KR100306144B1 - Apparatus for controlling tension in continuous hot rolling mill - Google Patents

Abstract

PURPOSE: An apparatus for controlling tension in a continuous rolling mill is provided which properly maintains tension of a material to be rolled hung between rolling stands in the continuous rolling mill by controlling roll speeds of the rolling stands and an angle of a looper mounted between roll stands in a rolling mill. CONSTITUTION: The apparatus for controlling tension in a continuous hot rolling mill comprises a load detection part(31) detecting a load of a material to be rolled loaded on a looper; a tension calculation part(32) converting into tension a load of the looper detected from the load detection part; a tension control part(33) obtaining an adjusted tension through proportional integral control from a deviation between a tension set value of a numerical formula model part(21) and an actual tension value outputted from the tension calculation part; a looper angle detection part(25) detecting an angle of the looper; an angle control part(34) obtaining an adjusted angle of the looper through proportional integral control from a deviation between an actual looper angle detected from the looper angle detection part and a set angle value of looper of the numerical formula model part; a total value compensation part(35) outputting a speed correction amount of rolling rolls and a torque correction amount of the looper; a current conversion part(37) outputting the converted current to a looper driving part(29) by converting into a current a value obtained by summing up a basic torque value and a torque correction amount of the looper outputted from the total value compensation part; and an addition part outputting the added value to a rolling roll driving part(28) by adding a standard speed of a speed control part to a speed correction amount of the rolling rolls outputted from the total value compensation part.

Description

Tension control device of hot rolling mill

The present invention relates to a continuous mill provided with a looper (LOOPER) device during the hot rolling process of a steel plant, and more particularly, to a steel mill of the rolling mill stand so as to properly maintain the tension of the control target material, which is a rolled material caught between rolling mill stands in the continuous rolling mill. The present invention relates to a tension control device for a continuous rolling mill by controlling the roll speed and the angle of the looper mounted between the mill stands.

In addition, the present invention eliminates the interference between the tension of the rolled material and the interference between the looper facilities in the filament rolling mill of hot rolling, and controls the looper while canceling mutual disturbances, and also has a simple structure and easy to adjust the tension control device of the continuous rolling mill. It is about.

In general, in a continuous rolling mill of a hot rolling process in which a plurality of rolling mills are continuously installed, a 'looper' is used to maintain a proper loop amount between each rolling mill stand and to maintain a stable tension of a rolled material (for example, a steel sheet). In order to improve the quality of the rolled material, it is important to control the tension which directly affects the quality of the rolled material and to control the variation of the looper angle.

For example, if an excessive tension is applied to the rolled material or an excessive loop occurs because a constant tension is not maintained, the influence of the width of the rolled material or the shape of the rolled material becomes poor due to the influence of tension variation and Minimizing looper angle variation is very important in terms of stabilization of operations.

1 shows a part of a continuous rolling mill equipped with a looper between rolling mill stands. As shown here, the rolling roll 11 of the I-th stand on the downstream side, the rolling roll 12 of the I + 1 st stand on the upstream side, the looper 13 provided therebetween, and the stand rolling roll ( The rolling roll motor 15 which controls the roll rotation speed of 12) and the looper motor 14 which control the angle (theta) of the looper 13 are provided. Rolling rolls of one stand of two consecutive rolling rolls 11 and 12 for adjusting the tension σ of the rolled material 10 caught on the rolling rolls 11 and 12 of the two rolling mill stands and the looper 13. The roll rotational speed of (12) is controlled by the rolling roll motor (15), the angle (θ) of the looper 13 is controlled by the looper motor 14, and the torque of the looper is determined by the looper angle (θ). Adjust to change.

FIG. 2 is a block diagram showing a looper control device of the continuous rolling mill shown in FIG. As shown here, the data on the thickness of the measured material and the width of the measured material are received, and the mathematical modeling of the hot rolling process is applied to obtain the looper angle setting value, the material tension setting value, the target plate thickness, and the target plate width. The looper angle detector 25 detects the amount of rotation of the looper motor 14 and measures the looper angle, and the looper angle detector 25 from the angle set value of the modified model unit 21. Automatic control of the thickness according to the instruction of the angle control unit 23 and the formula model unit 21 by outputting the value obtained by subtracting the looper angle detected by The speed control part 24 which outputs the reference speed of the rolling roll motor 15 for compensating for reduction of AGC: Auto Gauge Control, and the rolling speed of the rolling roll motor of the angle control part 23 and the rolling roll motor of the speed control part 22 According to the reference speed of The rolling roll driving unit 28 for driving the rolling roll motor, the current detecting unit 27 for detecting the load current of the looper motor, and the current of the current detecting unit 27 are converted into tensions, A tension control unit 24 for inputting the tension set value, target plate thickness and target plate width data to calculate the loop reference torque reference value, and a current converter 26 for converting the output torque of the tension control unit 24 to the looper motor driving current. ) And a looper motor driver 29 for driving the looper motor 14 in accordance with the current value of the current converter 26.

The looper control device of the continuous rolling mill of FIG. 2 has two types of continuous rolling rolls and two looper torques on the stand of the continuous rolling mill in which the looper is installed to control two control factors of tension between the stands and the looper angle. The manipulated value of is controlled. As shown in FIG. 2, in consideration of the angle of the looper appearing according to the rotational amount of the looper motor 14, the integral value control of the angle set value of the equation model unit 21 is performed in proportion to the integral and outputs the driving speed of the rolling roll motor. The rolling roll motor 15 is ultimately controlled by adjusting. In addition, the current value of the looper motor 14 according to the load received by the looper motor 14 is converted into a tension value, and in consideration of this, the tension setting value of the formula model unit 21 is calculated by calculating the reference torque of the looper accordingly. To drive. In other words, the angle control method to maintain the looper angle θ by modifying the roll rotational speed of the upstream stand (i) or the downstream stand (i + 1) according to the looper angle θ and the looper torque of the looper angle θ The tension between the stand and looper control is performed by the looper tension control method which indirectly controls the tension value? As a target value by adjusting to the variation.

However, the conventional apparatus shown in FIG. 2 has a problem that the effect of the tension control is bad because the tension control is made of an open loop that simply adjusts the torque of the looper according to the loop angle change without feedback control on the result of the tension control. have. In addition, mutual interference occurs between the tension between the stand and the looper angle, so that the tension variation causes the angular variation of the looper and the angular variation of the looper causes the tension variation between the stands. It does not take into account the mutual interference generated between the tension applied to the looper angle and, therefore, there is a problem in that the control stability is lowered.

The present invention has been proposed to solve the above conventional problems, the object of which is to adjust the rolling roll rotational speed according to the deviation value between the tension set value and the measured value, the deviation between the measured value and the set value of the looper angle It is to provide a looper control device of a hot rolling mill that adjusts the torque of the furnace looper to compensate for mutual disturbance or interference between the angle and tension of the looper.

1 shows a part of a continuous rolling mill equipped with a looper between rolling mill stands.

FIG. 2 is a block diagram showing a looper control device of the continuous rolling mill shown in FIG.

3 is a block diagram showing the configuration of an embodiment according to the present invention.

Figure 4 illustrates the dynamics acting on the rolling stand and the looper in the present invention.

5 (a) and 5 (b) show simulation results of the embodiment of the present invention in comparison with the prior art.

* Description of the symbols for the main parts of the drawings *

21 ... Mathematical model part 25 ... Looper angle detector

28 ... rolling roll driving part 29 ... looper driving part

31 ... load detection part 32 ... tension calculation part

33 ... tension control part 34 ... angle control part

35 ... Precompensation section 36 ... Reference torque section

37 ... current converter 38 ... adder

As a specific means for achieving the above object of the present invention, the present invention is a rolling roll driving unit for driving a continuous rolling roll, a looper driving unit for adjusting the angle of the looper provided between the continuous rolling roll, and the rolled material The mathematical model unit calculates the target plate thickness, target plate width, looper angle setting value and tension setting value by applying the measured plate thickness and plate width data to the mathematical model of the rolling process, and automatic thickness control according to the instructions of the mathematical model part (AGC). A tension control device for a continuous rolling mill including a speed control unit for outputting a reference speed of a rolling roll for compensating for rolling reduction of an auto gauge control, comprising: a load detection unit for detecting a load of a rolled material applied to a looper, and a target plate of a mathematical model unit; The tension calculation unit converts the load value detected from the load detection unit into the tension according to the thickness and the target plate width, and the tension calculation unit outputs the tension setting value of the mathematical model unit. The tension control unit for obtaining the adjustment tension through proportional integral control from the deviation of the actual tension value applied, the looper angle detection unit for detecting the looper angle, and the looper angle setting values detected from the looper angle detection unit. The angle control unit that obtains the adjustment angle of the looper through the proportional integral control from the deviation, and the compensation tension according to the mutual interference are added to the adjustment tension output from the tension control unit and the angle control unit and the adjustment angle of the looper, respectively. Pre-compensation unit for outputting torque compensation amount, Current converting unit for converting the value obtained by adding the basic torque value to the torque compensation amount of looper output from pre-compensation unit, and outputting it to looper driving unit, and rolling roll output from precompensation unit An addition unit for adding the speed compensation amount and the reference speed of the speed control unit to the rolling roll driving unit The.

Referring to the configuration and operation of the embodiment according to the present invention with reference to the accompanying drawings as follows.

3 is a block diagram showing the configuration of an embodiment according to the present invention. As shown here, the configuration of the embodiment according to the present invention can be largely divided into three parts. That is, the load detector 31 detects the tension value of the material to be rolled between the stand of the continuous rolling mill, the tension value corresponding to the detected load, and the tension set value calculated and calculated by the rolling process model in the mathematical model unit 21; The tension control part for varying and adjusting the rotational speed, that is, the rolling speed, of the rolling rolls installed in the continuous rolling mill by the proportional integral control in the tension control unit 33 with the deviation value of the looper, and the looper having the looper angle detector 25 installed between the stands. The angle value of the looper is adjusted by the proportional integral control in the angle control unit 34 with the deviation value between the detected value and the angle set value calculated and calculated by the rolling process model in the mathematical model unit 21. It can be divided into a looper angle control portion and the precompensation portion 35 to cancel the interference or disturbance generated between the tension and the looper angle between the stand.

In detail, the tension control part includes a load detecting part 31 installed at the lower part of the looper roll to detect the load of the rolled material applied to the looper, and a load detecting part 31 according to the target plate thickness and the target plate width of the mathematical model part. The tension value of the actual to-be-rolled material calculated by the tension calculation part 32 to the tension calculation part 32 which converts the load value detected from the to the tension applied to the to-be-rolled material, and the tension setting value of the mathematical model part 21 is output. Standard of the rolling roll for pressure reduction compensation of the automatic thickness control (AGC: Auto Gauge Control) according to the direction of the tension control unit 33 and the mathematical model unit 21 to obtain the adjustment tension through the proportional integral control from the deviation of The speed control part 22 which outputs a speed, and the rolling roll drive part 28 which drive a rolling roll by the addition value of the speed according to the adjustment tension of the tension control part 33, and the reference speed of the speed control part 22 are provided.

In addition, the looper angle control part is connected to the looper driving motor 14 to detect the angle of the looper according to the rotation amount of the motor, and the actual looper angle detected from the looper angle detector 25 and the mathematical model. The basic torque value is added to the torque according to the angle of the looper output from the angle control unit 34 and the angle control unit 34 to obtain the adjustment angle of the looper through proportional integral control from the deviation of the looper angle setting value of the unit 21. And a looper driver 29 for driving the looper in accordance with the output current of the current converter 37.

The precompensation unit 35 outputs the speed compensation amount of the rolling roll and the torque compensation amount of the looper by mutually adding a compensation value according to the mutual interference to the adjustment tension output from the tension control unit 33 and the angle control unit 34 and the adjustment angle of the looper. do.

Referring to the operation of the embodiment according to the present invention will be described.

As shown in the block diagram of Fig. 3, the present invention estimates the tension of the rolled material between the stand of the continuous rolling mill provided with the looper between the rolling stands by the measurement of the load detector 31 and the calculation of the tension calculator 32, and the target tension. A reference of the roll rotational speed of the rolling stand is calculated on the basis of the deviation of the actual tension and the actual tension, and the rotational speed of the rolling roll is corrected, and the looper angle detection unit 27 measures the looper angle and the deviation from the target looper angle. Correct the torque generated in the looper on the basis of the current to convert the current to the looper accordingly to correct the angle of the looper, and the precompensation unit 35 to cancel the mutual interference or disturbance generated between the tension and the looper angle is cross-control (CROSS CONTROL) enables fast and stable control.

As shown in FIG. 3, the tension calculation unit 32 calculates the load value of the load detection unit LOAD CELL attached to the looper according to the target plate thickness and the target plate width of the equation model unit 21, and converts the tension into a tension control unit 33. ) Is the adjustment tension value through the proportional integral (PI) control the deviation value between the value obtained in this way and the unit tension set value calculated by the mathematical model unit 21.

Here, the load detector 31 uses a load cell and the detected load calculates the tension by using the theoretical formula of Equation 1 in the tension calculator 32. Symbols here refer to the schematic of the rolling stand and LOOPER in FIG.

From here f1 (θ) , f2 (θ) Is the same as Equation 2 and Equation 3.

<cos (θ-θ1) * sin (θ-θ1) + cos (θ + θ2) * sin (θ + θ2)>

* <cos ² (θ-θ1) * cos ² (θ + θ2)>

In addition, in Equation 2 and Equation 3, F2 is the force (Kg) due to the strip weight, the banding (BANDING) force, the looper roll weight, F4 is the force due to the strip centrifugal force as shown in equations (4) and (5).

Here, the meaning of the symbol of the calculation equation used for the looper control is as follows.

θ = looper angle (Deg, Rad)

θ1 = strip angle between nth stand and looper (Deg, Rad)

θ2 = strip angle between (n + 1) th stand and looper (Deg, Rad)

FLC = load detected by load cell (kg)

E = Young's modulus (kg / mm2)

W = strip width width (mm)

h = strip thickness (mm)

L = distance between the nth stand and (n + 1) th stand in mm

H = top height of the looper roll in the pass line (mm)

WS = strip weight between stands (kg)

WR = weight of looper roll in kg

g = gravitational acceleration (9.8m / s ² )

v = rolling roll speed (mm / s)

α = mounting angle of load cell (Deg, Rad)

L1 = arm length of looper (mm)

The looper angle detector 27 installed in the looper motor obtains a feedback value of the looper angle, and the deviation value between the detected looper angle and the looper angle set value calculated and calculated by the mathematical model unit 21 is proportional through the angle controller 34. Integral control is used to obtain the loop angle adjustment angle. Interference occurs between the tension between the stand of the continuous rolling mill and the looper torque, which is offset by the cross control in the predistortion unit 35.

At this time, the values of parameters C11 (7), C12 (8), C21 (9), and C22 (10), which are the parameters of the predistortion unit 35, are to be controlled to control the mutual interference. The phenomena of continuous rolling mills are modeled and expressed as a function, which is simplified as a determinant.

When the equation 6 is solved and described, it is expressed as Equation 7 and Equation 8 below.

▵V = C11 * ▵σ + C21 * ▵θ

▵T = C12 * ▵σ + C22 * ▵θ

Here, the tension control unit 33 uses 100% of the output value, that is, C11 = 1, and adds C21, which is the interference term of the angle control unit 34, and cancels it, and also uses 100% of the value from the angle control unit 34, that is, C22 = 1. Then, the interference term C12 of the tension control unit 33 is added to cancel. Here, C21 = Kvn (angle loop constant), C12 = Kgσ (tension torque constant), and the value can be changed little by little in consideration of control stability.

As described above, in the tension control, the adjustment tension of the tension control unit 33 is output through the precompensation controller 35 as a speed control correction value of the rolling roll, and in the looper angle control, the adjustment angle of the angle control unit 34 is the precompensator ( This looper feedback control method has two input and two output control factors that are output in the current reference of looper control with the value passed through 35).

Figure 5 shows the simulation results of the embodiment of the present invention in comparison with the prior art. In conventional control, the stand speed is controlled by the angle value and the looper is controlled by the tension value. In the control according to the present invention, the control factor was changed by a method of controlling the looper driving unit with the angle value and controlling the stand speed by tension. As a result, the response data can be seen more quickly and more stable through the CHART DATA of the simulation as shown in FIG. 5.

The present invention controls the looper driving at the looper angle, controls the speed of the rolling roll by the tension, and uses a predistorter which cancels the mutual interference between the looper angle and the tension, thereby achieving a fast and stable control result. have.

Claims (2)

A rolling roll driving unit for driving a continuous rolling roll; A looper driving part for adjusting an angle of a looper provided between the continuous rolling rolls; A mathematical model unit for calculating target plate thickness, target plate width, looper angle setting value and tension setting value by applying the data of actual plate thickness and plate width of the rolled material to the mathematical model of rolling process; In the tension control device of the continuous rolling mill having a speed control unit for outputting the reference speed of the rolling roll for the compensatory reduction of the automatic thickness control (AGC: Auto Gauge Control) according to the instructions of the formula model unit, A load detection unit for detecting a load of the rolled material applied to the looper; A tension calculator for converting the load value of the looper detected from the load detector into a tension according to the target plate thickness and the target plate width of the mathematical model unit; A tension control unit for obtaining adjustment tension through proportional integral control from the deviation of the actual tension value output from the tension calculator to the tension setting value of the mathematical model unit; A looper angle detector for detecting an angle of the looper; An angle control unit for obtaining an adjustment angle of the looper through proportional integral control from the deviation between the actual looper angle detected from the looper angle detector and the looper angle set value of the mathematical model unit; A precompensation part for outputting the speed compensation amount of the rolling roll and the torque compensation amount of the looper by mutually adding a compensation value according to mutual interference to the adjustment tension output from the tension control part and the angle control part and the adjustment angle of the looper; A current converting unit converting the value obtained by adding the basic torque value to the torque correction amount of the looper output from the predistorter compensating unit into a current and outputting the current to the looper driving unit; And an adder configured to add the speed compensation amount of the rolled roll output from the predistorter and the reference speed of the speed control part to output the rolled roll drive part. The method of claim 1, wherein the predistortion unit, It is composed of C11, C12, C21 and C22, which are parameters expressed as a function by modeling the phenomenon of continuous rolling mill with looper

(here ▵V, ▵T Are the outputs of the precompensator and the speed compensation and torque compensation respectively. ▵σ, ▵θ Is a cross controller of each of the adjustment torque and the adjustment angle as inputs of the precompensation unit.

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