JPS5945017A - Controller for looper - Google Patents

Abstract

PURPOSE:To obtain a titled device capable of maintaining always the maximum loop gain even if the conditions of a material is changed and improved in stabilizing the quality of the material, by correcting automatically a loop gain in a looper position controlling system by the functions of the thickness, width, and elongation of a strip. CONSTITUTION:The position of a looper detected by a looper position detector 7 of a looper motor 6 is compared with a looper position instruction value 11 by means of a PID controller 12. The obtained correction value actuates a speed controlling device 13 to make the looper position coincide with the instruction value 11 by compensating the speed of a mill driving motor 14. In this case, a gain G' outputted from the PID controller 12 is divided by a function K of the thickness, width, and elongation of a strip transmitted from a function generator by means of a divider 15 to instruct the obtained compensation value to the device 13. Thus the looper position is always controlled by the maximum response frequency. Accordingly, the quality is always stable even if a material is changed.

Description

DETAILED DESCRIPTION OF THE INVENTION The present invention provides an inter-stand rolling process in a hot finishing stand.
This invention relates to an improvement of a looper control device 4 that controls the tension of an IJ knob at a constant level using an electrically movable looper.

Generally, when strip is rolled in a hot finishing mill, variations in the pull between each stand affect the quality of the product.
It is well known that this can happen. In other words, in hot finish rolling (to P, the tension between each stand changes)
ll, the thickness of the strip and the plate +jJ change. Therefore, in recent years automatic thick plate [1] control technology,
Stabilizing the tension between stands has become an important issue.

In hot finishing rolling mills, a) looper is used to control the tension between the stands of the IJ tube. In conventional loopers, the tension of the strip is controlled at a constant f11.
According to the tension set to 1? If-style all commands - tension to give to the turret! The lf control loop detects the root looper and corrects the speed of the rolling mill at the front or rear stage of the looper based on the difference between the detected position and the set position, and controls the looper to a constant level. There is an IV1 control loop, which controls the tension at a constant level by applying a torque corresponding to the force to the strip through the louver arm and controlling the looper position to a constant level. Here, if the louver position is controlled to be constant, the push-up blade by the looper and the push-down blade by the plate tension will be balanced and the tension C' will be kept constant. However, at the looper position 97, disturbances exceeding the response limit of the control system Noah.

If the above balance is lost, the tension fluctuates. Variations in tension between stands cause variations in strip width and thickness, which has a significant impact on product quality. The loop gain of the louver IN control system changes depending on the strip plate Oki-1 plate Is elongation rate, but in the conventional device, the plate thickness that gives the maximum loop gain,
The gain was determined to prevent the control system from divergence due to the board width and elongation rate.

That is, in the conventional GIF3, the response limit frequency varies depending on the thickness, width, and elongation of the strip, and it has a drawback that it cannot always be operated to obtain the maximum response frequency. On the other hand, due to energy-saving operation of heating furnaces, the disturbance frequency applied to the looper control device JF1 during low-temperature heating and low-temperature rolling of slabs tends to increase, and in the region of low response frequency, the tension fluctuates, which has a serious effect on the product tab soil. It extends to

The present invention is based on the loop gain of the control system (1h).
It is configured so that the maximum loop gain can be maintained at all times by automatically correcting it according to the functions of the IJ tube's plate thickness, plate width, and elongation rate.The INF characteristic is the same as the strip between the stands rolled in the hot finishing stand. This is a louver control device that controls the tension of the louver at a constant level using a movable molded louver, which detects the louver position 11'7 and multiplies the difference between the detected position and the set position 16 by a gain to In the system for correcting the speed of the rolling mill in the latter stage, a function generator and a divider τν are provided to correct the gain using a function of the plate width, the plate width, and the elongation rate, which vary depending on the length of the strip. . Below is one example of the present invention h11! Examples will be explained in detail with reference to the drawings.

The louver arm 3 is mechanically connected to the louver motor 6 through a deceleration (f1). , is controlled so that the current command is always 10, and a constant tension is applied to the strip 4 whose dimensions are 4.rG 1 and 2. On the other hand, a louver position detector 7 mechanically connected to the louver motor 6 The looper position 1f# is detected and compared with the louver position command 11, and the speed of the motor 14 which has a loop gain G and drives the rolling mill 2 is corrected by the PID controller 12 by tracing the speed control i1 ff13, and the louver position is The control 111 is performed so that position #9 always follows the command value. Conventional PID
The gain G of the controller 12 was fixed regardless of the monthly interest rate, but in the present invention, the signal from the generator f which increases the gain G of the PID controller is corrected by the following formula,
It always constitutes an optimal control system regardless of changes in materials.

G = G'/'K G' = City control gain (K
=1) K=J7 to plate J, plate rlj, function of elongation rate≦1 The operation of such a +111 will be described below. In other words, the gain of the louver position control system changes in proportion to the function K of the plate thickness, plate 11], and elongation rate in the above equation.

Therefore, the smaller K is, the lower the gain and the lower the response frequency. In the present invention, in order to eliminate such a drawback, the gain G of the PID controller 12 is corrected by dividing the maximum control gain G' when =l by a function of the elongation rate (marked on plate 1, plate 11), so that the gain G of the PID controller 12 is always maximized. It is possible to operate with a gain of .

As described above, according to the present invention, changes in the loop gain of the looper level 1f and '4 control systems due to differences in materials are automatically corrected, and a looper level l control system can always be configured with a response frequency of 1'i; large. It is something.

[Brief explanation of the drawing]

The drawing is a fourth, clear view of the louver cape 11 device i'f of the present invention. 1 and 2 are pressure row I: 4' diameter, 3-thick 1-looper arm,
4 is a strip, 5d looper speed reducer, 6 is a louver motor, 7 is a looper position 1hi 1" detector, 8 is a louver motor p-11 flow + fQ IJI device, 9 &;i: t
1' is the current command value, 11 is the louver position command value, 12 is the proportional, integral, and differential control device T11
3 is a speedo writing device, 14 rolls ((with driving box excitation, 1
5 is a division of 1;, a container, and 16 is a function generator. Applicant: ψ1st Wooden Steel Co., Ltd.

Claims (1)

[Claims] A looper control device that uses an electric movable looper to keep the tension of the inter-stand strip rolled in a hot finishing stand constant, the device detecting the louver position In and applying a gain to the difference between the detected position and the set position. In a system that corrects the speed of the rolling mill at the front stage and the rear stage of the looper,
A looper control device comprising a function generator and a divider for correcting the gain using a function of plate thickness, plate width, and elongation rate that vary depending on the strip.