JPH09253724A - Plate thickness controller - Google Patents

Abstract

PROBLEM TO BE SOLVED: To accelerate the convergence of a plate thickness fluctuation by correcting plate thickness deviation based on the deviation between a standard roll opening found from a target plate thickness and an actual roll opening, the deviation between a standard rolling load and an actual rolling load, and a mill rigidity constant. SOLUTION: In this controller 5, a roll opening S to be controlled, which becomes a target plate thickness (h0 ), is operated according to a prescribed formula by a rolling load signal from a load cell 6 and a roll opening signal from a roll gap, and the actual roll opening is adjusted through a hydraulic cylinder 4. For the mill rigidity constant K0 of a model formula by which a gage meter plate thickness is operated, a plate thickness fluctuation occurs by an error between the mill rigidity constant K0 and a true mill rigidity constant K. Therefore, the plate thickness fluctuation is suppressed by measuring a plate thickness (h) after rolling by the load cell 6, and by correcting the target plate thickness (h0 =) to be supplied to the controller 5 by second adder 14 and PID controller 15. Consequently, a settling time to the plate thickness fluctuation is expedited, and the convergence of the plate thickness fluctuation is accelerated.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a plate thickness control apparatus for controlling the plate thickness of a rolled material in hot rolling using a rolling mill and performing feedback control based on the plate thickness after rolling. .

[0002]

2. Description of the Related Art Generally, a feedback control for controlling a roll opening by adjusting a rolling amount of a rolling mill and the like while detecting a thickness after rolling by a thickness gauge is generally used for controlling a thickness of a rolled material. However, with this control, a delay between the strip thickness detection unit and the rolling operation unit cannot be avoided. As a countermeasure, a gauge meter method that calculates the plate thickness immediately after leaving the roll gap from the roll opening, rolling load and mill rigidity constant,
That is, it is a mainstream to use the rolling mill itself as a thickness gauge to detect the plate thickness and control the plate thickness in combination with BISRA control.

That is, the gauge meter plate thickness H is calculated from the following model formula, and the roll opening S is controlled by adjusting the amount of reduction so that the gauge meter plate thickness H becomes the target plate thickness h ₀ . H = S + (F / K) (1) where F is the rolling load, K is the mill rigidity load, and (F / K) is the roll opening based on the roll rigidity during rolling. This is a term for correcting a change in degree.

At this time, the above-mentioned mill stiffness constant K cannot be actually measured, and is obtained from a model formula or an experimental value. Therefore, the accuracy of the mill rigidity constant K affects the plate thickness accuracy. Therefore, as shown in FIG. 2, the plate thickness of the rolled material 51 after rolling is measured by the thickness gauge 50, and the gauge meter plate thickness is corrected by the plate thickness deviation between the measured plate thickness and the target plate thickness. Feedback control is performed.

In FIG. 2, reference numeral 52 denotes a rolling mill, which can adjust the plate thickness of the rolled material 51 by adjusting the roll opening between the rolls. Further, 53 is a hydraulic cylinder for adjusting the roll opening degree between the rolls of the rolling mill 52. The BISRA control system is omitted in FIG.

To further describe the above control, the target plate thickness is h
_0, and when the mill stiffness constants used in the gauge meter plate arithmetic thick and K _0, in the above BISRA control, from the formula (1), the control of the roll angle S such that the following expression is performed .

S = h ₀ − (F / K ₀ ) ... (2) However, since the mill rigidity constant K ₀ includes an error, the actual plate thickness on the outlet side of the rolling mill 51 is Let h be
Since an error of Δh = (h−h ₀ ) has occurred, the current gauge meter plate thickness H is corrected by this plate thickness deviation Δh,
The roll opening S is controlled so that the following equation is obtained.

S = (H + Δh)-(F / K ₀ ).

[0009]

However, in the conventional plate thickness control as described above, an error component is included in the plate thickness deviation Δh for correcting the gauge plate thickness H due to the error of the mill rigidity constant K _0. Therefore, there is a problem that the settling time is delayed by the amount of the error.

Next, the reason will be described. In the feedback control in the above-described conventional plate thickness control, the plate thickness deviation between the actually measured plate thickness h and the target plate thickness h ₀ is used as the control amount.

The plate thickness deviation Δh 'is expressed by the following equation. Delta] h '= measured thickness - target thickness = {S + (F / K )} - {S 0 + (F 0 / K 0)} = (S-S 0) + {(F / K) - (F 0 / K ₀ )} = dS + {(F / K)-(F / K ₀ )} + dF / K ₀ (3) where, S: actual roll opening during rolling F: actual during rolling Load K: True mill rigidity constant S ₀ : Roll opening target value calculated from target plate thickness F ₀ : Reference rolling load calculated from model formula K ₀ : Mill rigidity constant calculated from model formula dS = S −S ₀ dF = F−F ₀ .

However, in the above BISRA control,
Control is implemented as much as possible. h ₀ = S + (F / K ₀ ) ... (4) That is, the roll opening target value S ₀ obtained from the model formula so as to reach the target plate thickness should be manipulated, not the roll opening target value S _0. The roll opening S is calculated by the following formula.

S = h ₀ − (F / K ₀ ) The actual plate thickness h is expressed by the following equation. h = S + (F / K) (5) Here, since S = h ₀ − (F / K ₀ ) as described above, h = {h ₀ − (F / K ₀ )} + (F / K) = h ₀ + {(F / K) − (F / K ₀ )} ... (5), and the error of only − {(F / K) − (F / K ₀ )} is appear.

Here, when the above equation (3) is subtracted from the above equation (5) as a correction term by feedback, h ₀ + {(F / K) − (F / K ₀ )} − {dS + {(F / K) - (F / K 0)} + dF / K 0} = h 0 - a _{(dS + dF / K 0)} .

For this reason, since the above-mentioned control based on the actually measured plate thickness is a feedback control, the plate thickness is finally set to the target plate thickness h ₀ , but the settling time is set by the error of (dS + dF / K ₀ ). There is a problem that is delayed.

The present invention has been made in view of the above problems, and an object of the present invention is to provide a plate thickness control device capable of improving the plate thickness accuracy by shortening the settling time. Is.

[0017]

In order to solve the above-mentioned problems, the strip thickness control device of the present invention is based on a gauge meter strip thickness so that the strip thickness on the delivery side of the strip rolling mill becomes a target strip thickness. Roll opening control means for controlling the roll opening of the rolling mill, and plate thickness correction for correcting the gauge meter plate thickness based on the plate thickness deviation between the measured plate thickness of the rolled material measured on the rolling mill exit side and the target plate thickness In the plate thickness control device including means, the roll opening deviation between the reference roll opening previously obtained from the target plate thickness and the actual roll opening, and the reference rolling load previously obtained from the target plate thickness and the actual rolling. It is characterized in that a plate thickness deviation correcting means for correcting the plate thickness deviation based on a load deviation from a load and a mill rigidity constant of the rolling mill is provided.

Here, the reference roll opening and the reference rolling load are values obtained in advance from an arithmetic expression for calculating the gauge meter plate thickness and a model for the arithmetic expression. Further, in the present invention, the plate thickness deviation correcting means obtains the corresponding error amount of (dS + dF / K ₀ ) described above, and corrects the conventional plate thickness deviation by the error amount. This allows
The accuracy of plate thickness control is improved.

[0019]

Next, embodiments of the present invention will be described with reference to the drawings. First, the configuration will be described. As shown in FIG. 1, a four-roll rolling mill is illustrated as a rolling mill 1, and a rolled material 2 is rolled by a pair of work rolls 1 a facing each other vertically. In the figure, 1
b is a backup roll.

The roll opening S between the pair of work rolls 1a can be realized by driving the reduction screw 3 and the hydraulic cylinder 4. Where, in general,
The reduction screw 3 has a large stroke amount but a slow moving speed, and the hydraulic cylinder 4 has a small stroke amount but a fast moving speed. Therefore, the initial setting of the roll opening S is mainly performed by the reduction screw 3, and the adjustment of the roll opening S after the start of the operation, that is, the plate thickness control is performed by driving the hydraulic cylinder 4.

The hydraulic cylinder 4 is driven by a drive command from the controller 5 to adjust the roll opening S. In addition, a load cell 6 including a load cell and the like is installed in the rolling mill 1. The load meter 6 is capable of measuring the rolling load F applied to the roll and supplying a load signal corresponding to the load to the controller 5 and the error correction term calculator 7 which will be described later.

The position detecting sensors 8 and 9 detect the cylinder position and the screw down position, and the position signals of the detected cylinder position and screw down position can be supplied to the roll gap calculator 10.

The roll gap calculator 10 is capable of calculating the current roll opening from the two input position signals and supplying the roll opening signal to the error correction term calculator 7 and the controller 5.

The error correction term calculator 7 is a preset device 1
1, the roll opening target value S ₀ calculated from the target plate thickness h ₀ , the reference rolling load F ₀ calculated from the model formula, and the reference mill rigidity of the rolling mill 1 calculated from the model formula or the experimental formula. The constant K ₀ is supplied. Then, the error correction term calculator 7 performs the correction value dM of the plate thickness deviation Δh as follows.
Is calculated, and the correction value dM can be supplied to the first adder 13. Here, the error correction term calculator 7 and the first adder 13 constitute a plate thickness deviation correction means.

Correction value d in the error correction term calculator 7
Calculation of M is performed as follows. First, the opening correction value dS is obtained from the difference between the actual roll opening S supplied from the roll gap calculator 10 and the roll opening target value S ₀ .

Next, the load deviation dF between the actual rolling load F from the load meter 6 and the reference rolling load F ₀ is obtained, and then the load deviation dF is divided by the reference mill rigidity constant K ₀ to obtain the load. An elongation amount correction value (dF / K ₀ ) is calculated.

Next, the opening correction value dS and the load elongation correction value (dF / K ₀ ) are added to obtain a correction value dM.
That is, in the error correction term calculator 7, dM = dS
+ (DF / K ₀ ) is calculated.

A thickness gauge 12 is installed on the exit side of the rolling mill 1. The thickness gauge 12 is capable of measuring the plate thickness h of the rolled material 2 after rolling and supplying the plate thickness signal to the second adder 14.

Further, the first adder 13 can subtract the correction value dM from the target plate thickness h ₀ and supply it to the second adder 14. The second adder 14 is the first adder 13
The plate thickness deviation Δh is calculated by subtracting the actually measured plate thickness h from the thickness gauge 12 from the corrected target plate thickness h ₀ from the above, and is supplied to the PID controller 15.

The PID controller 15 calculates the plate thickness correction amount based on the input plate thickness deviation Δh, and the third adder 16
Can be supplied to the controller 5 via the. Here, the thickness gauge 12, the second adder 14 and the PID controller 15 constitute a plate thickness correcting means.

The controller 5 is provided with a roll opening control means, and the roll opening S at which the gauge meter plate thickness becomes the corrected target plate thickness h ₀ supplied through the PID controller 15 is calculated by the following formula. It is possible to calculate and supply the drive amount that provides the calculated roll opening S to a drive device (not shown) of the hydraulic cylinder 4.

S = H- (F / K ₀ ) Here, the third adder 16 improves the position control accuracy of the hydraulic cylinder 4 by feeding back the actual cylinder position.

Next, the operation and action of plate thickness control in the above apparatus will be described. In the above-described apparatus, the controller 5 uses the rolling load signal from the load meter 6 and the roll opening signal from the roll gap to obtain the target plate thickness h ₀ based on the above-described formula, and the roll opening to be controlled. S is calculated and the actual roll opening is adjusted via the hydraulic cylinder 4.

Here, since the mill stiffness constant K ₀ used in the model formula for calculating the gauge meter plate thickness has an error between the mill stiffness constant K ₀ and the true mill stiffness constant K, the The plate thickness varies. Therefore, the load gauge 6 measures the strip thickness h after rolling, and the second adder 14 and PI
The D controller 15 performs feedback control so as to correct the target plate thickness h ₀ supplied to the controller 5 and suppress the plate thickness variation.

At this time, as described above, the correction by dM = dS + (dF / dF / (dF /
Although it has an error of K ₀ ), in the present embodiment,
The first adder 13 corrects the target plate thickness h ₀ with dM calculated by the error correction term calculator 7.

As a result, the error of the plate thickness deviation Δh is constantly corrected, so that the required true plate thickness deviation amount is PI.
It is supplied to the D controller 15 and further to the controller 5, and the settling time is shortened by the correction of the error, and the responsiveness of control is improved. That is, even if the plate thickness fluctuates, its convergence will be faster than before.

The first adder 13 for correcting the above error
Has been described as having a configuration that operates before the second adder 14 that performs the correction based on the actual plate thickness h.
After the actual plate thickness h is corrected by
The correction according to 3 may be activated.

[0038]

As described above, in the plate thickness control apparatus of the present invention, when the roll opening is controlled by the gauge meter plate thickness to adjust the plate thickness, the target plate thickness and the measured plate thickness are The accuracy of the feedback control based on the plate thickness deviation is improved by correcting the error of the plate thickness deviation. That is, there is an effect that the settling time with respect to the plate thickness fluctuation is shortened and the convergence of the plate thickness fluctuation is accelerated.

[Brief description of drawings]

FIG. 1 is a diagram showing a schematic configuration of plate thickness control according to an embodiment of the present invention.

FIG. 2 is a diagram showing a schematic configuration of a conventional plate thickness control.

[Explanation of symbols]

1 Rolling Mill 2 Rolled Material 4 Hydraulic Cylinder 5 Controller 6 Load Meter 7 Error Correction Term Calculator 10 Roll Gap Calculator 12 Thickness Gauge 13 1st Adder 14 2nd Adder S Actual Roll Opening at Rolling F Rolling Actual load K True mill rigidity constant S ₀ Roll opening target value calculated from target plate thickness F ₀ Standard rolling load calculated from model formula K ₀ Mill rigidity constant calculated from model formula h Plate after rolling Thickness h ₀ Target thickness Δh Thickness deviation

Claims (1)

[Claims] 1. Roll opening control means for controlling the roll opening of the rolling mill based on the gauge meter plate thickness so that the plate thickness at the rolling mill exit side becomes the target sheet thickness, and actual measurement at the rolling mill exit side is performed. In a plate thickness control device equipped with a plate thickness correcting means for correcting the gauge meter plate thickness based on the plate thickness deviation between the measured plate thickness of the rolled material and the target plate thickness, a reference roll opening previously obtained from the target plate thickness And the roll opening deviation between the actual roll opening, and, based on the load rigidity between the reference rolling load and the actual rolling load previously obtained from the target plate thickness and the mill rigidity constant of the rolling mill, the plate thickness deviation A plate thickness control device comprising a plate thickness deviation correcting means for correcting.