JP2009034730A - Tension control device for tandem rolling mill - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a tension control device for tandem rolling mills capable of highly accurately controlling the tension of a rolled stock. <P>SOLUTION: This device is a tension control device for tandem rolling mills with which the rolled stock 1 is rolled by passing through a plurality of rolling stands in series and which is provided with: tension calculating means 12a, 12b for calculating the tension of the rolled stock between the rolling stands by the expression; controlling and calculating means 13a, 13b for calculating the speed command value of rolling main motors so as to make the calculated tension of the rolled stock follow a tension command value; means 10a, 10b, 10c for controlling the speed of the rolling main motors for controlling the speed of the rolling main motors so as to follow the calculated speed command value and a speed measuring means of the rolled stock for measuring the speed of the rolled stock on the outlet side of the rolling stands. tfi=(Ei/Li)∫((Vi+1)-vi)dt. Where, the Young's modulus of the rolled stock is expressed by E, the distance between the stands by L, the speed of the material on the inlet side by V, the speed of the material on the outlet side by v, subscripts showing the No.i and (i+1) stands by i and (i+1), and the tension of the rolled stock between No.i and No.(i+1) stands by tfi. <P>COPYRIGHT: (C)2009,JPO&INPIT

Description

  The present invention relates to a tension control device for a tandem rolling mill that controls the tension of a rolled material without using looper control.

The plate thickness and the plate width are used as indicators indicating the quality of the final product in hot rolling and cold rolling. Among these indexes, automatic plate thickness control (AGC) is performed for the plate thickness, and automatic plate width control is performed for the plate width.
On the other hand, the tension applied to the material being rolled not only affects the thickness and width of the quality index, but also a well controlled tension contributes to stable operation, and therefore tension control is generally performed.

In particular, the rolling material in the hot rolling is heated to a high temperature, the deformation resistance of the rolling material is small, and if the tension is high, the material tends to break. If the tension is set small to prevent this breakage, there may be no tension due to disturbance or incorrect setting. If the tension does not continue, a large loop will occur between the rolling stands, causing an accident. Sometimes.
Therefore, in the hot rolling mill, a looper device is provided between the rolling stands, the tension is controlled by this looper device, and the height of the looper is controlled from the viewpoint of improving the plate-through property of the material.

  However, in order to support a rolled material having a large cross-sectional area, a large-capacity looper drive motor is required, but various sensors are installed between rolling stands on which the motor driving the looper is installed. In some cases, it is not possible to secure a sufficient space for the looper drive motor. Large capacity motors are also expensive.

  For this reason, the capacity of the looper motor is reduced as much as possible, high-performance tension control using a looper is performed on rolled material with a small cross-sectional area, and tension control without using a looper is performed on rolled material with a large cross-sectional area. In many cases, so-called looperless control is performed.

FIG. 10 shows a rolling control apparatus provided with a conventional general tension control means 24. In FIG. 10, the rolled material 1 has an upstream NO. i-1 Rolling stand 2a, NO. i rolling stand 2b, NO. i + 1 rolling stand 2c, NO. It is sent to the i + 2 rolling stand 2d and rolled.
Here, assuming that the total number of stands of the tandem rolling mill is n, n = 5 to 7 is common, but only four stands are exemplarily shown in the figure. Tension control can be performed between each stand, but considering the state between the four stands i-1 to i + 2 shown in the figure, it can be easily expanded to all n stands, so here, between four stands Consider only the state. Note that i is in the range of 2 ≦ i ≦ n−2.
Further, in the control device described below, the symbols indicating the elements are expressed by combinations of numbers and alphabets, but the numbers indicate the types of elements, and the alphabets a to d indicate which rolling stand according to the alphabet of the rolling stand. It represents whether it belongs to.
It should also be noted that the alphabet may be omitted and used as a generic term for elements belonging to each rolling stand with only numbers. Further, in FIG. 10, illustration of a reduction device provided in each rolling stand is omitted.

  Rolling load detectors 4a, 4b, 4c such as load cells (L / C) are installed in the rolling stands 2a, 2b, 2c, respectively, and the rolling load is detected for each rolling stand. The speeds of the rolling main motors (main machines M) 5a, 5b, 5c for driving the rolling rolls of the respective rolling stands are controlled by main machine speed control means 10a, 10b, 10c, respectively.

There may be a looper between each stand. i + 1 rolling stand 2c and NO. Only the looper 6c provided between the i + 2 rolling stands 2d is illustrated as an example. i-1 rolling stand 2a and NO. i between the rolling stands 2b and NO. i rolling stand 2b and NO. The illustration of the loopers provided between the i + 1 rolling stands 2c is omitted.
The looper 6c is driven up and down by a looper motor (M) 7c, and the looper motor 7c is provided with a looper angle detector 9c for detecting the angle of the looper arm from its height. Although an electric motor (electric motor) is shown here as a driving means for driving the looper 6c, it can be replaced by a hydraulic motor or a pneumatic motor.

  In the tension control using the looper, the looper angle detected by the angle detector 9c and the tension detected by the tension detector 8c are used to control the looper angle via the looper motor 7c by the looper control means 15c. The looper control means 15c gives a correction value for the main machine set speed to the main machine speed control means 10c. As a result, NO. i + 1 rolling stand 2c and NO. The tension and looper angle of the rolled material 1 between the i + 2 rolling stands 2d are controlled.

  When controlling the tension of the rolled material 1, the tension calculating means 12a, 12b uses the rolling load detected by the rolling load detectors 4a, 4b and the rolling torque calculated by the main machine speed control means 10a, 10b. The output side tension is calculated, and the control calculation means 13a, 13b calculates a speed correction value that reduces the deviation from the tension target value, thereby correcting the set speed given from the outside, and the main engine speed control A speed command is given to the means 10a and 10b.

  The rolling torque used for the tension calculation is not the torque itself generated by the main machine 5, but the load torque obtained by removing the acceleration / deceleration torque from the generated torque, that is, the total torque, and subtracting the loss torque related to the rotational speed. use.

In the tension control using the looper, the tension can be calculated from the load received by the load cell attached to the looper, or the tension can be accurately calculated using the load torque of the looper driving device.
In looperless control, since there is no member that contacts the rolled material between the stands, the rolling load and rolling torque of the rolling stand are used to estimate the rolled material tension. This estimation is performed as follows.

First, the basic formula is the following three formulas. That is,
Pi = Pi0−αi · ti−βi · ti−1 (1)
Gi = Gi0−γi · ti + δi · ti−1 (2)
Gi0 = Ai0 · Pi0 (3)
here,
i: Stand number P: Rolling load G: Rolling torque A: Torque arm α: Influence coefficient from forward tension to rolling load (∂Pi / ∂ti)
β: Influence coefficient from rear tension to rolling load (∂Pi / ∂ti-1)
γ: Influence coefficient from forward tension to rolling torque (∂Gi / ∂ti)
δ: Influence coefficient from backward tension to rolling torque (∂Gi / ∂ti-1)
In each formula, subscript 0 indicates no tension.

  The meaning of equation (1) is that the rolling load decreases if forward tension or backward tension is applied, and the meaning of equation (2) is that rolling torque is reduced if forward tension is applied. It means that if the rear tension is decreased, the rolling torque increases.

  In general, the rolling load and the rolling torque at the time of no tension are locked on before the tension is applied and corrected by the following method after the tension is applied (corrected values P0M and G0M). .

によって行う。ここで、Ｈはスタンド入厚（スタンド入側板厚）、ｈはスタンド出厚（スタンド出側板厚）、ｂは板幅、ｋは変形抵抗である。 The estimation of the load and torque at no tension that changes during rolling is as follows:

Do by. Here, H is the thickness of the stand (stand entry plate thickness), h is the stand exit thickness (stand exit plate thickness), b is the plate width, and k is the deformation resistance.

とし、圧延荷重に対する影響係数ベクトルを

とし、ロックオン値からのベクトルＸｉの偏差を、

とする。ここで、Ｈｉ０、ｈｉ０、ｂｉ０、ｋｉ０はそれぞれロックオン（メモリー）値である。なお、一般に板幅変化は小さいものとして、考慮の対象から外すことが多い。 The influence coefficient vector for rolling torque is

And the influence coefficient vector for rolling load

And the deviation of the vector Xi from the lock-on value,

And Here, Hi0, hi0, bi0, ki0 are lock-on (memory) values, respectively. In general, it is often excluded from consideration because the change in the plate width is small.

The rolling load and rolling torque in the non-tension state at the time of lock-on are set as Pi0 and Gi0, respectively, and these values are corrected according to the change in the rolling state, and the rolling load Pi0M and rolling torque Gi0M during rolling are
Pi0M = Pi0 + Zi · ΔXi (8)
Gi0M = Gi0 + Yi · ΔXi (9)
Estimate as

Thereby, the above formulas (1), (2) and (3) are respectively
Pi = Pi0M−αi · ti−βi · ti−1 (10)
Gi = Gi0M−γi · ti + δi · ti−1 (11)
Gi0M = Ai0M · Pi0M (12)
It is corrected as follows.

・前方張力ｔ_ｉから後方張力ｔ_ｉ−１を推定する式として、

ＮＯ．ｉスタンド２ｂおよびＮＯ．ｉ−１スタンド２ａ間では、

上記（１３）式から圧延荷重、圧延トルクおよび後方張力を用いて前方張力を推定することができる。これは、後方張力を測定することができる場合に適用可能なものである。同様に、上記（１４）式および（１５）式から圧延荷重、圧延トルクおよび前方張力を用いて後方張力を推定することができる。これは、前方張力を測定できる場合に適用可能なものである。 From the above equations (10), (11) and (12), the following equation is obtained as an equation for estimating the tension. That is,
- from the rear tension _{t i-1} as an expression for estimating the forward tension _{t i,}

- from the front tension _{t i} as an expression for estimating the posterior tension _{t i-1,}

NO. i stand 2b and NO. Between the i-1 stands 2a,

From the above equation (13), the front tension can be estimated using the rolling load, the rolling torque, and the rear tension. This is applicable when the back tension can be measured. Similarly, the rear tension can be estimated from the above formulas (14) and (15) using the rolling load, rolling torque and front tension. This is applicable when the forward tension can be measured.

  The concept of tension estimation in looperless control will be described with reference to FIG. During rolling, only the rolling load Pi and the rolling torque Gi when tension is applied can be measured, but the tension load Pi0 and the rolling torque Gi0 at the time of tension before the point A of i + 1 stand-on are stored. The tension ΔR is estimated by an arithmetic expression using an influence coefficient by using the change ΔR after the point A of i + 1 stand-on.

On the other hand, Japanese Patent Publication No. 2-14124 discloses a method of estimating a tension between stands of a rolled material by calculating a torque arm by an on-line least square method.
However, in this method, in order to eliminate the tension term included in the basic expression representing the rolling state, it is assumed that the tension calculation between all the stands is performed, and cannot be applied when partial application is desired. .

  The looperless tension estimation method described above requires a forward tension or a rear tension in addition to the rolling load and the rolling torque. For example, when looperless control is continuously performed, the front tension or the rear tension is an estimated value, and further estimation of the tension based on the estimated value may cause a deterioration in estimation accuracy.

In addition, when looperless control is performed between consecutive stands, since the rear tension has already occurred between the downstream stands, it becomes impossible to actually measure the rolling load and rolling torque in the no-tension state, and the influence coefficient is It must be used to estimate the rolling load and rolling torque under no tension.
At this time, due to the influence coefficient and the estimated tension value, the estimated tension value from the rolling load and the rolling torque in the non-tension state includes an error. For this reason, the accuracy of tension estimation decreases as going downstream.
Furthermore, since the influence coefficient is generally a value calculated in the state of the setting calculation at the tip of the rolled material, the influence coefficient itself may change during rolling.

In the above formulas (8) and (9) for calculating the rolling load and rolling torque when there is no tension, the rolling load and rolling torque are corrected using only the changes in the inlet side plate thickness, outlet side plate thickness and deformation resistance. ing.
Generally, in normal rolling, AGC (automatic plate thickness control) is performed in order to ensure product plate thickness accuracy, so that the inlet side plate thickness H and the outlet side plate thickness h are substantially constant. For this reason, the influence of the change of the deformation resistance k is largely reflected.
Changes in rolling load P and rolling torque G are caused not only by changes in deformation resistance k, but also by changes in friction coefficient, changes in rolling speed, changes in advanced rate, and the like. Inferring the change of k adversely affects the estimated accuracy of the rolling load Pi0 and the rolling torque Gi0 when there is no tension.
In recent years, especially in hot rolling, lubricating oil is often used for the purpose of improving the smoothness of the product surface and reducing the rolling power. This is because the friction coefficient is changed to change the rolling load rapidly. It is necessary to reduce the influence.

  The present invention has been made to solve the above-mentioned problems, and it is possible to control the rolling material tension between the stands in the tandem rolling mill without using the conventional tension control by a looper. An object of the present invention is to provide a tension control device for a tandem rolling mill that can be realized.

In order to achieve the above object, the present application provides first and second inventions.
The first invention is a tension calculating means for calculating a rolling material tension between rolling stands, and a control calculating means for calculating a speed command value of a rolling main motor that causes the calculated rolling material tension to follow the tension command value. A rolling material comprising: a main machine speed control means for controlling the speed of the rolling main motor so as to follow the calculated speed command value; and a rolling material speed measuring means for measuring the rolling material speed on the rolling stand exit side. In the tension control device of a tandem rolling mill that rolls through a plurality of rolling stands in series,
The tension calculating means is
The Young's modulus of the rolled material is E, the distance between the stands is L, the incoming material speed is V, the outgoing material speed is v, NO. The subscript indicating i stand is i, NO. The subscript indicating i + 1 stand is i + 1, NO. i stand and NO. The rolling material tension between the i + 1 stand is tfi, and the rolling material tension tfi is a basic expression for tension generation. tf1 = (Ei / Li) ∫ (Vi + 1−vi) dt
It is characterized by calculating by

The second invention is
Tension calculating means for calculating the rolling material tension between the rolling stands, control calculating means for calculating the speed command value of the rolling main motor that causes the calculated rolling material tension to follow the tension command value, and the calculated speed command In a tension control device for a tandem rolling mill, which comprises a main machine speed control means for controlling the speed of a rolling main motor so as to follow the value, and rolls the rolled material in series through a plurality of rolling stands.
The first data group consisting of the rolling load and rolling torque of each rolling stand that can be measured in real time, and the rolling load and rolling torque of each rolling stand that can be measured in real time. A torque arm identifying means for sequentially identifying the torque arm using any one of the second data group consisting of the entry side plate thickness, the exit side plate thickness, and the rolling material tension between the rolling stands,
The tension calculating means calculates the rolling material tension based on the torque arm coefficient or the torque arm identified by the torque arm identifying means.

  According to the present invention, it is possible to improve the tension estimation accuracy when the looper control is not used, thereby to improve the tension control performance, and to achieve more stable operation and higher product quality.

  Hereinafter, embodiments of the present invention will be described in detail with reference to the accompanying drawings.

<Configuration example of related technology>
FIG. 1 is a diagram showing a configuration example according to the related art of the present invention, and FIG. 2 is a control block diagram of the configuration example.

In FIG. 1, the same elements as those in FIG. 10 are denoted by the same reference numerals, and their individual descriptions are omitted. In FIG. i-1 stand 2a and NO. i stand 2b and NO. i stand 2b and NO. Loopers 6a and 6b between the i + 1 stand 2c are also shown, and similarly, the looper motors 7a and 7b, and the respective tension detectors 8a and 8b and angle detectors 9a and 9b are also shown.
The detection outputs of the angle detectors 9a and 9b are guided to the looper angle control means 11a and 11b and used to control the looper motors 7a and 7b. The tension calculating means 12a and 12b do not estimate and calculate the tension based on the outputs from the main machine speed control means 10a and 10b and the rolling load detectors 4a and 4b, but the tension detectors 8a and 8b attached to the loopers 6a and 6b. The rolling material tension is calculated based on the detection output of 8b, or the rolling material tension is calculated based on the power of the looper motors 7a and 7b, that is, the current.

According to the tension control device of FIG. 1, the looper 6 is raised to a position where the rolled material 1 can be brought into contact with the rolled material 1 after a certain time since the rolled material 1 is caught in the downstream rolling stand, and is attached to the looper 6. The tension of the rolled material is calculated from the current of the tension detector 8 or the looper electric motor 7 thus obtained.
In that case, the angle at which the looper 6 is raised is determined by characteristics such as the weight of the rolled material 1 and the ability to drive the looper 6. For example, in the case of a large cross-sectional area material, the weight of the rolled material 1 is large, and the torque that the looper 6 receives from the rolled material 1 increases, so that the torque that the looper motor 7 should generate increases.

  On the other hand, as shown in FIG. 3, the relationship between the looper torque and the looper angle increases as the looper angle increases up to a certain angle. FIG. 3 shows that the total torque is composed of the torque for the tension, the torque due to the looper's own weight, the bias torque for compensating the torque acceleration due to the weight of the rolled material, and the bending torque of the rolled material 1. .

In FIG. 3, when the looper 6 lifts the rolled material 1 and an appropriate tension is applied to the rolled material 1, assuming that the looper angle is 20 degrees, the total torque that the looper 6 should generate is about 19000 kNm. Become. Here, assuming that the looper angle is 10 degrees, the total torque to be generated by the looper 6 is about 12,500 kNm.
That is, depending on the setting of the looper angle, there is a large or small difference in the torque that the looper 6 should generate. When the rolled material 1 has a large cross-sectional area and a large looper torque, the torque that the looper 6 should generate can be reduced by reducing the looper angle.

As a method for determining the looper angle, the total torque of the looper 6 calculated according to rolling conditions based on the rolling size such as the thickness and width of the material to be rolled next and the tension setting value is predetermined as the maximum torque that the looper motor 7 can generate. The looper angle should not exceed the value multiplied by the safety factor. Specifically, the processing flow of the following steps may be used. That is,
(1) For calculation, an initial value of the looper angle is set.
(2) Calculate the total torque at the set angle.
(3) If “total torque” <“value obtained by multiplying the maximum torque by the safety factor”, the set angle is set as the looper angle of the next material.
(4) If “total torque” ≧ “value obtained by multiplying the maximum torque by the safety factor”, the set angle is decreased and the process returns to (2).
The above steps (1) to (4) are repeated. However, a lower limit value is set for the looper angle.

FIG. 2 shows a control block diagram of the control device of FIG. In FIG. 2, it is assumed that the looper angle is controlled to an appropriate angle. In the tension control means 14, the tension calculation means 12 calculates the rolling material tension from the current of the tension detector 8 or the looper motor 7 attached to the looper 6, and this tension value matches the tension target value given separately. Then, the upstream main engine speed command value is calculated.
This main machine speed command value is given to the main machine speed control means 10, but in FIG. 2, the main machine speed control is shown as a system showing the overall response of the main machine speed control means 10, the rolling main motor 5 and the rolling stand 2. It is generally expressed as system 3.
The output of the main machine speed control system 3 is the speed of the rolling roll (not shown) of the rolling stand 2 and is converted into the rolling material speed in consideration of the advanced rate f. i stand and NO. The difference in the rolling material speed of the i + 1 stand is integrated, and the tension (tensile stress) t is generated in consideration of the rolled material Young's modulus E and the distance L between the stands.

  Note that the tension calculation start time in the tension calculation means 12 and the control start time of the control calculation means 13 are after a certain time after the rolling material 1 is caught in the downstream rolling stand, or the downstream rolling stand. After the rolled material 1 is bitten, the other tension control such as looper control is performed, and then a certain time has passed.

  As described above, in this configuration example, in a control method in which tension control is performed without using the looper control that has been conventionally performed, after a certain period of time after the rolling material is caught in the downstream rolling stand, The looper 6 is raised to a position where it can come into contact with the rolled material 1, and the rolled material tension is calculated from the tension detector 8 attached to the looper 6 or the power that drives the looper 6. In that case, the angle at which the looper 6 is raised is determined by characteristics such as the weight of the rolled material 1 and the ability to drive the looper 6.

  As described above, according to the configuration example of the related art, when the tension control of the rolled material 1 is performed, the tension of the rolled material 1 can be detected with high accuracy by using the looper as a means for detecting the tension. it can. At this time, since the looper angle suitable for the size of the rolled material and the rolling conditions can be determined, stable rolling control can be performed within the range of the specifications of the looper.

<Reference example>
Next, reference examples of the present invention will be described. FIG. 4 is a diagram showing a configuration of the reference example.

In the apparatus of FIG. 4, rolling material speedometers 16a, 16b, and 16c are installed on the exit sides of the rolling stands 2a, 2b, and 2c, respectively. As this rolling material speedometer, for example, a speedometer utilizing a laser beam Doppler effect can be used.
FIG. 4 also shows the reduction devices 17a, 17b, and 17c of the rolling stands 2a, 2b, and 2c that are not shown in FIG. The reduction means 17a to 17c may be either electric or hydraulic. Outboard plate thickness calculating means 18a, 18b, 18c are provided for the rolling stands 2a, 2b, 2c.
The rolling stands 2a and 2b are provided with rolling material speed control means 19a and 19b. In each rolling stand, each exit side plate is based on the rolling load P detected by the rolling load detector 4 of the rolling stand, the rolling roll gap S detected by the rolling means 17 of the rolling stand, and the mill constant M. The thickness h is calculated.

This reference example is intended to keep the mass flow constant, and therefore, it is necessary to calculate the thickness of the exit side of each rolling stand. As the outlet side thickness h of each rolling stand, a gauge meter thickness generally used is used. The gauge meter plate thickness is generally determined by using a rolling load P, a rolling roll gap S, and a mill constant M.
h = S + P / M (18)
As given.

  The rolling load detectors 4a to 4c measure the rolling load P for each rolling stand, and based on the rolling roll gap S measured by the rolling-down means 17a to 17c, the calculation of the thickness h on the exit side of each rolling stand is performed on the exit side plate. This is performed by the thickness calculating means 18a to 18c. In addition, a thickness gauge using X-rays or the like may be installed on the exit side of the rolling stand, and in that case, the exit thickness measured by the thickness gauge may be used.

The rolling material speed control means 19a and 19b provided for the rolling stands 2a and 2b perform the following calculation. NO. i stand and NO. If the mass flow between the i + 1 stands is kept constant, assuming that the change in the plate width is small, the material speed is v,
hi + 1 · vi + 1 = hi · vi (19)
Is established.

The rolling material speed command value VRiREF is calculated using the above equation (19).
viREF = (hi + 1 / hi) vi + 1ACT (20)
It is represented by Here, hi and hi + 1 are the sheet thicknesses on the exit side of the rolling stands 2b and 2c calculated by the exit side sheet thickness calculating means 18b and 18c, respectively, and vi + 1ACT is the exit side of the rolling stand 2c measured by the rolling material speedometer 16c. It is a rolling material speed actual value.
Therefore, the above-mentioned equation (19), which is a constant mass flow condition, can be realized by giving the main machine speed control value 10b to the main machine speed control means 10b so that the rolling material speed actual value viACT becomes the rolled material speed command value viREF. it can.

  FIG. 5 shows a control block diagram of the control device of FIG. The above-described control calculation is executed in the tension control means 20 in FIG.

In the rolling material speedometers 16a to 16c, as described above, the rolling material speed is directly measured by using a speedometer based on the Doppler effect using the wave of a laser or the like, and the advanced rate f is calculated by a model formula, and advanced. There is also a method of calculating the rolling material speed v from the rate f and the rolling roll peripheral speed VR.
If the rolling material speed v is calculated using the advanced rate f, it can be used as a backup when the speedometer breaks down, and can also be used as a filter for removing noise from the speedometer.

First, the model formula of the advance rate f is, for example,
f = arb (21)
It is expressed. Here, a and b are coefficients, r is a rolling reduction, and the rolling reduction r is determined by using the inlet side plate thickness H and the outlet side plate thickness h of the rolling stand,
r = (H−h) / H (22)
It is expressed.

The relationship between the speed v of the rolling material and the peripheral speed VR of the rolling roll is
v = (1 + f) VR (23)
It is represented by

When calculating the advanced rate f by the model formula, the accuracy of the model formula is important, and it is necessary to identify the coefficients a and b with high accuracy. The regression equation for identification is
y = cx + d (24)
y = ln (v / VR-1), x = ln (r), d = ln (a)
It is represented by

By identifying the coefficients c and d by the regression equation,
c = ln (a), b = d (25)
Thus, the coefficients a and b in the equation (21) can be obtained. The regression can be obtained by applying a sequential least square method or a general least square method that handles data collectively.

  The parameters of the advanced rate model equation (21) obtained in this way are classified according to the properties of the rolled material and stored in the in-computer parameter table. The advanced rate f is calculated by taking out the parameters from the parameter table for the rolled material having, and the calculated value of the rolled material speed calculated by the above equation (23) from the advanced rate f and the rolling roll peripheral speed VR is used as the rolled material speed v. Use as Thereby, even when the speedometer cannot be used, the above control method can be continued.

  In addition, the parameters of the advanced rate model formula are classified according to the characteristics of the rolled material and stored in the parameter table in the computer. When the speedometer cannot be used due to a failure or the like, the parameter table is used for the rolled material having similar characteristics. The parameter is taken out and the advanced rate is calculated, and the calculated rolling material speed calculated from the advanced rate and the rolling roll peripheral speed is compared with the rolling material speed actual value measured by the speedometer. When exceeding, the calculated rolling material speed is used as the rolling material speed. Thereby, when a large noise gets on a speedometer, the value can be taken in and the situation which becomes disturbance to control can be prevented.

  In the method shown in FIG. 5, it is possible to keep the mass flow constant after the tension is established, but it is necessary to form the initial state of the tension. For this reason, after the rolling material is caught in the downstream rolling stand, looper control is performed or the invention of FIGS. 1 and 2 is performed in order to establish tension.

  According to this reference example, when there is a rolling material speed meter for measuring the rolling material speed between rolling stands, stable tension control can be performed by keeping the mass flow constant. When the rolling material speedometer cannot be used due to a failure or the like, the rolling material speed can be calculated with high accuracy using the identified advanced rate model, and the mass flow can be kept constant.

<Example 1>
Next, Example 1 of the present invention will be described. FIG. 6 is a diagram showing the configuration of the first embodiment of the present invention.

  In FIG. 6, rolling material speedometers 16a, 16b, and 16c are installed on the exit side of the rolling stands 2a, 2b, and 2c. Based on the rolling roll gap S of each rolling stand measured by the rolling means 17a, 17b, 17c, the sheet thickness on the exit side of each rolling stand can be predicted, and the calculation of the exit side sheet thickness is performed on the exit side thickness calculation means 18a. ~ 18c.

  When controlling the tension of the rolled material 1 in the tension control means 21, the stand output side plate thickness h by the output side thickness calculating means 18 is calculated, and using this and the rolling material speed v, the tension calculating means 12a, 12b. To calculate the tension of the outgoing rolled material, and output to the main machine speed control means 10a, 10b a main machine speed command value that reduces the deviation from the target tension value in the control calculation means 13a, 13b. The tension calculation in the tension calculation means 12 is performed based on the above expression (16) which is a basic expression for tension generation.

NO. Since it is not possible to directly measure the incoming material speed Vi + 1 of the i + 1 stand, using the reverse speed b and the roll peripheral speed VR,
Vi + 1 = (1-bi + 1) VRi + 1
= (1 + fi + 1) (hi + 1 / Hi + 1) VRi + 1
= (Hi + 1 / Hi + 1) vi + 1 (26)
Calculate with

  The rolled material Young's modulus E and the tension feedback coefficient have a parameter table according to the classification of the rolled material characteristics. Further, the tension calculation in the tension calculating means 12 is performed using the above equation (17) which is a simple model equation derived from the above equation (16) which is a basic equation of tension generation.

  As described in the reference example, the rolling material speed can be obtained by directly measuring the rolling material speed using a speedometer or the like. In addition, the rolling rate is calculated from the advanced rate and the rolling roll peripheral speed. There can also be a way to calculate the velocity.

  FIG. 7 is a control block diagram of the control device of FIG. In the tension calculation means 12a and 12b, the rolling material tension tfi is obtained using the method of the above equation (16), and the speed command value of the rolling main motor is controlled and calculated so that the rolling material tension follows the tension command value. The speed of the rolling main motor 5 is controlled by the main machine speed control means 10 so as to be calculated by the means 13 and follow the speed command value.

  FIG. 8 is also a control block diagram according to the first embodiment of the present invention, and the tension calculating means 12 calculates the rolling material tension tfi using the method of the above equation (17).

  Thus, according to Example 1, when there is a speedometer for measuring the rolling material speed between rolling stands, stable tension control can be performed by calculating the tension of the rolling material with high accuracy by the model formula of tension generation. Can be implemented. Even if the speedometer cannot be used due to negotiations, the identified advanced rate model can calculate the rolling material speed with high accuracy and continue stable tension control.

<Example 2>
Next, a second embodiment of the present invention will be described. FIG. 9 is a diagram illustrating the configuration of the second embodiment.

  The tension control means 23 in FIG. 9 includes a torque arm identification means 22. The torque arm identification means 22 sequentially identifies the torque arm coefficient using the rolling load P of each rolling stand, the rolling torque G, and the rolling material tension tf between the rolling stands, which can be measured in real time, or in real time. Using the rolling load P, rolling torque G, entry side thickness H, exit side thickness h, and rolling material tension tf between the rolling stands that can be measured, a sequential torque arm is identified, and this torque arm Based on the coefficient or torque arm, the tension calculating means 12a, 12b calculates the rolling material tension.

  Specifically, the torque arm identification means 22 performs the following calculation.

First, the case where the torque arm coefficient is identified will be shown. In addition to the above formulas (1), (2) and (3),
A = 2aLd (27)
Consider. Here, A is a torque arm, a is a torque arm coefficient, and Ld is a projected contact arc length.

Of the influence coefficients in the above equations (1) and (2), γ and δ can be expressed as follows. That is,
γi = ARi · Ri (28)
δi = ARi−1 · Ri (29)
Here, AR is a rolling material exit side cross-sectional area, and R is a rolling roll radius.

となる。 NO. From i-1 stand 2a, NO. Consider up to i + 1 stand 2c.
From the above formulas (1) to (3),
Gi-1 = Ai-1Pi-1-ARi-1Ri-1tfi-1
+ ARi-2Ri-1tfi-2 (30)
Gi = AiPi-ARiRitfi
+ ARi-1Ritfi-1 (31)
Gi + 1 = Ai + 1Pi + 1-ARi + 1Ri + 1tfi + 1
+ ARiRi + 1tfi (32)
Here, NO. i + 1 to NO. The tension between the i + 2 stands is known (assuming that it can be accurately measured by performing looper control, etc.), and NO. The tension upstream from the i-2 stand is assumed to be zero. When both sides of the above expressions (30) to (32) are normalized by the roll radius R,

It becomes.

を得る。ここで、上記（２７）式を適用して、

トルクアーム係数ａを求めるために、回帰式を、

と定義する。 Add the left sides and the right sides of the above formulas (33) to (35),

Get. Here, applying the above equation (27),

In order to obtain the torque arm coefficient a, the regression equation is

It is defined as

  Based on the actual values such as rolling load, rolling torque, entry / exit side plate thickness, tension, etc., the torque arm coefficient is calculated by sequentially applying the least square method based on the regression equation.

として同定する。 Next, the case where a torque arm is identified is shown. The same calculation is performed up to the above equation (36), but the above equation (37) is not used, and the torque arm A is

Identify as

となり、スタンド間の材料張力ｔｆを計算することができる。 Next, the tension is calculated from the identified torque arm coefficient. From the above equation (27), equation (33), equation (34), and equation (35),

Thus, the material tension tf between the stands can be calculated.

  Similarly, in the case of the identified torque arm A, the tension tf can be obtained.

  In the above, in order to obtain the tension between the two rolling stands, the relational expression of the torque arms of the three rolling stands has been considered, but of course, between two rolling stands, or between four or more rolling stands. Can also be applied easily.

  The control calculation means 13 calculates a speed command value of the rolling main motor 5 that causes the obtained rolled material tension to follow the tension command value, and the main machine speed control means 10 calculates the speed command value so as to follow the speed command value. The speed of the electric motor 5 is controlled.

  As described above, according to the second embodiment, it is possible to accurately calculate the real-time change of the torque arm coefficient or the torque arm A, capture the change of the state during rolling, and accurately consider the influence on the tension.

The functional block diagram which shows the structural example by the related technique of this invention. The control block diagram of the tension control apparatus of FIG. Explanatory drawing for demonstrating the torque concerning a looper in relation to the structural example by related technology. The functional block diagram which shows the reference example of the tension control apparatus by this invention. FIG. 5 is a control block diagram of the tension control device of FIG. 4. The functional block diagram which shows Example 1 of the tension control apparatus by this invention. FIG. 7 is a control block diagram of the tension control device of FIG. 6. The control block diagram which shows Example 1 of the tension control apparatus by this invention. The functional block diagram which shows Example 2 of the tension control apparatus by this invention. The figure which shows the whole structure of the conventional tension control apparatus. Explanatory drawing for demonstrating the concept of the conventional tension control apparatus.

Explanation of symbols

1 Rolled material 2 Rolling stand 3 Main machine speed control system 4 Rolling load detector (L / C)
5 Rolling main motor 6 Looper 7 Looper motor 8 Tension detector 9 Angle detector 10 Main machine speed control means 11 Looper angle control means 12 Tension calculation means 13 Control calculation means 14 Tension control means 15 Looper control means 16 Rolling material speedometer 17 Reduction Means 18 Delivery side thickness calculation means 19 Rolled material speed control means 20 Tension control means 21 Tension control means 22 Torque arm identification means 23 Tension control means 24 Tension control means

Claims (4)

Tension calculating means for calculating the rolling material tension between the rolling stands, control calculating means for calculating the speed command value of the rolling main motor that causes the calculated rolling material tension to follow the tension command value, and the calculated speed command The rolling material is provided in a plurality of rolling stands, comprising main machine speed control means for controlling the speed of the rolling main motor so as to follow the value, and rolling material speed measuring means for measuring the rolling material speed on the exit side of the rolling stand. In the tension control device of a tandem rolling mill that rolls in series,
The tension calculating means is
The Young's modulus of the rolled material is E, the distance between the stands is L, the incoming material speed is V, the outgoing material speed is v, NO. The subscript indicating i stand is i, NO. The subscript indicating i + 1 stand is i + 1, NO. i stand and NO. The rolling material tension between the i + 1 stand as _{t fi,} basic equation t of the rolling material tension _{t fi} tensioning _{f1 = (E i / L i} ) ∫ (V i + 1 -v i) dt
A tension control device for a tandem rolling mill, characterized by: Tension calculating means for calculating the rolling material tension between the rolling stands, control calculating means for calculating the speed command value of the rolling main motor that causes the calculated rolling material tension to follow the tension command value, and the calculated speed command A rolling stand comprising a plurality of rolling stands, comprising: main machine speed control means for controlling the speed of the rolling main motor so as to follow the value; and rolling material speed measuring means for measuring the rolling material speed on the exit side of the rolling stand. In the tension control device of a tandem rolling mill that performs rolling in series with
The tension calculating means is
The tension feedback coefficient is K ₁₀ , the rolled material Young's modulus is E, the distance between the stands is L, the exit side material speed is v, the NO. The subscript indicating i stand is i, NO. i stand and NO. The rolling material tension between the i + 1 stand is t _fi , NO. The speed deviation from the initial speed at the i stand is Δv _i , the Laplace operator S is used, and the rolling material tension t _fi is a simple model formula

A tension control device for a tandem rolling mill, characterized by:   The rolling material speed measuring means includes a speedometer that directly measures the rolling material speed, an advanced rate obtained using a model formula, and a speed calculating means that calculates the rolling material speed from the rolling roll peripheral speed, 3. The tension control device according to claim 1, wherein either one of the speedometer and the speed calculation means is selectively used. Tension calculating means for calculating the rolling material tension between the rolling stands, control calculating means for calculating the speed command value of the rolling main motor that causes the calculated rolling material tension to follow the tension command value, and the calculated speed command In a tension control device for a tandem rolling mill, which comprises a main machine speed control means for controlling the speed of a rolling main motor so as to follow the value, and rolls the rolled material in series through a plurality of rolling stands.
The first data group consisting of the rolling load and rolling torque of each rolling stand that can be measured in real time, and the rolling load and rolling torque of each rolling stand that can be measured in real time. A torque arm identifying means for sequentially identifying the torque arm using any one of the second data group consisting of the entry side plate thickness, the exit side plate thickness, and the rolling material tension between the rolling stands,
The tension control device for a tandem rolling mill, wherein the tension calculating means calculates a rolling material tension based on a torque arm coefficient or a torque arm identified by the torque arm identifying means.

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