JP2626420B2 - Strip width control method for rolling mill - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a method for controlling a strip width of a strip in a rolling mill, and more particularly, to estimate a strip width and a tension influence coefficient of a strip with high accuracy irrespective of the dimensions, material and temperature of the strip. Thus, the present invention relates to a strip width control method capable of controlling strip width with high accuracy.

[0002]

2. Description of the Related Art Finishing mills (hereinafter simply referred to as rolling mills)
When rolling the rough rolled sheet into strips having a desired plate width by adjusting the plate width of the strip, rolling stands (hereinafter, simply referred to as the stand) is performed by adjusting the looper is arranged between.

For example, when the strip width of the strip on the rolling mill exit side is narrower than the target strip width, the looper is adjusted to reduce the tension of the strip, while the strip width of the strip on the rolling mill exit side is reduced. When the width is wider than the target plate width, the looper is adjusted to increase the strip tension.

When the strip width is controlled by adjusting the tension of the strip with a looper as described above, it is particularly important to obtain the strip width / tension influence coefficient with high accuracy.

Conventionally, the strip width / tensile influence coefficient for the strip A having specific conditions such as the strip width, material, and temperature has been estimated as follows. That is, for example, from F ₁
When estimating the plate width, tension influence coefficient by the installed looper between F _i stand and F _{i + 1} stand having a plurality stand F _n, the tension of the strip between these stands to adjust the looper The strip width is changed stepwise, and the amount of change (ΔW) in the strip width of the strip is measured by a width meter installed after the _Fi stand exit side. Then, as shown in FIG. 2, thus plotting the tension variation Δσ and the sheet width change amounts were measured ([Delta] W) was, by linear regression of these measured data by a least squares estimation method, thus, the plate width, The tension influence coefficient (∂W / ∂σ) was estimated.

[0006]

In this way, the strip width / tensile influence coefficient (∂W / ∂σ) for the strip A is obtained, and the strip width of a strip having a strip width within a predetermined range is determined.
• To estimate the tension influence coefficient (∂W / ∂σ), was as follows. That is, the relationship between the plate width of several types of strips having different plate widths and the plate width / tensile influence coefficient (∂W / ∂σ) is obtained in the same manner as in the strip A, and FIG.
As shown in the above, these measurement data are linearly regressed by the least squares estimation method, and the relationship between the strip width and the strip width / tensile influence coefficient (∂W / ∂σ), that is, the strip width direction strain parameter is obtained. Based on this relationship, the strip width and the tension influence coefficient (∂W / ∂σ) of the strip having the strip width within a predetermined range.
Was estimated.

However, according to FIG. 3, the strip width and the tension influence coefficient (∂W) of a strip having a strip width within a predetermined range are determined.
/ ∂σ) can be estimated, but this relationship cannot be applied to strips having different conditions such as material and temperature. Therefore, it was necessary to carry out actual machine experiments for every condition, and extremely complicated work was required.

Accordingly, an object of the present invention is to estimate the strip width / tensile influence coefficient (∂W / ∂σ) with high accuracy online, regardless of the conditions such as the dimensions, material, and temperature of the strip. Another object of the present invention is to provide a strip width control method capable of controlling strip width with high accuracy.

[0009]

SUMMARY OF THE INVENTION According to the present invention, F ₁ to F _1
n the rolling mill F _i stand entry side of the strip tension having a plurality stand (σ _i-1), wherein F _i stand delivery side of the strip tension (sigma _i) and the plate of the F _i stand delivery side of the strip The width (W _i ) is detected, and these three detections are performed.
Output value and the preset target finish plate width (W
with _{f aim)} and the F _i stand entry side of the strip in the plate width direction distortion parameters (α _i-1) and the F _i stand delivery side of the strip in the plate width direction distortion parameters (alpha _i) to estimate the , in this way, the parameters estimated (α _i-1) and using (alpha _i), wherein F _i stand plate width, tension influence coefficient of the incoming side of the strip (∂W _i /
∂σ _i-1) and calculates the F _i stand delivery side of the plate width and tension influence coefficient of the strip (∂W _i / _{∂σ i),} In this manner the plate width and the tension effect of the entering-side computed Coefficient (∂
With _{W i / ∂σ i-1)} , wherein F _i to adjust the installed looper to stand entry side, and the plate width and tension influence coefficient of the exit-side computed this way (∂W _i / ∂
with sigma _i), it has the characteristics to adjust the installed looper to the F _i stand outlet side.

Next, the method for controlling the strip width of the strip according to the present invention will be described in more detail with reference to the drawings.

[0011] Figure 1 is a block diagram in the case of estimating the plate width, tension influence coefficient of the strip of F _i stand entry side and exit side of the rolling mill by the sheet width control method of the strip of the present invention.

In FIG. 1, 1 is a plurality of F ₁ to F _n .
First looper installed in F _i stand entry side with stand, 2, F _i stand and F _{i + 1} the installed second looper between the stand 3, F _i stand and F _{i + 1}
A width gauge for measuring the width of the strip between the stand and the strip, and 4 is a width direction distortion parameter estimator.

[0013] First, the amount of change in plate width of F _i stand delivery side of the strip ([Delta] W _i) is expressed by the following (1).

ΔW _i = (∂W _i / ∂σ _i-1 ) Δσ _i-1 + (∂W _i / ∂σ _i ) Δσ _i --- (1) In the equation (1), ∂W _i / ∂ σ _i-1: F _i stand entry side of the plate width and tension influence coefficient of the _{strip, ∂W i / ∂σ i: F} i stand delivery side of the plate width and tension influence coefficient of the strip, Δσ _i-1: F _i the amount of change in the tension of the strip of stand entry side, Δσ _i: F _i amount of change in the tension of the stand delivery side of the strip. Here, the plate width and tension influence coefficient, F _i stand delivery side of the
The width change of the strip (ΔW _i ) and the entrance and exit sides
The amount of change in the tension of each strip (Δσ _i-1 , Δσ
_i ) is a coefficient when the relationship with
Which is the slope of the straight line shown in FIG.

In equation (1),

∂W _i / ∂σ _i-1 = α _i-1 · W _{f aim} --- (2) ∂W _i / ∂σ _i = α _i · W _{f aim} --- (3) (2) and (3), α _i-1: F _i stand entry side of the plate width direction distortion parameters of the strip, alpha _i: F _i stand delivery side of the plate width direction distortion parameters of the strip. Here, the strain parameter in the width direction is apparent from (2) and (3).
As can be seen, the above plate width / tension effect coefficient and target
It is a proportional coefficient with W _{f aim,} and is the slope of the straight line shown in FIG.
is there.

From equations (2) and (3), ΔW _i / W _{f aim} = α _i−1 · Δσ _i-1 + α _i · Δσ _i --- (4)

The parameters α _i-1 and α _i are obtained by a sequential least squares method with a forgetting factor (weighted least squares method). That is, the equation (4) is transformed into the equation (5).

Y = θ ^T · φ + ε --- (5) where y: ΔW _i / W _{f aim} , (known parameter scalar) θ: [α _i-1 α _i ] ^T , ( Unknown parameter vector) φ: [Δσ _i-1 Δσ _i ] ^T , (known parameter vector) ε: error scalar.

Therefore, it is only necessary to select a (θ) vector that minimizes the sum of squares of (ε) in equation (5). That is, a (θ) vector that minimizes (J) in the following equation (6) is obtained.

[0021]

(Equation 1)

(Α _{i -1} ) and (α _i ) are identified based on equation (6).

[0023] In this way, (α _i-1) and (α _i) After determining the, plate width and tension influence coefficient of the F _i stand entry side strip _{(∂W i / ∂σ i-1} ) and F _i Strip width and tension influence coefficient (出 W _i
/ ∂σ _i ) is calculated based on equations (2) and (3).

In this way, the sheet width / tension influence coefficient (∂
When W _i / _{∂σ i-1)} and the (∂W _i / ∂σ _i) is calculated, (based on the _{∂W i / ∂σ i-1)} , a first looper installed in F _i stand entry side Adjust 1 and (∂
Based on the W _i / ∂σ _i), adjusting the second looper 2 installed on the delivery side of the F _i stand. Thus, a strip having a target thickness can be obtained.

[0025]

As described above, according to the present invention, there is no need to obtain the strip width direction distortion parameter of the strip in advance as in the conventional method, and the strip width can be automatically controlled online. Moreover, since the width and tension influence coefficient of the stand on the entrance side and the exit side can be independently estimated, the distribution of the tension adjustment of the strip by the loopers on the entrance side and the exit side of the stand can be performed accurately. Thus, a useful effect that the thickness can be controlled with higher accuracy can be obtained.

[Brief description of the drawings]

FIG. 1 is a block diagram of a strip width control method of the present invention.

FIG. 2 is a graph showing a relationship between a change amount of a sheet width and a change amount of a tension.

FIG. 3 is a graph showing a relationship between a plate width / tension influence coefficient and a plate width.

[Explanation of symbols]

 1: First looper 2: Second looper 3: Sheet width meter 4: Parameter estimator

Claims (1)

(57) [Claims] 1. A F _i stand entry side of the strip tension pressure <br/> caster from F ₁ having a plurality stand _{F n (σ i-1)} , wherein F _i stand delivery side of the strip tension ( sigma _i) and the F _i detects the stand delivery side of the strip of sheet width (W _i), pre-set of these three detection values
The use and stop of the finishing target plate width (W _{f aim),}
Wherein said F _i stand entry side of the strip in the plate width direction distortion parameters (α _i-1) and the F _i stand delivery side of the strip in the plate width direction distortion parameters (alpha _i) estimates were estimated in this way parameter (α _i-1) and with (α _i), wherein F _i plate width, tension influence coefficient of the strip of the stand entry side _{(∂W i / ∂σ i-1} ) and the F _i stand delivery side calculates the strip width, tension influence coefficient of the strip (∂W _i / ∂σ _i), the plate width and tension influence coefficient of the entering-side computed this way _{(∂W i / ∂σ i-1} )
Used, the adjusting the looper installed in F _i stand entry side, and, with the plate width, tension influence coefficient of the exit-side computed this way (∂W _i / ∂σ _i), wherein F
_i . A method for controlling a strip width of a strip in a rolling mill, comprising adjusting a looper installed on a stand exit side.