JPH03216206A - Control method of looper of hot continuous rolling mill - Google Patents

Abstract

PURPOSE:To improve the control accuracy of a looper by selecting a pattern in accordance with the natural frequency and absolute value of oscillating quantity of measured values which are obtained by picture processing and correcting a prescribed control gain automatically with correction coefficient corresponding the selected pattern. CONSTITUTION:In accordance with the deviation from reference set value of the measured angle of the looper 4 and measured tension of a material 3 to be rolled, the angle of the looper 4 and the tension of the material 3 to be rolled are controlled based on the prescribed control again. Then, the pattern in accordance with the natural frequency and absolute value of oscillating quantity of the measured value which are obtained with a picture processor 13 is selected. The prescribed control gain is automatically corrected with the correction coefficient corresponding to the selected pattern by using a controller 11 for looper control system. In this way, the stability of rolling operation can be ensured.

Description

DETAILED DESCRIPTION OF THE INVENTION [Field of Industrial Application] The present invention relates to a method for controlling a looper arranged between rolling stands in a continuous hot rolling mill to adjust the tension of a rolled material.

[Prior Art] Fig. 4 is a configuration diagram showing a general looper. In Fig. 4, 1 and 2 are rolling mills, 1a and 2a are work rolls in each rolling mill 1 and 2, and 3 is a rolling mill. A steel plate (rolled material) to be rolled by the rolling mills 1 and 2, and a looper 4 arranged between the rolling mills 1 and 2 to adjust the tension of the steel plate 3.

The looper 4 has a structure that allows it to rotate freely around point A, and is driven by an electric motor or the like (not shown).
Steel plate 3 is being pushed up. Furthermore, if the angle between the arm axis of the looper 4 and the horizontal line is defined as the looper angle θ, if the steel plate 3 between the rolling mills 1 and 2 becomes slack, the looper 4 will lift up and the looper angle θ will increase, while the steel plate 3
When the tension acting on the looper 4 increases and becomes a tensile state, the looper 4 is pressed down and the looper angle O becomes smaller.

Here, the looper control system refers to control that maintains the looper angle θ at a constant value and the tension of the steel plate 3 at a constant value, and its stability and responsiveness are determined by the width of the steel plate 3. It plays an important role in fluctuation and operability.

Now, a conventional control device for such a looper 4 is configured as shown in FIG. 5, for example. In FIG. 5, 5 is a driving motor that rotationally drives the work roll 1a of the rolling mill 1, 6 is a driving motor that applies a driving torque to the looper 4, and 7 is a driving motor that adjusts the rotational state of the driving motor 5. A rolling speed control device 8 controls the rolling speed of the rolling stand 1, a looper drive torque control device 8 adjusts the drive torque of the drive motor 6 to position the looper 4, and controls the tension of the steel plate 3; A looper angle detector 10 detects the angle θ, a steel plate tension detector 10 detects the tension of the steel plate 3 via the looper 4, and 11 a rolling device that receives detection signals from the looper position detector 9 and the steel plate tension detector 10. a looper control system controller 1 that controls the angle of the looper 4 and the tension of the steel plate 3 by giving control commands to the speed control device 7 and the looper drive torque control device W8;
Reference numeral 2 denotes an initial control gain setting device that sets an initial control gain according to changes in the cross-sectional area, steel type, plate width, etc. of the steel plate 3 and outputs it to the looper control system controller 11.

In such a conventional device, the looper control system controller 11 detects the looper angle θ from the looper angle detector 9.
and the preset target looper angle θ8, and also determine the deviation between the steel plate tension from the steel plate tension detector 10 and the preset target steel plate tension, and based on each deviation, initial control gain setting device l2 With the initial control gain set according to the cross-sectional area, steel type, and plate width of the steel plate 3, proportional-integral control is performed to control the looper angle θ and the steel plate tension to the target values.

Setting the initial control gain based on the cross-sectional area, steel type, and plate width of the steel plate 3 involves a long period of actual machine adjustment and artificial data statistical processing, and after the control gain setting is completed, the control gain will not be changed.

[Problems to be Solved by the Invention] However, setting control gains using actual machine adjustment and artificial statistical processing has been a laborious and time-consuming task that takes a long time. In addition, for data statistical processing,
Skilled judgment is required, and the judgment results vary from person to person.

Furthermore, once the control gain is set, it is not changed, so if characteristics change over time in the looper control system, the control gain will deviate from the optimal setting value, resulting in As a result, looper control accuracy deteriorates and plate width fluctuations due to steel plate tension fluctuations increase.
There were also issues such as the inability to ensure stable operations.

The present invention aims to solve the above-mentioned problems by making it possible to constantly optimize control gains without relying on skilled workers, improving looper control accuracy, and improving the stability of rolling operations. The purpose of this invention is to provide a method for controlling the looper of a hot continuous rolling mill.

[Means for Solving the Problems] In order to achieve the above object, the looper control method for a continuous hot rolling mill of the present invention includes: ■ performing image processing on at least one of the measured angle and the measured tension; From among the multiple fluctuation patterns, select a pattern that corresponds to the natural frequency and absolute value of the fluctuation amount of the actual measurement value obtained as a result of the image processing, and ■ adjust the predetermined control gain using the correction coefficient corresponding to the selected pattern. It is characterized by automatic correction.

[Function] In the looper control method for a continuous hot rolling mill of the present invention described above, image processing is performed on at least one of the measured angle and the measured tension, and the natural frequency and fluctuation of the measured value obtained as a result of the image processing are A pattern corresponding to the absolute value of the quantity is selected from among a plurality of preset fluctuation patterns. Then, the predetermined control gain is automatically corrected using the correction coefficient corresponding to the selected pattern.

Therefore, the control gain can be set without relying on a skilled person, and characteristic fluctuations of the looper control system can be corrected and reflected in the control gain, so that the control gain is maintained in an optimal state.

[Embodiments of the Invention] Hereinafter, a looper control method for a continuous hot rolling mill as an embodiment of the present invention will be explained with reference to the drawings. Fig. 1 is an overall configuration diagram showing an apparatus to which the method is applied. Note that, in the drawings, the same reference numerals as those already described indicate the same parts, so the explanation thereof will be omitted.

In Fig. 1, 13 is the actually measured angle from the looper angle detector 9 (or the actually measured tension from the steel plate tension detector 1o)
This image processing device 13 performs image processing on the natural frequency f and the absolute value of variation (angle variation θ or steel plate tension variation σ) of the actually measured angle obtained as a result of image processing. The corresponding pattern is compared and selected from among a plurality of preset fluctuation patterns (in this embodiment, five patterns ■ to ■ shown in FIGS. 2(a) to (e)), and the looper control system controller 11 This is what is output to. Reference numeral 14 denotes a timer that operates as described later to provide timing for image processing and control gain correction.

The looper control system controller 11 of this embodiment has a function of automatically correcting a predetermined control gain G using the following equation (1) using a correction coefficient α (described later) corresponding to a pattern selected by the image processing device 13. Therefore, proportional-integral control is performed after gain correction.

σ=PiXα...(1) However,
α=0.8 (Pattern I) 0.9 (Pattern ■) 1.0 (Pattern ■) 1.1 (Pattern ■) 1.2 (Pattern ■) In the above formula (1), automatic learning is performed as described later. The set control gain vector is the control gain vector set by the initial control gain setting device 12 before rolling, or the control gain vector modified last time.

In the apparatus configured as described above, the looper control method according to this embodiment is performed as follows. Basically, as in the past, first, in the looper control system controller l1, the detection signals from the looper position detector 9 and the steel plate tension detector 10 are set to predetermined looper position set values and steel plate tension set values, respectively. The looper position deviation and steel plate tension deviation from each set value are determined. Then, according to each deviation, a work roll speed (rolling speed) correction amount and a looper drive torque correction amount are calculated with a predetermined control gain, and control commands are sent to the rolling speed control device 17 and the looper drive torque based on each correction amount. Torque control device 8
The angle θ of the looper 4 and the tension of the steel plate 3 are controlled by proportional integral control.

At this time, in this embodiment, as shown in FIG.
When the control gain G1 is set by the initial control gain setting device 12 (step SL) and rolling is started (step S2), initially the correction coefficient α is set to 1.0 and control is performed using the initial control gain as is. (Step S3,
S4). During control, as mentioned above, the looper angle θ is constantly determined by the looper position detector 9 and the steel plate tension detector 10.
, tension are actually measured (step S5), and at least one of these measured values (looper angle θ in this embodiment) is subjected to image processing by the image processing device 13 to perform frequency analysis and fluctuation absolute value calculation. (Step S6).

When a preset time T (for example, 15 seconds) has elapsed, a timing is given from the timer 14, and at that point, the image processing device 13 compares and selects the corresponding pattern from among the five preset patterns. (Steps S7, S8).

Here, the five fluctuation patterns in this example will be briefly explained with reference to FIGS. 2(a) to 2(e). Figure 2(a)
is the natural frequency f1 (e.g. 0.71{z) or more, the angle variation θ1 (e.g. 10°) or more, the steel plate tension variation σ, (
For example 1. 5 kg/ms+2) or more, and ? Figure 2 (b) shows that the natural frequency f■ or more, the angular variation θ,
The following shows the case where the plate tension variation is less than σ1, and Fig. 2 (c) shows the case where the natural frequency fz (for example, 0.05 beads) or less, the angular variation θ■ or less, and the steel plate tension variation less than σ1. Figure 2(d) shows the case where the natural frequency f2 to fe, the angular variation θ, and below, the steel plate tension variation σ1, and the second
Figure (e) shows the case where the natural frequency is f2 to fe, the angular variation is 01 or more, and the steel plate tension variation is σ or more.

When the fluctuation pattern is selected, the looper control system controller 11 determines an appropriate one [see equation (1) above] from among the five preset correction coefficients α according to the selected pattern (step S9). , if rolling has not been completed, the process returns to step S4 again, and after performing control gain correction based on equation (1), the looper 4 is adjusted based on the gain.
The position of the steel plate 3 and the tension of the steel plate 3 are controlled proportionally and integrally.

During rolling of the same steel plate 3, the above-mentioned correction is performed several times.

After rolling, the difference between the control gain set before rolling and the final control gain (control gain correction amount) is set according to the cross-sectional area, steel type, and plate width of the steel plate 3 that is the material to be rolled. It is added to the control gain and learned, and set as the control gain G1 for the next rolled material and thereafter (steps Sll to S14). Learning is performed based on the following equation.

No 5 = σπ + β, ・(repeating) 0π = No π + β2 ・(rotten egg) Cπ = drunkenness + β3 ・(be 100D However, drunkenness: Set according to the cross-sectional area of the steel plate (initial setting value) Control gain vector π: Control gain vector set according to #I sheet steel type (initial setting value) ζ: Control gain vector set according to steel sheet width (initial setting value) Possible: Initial setting Total control gain vector possible: final total control gain vector after correction β1, β2, β3 = learning correction coefficient, β1+β2+β,
=1, for example, β1 = β2 =β, = 1/3 By applying the control method of this embodiment to various steel plates, it was confirmed that the control accuracy of the looper 4 was improved. The table below shows a comparison of accuracy between the conventional method (control method in which the control gain is kept constant at the initial value) and the control method of this embodiment with respect to the looper position fluctuation amount and the steel plate tension fluctuation amount.

(However, the total number of rolling rolls is 100.) In this way,
As a result of applying the looper control method of this example to an actual machine, it was possible to complete the adjustment of the looper control system on the actual machine without requiring a long period of adjustment by an expert, and the looper control accuracy after adjustment is shown in the table above. I was able to improve it significantly.

[Effects of the Invention] As detailed above, according to the looper control method for a continuous hot rolling mill of the present invention, the actual measured values (looper A pattern is selected according to the natural frequency and the absolute value of the amount of variation (angle or tension), and the predetermined control gain is automatically corrected using the correction coefficient corresponding to the selected pattern, so there is no need to rely on experts. This allows the control gain to be constantly optimized, greatly improving looper control accuracy.

Therefore, it is possible to reduce plate width fluctuations due to tension fluctuations, and the stability of the rolling operation is ensured.

[Brief explanation of drawings]

1 to 3 show a looper control method for a continuous hot rolling mill as an embodiment of the present invention, FIG. 1 is an overall configuration diagram showing an apparatus to which the method is applied, and FIG. )～(e
) are graphs showing variation patterns of the looper angle (II plate tension), Fig. 3 is a flowchart for explaining the operation of the above device, Fig. 4 is a configuration diagram showing a general looper, Fig. 5 is that of a conventional continuous hot rolling mill. FIG. 1 is an overall configuration diagram showing a looper control device. In the figure. 1.2-rolling mill, la, 2a-work roll, 31 steel plate (rolled material), 4-looper 5.6-11 translation motor, 71 rolling speed control device, 8 looper drive torque control device, 9 - Looper angle detector, 101 Steel plate tension detector, 11- Looper control system controller, 12- initial control gain setting device, 13- image processing device, 14-
timer.

Claims (1)

[Scope of Claims] When continuously hot rolling a material to be rolled by a continuous hot rolling mill having a plurality of rolling stands, the actual angle of the looper disposed between each of the rolling stands and the In the looper control method for a continuous hot rolling mill, the looper control method for a continuous hot rolling mill controls the angle of the looper and the tension of the rolled material based on a predetermined control gain according to a deviation from a reference setting value of each measured tension of the rolled material, Image processing is performed on at least one of the measured angle and the measured tension, and a pattern is selected from among a plurality of preset fluctuation patterns according to the natural frequency and the absolute value of the fluctuation amount of the measured value obtained as a result of the image processing. A looper control method for a continuous hot rolling mill, characterized in that the predetermined control gain is automatically corrected using a correction coefficient corresponding to the selected pattern.