KR100780426B1 - looper control apparatus and its method at hot strip mill - Google Patents

Abstract

The present invention not only reduces the tension control time by improving the looper responsiveness at the tip end in hot finishing rolling but also reduces the contact time with the rolled plate, and ultimately solves the problems such as the quality of the rolled plate, in particular, the tip width defect. It's about technology. To this end, the present invention changes the PID control gain of the looper quickly to improve the looper response at the tip in hot finishing rolling, thereby reducing the contact time with the rolling plate and ultimately reducing the tension control time. In particular, the present invention provides an apparatus and a method for solving a problem such as poor tip width.

Hot Rolled, Looper, Height Control

Description

Hot loop rolling tip looper responsiveness improving device and its method {looper control apparatus and its method at hot strip mill}

1: Structural Drawing of Conventional Hot Rolling Controller

2 is a flowchart of the detailed algorithm of the present invention.

3 is a system diagram proposed in the present invention

********** Symbol description of the main parts of the drawing **********

1. Upper and lower finishing rolls 2. Rolled plate

3. Looper Roll 4. Looper Arm

5. Load cell 6. Looper driver

7. Hydraulic Pressure Gauge 10. SCC Setting Device

11. Metal-in judgment device 12. Data collection system

13. Angle deviation and time change rate calculator 14. Fuzzy calculator

15. Unfuzzy Arithmetic Unit 16. Control Parameter Arithmetic Unit

17. PID control gain operation device 18. Looper PLC

The present invention relates to a method and apparatus for improving looper responsiveness at tip ends in hot finishing rolling, in particular to reduce the tension control time by reducing the contact time with the rolled plate and ultimately to the quality of the rolled plate, in particular to the tip. The present invention relates to a technique for solving problems such as poor width.

In the conventional hot finishing rolling, the looper control method first starts the looper by the forcing current of the looper motor about 0.1 second after the rolled plate is etched into the I + 1st stand. The looper's height control (PID control) is then started. However, the set time is not changed according to the steel grade or the size of the rolled plate, but it is a fixed value, which causes the control point to be delayed, which causes the looper control to be started late and degrades the control performance of the looper. do. In addition, since the control gains of the looper control system are set for the case where the looper is in the normal position, there is a disadvantage that the looper gain does not match while the looper is activated at the tip end. Therefore, there is a need for a technique capable of reducing the tension control start time by reducing the contact time with the rolled plate by improving the responsiveness of the looper at the tip end.

Looking at the patent associated with the present invention so far as follows.

1) Japanese Patent Application Publication No. 1995-214129, “Tension Control Device for Rolling Mill”, Samneung Electric Co., Ltd.

This patent relates to a technique for inventing a looper angle purge controller and a purge controller of a tension system in order to invent a tension control device of a rolling mill having a desirable performance against unexpected disturbance or noise.

2) Japanese Patent Application Laid-Open No. 07-108313, "looper control device", New Nippon Steel Co., Ltd.

This patent detects the looper angle and the tension of the rolled plate by the looper angle detector and the tension detector of the rolled plate when the rolled plate is inserted into the tip end, and the mill motor speed corresponding to the looper angle and the tension deviation when it is exaggerated from the detection signal. Patent on how to modify mill motor speed and looper angle using the correction amount and looper motor current correction amount.

3) Japanese Patent Application Publication No. 1993-285518, "Method and apparatus for controlling starter of looper", Toshiba Corporation

This patent applies the starting current from the starting current device to maintain the starting current forcing time in order for the looper to start up to the target position in a short time after the rolling plate is inserted into the next stand. It is a patent on a method

Etc. The problems of patents and known technologies filed so far are as follows.

First, the patent of "Japanese Patent Application Publication No. 1995-214129" constitutes a controller having robust performance against disturbances, but has a problem such as a long learning time by constructing a fuzzy controller over the whole length.

Second, the patent of “Japanese Patent Application Laid-Open No. 07-108313 is a patent relating to a technique for controlling tension by measuring a looper angle and tension, but tension between stands is difficult to be measured at the distal end due to the calibration time of the sensor. This is a problem for tip tension control.

The present invention has been made to solve the problems of the prior art, and improves looper responsiveness at the tip end during hot finishing rolling, thereby reducing the time for contacting the rolled plate and ultimately reducing the tension control time. It is an object of the present invention to provide an apparatus and a method for solving the problem of quality, in particular, the tip width is poor.

The structure of this invention for achieving such an object is the SCC which applies the setting value, such as a looper angle, a regression parameter, and the metal-in determination apparatus 11 for judging whether the rolling plate 2 was metal-in to the stand. (Supervisory Control Computer, 10) Data collection device 12 that collects actual data such as rolling load, looper angle, etc., angle deviation for calculating looper angle deviation and time change rate of deviation using data such as looper angle And a time change rate calculating device 13, a fuzzy arithmetic unit 14 for calculating the angle deviation and the time change rate of the deviation as fuzzy variables E and R, and a non-fuge for performing afuge from the fuzzy variable H, respectively. Arithmetic unit 15, a control parameter arithmetic unit 16 for calculating the control parameter ?? of the looper controller, and a PID control gain linkage for calculating the PID controller gain of the looper. And the gain equipped with a device (17) characterized in that the control device is configured as a quality of rolled sheet, characterized in that for outputting a looper PLC (18). Hereinafter, exemplary embodiments of the present invention will be described in detail with reference to the accompanying drawings.

 1 is a configuration diagram schematically showing the structure of a conventional hot finishing loop loop controller, Figure 2 is a flow chart showing in detail the control method proposed in the present invention, Figure 3 is a structure of the control system proposed in the present invention The block diagram shown. Referring to FIG. 1, the looper located between each adjacent rolling roll 1 is composed of a looper roll 3 and a looper arm 4, and serves to maintain a constant tension of the rolling plate 2. . In general, the looper measures the speed of the main motor in order to measure the looper angle and reduce the error from the target angle through the height controller.

The control method first detects the looper angle θ and feeds it back to the looper drive system 6, that is, the looper motor for rotating the looper arm 4, so that the detected looper angle θ is adjusted to the target angle. In addition, the detected looper angle is controlled by the height controller to calculate the rotational speed target value and input to the main motor to control the rotational speed of the rolling roll 1 by adjusting the rotational speed of the main motor. At this time, the looper drive system 6 is driven by a current for moving the looper drive system 6 after 0.1 seconds after the rolling plate 2 is inserted into the I + 1 stand, and after about 0.6 seconds, the height controller of the looper (PI controller) The control starts according to the output of. However, the looper will operate and after about 0.2 to 0.3 seconds the looper will touch the strip. However, due to the delay in the responsiveness of the main motor, the control commands of the height control and the tension controller by the looper take a long time to move the main motor.

3, the control device proposed in the present invention is shown. First, the set-up value of the metal-in determination device 11 for determining whether the rolled plate 2 is metal-in at the stand I + 1 in step 1 of FIG. 2 and the looper angle and regression parameters required in the second step are set. Equipped with an SCC (Supervisory Control Computer) computer, and equipped with a data collection device 12 for collecting data such as rolling load required in steps 3 and 4. In addition, an angle deviation and a time change rate calculating device 13 are installed to calculate the looper angle deviation and the time change rate of the deviation using data such as the looper angle collected by the data collecting device 12 in five stages, and purge each of them. Step 6 is equipped with a fuzzy arithmetic unit 14 for calculating with variables E and R. In addition, in order to carry out the defusification from the fuzzy variable H, the non-fuzzy arithmetic unit 15 is performed to perform seven steps, and a control parameter arithmetic unit 16 for obtaining the control parameter? As shown in Equation 5, a PID control gain calculating device 17 for calculating the PID controller gain of the looper is provided, and the gain is output to the looper PLC 18.

Referring to FIG. 2, the proposed tension control method is composed of the following algorithm. First, in the first step, it is determined from the load cell 5 installed on the stand I + 1 to determine whether the plate is inserted into the stand I + 1 (S10). To start. In the second step, setting values such as looper angles and regression parameters between the stands set according to the rolling conditions are read (S20). In the third step, it is determined whether the rolling time t has passed 0.6 seconds after the I + 1 stand insertion (S30). This is because the control of the looper is started after 0.6 seconds to apply the present algorithm only to the tip of the rolled plate, so the algorithm proposed in the present invention is stopped.

In the fourth step, measured values such as the looper angle are read from the data collection device 12 (S40). In step 5, the deviation of the looper angle and the time change rate of the deviation are calculated (S50). Here, the deviation e (t) of the looper angle and the time change rate e '(t) of the deviation are fuzzy into the fuzzy variables E and R in the sixth step, respectively (S60). It can be represented by seven different fuzzy sets.

[Equation 1]

Here, NL is Negative Large, NM is Negative Medium, NS is Negative Small, ZO is Zero, PL is Positive Large, PM is Positive Medium, and PS is Positive Small.

Table 1 below is a fuzzy rule for mapping from fuzzy variables E and R obtained in step 6 to another fuzzy variable H. Here, H is composed of seven fuzzy sets as in Equation 2 below.

[Setting Table 1]

[Equation 2]

In a seventh step, h (t) is obtained from the fuzzy variable H through a defuzzification method (S70). When h (t) is obtained, in step 8, the control parameter α may be obtained by a regression equation as shown in Equation 3 below (S80).

[Equation 3]

    Where α and γ are positive constants as regression parameters and are appropriately chosen to be less than one. In the above equation, since h (t) is bound from 3 to 3 and converges to 0, α also converges to 0 within the range of [-3 3]. In the ninth step, a control gain of the PID controller is obtained from the control parameters obtained in step 8 (S90), and the control gain of the PID controller has a general structure as shown in Equation (4).

[Equation 4]

Where K _c , T _d , and T _i are tuned on-line, representing the proportional gain, derivative time, and integration time of the controller, respectively.

PID control gains proposed in the present invention may be represented by Equation 5 by introducing a parameter α.

[Equation 5]

Here, k _u and t _u are referred to as the critical gain and the critical period, respectively, which represent the control gain and vibration period at that time when the proportional control gain is increased until the proportional control system reaches a stable limit.

PID control gains of the looper controller obtained from Equation 5 are performed in step 10 of outputting to the looper PLC (S100).

Although the invention has been particularly shown and described with reference to the preferred embodiments, those skilled in the art will appreciate that various modifications are possible without departing from the spirit and scope of the invention. Accordingly, the invention is limited only by the claims.

As described above, the present invention improves the looper responsiveness at the tip end during hot finishing rolling, thereby reducing the tension control time and ultimately improving the quality of the rolled plate. There is.

Claims (2)

In the hot finishing rolling looper response control device for improving looper response at the leading end in hot finishing rolling by quickly changing the PID control gain of the looper,  A metal in determination device for determining whether the rolled plate is metal in the I + 1 stand; A supervisory control computer (SCC) computer for applying set values such as a looper angle and a regression parameter; A data collection device for collecting measured data such as rolling load and looper angle; An angle deviation and time change rate calculating device for calculating a looper angle deviation and a time change rate of the deviation using data such as the looper angle; A fuzzy arithmetic unit for calculating the angle deviation and the time variation rate of the deviation as fuzzy variables, respectively; An unfuzzy arithmetic device for performing afuge from a separate fuzzy variable mapped from the fuzzy variable with respect to the angle deviation and the rate of time variation of the deviation; A control parameter calculating device for obtaining a control parameter of the looper controller; PID control gain calculation device for calculating the PID controller gain of the looper; And A quality control device for a rolled plate for outputting a PID control gain from the PID control gain calculating device to a looper PLC; Hot finishing rolling looper response control device comprising a. In the hot finishing rolling looper response control method for improving looper response at the leading end in hot finishing rolling by quickly changing the PID control gain of the looper, Determining whether the rolled plate is metal in the I + 1st stand, Reading setting values such as looper angle, regression parameter, etc. from the setting computer, Determining the tip by collecting measurement data such as the rolling load and the looper angle and determining whether a predetermined time has elapsed after the rolled plate is metal-in the I + 1 stand; Calculating a looper angle deviation and a time variation rate of the deviation using the measured data such as the looper angle; Calculating the looper angle deviation and a time variation rate of the deviation as fuzzy variables, respectively; Obtaining another fuzzy variable from the fuzzy variable, Performing unpurging from the other fuzzy variable, Obtaining control parameters of the looper controller, Calculating the PID controller gain of the looper from the control parameter, And outputting the PID control gains to the looper PLC.

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