JPS638846B2 - - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION The present invention relates to an adaptive control device for a rolling mill that continuously performs cold rolling.

In the conventional adaptive control device for cold rolling, the first
The rolling load is calculated from the actual data such as the stand and final stand exit plate thickness records, each stand roll speed record, tension record, etc., and this calculated value is used as the ratio of the detected value of the actual rolling load as an adaptive correction coefficient for the next rolling mill. Applied to setup calculations.

However, in determining this calculated rolling load,
Although the plate thickness at the outlet side of each stand is required, in reality, due to cost considerations, a plate thickness detector is not installed on the outlet side of the intermediate stand. Therefore, it is necessary to estimate the thickness of the outlet side of the intermediate stand.

For this purpose, it is sufficient to know the advance rate of each stand, but since this cannot be measured, the exit plate thickness was estimated using the following method. That is, first, calculate the exit side plate thickness of each stand using the constant mass flow law with the advance rate as zero, and calculate the difference between the actual exit side plate thickness of the first stand and the actual final stand exit side plate thickness, and the actual calculated exit side plate thickness of the first stand. The intermediate stand outlet side plate thickness was estimated by proportionally distributing the difference from the side plate thickness.

However, since this conventional method does not take the advance rate into consideration, the rolling load itself, which is calculated later, has an error, unlike the actual exit plate thickness, making it difficult to perform appropriate adaptive control.

SUMMARY OF THE INVENTION An object of the present invention is to provide a rolling mill adaptive control device that eliminates the drawbacks of the prior art described above and is capable of accurately calculating and controlling rolling load.

The present invention utilizes the fact that the ratio of advance rate and rolling rate in each stand is almost constant regardless of the friction coefficient, and first estimates the intermediate stand outlet side plate thickness, and then Examine the difference between the advance rate obtained by substituting the first estimated value of plate thickness obtained above into the rate calculation formula and the advance rate used in the first estimate, and if this does not fall below the allowable value, use the above method. Perform a second estimation of the plate thickness from the advance rate obtained from the advance rate calculation formula, calculate the advance rate again from the result, and repeat this until it is confirmed that it is below the above tolerance value to calculate the actual performance of each stand. The present invention is characterized by improving the accuracy of the estimated value of the exit plate thickness, thereby improving the accuracy of the calculated rolling load value, and enabling more advanced adaptive control.

Hereinafter, the present invention will be described in detail, starting with an explanation of its principle.

In general, the advance rate f _i of any stand i (i = 1 to 5; 5 stands is assumed for simplicity) is the rolling reduction rate r _i
There is a nearly linear relationship between them as shown in FIG. In the figure, the solid line part is μ=0.10, and the dotted line part is μ=0.10.
Shows 0.02. This relationship is not significantly influenced by the friction coefficient μ _i . Therefore, when calculating the exit side plate thickness, assume that the reduction rate/advance rate is a constant α _i ; α _i = r _i /f _i , i = 1 to 5 ...... (1) Furthermore, The actual plate thickness on the exit side is H _A1 , h _A1 , and the exit plate thickness of the i-th stand is h _i (i=
2 to 5), the rolling reduction ratio r ₁ and r _i are each expressed by the following formula; r ₁ =H _A1 −h _A1 /H _A1 ………(2) r _i =h _i-1 −h _i / h _i-1 , i=2 to 5 (3) Next, the following equation holds true according to the constant mass flow law.

V _A1 (1 + f ₁ ) h _A1 = V _Ai (1 + f _i ) h _i , i = 2 to 5 ...... (4) Here, V _Ai is the actual roll peripheral speed of the i-th stand (i = 1 to 5). be. The above equations (1), (2), and (3) can be converted into equation (4)
Substituting into and solving for h _i , we get However, β=h _A1 (+1H _A1 −h _A1 /H _A1 α ₁ ) v _A1 ………(6) Therefore, the actual input and exit plate thickness of the first stand
From H _A1 , h _A1 , the actual roll circumferential speed v _Ai , and the constant α _i , the exit side plate thickness h _i (i=2 to 5) of the intermediate stand where the actual output side plate thickness cannot be detected can be calculated. However, in general, the final stand exit plate thickness h ₅ calculated as above
Since an error occurs between the actual exit plate thickness h _A5 measured by the final stand exit side X-ray thickness meter, this error is distributed to each intermediate stand and used as the actual exit plate thickness. That is, the first estimated value h _Ai of the plate thickness on the exit side of the intermediate stand is expressed by the following equation; The calculations so far have assumed equation (1), which has assumed the advance rate f _i to be the following equation; f _i = h _A(i-1) −h _Ai /h _A(i-1) α _i , i=1 to 5 ......(8) On the other hand, by substituting the first estimated value h _Ai obtained up to equation (7) into the Bland &Ford's advanced rate calculation formula, Actual value f _Ai
When you ask for However, f _Ai is the actual rolling reduction rate μ _Ai of the i-th stand.
The actual friction coefficient of the stand, R _iM is the flat roll radius of the i-th stand, t _bAi and t _fAi are the actual unit tensions on the entrance and exit sides of the i-th stand, S _bAi and S _fAi are the actual results on the entrance and exit sides of the i-th stand Deformation resistance, these are given from actual measurements.

Here, two advanced rates f _i and f _Ai have been obtained, and it is determined whether the difference between these two values is within a certain range. That is, |f _i −f _Ai | ε (ε is a constant of about 0.0005), and if i=1 to 5, Equation (7)
Assuming that the plate thickness h _Ai on the exit side of the intermediate stand calculated in is correct, the calculated rolling load P _CA is calculated from a known rolling load formula as described later, and the adaptive correction coefficient z _P is determined.

On the other hand, if |f _i −f _Ai |>ε, i=1 to 5,
It was judged that the first estimation of the thickness of the exit side of the intermediate stand was not appropriate, and f _Ai (i=1
~5) Calculate the thickness h _Ai (secondary estimated value) of the exit side of the intermediate stand; h _Ai = v _AS (1 + f _AS ) h _AS + {v _Ai (1 + f _A1 ) h _A1 − v _A5
−(1+f _A5 )h _A5 }γ _i /v _Ai (1+f _Ai )……(10) However, γ _i =1/v _Ai −1/v _AS /1/v _Ai −1/v _AS ………( 11
), let f _Ai used at this time be f _i , and compare f _Ai and f _i recalculated using equation (9) from the second estimated value h _Ai obtained from equation (10), and find out the difference between them. The above process is repeated until the estimated order is less than or equal to ε. This improves the accuracy of estimating the thickness of the exit side of the intermediate stand.

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

FIG. 2 shows an embodiment in which the present invention is applied to control a continuous rolling mill having five rolling mills (No. 3 and No. 4 stands are not shown). Each stand includes a pair of work rolls 1, 2, 3, a reduction drive device 17, 18, 19 for raising and lowering the rolls, a pulse transmitter 6, 7, 8 attached to the work rolls 1, 2, 3, and rolling load detector 12,1
3 and 14 are provided.

The exit plate thickness calculation device 20 includes base material rolling information, a 1-stand exit thickness gauge 15, and a 5-stand exit thickness gauge 1.
6 and the outputs of the roll circumferential speed detectors 9, 10, and 11, and use equations (1) to (7) to determine the intermediate stand (No.
Calculate the exit side plate thickness actual value h _Ai of 2 to 4).

The advanced rate calculating device 21 calculates the advanced rate f _i according to equation (8) and the advanced rate f _Ai according to equation (9).

Next, the comparator 22 compares |f _i −f _Ai | with ε, and if |f _i −f _Ai | > ε, the exit plate thickness recalculation device 23 uses equations (8) to ) is used to calculate the actual value of the exit plate thickness.
h Recalculate _Ai . Then, the advanced rate calculation device 21
Return to and calculate the advanced rate f _Ai again. On the other hand, comparator 2
In 2, if it is determined that |f _i −f _Ai |ε, then
The rolling load calculation device 24 calculates a rolling load calculation value P _CAi using the input values from the tension detectors 4, 5 and the roll circumferential speed detectors 9, 10, 11 using the following well-known formula.

P _CAi =K _Ai b√ _iM ( _Ai − _Ai )Qμ _Ai
Qσ _Ai ………(12) However, K _Ai is the deformation resistance, b is the plate width, Qμ _Ai is a correction term including the friction coefficient, Qσ _Ai is a tension correction term, and R _iM in equation (12) is R When _i is the work roll radius of the i stand and C is the constant of the hitch, it can be calculated using the following well-known formula; R _iM = R _i (1 + CP _CAi / H _Ai - h _Ai ) ...... (13) Furthermore, an adaptive correction coefficient Z _Pi is calculated from the input values P _Ai of the rolling load detectors 12, 13, and 14 using the following equation.

Z _Pi =P _Ai /P _CAi (14) The storage device 25 takes out Z _Pi stored at the setup timing and inputs it to the rolling load calculation device 27.

The rolling load calculation device 27 calculates the rolling load P _i using the following equation using the plate thickness h _i of each stand exit side from the draft schedule generator 26 and Z _Pi from the storage device 25 .

P _i =Z _Pi・K _i・b√ _iM ( _i − _i )Qμ _i Q
σ _i (15) R _iM = R _i (1+CP _i /H _i −h _i ) (16) The roll down position calculating device 28 calculates the roll down position S _i using the following well-known formula.

S _i = S _pi +h _i −P _i /M _i (17) However, S _pi is the value corresponding to the zero point of the rolling position,
M _i is the mill stiffness coefficient.

The rolling position S i of each stand calculated by the rolling position calculating device 28 is determined by the rolling position S _i of each stand calculated by the rolling position calculating device 28.
19, which controls the roll opening degree.

As described above, according to the present invention, the advanced rate, which is normally difficult to measure, is calculated using the well-known Bland & Ford advanced rate calculation formula using actual data,
By repeatedly calculating the intermediate stand outlet side plate thickness until it falls within a certain error range from the previously estimated advance rate, accurate intermediate stand outlet side plate thickness and advance rate can be determined, allowing for more accurate adaptive control. It has the effect of being able to do the following.

[Brief explanation of the drawing]

Figure 1 is a diagram showing the relationship between advance rate and rolling reduction rate, Figure 2
The figure is a configuration diagram showing an embodiment of the present invention. 9-11...Roll circumferential speed detector, 15...1 stand outlet thickness gauge, 16...5 stand outlet thickness gauge, 20... Outlet plate thickness calculation device, 21...Advanced rate calculation device, 22... ... Comparator, 23 ... Output plate thickness recalculation device, 24 ... Rolling load calculation device.

Claims (1)

[Claims] 1 Assuming that the ratio of the rolling reduction rate and the advancement rate of each stand (1, 2,...n) is constant, the trial advancement rate (fi) is calculated.
is calculated, and based on the calculated trial advance rate, from the detected roll circumferential speed of each stand and the detected exit plate thickness of the first and final stands, other than the first and final stands (2, 3,...n-1 , ), and the actual advanced rate (f _A i), and when the difference between the trial advanced rate (fi) and the actual advanced rate (f _A i) exceeds a predetermined tolerance value, the second calculation means calculates the trial advanced rate (f A i). The actual advanced rate is used as the trial advanced rate and the intermediate stand (2, 3,...
n-1,) for estimating the exit side plate thickness, and the trial advance rate used for estimation by the first or third calculation means and the third calculation means The plate thickness estimation is repeated until the difference between the estimated plate thickness and the actual progress rate calculated by the second calculating means is equal to or less than the allowable value, and when the estimated value is less than the allowable value, The intermediate stand (2,
3,...n-1,) Control the lowering position of each stand so that the estimated value of the plate thickness on the outlet side and the detected value of the plate thickness on the outlet side of the first and final stands are satisfied at each corresponding stand. Features a rolling mill adaptive control device.