exceeds the limit, plate crown control corresponding to the limit is performed. The amount ΔC ₄ ′ is obtained, and the work roll bend force control amount Δ corresponding to the plate crown control amount ΔC ₄ ′ is obtained.
_Find F _B4 ′.

Now, the plate crown is measured by a total of 10 plate crowns.
Measurement of the plate flatness by the plate flatness meter 13.
When each is started, the plate crown control device 24 uses the formula (34).
Work roll bend force control amount ΔF_B4Or its correction amount Δ
F_B4'Control is performed, and at the same time, the first to third stands
Corresponding plate crown control devices 21 to 23 are the formulas (21) and (22).
Rui is the work roll calculated by Eqs. (24) to (27)
Bending force control amount ΔF _B1~ ΔF_B3Control by
It

Next, when the control point of the third stand reaches the fourth stand, the plate crown controller 24 applies the work roll bend force to the fourth stand by the control amount of the work roll bend force calculated by the following equation. Reverse compensation. That is, those with a minus sign are added.

[0088]

[Equation 15] Next, when the control point of the second stand reaches the fourth stand, the plate crown controller 24 inversely compensates the work roll bend force for the fourth stand by the control amount of the work roll bend force calculated by the following equation. .

[0089]

[Equation 16] Finally, when the control point of the first stand reaches the fourth stand, the plate crown controller 24 inversely compensates the work roll bend force for the fourth stand by the control amount of the work roll bend force calculated by the following equation. .

[0090]

[Equation 17] As a result, it is possible to control the plate crown over almost all parts of the rolled material upstream from the measurement position.

FIGS. 14 and 15 are flowcharts showing the processing procedure of the plate crown controllers 21 to 24 corresponding to this control. When it is detected in step S51 that the tip of the plate has reached the plate crown meter, In step S52, an error between the measured value and the calculated value is calculated, and in step S53, the first control amount for each stand rolling mill and the second control amount for the fourth stand rolling mill are calculated. Subsequently, of the two steps represented as step S54, it is determined in step S54A whether or not the second controlled variable is within the allowable limit of the equipment. If it is determined that the second controlled variable exceeds the allowable limit, the second step is performed. The control amount of is corrected to the allowable limit, and the process proceeds to step S55. Step S55
Then, the work roll bend force of the fourth stand is corrected by the second control amount, and the work roll bend forces of the first to third stands are corrected by the first control amount. Then, step S56
Sets the stand number counter to "3" at step S57, determines at step S57 whether or not the control point of the third stand has reached the fourth stand, and at step S58 the control for the third stand becomes Inverse compensation with 4 stands, next step S60
In step S57, it is determined whether or not the value of the stand number counting counter has become "1". If not, the value is decremented by "1" in step S57, and then step S58.
At each of the control points of the second stand and the first stand, the reverse compensation is sequentially executed every time when the control points of the second stand and the first stand reach the fourth stand. Thereafter, the control points of the first rolling mill are set to the fourth control point by the processing of steps S61 and S62. Make sure you have reached the stand and finished rolling.

Although these treatments were determined based on the transfer rate and the genetic coefficient so that the control amounts of the work roll bending forces of the respective rolling mills were equal to each other or were in a predetermined ratio,
FIG. 16 and FIG. 17 show the processing procedure when the control amounts of the bending forces of these work rolls are the same as each other or are determined to be a predetermined ratio. This is the step S71, S72, S
The processing of 74 to S82 is the step S of the processing procedure of FIG. 14 and FIG.
51, S52, and S54 to S62 are exactly the same as those shown in FIG.
Since the processing of step S73 in the figure is only different from step S53 in FIG. 14, only step S73 will be described. Here, when the first control amount is calculated, the control amounts of the ratio plate crowns of the rolling mills are calculated to be the same as each other or to have a predetermined ratio.

On the other hand, the second method is controlled as shown in FIG. That is, when the plate crown meter 10 starts to measure the plate crown and the plate flatness meter 13 starts to measure the plate flatness, the plate crown controller 24 controls the work roll bending force ΔF _B4 or The correction amount ΔF
_The control by _B4 'is executed.

At this time, the plate crown control device 23 corresponding to the third stand executes control by the control amount of the work roll bending force calculated by the following equation.

[0095]

[Equation 18] Further, the plate crown control device 22 corresponding to the second stand executes control by the control amount of the work roll bending force calculated by the following equation.

[0096]

[Formula 19] Further, the plate crown control device 21 corresponding to the first stand 21
Executes the control by the control amount of the work roll bending force calculated by the following equation.

[0097]

[Equation 20] These controls by the plate crown controllers 21 to 23 are executed at the same time when the plate crown controller 24 executes the control of the work roll bending force.

Next, when the control point of the third stand reaches the fourth stand, the plate crown controller 24 applies the work roll bend force to the fourth stand by the control amount of the work roll bend force calculated by the following equation. Reverse compensation. That is, those with a minus sign are added.

[0099]

[Equation 21] Next, when the control point of the second stand reaches the third stand, the plate crown controller 23 inversely compensates the work roll bend force for the third stand by the control amount of the work roll bend force calculated by the following equation. .

[0100]

[Equation 22] Finally, when the control point of the first stand reaches the second stand, the plate crown controller 22 inversely compensates the work roll bend force for the second stand by the control amount of the work roll bend force calculated by the following equation. .

[0101]

[Equation 23] Deviation of the plate crown in the above equations (35) to (43) ΔC _i ^CTL (i
= 1, 2, 3) is the equation (21), (22) or (15), (16)
Work roll bend force control amount Δ
F _Bi is converted into a plate crown change amount by using the equation (23).

19 and 20 are flowcharts showing the processing procedure of the plate crown control devices 21 to 24 corresponding to this control. In step S91, it is detected that the plate front end has reached the plate crown meter, and step The deviation of the plate crown is detected in S92, and in step S93, the first control amount of the bending force with respect to the bending force of the work roll of each stand is the same as the control amount of the bending force of the work roll of each stand.
Alternatively, the first control amount is calculated so that the ratio becomes a predetermined ratio, and the second control amount of the bending force with respect to the bending force of the work rolls of the second and subsequent stands is calculated. in this case,
It is determined by adding the first controlled variable of the bending force of the work roll of the stand to the first controlled variable of all the stands located upstream of the stand.

Next, of the five processing procedures collectively shown as step S94, the value of the counter for counting the stand number is set to "4" at step S94A, and the second control amount for the fourth stand is set. Is within the allowable limit of the equipment, and if it is within the allowable limit, proceed to the processing of step S94D,
If it is not within the allowable limit, the second controlled variable is limited to the allowable limit in step S94C, and the process proceeds to step S94D. Step S94D
Then, it is determined whether or not the value of the counter is "1" indicating the first stand, and if it is not "1", the value is decremented by "1" in step S94E and step S9 is performed.
Execute the processing below 4B. Then, the processing of limiting the control amounts of the first to fourth stands to the allowable limit is executed by the processing of step S94C.

Next, in step S95, the roll bender of the first stand is added with the first control amount, and the roll benders of the second and subsequent stands are added with the second control amount. Then, it is determined whether or not the (i-1) th control point has arrived at the i-th stand, and then, in steps S97, S98 ..., Corresponding to the first control amount of all stands located upstream respectively. Inversely compensate only the value. Then, in step S99, it is determined whether or not the reverse compensation has been completed for all the stands upstream of the plate crown meter, and in steps S100 and S101, the control point at the most upstream stand reaches the installation position of the plate crown meter. The above process is repeated until that time, and it is confirmed that the control point on the most upstream stand has reached the installation position of the strip crown gauge and that the rolling has been completed, and the process is completed.

Although these treatments were determined on the basis of the transfer rate and the genetic coefficient so that the control amounts of the work roll bending forces of the respective rolling mills were equal to each other or became a predetermined ratio,
21 and 22 show a processing procedure in the case where the control amounts of the bending forces of these work rolls are equal to each other or are set to be a predetermined ratio. This is step S111, S112,
The processing of S114 to S121 is the step of the processing procedure of FIG. 18 and FIG.
The processing is exactly the same as that of S91, S92, and S94 to S101.
Since the processing of step S113 in the figure is only different from that of step S93 in FIG. 19, this step S113 will be described. Here, when calculating the first control amount, the control amount of the ratio plate crown of each rolling mill is Calculations are made to be the same as each other or to be a predetermined ratio.

Next, the operation of the plate crown controllers 25 to 27 in the delay control will be described.

The plate crown meter 11 measures the plate crown on the exit side of the fifth stand, and the point at which the plate crown meter 10 measures the plate crown on the exit side of the fourth stand. The plate crown controller 25 calculates the plate crown deviation ΔC ₅ based on this measured value, and then executes the control by the control amount of the work roll bending force calculated by the following equation.

[0108]

[Equation 24] Further, the plate crown meter 12 measures the point where the plate crown meter 10 measures the plate crown on the exit side of the seventh stand and the plate crown meter 10 on the exit side of the fourth stand. The plate crown controller 26 calculates the plate crown deviation ΔC ₆ based on this measured value, and then executes the control by the control amount of the work roll bending force calculated by the following equation.

[0109]

[Equation 25] Then, the plate crown control device 27 calculates the plate crown deviation ΔC ₇ based on this measured value, and subsequently executes the control by the control amount of the work roll bending force calculated by the following equation.

[0110]

[Equation 26] It should be noted that ΔC ₆ ^CTL in the equation (46) is the control amount of the exit side plate crown of the sixth stand by the control amount ΔF _B6 of the work roll bending force of the equation (45).

23 and 24 are flowcharts showing the processing procedure of the plate crown controllers 21 to 27 corresponding to the above-mentioned control. Here, it is detected that the tip of the plate has reached the plate crown meter in the first step S130, and the next step
In S131, find the deviation between the measured value and the calculated value, and
In S132, the control amount of the bending force with respect to the roll bender of the fifth to seventh stands is calculated by using the equations (44), (45) and (46).

Next, in the processing collectively shown as step S133, it is determined as the control amount of the bending force calculated at step S133A, and the value of the counter for counting the stand number is set to "7" at step S133B. Set whether or not the control amount of the bending force for the 7th stand is within the allowable limit of the equipment in step S133C, and if it is within the allowable limit, proceed to the processing of step S133E. In S133D, the control amount of the bending force is limited to the permissible limit, and the control amount of the cross angle is calculated for the amount exceeding the allowable limit. In step S133E, it is determined whether or not the value of the counter is "1" indicating the first stand, and if it is not "1", the value is decremented by "1" in step S133F, and the following steps S133C and Execute the process. Then, the process of limiting the control amounts of the first to seventh stands to the allowable limit is executed by the process of step S113D.

In the delay control described above, the control is performed when the measured values of the flatness meters 13, 14, 15 are within the allowable range. If the measured values of the plate flatness meter 13 exceed the allowable range. For example, flatness control is performed on the 4th stand,
If the measurement value of the plate flatness meter 14 exceeds the allowable range, the flatness control is performed on the fifth stand, and further, the plate flatness meter
If the 15 measured values exceed the allowable range, the flatness control is performed on the seventh stand, and details of these will be described later.

By the way, as a method of controlling the plate crown and the plate flatness based on the outputs of the plate crown gauges 10, 11, and 12, not only simultaneous control and delay control, but also monitor control can be executed. In this case, the control amount for the work roll bender can be determined as follows, for example.

In the first to fourth stands, the plate crown deviation ΔC ₄ is obtained by the equation (5) using the measured value of the plate crown meter 10, and then the i (= 1, 2, 3) stand is calculated by the following equation. Calculate the work roll bend force control amount.

[0116]

[Equation 27] However, G _Mi : control gain S: Laplace operator.

During this monitor control, for the first to third stands, the plate flatness expressed by the equation (28) is the upper and lower limit values a and b.
If the work roll bend force exceeds the facility capacity limit, the work roll bend force is limited to this limit value. In order to compensate for the excess by the cross angle, the cross angle correction amount Δθ _i is calculated using the equation (31), and the cross angle is controlled accordingly.

Further, for the fifth stand, using the measured value of the plate crown meter 11, the plate crown deviation Δ is calculated by the equation (5).
C ₅ is obtained, and then the control amount of the work roll bending force of the fifth stand is calculated by the following equation.

[0119]

[Equation 28] Then, the upper and lower limits of the plate flatness are checked, and the processing when the work roll bend force exceeds the equipment capacity limit is the same as described above. Further, in the 6th and 7th stands, the plate crown deviation ΔC ₇ is obtained by using the measurement value of the plate crown meter 12 by the formula (5), and then the work roll bend of the i (= 6, 7) stand is calculated by the following formula. Calculates the control amount of force.

[0120]

[Equation 29] Then, the upper and lower limits of the plate flatness are checked, and the processing when the work roll bend force exceeds the equipment capacity limit is the same as described above.

On the other hand, each of the above-mentioned controls is based on the flatness meter 13, 1
This is a configuration example when the measured values of 4 and 15 are within the allowable range. When the measured values of the flatness meters 13, 14 and 15 are not within the allowable range, the plate flatness is directly controlled. .

FIG. 25 shows a configuration example of the apparatus when the measured values of the flatness meters 13, 14, 15 are not within the allowable range.
The same elements as those in FIG. 1 are designated by the same reference numerals and the description thereof will be omitted. Here, based on the output of the plate flatness meter 13, the plate flatness control device 16 controls one or both of the bending force and the leveling of the work roll of the fourth stand, and based on the output of the plate flatness meter 14. The fourth plate flatness control device 17
Controls the level of the work roll bender on the stand, and further controls the flatness of the plate based on the output of the flatness meter 15.
18 controls the bending force and / or the leveling of the work roll of the fourth stand. The input paths of the plate flatness gauges 13 to 15 to the plate crown controllers 21 to 27 are omitted for simplification of the drawing.

Here, the plate flatness meter 13 measures the plate flatness at each of N points in the plate width direction. Of these measured values, the measured value near the center in the plate width direction is δ _c ^MEAS . On the other hand, the measured values in the vicinity of X _F from the plate width end on the drive side and the operator side are δ _DR ^{ME AS} and δ _OP ^MEAS , respectively.

The plate flatness control device 16 can be constructed, for example, as shown in FIG. In the figure, the deviation between the plate flatness command 50 and the plate flatness measurement value 57, that is, the plate flatness deviation 51 is added to the PI control unit 52. The PI controller 52 has a total gain G _k , an integral gain 1 / T ₁ , and a proportional gain T ₂ / T ₁ . The output of the PI control unit 52 is applied to the work roll bender 54 via the conversion gain 53. The work roll bender 54 bends the work roll of the rolling mill 55. A plate flatness measurement value 57 is obtained from a plate flatness meter 56 provided on the exit side of the rolling mill 55. Here, the plate flatness command 50 is given by the following equation.

[0125]

[Equation 30] However, δ _DR ^REF : Target value of flatness on the drive side δ _OP ^REF : Target value of flatness on the operator side δ _c ^REF : Target value of flatness centered in the width direction. The plate flatness measurement value 57 is given by the following equation.

[0126]

[Equation 31] Thus, the plate flatness control device 16 controls the bending force of the work roll so that the deviation between the plate flatness command 50 and the plate flatness measurement value 57 becomes zero. Similarly, the plate flatness control devices 17 and 18 control the bending force of each work roll of the fifth and sixth stands.

FIG. 27 shows another one of the plate flatness control devices 16, 17, and 18.
One configuration example, especially for controlling the reduction leveling
Is shown. In the figure, plate flatness command 60 and plate flatness
Deviation from the measured value 67, that is, plate flatness deviation 61 is PI
It is added to the control unit 62. This PI control unit 62 is a total game
In G_M, Integral gain 1 / T₃, Proportional gain T_Four/ T ₃
have. The output of the PI control unit 62 is the conversion gain 63.
To the reduction leveling 64 via. Reduction Levelin
The gu 64 operates the leveling of the rolling mill 65. This rolling mill 65
From the plate flatness meter 66 installed on the output side of the
Is obtained.

Here, the plate flatness command 60 is given by the following equation. δ _DR ^REF −δ _OP ^REF The plate flatness measurement value 67 is given by the following equation. δ _DR ^MEAS −δ _OP ^MEAS Meanwhile, the conversion gain 63 is given by the following equation.

[0129]

[Equation 32] Is. Note that the plate wedge is the difference between the operator side and the drive side of the plate thickness, and is distinguished from the mechanical plate wedge, that is, a virtual plate wedge when the rolling load distribution is uniform in the width direction, in the rolling leveling 64. T _H is a time constant.

According to these methods, it is possible to prevent the situation where the flatness is deteriorated by controlling the plate crown.

The flatness control by the plate flatness control device shown in FIG. 26 or 27 may be performed every predetermined period T _s1 or continuously.

Of the above-mentioned control, the processing procedure when the measured value of the plate flatness is not within the allowable range is as shown in FIG. 28, in which the plate flatness is measured in step S141, and in step S142.
To determine whether the measured value is within the allowable range,
If it is present, the processing is terminated, and if not, in step S143, the processing based on the count value of the plate crown meter is terminated, and the stand having the plate flatness meter on the output side based on the plate flatness meter. One or both of the work roll bending force and the leveling are controlled to complete the processing.

FIG. 29 shows a specific processing procedure for controlling the roll bender when the flatness of the flatness meter is not within the allowable range. The flatness of the plate is measured in step S151, and the flow proceeds to step S152. If it is determined that the measured value is not within the allowable range, the processing by the plate crown meter is stopped in step S153, the difference between the operator side and the drive side is calculated in step S154, and the roll bender's value is calculated in step S155. The control amount is calculated and output in step S156. These processes correspond to the control method of claim 18.

FIG. 30 shows a specific processing procedure for controlling the leveling when the flatness of the plate flatness meter is not within the allowable range. The flatness of the plate is measured in step S161.
If it is determined in step S162 that the measured value is not within the allowable range, the process by the plate crown meter is stopped in step S163, the difference between the operator side and the drive side is calculated in step S164, and in step S165. The leveling control amount is calculated and output in step S166.

FIG. 31 is a block diagram showing the configuration of the third embodiment of the present invention. In the figure, the same elements as those of FIG. 25 are designated by the same reference numerals, and the description thereof will be omitted. In the third embodiment, in addition to the above-mentioned control, feedforward control of the plate crown is performed. Load interlocking control devices 31 to 37 are provided corresponding to the first to seventh stands, and the work roll bend force is controlled. The control amounts are added via the adders 41 to 47, respectively. Further, feedforward control devices 28 and 29 for the fifth stand and the sixth stand are newly added.

Here, the feedforward controller 28,
Reference numeral 29 is for calculating the control amount of the work roll bending force for removing the plate crown deviation and adding it to the plate crown control devices 26, 27 of the downstream stand.

Of these, the feedforward controller 28
^Calculates the deviation ΔC ₄ ^FF between the plate crown target value C ₄ ^{REF on the} delivery side of the fourth stand and the measured value C ₄ ^MEAS by the plate crown meter 10. Then, when this measurement point reaches the fifth stand, the work roll bend force control amount ΔF _B5 ^FF obtained by the following equation is added to the plate crown controller 25.

[0138]

[Expression 33] However, G ₅ ^FF is a control gain.

Next, the above-mentioned measuring point is the installation of the plate crown meter 11.
When the point is reached, the feedforward controller 29 will
Measured value C_Five ^MEASAnd plate crown target value C_Five ^REFDeviation from
ΔC _Five ^FFAnd this measurement point reached the 6th stand
Work roll bending force obtained by the following formula
Control amount ΔF_B6 ^FFTo the plate crown controller 26.

[0140]

[Equation 34] However, G ₇ ^FF is a control gain.

By adopting this feedforward control, it is possible to perform control in various combinations with other controls.

FIG. 32 is a flow chart showing a concrete processing procedure of the feedforward control devices 28, 29 corresponding to these controls. In this case, it is detected in step S181 that the plate tip has reached the plate crown meter, and step S1
At 82, find the deviation between the measured value and the predicted value or calculated value,
In the next step 183, the bending force of the roll bender of the stand downstream of the plate crown meter is calculated, and step S1
The controlled variable calculated in 84 is output.

Since the embodiment shown in FIG. 31 is equipped with all the controllers for the simultaneous control or delay control of the plate crown, the monitor control, the plate flatness control, the load interlocking control, and the feed forward control, the rolling schedule In most cases, it is possible to maintain the plate crown and the plate flatness within the desired ranges. However, even if any one of these controls is performed, or two or more controls are performed. They may be implemented together, and the type and the number thereof may be appropriately selected according to the control accuracy.

Further, in each of the above-described embodiments, as the actuator for controlling the plate crown and the plate flatness, the one provided with the roll bender and the cross angle control device has been described. Even if a six-roll rolling mill is equipped with intermediate roll bending, local cooling of work rolls, work roll shifter, intermediate roll shifter, etc., it shows the relationship between the mechanical plate crown and the state quantities of the factors affecting it. (1) formula, mechanical plate crown,
Based on the equation (2) showing the relationship between the transcription rate and the genetic coefficient and the equation (3) showing the relationship between the transcription rate, the genetic coefficient and the plate thickness, by performing the same deformation and expansion as described above, other types of The control amount for the actuator can be obtained.

Furthermore, in the above embodiment, the continuous rolling mill was targeted, but these controls are also applicable to a single-stand rolling mill, and the CVC (Continuous Variable Cro
wn) It goes without saying that it can also be applied to rolling mills.

[0146]

As is apparent from the above description, according to the present invention, there is provided a control method for a continuous rolling mill for controlling the strip crown and strip flatness of a rolled material in a continuous rolling mill to desired values. You can

[Brief description of drawings]

FIG. 1 is a block diagram showing a configuration of a first embodiment of the present invention together with an applicable rolling mill.

FIG. 2 is a flowchart showing a specific processing procedure of the first embodiment of the present invention.

FIG. 3 is a flowchart showing a specific processing procedure of the first embodiment of the present invention.

FIG. 4 is a flowchart showing a specific processing procedure of the first embodiment of the present invention.

FIG. 5 is a time chart showing the simultaneous control of the first embodiment of the present invention.

FIG. 6 is a flowchart showing a specific processing procedure of the first embodiment of the present invention.

FIG. 7 is a flowchart showing a specific processing procedure of the first embodiment of the present invention.

FIG. 8 is a flowchart showing a specific processing procedure of the first embodiment of the present invention.

FIG. 9 is a flowchart showing a specific processing procedure of the first embodiment of the present invention.

FIG. 10 is a flowchart showing a specific processing procedure of the first embodiment of the present invention.

FIG. 11 is a flowchart showing a specific processing procedure according to the first embodiment of the present invention.

FIG. 12 is a flowchart showing a specific processing procedure of the first embodiment of the present invention.

FIG. 13 is a time chart showing the delay control of the present invention.

FIG. 14 is a flowchart showing a specific processing procedure of the first embodiment of the present invention.

FIG. 15 is a flowchart showing a specific processing procedure of the first embodiment of the present invention.

FIG. 16 is a flowchart showing a specific processing procedure of the first embodiment of the present invention.

FIG. 17 is a flowchart showing a specific processing procedure of the first embodiment of the present invention.

FIG. 18 is a time chart showing delay control according to the first embodiment of the present invention.

FIG. 19 is a flowchart showing a specific processing procedure according to the first embodiment of the present invention.

FIG. 20 is a flowchart showing a specific processing procedure of the first embodiment of the present invention.

FIG. 21 is a flowchart showing a specific processing procedure of the first embodiment of the present invention.

FIG. 22 is a flowchart showing a specific processing procedure of the first embodiment of the present invention.

FIG. 23 is a flowchart showing a specific processing procedure of the first embodiment of the present invention.

FIG. 24 is a flowchart showing a specific processing procedure of the first embodiment of the present invention.

FIG. 25 is a block diagram showing a configuration of a second embodiment of the present invention together with an applicable rolling mill.

FIG. 26 is a block diagram showing a detailed configuration example of main elements of a second embodiment of the present invention.

FIG. 27 is a block diagram showing another detailed configuration example of the main elements of the second embodiment of the present invention.

FIG. 28 is a flowchart showing a specific processing procedure of the second embodiment of the present invention.

FIG. 29 is a flowchart showing a specific processing procedure according to the second embodiment of the present invention.

FIG. 30 is a flowchart showing a specific processing procedure of the second embodiment of the present invention.

FIG. 31 is a block diagram showing a configuration of a third embodiment of the present invention together with an applicable rolling mill.

FIG. 32 is a flowchart showing a specific processing procedure of the third embodiment of the present invention.

[Explanation of symbols]

1-7 1st-7th stand rolling mill 8 rolled material 10-12 Plate crown meter 13-15 Plate flatness meter 16-18 Plate flatness control device 21-27 Plate crown control device 28,29 Feedforward control device 31-37 Load interlocking control device 41-47 adder

   ─────────────────────────────────────────────────── ─── Continued front page    (72) Inventor Yoshimitsu Fukui             2-3 2-3 Uchisaiwaicho, Chiyoda-ku, Tokyo J             Within FE Steel Co., Ltd. (72) Inventor Nobuaki Nomura             2-3 2-3 Uchisaiwaicho, Chiyoda-ku, Tokyo J             Within FE Steel Co., Ltd. (72) Inventor Kanji Abe             No. 1 Toshiba-cho, Fuchu-shi, Tokyo Toshiba Corporation             Fuchu Office (72) Inventor, Yoshiyasu Okiya             No. 1 Toshiba-cho, Fuchu-shi, Tokyo Toshiba Corporation             Fuchu Office (72) Inventor Taichi Hatta             No. 1 Toshiba-cho, Fuchu-shi, Tokyo Toshiba Corporation             Fuchu Office (72) Inventor Tomoyuki Tezuka             No. 1 Toshiba-cho, Fuchu-shi, Tokyo Toshiba Corporation             Fuchu Office F-term (reference) 4E024 AA02 AA03 CC01 DD02 EE01

Claims (5)

[Claims] 1. A plurality of rolling mills arranged in tandem and each having an actuator for controlling the strip crown, a strip crown meter is installed on the exit side of an intermediate rolling mill, and the strip crown meter is installed by the strip crown meter. A control method for a continuous rolling mill that brings a deviation between a measured value and a target value of a pre-calculated strip crown close to zero, for each rolling mill upstream of a rolling mill having a strip crown gauge on the output side, The deviation of the plate crown is divided for each rolling mill by the product of the coefficient of influence of the control amount of the actuator on the plate crown and the transfer rate, and the control amount of the actuator proportional to the obtained value is obtained, and the corresponding actuator Control the continuous rolling mill control method. 2. A plurality of rolling mills each have a first actuator and a second actuator for controlling a strip crown, and when the control amount of the first actuator exceeds a facility allowable limit, the facility is installed. The control amount for the second actuator corresponding to the amount exceeding the allowable limit is obtained, the control amount of the first actuator is held at the equipment allowable limit value, and the second actuator exceeds the equipment allowable limit. The control method for a continuous rolling mill according to claim 2, wherein the control is performed according to a control amount corresponding to. 3. A plate flatness meter is installed between stands on which a plate crown meter is installed, and when the measured value of the plate flatness measured by the plate flatness meter exceeds an allowable range, the measured value of the plate crown meter is measured. The control based on the plate flatness meter is stopped, and one or both of the bending force and the leveling of the work roll of the rolling mill having the plate flatness meter on the output side are controlled based on the measurement value of the plate flatness meter. Alternatively, the method for controlling the continuous rolling mill according to Item 2. 4. When controlling the bending force of a work roll, the plate flatness meter on the operator side, the plate flatness on the drive side, and the plate flatness at the central portion in the plate width direction are measured by the plate flatness meter, and the operator The difference between the average value of the plate flatnesses on the drive side and the drive side and the plate flatness at the central portion in the plate width direction is obtained, and PI calculation is performed on the deviation between this difference and the plate flatness command value. Mechanical rate of transfer rate and bending force
Impact factor for the round and rolling machine and rolling schedule
The method for controlling a continuous rolling mill according to claim 3, wherein a bending force control amount that is inversely proportional to the shape change coefficient determined by and is proportional to the plate thickness is obtained. 5. When controlling the leveling of a work roll, the flatness of the operator side and the flatness of the drive side are measured by the flatness meter, and the difference between the flatnesses of the operator side and the drive side is measured. Find this difference and plate flatness
In addition to executing PI calculation for the deviation from the command value, leveling is inversely proportional to the transfer rate, the effect coefficient of the bending force on the mechanical plate crown, and the shape change coefficient determined by the rolling mill and rolling schedule, and is proportional to the plate thickness. The control method for the continuous rolling mill according to claim 3, wherein the control amount is obtained.