JPH02137607A - Control method for loopers of continuous hot rolling mill - Google Patents

Abstract

PURPOSE:To decrease the fluctuation of sheet width and to stabilize rolling work by controlling positions of loopers and the tension of stock to be rolled as given control gain is corrected usually based on actual measured temperatures and the relation of temperature - deformation resistance of the stock to be rolled. CONSTITUTION:A steel sheet 3 as a stock to be rolled is continuously hot rolled by a rolling mill composed of plural roll stands F1-Fn. At that time, the positions of te loopers 4 located between every roll stand F1-Fn and the tension of the steel sheet 3 is detected respectively with detectors 8, 9. The detected values are compared with the set values from a data setting device 13 in a controller 11 in a looper control system. Corresponding to the deviation obtained in this way and according to the given control gain, the positions of the loopers 4 and the tension of the steel sheet 3 are controlled through controllers 6, 7. In point of the above control method, temperatures of the steel sheet 3 are measured with thermometers TM1-TMn. The corrected value of the gain is operated with a arithmetic unit 12 from these actual measured temperatures and the relation of temperature - deformation resistance of the steel sheet 3, and the above given control gain is corrected usually during the rolling. Therefore, the precision of the looper control can be improved following temperature fluctuations.

Description

DETAILED DESCRIPTION OF THE INVENTION [Industrial Application Field] 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] A conventional looper control device for a continuous hot rolling mill is, for example,
It is constructed as shown in FIG. Here, as shown in FIG. 8, a looper 4 disposed between the n-1st stage rolling stand Fn-1 and the nth stage rolling stand Fn is used.
The control will be explained below.

In FIG. 8, 1 indicates each rolling stand F n-x y
FO work roll, 2 is a drive motor that rotationally drives this work roll 1, 3 is each rolling stand F, 1°Fn
A steel plate (to-be-rolled material) which is continuously hot-rolled by 4 is arranged between rolling stands F rl-1 + F 0, and is used to adjust the tension of the steel plate 3 between these rolling stands F [1-1 + F 0. 5 is a drive motor for applying a drive torque to the looper 4; 6 is a rolling speed control device that adjusts the rotational state of the drive motor 2 to control the rolling speed of the rolling stand Fn-1; 7 is a drive motor 5; A looper drive torque control device that adjusts the drive torque of the looper 4 to position the looper 4 and control the tension of the steel plate 3; 8 is the looper 4;
A looper position detector 9 detects the position of the looper 4.
a steel plate tension detector for detecting the tension of the steel plate 3 via the
1i A looper that receives detection signals from the looper position detector 8 and the steel plate tension detector 9 and gives control commands to the rolling speed control device 6 and the looper drive torque control device W7 to control the position of the looper 4 and the tension of the steel plate 3. It is a control system controller.

In such a device, the looper control system controller 10 first compares the detection signals from the looper position detector 8 and the steel plate tension detector 9 with pre-given looper position set values and steel plate tension set values, respectively. , find the looper position deviation and steel plate tension deviation from each set value. Then, according to each deviation, a work roll speed (rolling speed) correction amount and a looper drive torque correction amount are calculated with a constant control gain, and control commands are sent to the rolling speed control device 6 and the looper drive torque based on each correction amount. The torque is output to a torque control device 7 to control the position of the looper 4 and the tension of the steel plate 3.

[Problems to be Solved by the Invention] Generally speaking, as shown in FIG.
The deformation resistance varies depending on the temperature, and the steel type.

Even if the size and set tension are the same, the characteristics of the looper control system change depending on the deformation resistance. In particular, for rolled materials whose deformation resistance is highly dependent on temperature, the control gain of the looper control system controller 10 is determined by the temperature of the rolled material (for example, the If it is constant regardless of the material temperature, the gain margin 2 phase margin will vary greatly depending on the temperature, and the entire control system may become unstable, or the response may deteriorate due to insufficient gain. FIG. 5 is a timing chart showing a state where the looper control system (looper position and steel plate tension) cannot be satisfactorily controlled due to the temperature of the rolled material. Also, FIG. 6(a).

(b) shows the case where the average temperature value t of the rolled material at the exit side of the rough mill (inlet side of the continuous rolling mill) is 950°C;
b) shows a state in which the looper control system (looper position and steel plate tension) cannot be satisfactorily controlled when the average temperature value t of the rolled material at the exit side of the rough mill (inlet side of the continuous rolling mill) is 1020°C. ing.

In other words, looper control accuracy largely depends on the deformation resistance of the rolled material, and especially for rolled materials whose deformation resistance is highly temperature dependent, the temperature of the rolled material between rolling stands has a large effect on the looper control system. Therefore, it is not possible to improve the control accuracy of the looper control system without considering the temperature.

The present invention aims to solve the above-mentioned problems, and aims to improve the looper control accuracy by following the temperature fluctuations of the rolled material, reduce strip width fluctuations due to tension fluctuations, and stabilize rolling operations. The purpose of the present invention is to provide a looper control method for a continuous hot rolling mill that ensures performance.

[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 measures the temperature of a rolled material, and compares the measured temperature value with the above-mentioned rolled material. The method is characterized in that the position of the looper and the tension of the material to be rolled are controlled while constantly correcting a predetermined control gain during rolling based on the temperature-deformation resistance relationship of the material.

[Function] In the above-described looper control method for a continuous hot rolling mill of the present invention, the actual temperature value of the rolled material and the temperature-deformation resistance relationship (transformation temperature, deformation resistance slope near the actual temperature value) of the rolled material are determined. etc.), a predetermined control gain for controlling the position of the looper and the tension of the material to be rolled is constantly corrected during rolling. Therefore, the temperature of the rolled material can be reflected in the control, and the characteristics of the looper control system are always maintained optimally without being affected by the temperature of the rolled material.

[Embodiments of the invention] Hereinafter, embodiments of the present invention will be described with reference to the drawings.
FIG. 1 is an overall configuration diagram showing an apparatus to which a looper control method for a continuous hot rolling mill is applied as a first embodiment of the present invention. n
In a hot continuous rolling mill equipped with n rolling stands up to Fn, the control of the looper 4 disposed between each rolling stand will be described. In addition, Figure 1 shows the final 2
The rolling stands F n-1r F n of stages and the looper 4 provided between these rolling stands F n-1+ F 1 are shown.

In FIG. 1, like the conventional one shown in FIG.
are the work rolls of each rolling stand F1 to Fn, 2 is a drive motor that rotationally drives this work roll 1, 3 is a steel plate (rolled material) that is continuously hot rolled by the rolling stands F to Fn, and 4 is a continuous A looper is arranged between the rolling stands F-Fn to adjust the tension of the steel plate 3 between the rolling stands F1-Fn, 5 is a drive motor for applying a drive torque to the looper 4, 6 is a drive motor 2
A rolling speed control device 7 controls the rolling speed of the front rolling stand by adjusting the rotational state of the rolling stand, and a looper drive torque control device 7 adjusts the drive torque of the drive motor 5 to position the looper 4 and control the tension of the steel plate 3. , 8 is a looper position detector that detects the position of the looper 4, and 9 is a steel plate tension detector that detects the tension of the steel plate 3 via the looper 4.

In this embodiment, 11 is a looper control system controller, which receives detection signals from the looper position detector 8 and steel plate tension detector 9, and responds to the deviation of each detection signal from a reference setting value (preset). , a control amount is calculated based on a predetermined control gain, and control commands are given to the rolling speed control device 6 and the looper drive torque control device 7 to control the position of the looper 4 and the tension of the steel plate 3.

In addition, TM1 to TM are rolling stands F to F, respectively.
A thermometer that measures the temperature of the steel plate 3 between n, 12 is a thermometer T
A predetermined control gain in the looper control system controller 11 is set as described below (1) based on the actual temperature values from the M□ to TM ports and data from various data setting devices 13 described later.
A gain correction calculation device 13 corrects and calculates based on the formula and outputs it, 13 is various data, for example, control gain initial value vector aio(,1-=1~nL for each looper 4)
Rolled material (steel plate) transformation temperature T'1. The looper control system controller 1 controls the temperature deformation resistance of the rolled material (steel plate), etc.
1 and the gain correction calculation device 12.

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 11, the detection signals from the looper position detector 8 and the steel plate tension detector 9 are set to predetermined looper position setting values and steel plate tension setting values, respectively. compared to
Find the looper position deviation and steel plate tension deviation from each set value. Then, according to each deviation, a work roll speed (rolling speed) correction amount and a looper drive torque correction amount are calculated using a predetermined control gain, and control commands are sent to the rolling speed control device 6 and the looper drive torque based on each correction amount. The torque is output to a torque control device 7 to control the position of the looper 4 and the tension of the steel plate 3.

At this time, in this embodiment, the thermometers TM□ to TMn are always
The temperature of the steel plate 3 on the outlet side of each rolling stand F□ to pn is measured, and the actual temperature values T1 to To are input to the gain correction calculation device 12.

Then, when the steel plate 3 is caught in the first rolling stand Fi, the gain correction calculation device 12 calculates a control gain initial value vector based on the temperature actual value T3 from the thermometer TM machine based on the following equation (1). An optimal control gain vector correction is calculated by correcting G1°, and this control gain vector correction is output to the looper control system controller 11 and used in place of the predetermined control gain.

T" However, 艙 is the control gain vector for the j-th looper (looper placed between rolling stands Fi and F 1) 4, and 马 is the control gain initial value for the j-th looper 4. Vector, Ti is the actual temperature value of the steel plate 3 measured with the thermometer TMi, and T1 is the transformation temperature of the steel plate 3 (
(see FIG. 2), kl is the deformation resistance slope (see FIG. 2) near the actual measured value of the steel plate temperature, and i=1 to n.

While rolling continues, the temperature of the steel plate 3 on the outlet side of each rolling stand F1 to Fn is determined by the thermometers TM, to TMn.
By constantly measuring and feeding back, calculations are performed to correct the control gain initial value vector C according to equation (1) to the optimum control gain vector C, and the position of the looper 4 and the steel plate 3 are
tension is controlled.

In addition, as a result of applying the control method of this example 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.

As described above, according to the looper control method of the first embodiment of the present invention, the temperature of each rolling stand F-F and the steel plate 3 on the exit side can be reflected in the control, and the characteristics of the looper control system can be Since the steel plate 3 is always held optimally without being affected by the temperature, it can follow temperature fluctuations in the steel plate 3, greatly improving looper control accuracy, reducing plate width fluctuations due to tension fluctuations, and stabilizing rolling operations. gender is ensured.

Next, a description will be given of a looper control method for a continuous hot rolling mill as a second embodiment of the present invention.
Overall configuration diagram showing the apparatus to which the method of the embodiment is applied, No. 4
The figure is a flowchart for explaining the operation.

In addition, in the figures, the same reference numerals as those already described indicate the same parts.

The explanation will be omitted.

In this second embodiment, the first embodiment is replaced by a rolling stand F.
In contrast to measuring the temperature of the steel plate 3 between □ and Fn, the temperature of the steel plate 3 at the entrance side of the continuous hot rolling mill (the entrance side of rolling stand F1) is measured and reflected in the control. .

In FIG. 3, TM is a thermometer 1 for measuring the temperature of the steel plate 3 on the outlet side of the rough mill 14, that is, on the inlet side of the rolling stand F1.
2A corrects and calculates a predetermined control gain in the looper control system controller 11 based on the average value of the actual temperature measurements from the thermometer TM and data from the various data setting bag W13 based on equation (2) described later. This is a gain correction calculation device that outputs. In addition, in this embodiment, the rolling stand F
This shows an example in which the method of this embodiment is applied to a looper 4 placed between n-1 and Fn, and the various data setting device 13 sets the control gain initial value vector for this looper 4, etc. As in the first embodiment, the signal is input to the looper control system controller 11 and the gain correction calculation device 12.

With the above-described configuration, looper control is carried out in the second embodiment in almost the same manner as in the first embodiment. The temperature of the steel plate 3 on the exit side of
At step SL in FIG. 4), the actual measured temperature value is input to the gain correction calculation device 12, and the average value of the measured temperature is calculated (step S2 in FIG. 4). Then, the gain correction calculation device 12 corrects the control gain initial value vector G0 based on the following equation (2) using the temperature average value τ based on the actual temperature measurement value from the thermometer TM, and calculates the optimum control gain vector. is calculated (step S3 in FIG. 4),
This control gain vector -d- is output to the looper control system controller 11 and used in place of the predetermined control gain.

Here, α is a correction coefficient.

While rolling continues, the temperature of the steel plate 3 on the entry side of the rolling stand F□ is constantly measured and fed back by the thermometer TM, and the control gain initial value vector according to the above equation (2) is converted into the optimum control gain vector. A computation for correction is already performed, and the position of the looper 4 and the tension of the steel plate 3 are controlled by the optimum control gain vector, and rolling is performed (step S4 in FIG. 4).

In addition, as a result of applying the control method of the second 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 (controlling force Y with the control gain kept constant at the initial value) and the control method of this example in terms of looper position variation and steel plate tension variation. be.

In this way, the looper control method according to the second embodiment of the present invention provides the same effects as those of the first embodiment described above.

[Effects of the Invention] As detailed above, according to the looper control method for a continuous hot rolling mill of the present invention, the control method is based on the actual measured temperature of the material to be rolled and the temperature-deformation resistance relationship of the material to be rolled. Since the predetermined control gain for controlling the position of the looper and the tension of the rolled material is constantly corrected during rolling, the temperature of the rolled material can be reflected in the control and the temperature fluctuations of the rolled material can be followed. The looper control accuracy is greatly improved. 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 the drawing]

FIG. 1 is an overall configuration diagram showing an apparatus to which a looper control method for a continuous hot rolling mill is applied as a first embodiment of the present invention;
Fig. 2 is a graph showing the temperature-deformation resistance relationship of the material to be rolled (steel plate), and Figs. 3 and 4 show a looper control method for a continuous hot rolling mill as a second embodiment of the present invention. 3 is an overall configuration diagram showing an apparatus to which the method of this embodiment is applied, and FIG. 4 is a flowchart for explaining its operation. Figure 7(a),
(b) is a timing chart showing a state in which the looper control system becomes unstable due to the temperature of the rolled material, and FIG. 8 is an overall configuration diagram showing the looper control device of a conventional continuous hot rolling mill. In the figure, ■ - Work roll, 2 - Drive motor, 3 - Steel plate (rolled material), 4 - Looper, 5 -
... Drive motor, 6... Rolling speed control device, 7...
Looper drive torque control device, 8... Looper position detector, 9... Steel plate tension detector, 11-... Looper control system controller, 12... Gain correction calculation device, 13... Various data settings Equipment, 14...-set mill, F
0~Fn・Rolling stand, TM, TM engineering~TMn-Thermometer. Patent applicant: Kobe Steel, Ltd.

Claims (1)

[Claims] When hot continuous rolling of a material to be rolled is carried out by a hot continuous rolling mill having a plurality of rolling stands, standards for the position of the looper placed between each of the rolling stands and the tension of the material to be rolled. In a looper control method for a continuous hot rolling mill that controls the position of the looper and the tension of the rolled material based on a predetermined control gain according to a deviation from a set value, the temperature of the rolled material is measured. , controlling the position of the looper and the tension of the rolled material while constantly correcting the predetermined control gain during rolling based on the measured temperature value and the temperature-deformation resistance relationship of the rolled material; A looper control method for a continuous hot rolling mill, characterized in that: