JPS6120368B2 - - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION The present invention relates to an automatic plate thickness control device, and more particularly to an automatic plate thickness control device suitable for rolling a rolled material used in rolling mill equipment to a target thickness.

Fig. 1 is a schematic configuration diagram showing an example of a well-known rolling mill equipment equipped with an automatic plate thickness control device, in which 1 is the first stand for rolling, 2 is the second stand, and 3 is the post-rolling stand. winding machine for winding, 4, 5
are electric motors for driving the rolls of the first and second stands 1 and 2; 6 and 7 are roll speed control devices that control the speed of each of the electric motors 4 and 5; and 8 is a device that detects the exit side plate thickness of the second stand 2. 9 is an automatic plate thickness control device, and 10 is a rolled material to be subjected to rolling processing.

In this configuration, when rolling the rolled material 10 at the outlet side of the second stand 2 to the target thickness h ₀ , the thickness detector 8 detects the difference between the target thickness h ₀ and the actual thickness. The roll speed of the second stand 2 is adjusted by the automatic plate thickness control device 9 in order to detect the plate thickness deviation Δh and make it zero or close to zero. Note that the first and second stands 1 and 2 are driven by electric motors 4 and 5, and the electric motors 4 and 5 are controlled by roll speed control devices 6 and 7.
The roll speed control devices 6 and 7 are given roll speed standards V _1REF and V _2REF based on the rolling schedule, and drive and control the electric motors 4 and 5 so that the roll speed becomes equal to the given standards. .

Now, if you change the roll speed of the second stand 2,
The tension of the rolled material 10 between the first and second stands 1 and 2 changes, and the thickness of the outlet side of the second stand 2 changes. That is, when the speed of the second stand 2 is increased, the tension between the first and second stands 1 and 2 increases,
The outlet side plate thickness of the second stand 2 becomes thinner, and on the other hand, when the speed of the second stand 2 decreases, the tension between the first and second stands 1 and 2 decreases, and the outlet side plate thickness becomes thicker.

FIG. 2 shows a schematic circuit configuration diagram of a conventional automatic plate thickness control device used in rolling mill equipment as shown in FIG. 1, in which 21 is a gain multiplier;
22 is an integrator.

In the configuration as described above, the plate thickness deviation Δh is multiplied by the gain G ₁ by the gain multiplier 21 in order to obtain a stable response of the automatic plate thickness control system. The gain G ₁ multiplied here is as follows: G ₁ =V _2REF ×1/h ₀ ×K ₁ (1). Here, V _{2 REF} is the roll speed reference of the second stand 2, h ₀ is the target plate thickness, and K ₁ is the rate of change in the plate thickness when the roll speed is changed, that is, the influence coefficient. The output Δh×G ₁ of the gain multiplier 21 is integrated by an integrator 22 and output as an output ΔV _2REF that controls the roll speed of the second stand 2.

Note that the integrator 22 shown in FIG. 2 may be a proportional + integrator 22A as shown in the block diagram of FIG.
may also be used.

Now, when rolling the rolled material 10, if there is an abnormal part of the rolled material such as a welded part of the rolled material 10 where the thickness deviation Δh is abnormally large, the thickness deviation Δh will be changed to the waveform shown in FIG. It is detected as a change as shown in the figure. In such a case, when the automatic plate thickness control device 9 performs plate thickness control, in the configuration shown in FIG. 2, since the integrator 22 is included, the plate thickness deviation Δh
When is positive, the roll speed reference ΔV _2REF is integrated by the integrator 22 in the direction of increasing the speed of the second stand 2.

Therefore, as shown in the waveform diagram of FIG. 5, the plate thickness deviation Δh is a large positive deviation in the A period, so the roll speed reference ΔV _2REF is output as a large signal in the speed increasing direction. This signal in the speed increasing direction acts in a direction to reduce the thickness of the outlet side of the second stand 2. This signal is integrated in the speed increasing direction by the action of the integrator 22 as long as the plate thickness deviation Δh does not become negative. Even if the abnormal part of the rolled material 10 passes under the thickness detector 8 and the plate thickness deviation Δh suddenly becomes normal, that is, Δh becomes close to zero, due to the output of the integrator 22 in the speed increasing direction, As shown in FIG. 5, in period B, a large negative plate thickness deviation Δh occurs, exceeding the desired plate thickness deviation range, resulting in abnormal undergauge.

As mentioned above, the conventional automatic plate thickness control device tends to cause abnormal undergauge in the abnormal part of the rolled material, and this undergauge causes the rolled material to
As the off-gauge part of the steel plate becomes longer and the thickness of the under-gauge part becomes thinner, the rolled material may break during the next processing step, which seriously deteriorates the quality of the rolled material. There is a drawback that it does. Furthermore, since this undergauge has a greater influence on the quality of the rolled material 10 than an overgauge in which the sheet thickness deviation is too large, some measure is required to prevent the occurrence of undergauge.

Therefore, an object of the present invention is to eliminate the drawbacks of the above-mentioned prior art, and to provide a method for rolling an abnormal part of a rolled material where the plate thickness deviation is abnormally large, such as a welded part of the rolled material.
To provide an automatic plate thickness control device for a rolling mill that enables effective plate thickness control without causing abnormal undergauge of rolled material.

More specifically, the present invention provides a method for preventing the occurrence of abnormal undergauge in automatic plate thickness control when rolling an abnormal part of a rolled material with an abnormally large plate thickness deviation such as a welded part of the rolled material. During the period when the plate thickness deviation is positive in the detection of , the automatic plate thickness control is switched from integral control or proportional + integral control to proportional control.
Once the plate thickness deviation becomes zero, a configuration is adopted in which automatic plate thickness control returns to integral control or proportional + integral control. Usually, integral control or proportional control is used, which allows the gain of the control system to be larger than proportional control. Automatic plate thickness control is performed using integral control, and during automatic plate thickness control when the plate thickness deviation becomes abnormally large and suddenly shifts to zero, switch to proportional control when the plate thickness deviation Δh is zero. In this way, the deviation output for controlling the second stand is set to zero, and once the deviation output becomes zero, it is switched back to integral control or proportional + integral control, and the control at the abnormal part of the rolled material plate thickness is controlled. A novel automatic plate thickness control device configured to eliminate abnormal undergauge is provided.

FIG. 6 shows a circuit configuration diagram of an automatic plate thickness control device for a rolling mill according to an embodiment of the present invention. In the figure, 32 is a proportional device used when automatic plate thickness control is performed through a proportional control system. , 34 is a plate thickness deviation detector that detects that the plate thickness deviation Δh has become zero, 35 is a plate thickness deviation detector that detects that the plate thickness deviation Δh has become abnormally large, and 36 is the plate thickness deviation detector 34,
A rolled material abnormality detection circuit detects an abnormality in the rolled material 10 based on the output of 35;
and a relay that selectively connects the proportional device 32 to the control system.

In the configuration as described above, the plate thickness deviation Δh detected by the thickness detector 8 is multiplied by the gain G ₁ by the gain multiplier 21. Incidentally, this multiplication corresponds to the operation shown in equation (1). Further, the plate thickness deviation detector 35 detects that the plate thickness deviation Δh becomes abnormally large, while the plate thickness deviation detector 34 detects that the plate thickness deviation Δh becomes zero. . The rolled material abnormality detection circuit 36 includes the plate thickness deviation detectors 34 and 35.
Based on the detection output from the sensor, the period from when the plate thickness deviation Δh becomes abnormally large until the plate thickness deviation becomes zero is detected, and the relay RY is turned on during this period.

In addition, when relay RY is on, proportional device 32
The output of the integrator 22 becomes the output ΔV _2REF from the automatic plate thickness control device, and the output of the integrator 22 is reset to zero when the relay RY is turned on. Further, when the relay RY is turned off, the output of the gain multiplier 21 is integrated by the integrator 22, and the output of the integrator 22 becomes the output ΔV _2REF from the automatic plate thickness control device.

As described above, the relay RY of the rolled material abnormality detection circuit 36 is normally off, and therefore automatic plate thickness control is performed by the integral control system via the integrator 22, and when abnormality in plate thickness etc. Therefore, when the plate thickness deviation Δh becomes abnormally large, the rolled material abnormal portion detection circuit 36 detects the period from when the plate thickness deviation Δh becomes abnormally large until the plate thickness deviation Δh becomes zero,
During this period, the relay of the rolled material abnormality detection circuit 36
To turn on RY, automatic plate thickness control uses proportional regulator 3.
This is done in a proportional control system via 2.

According to this proportional control, the roll speed of the second stand 2 is controlled according to the plate thickness deviation Δh in a direction in which the plate thickness deviation Δh becomes zero.
Controlled by _2REF . In addition, if the plate thickness deviation rapidly approaches zero at the end of the abnormal part of the rolled material,
The speed reference ΔV _2REF due to proportional control also approaches zero,
Thereafter, when the plate thickness deviation becomes zero, the relay RY of the rolled material abnormality detection circuit 36 is turned off, and automatic plate thickness control is performed by integral control via the integrator 22. In this case, the output of the integrator 22 is reset to zero at the time of proportional control by the relay RY of the rolled material abnormality detection circuit 36, so it is zero at the start of the integral control. Therefore, when constant integral control is utilized, a large roll speed reference ΔV _2REF in the acceleration direction is output even when the plate thickness deviation Δh approaches zero, but this switching seems to cause a large undergauge. No output will be generated.

FIG. 7 is a waveform chart showing an example of the output ΔV _2REF and the thickness deviation Δh of the automatic plate thickness control device shown in FIG. 6.

As is clear from Fig. 7, according to the configuration shown in Fig. 6, automatic plate thickness control is performed by integral control up to point A, but when abnormal plate thickness is detected at point A, proportional control is performed. At point B, the plate thickness deviation Δ
When it is detected that h has become zero, the control is switched to integral control, and normal control is restored.

In addition, since the gain of the proportional control system is set high in the proportional control, an output ΔV _2REF is sent out such that the plate thickness deviation Δh is smaller than in the case of the integral control. Further, when the plate thickness deviation Δh approaches point B, the output ΔV _2REF also approaches zero, and at point B, ΔV _2REF also becomes zero. Therefore, after passing the abnormal part of the rolled material,
That is, the automatic plate thickness control after passing point B will not send out an output that would cause a large undergauge.

FIG. 8 shows a schematic configuration diagram of an automatic plate thickness control device for a rolling mill according to another embodiment of the present invention, in which reference numeral 54 indicates a roll gap control device.

That is, in the configuration shown in FIG. 8, the roll gap control device 5
4 is an example of rolling mill equipment in which the roll gap is controlled and the plate thickness at the exit side of the stand 2 is set to the target plate thickness, and the automatic plate thickness control device 9 is equipped with an integrator or a proportional + integrator and a proportional device. , has substantially the same configuration as that in FIG.

According to this configuration, the automatic plate thickness control device 9 outputs the roll gap control output ΔS based on the plate thickness deviation Δh, and the roll gap control device 54 outputs the roll gap control output ΔS based on the roll gap reference S and the control output ΔS. This is to control the gap between the rolls of the stand 2 by abutting against each other.

In this case as well, automatic plate thickness control is usually performed using integral control or proportional + integral control, and in order to prevent the undergauge phenomenon described above in abnormal parts of the rolled material where the plate thickness deviation is abnormally large. A control method is adopted in which proportional control is performed at the abnormal part of the rolled material, and after the abnormal part of the rolled material passes, the control is switched to normal integral control or proportional + integral control.

FIG. 9 shows a schematic configuration diagram of an automatic plate thickness control device for a rolling mill according to still another embodiment of the present invention,
In the figure, 62 is a rewinding machine, 66 is a tension control device, and 67
1 and 2 respectively show driving motors of the rewinding machine 62.

That is, in the configuration shown in FIG. 9, the unwinding machine 66 is
The automatic plate thickness control device 9 is equipped with an integrator or a proportional device + an integrator and a proportional device. It has substantially the same configuration as FIG. 6.

According to this configuration, the automatic plate thickness control device 9 adjusts the tension control output ΔT based on the plate thickness deviation Δh.
The tension control device 66 compares the tension reference T with the control output ΔT to control the rewinding tension of the rewinding machine 62.

In this case as well, automatic plate thickness control is usually controlled using integral control or proportional + integral control, and the abnormal part of the rolled material where the plate thickness deviation is abnormally large is controlled to prevent the undergauge phenomenon as described above. Proportional control is performed at the abnormal part of the rolled material, and after the abnormal part of the rolled material is normal,
A control method that switches to normal integral control or proportional + integral control is adopted.

As described above, according to the present invention, automatic plate thickness control is normally performed using integral control or proportional + integral control, and abnormal areas of rolled material where the plate thickness deviation is abnormally large, such as welded parts of rolled material, are detected. In such cases, automatic plate thickness control is performed by switching from normal integral control or proportional + integral control to proportional control, and then detects the timing when the abnormal part of the rolled material is normal and the plate thickness deviation shifts to zero, and performs proportional control. Because the control is switched to normal integral control or proportional + integral control,
Unlike the case where the abnormal part of the rolled material is controlled using integral control or proportional + integral control, the automatic plate thickness control output can prevent large undergauge after the rolled material has passed through the abnormal part. An automatic plate thickness control device can be obtained.

[Brief explanation of the drawing]

Fig. 1 is a schematic configuration diagram showing an example of well-known rolling mill equipment equipped with an automatic plate thickness control device, and Fig. 2 is a schematic diagram of a conventional automatic plate thickness control device used in rolling mill equipment as shown in Fig. 1. Circuit configuration diagram, Fig. 3 is a block diagram of the proportional + integrator, Fig. 4 is a waveform diagram of plate thickness deviation in the abnormal part of the rolled material, Fig. 5 is a waveform diagram of the rolling characteristics in the abnormal part of the rolled material, and Fig. 6 is a circuit configuration diagram of a rolling mill automatic plate thickness control device according to an embodiment of the present invention,
FIG. 7 is a waveform diagram of the rolling characteristics of the abnormal part of the rolled material in the configuration shown in FIG. 6, and FIGS. 8 and 9 are automatic plate thickness diagrams of rolling mills according to other and still other embodiments of the present invention. FIG. 2 is a schematic configuration diagram of a control device. 1...First stand, 2...Second stand,
6, 7...Roll speed control device, 8...Thickness detector, 9...Automatic plate thickness control device, 10...Rolled material,
32...Proportional device, 34, 35...Plate thickness deviation detector, 36...Rolled material abnormality detection circuit.

Claims (1)

[Claims] 1. A stand for rolling a rolled material, a thickness detector for detecting a thickness deviation on the outlet side of the stand, a thickness control means for changing the thickness of the rolled material, and at least an integral function based on the output of the thickness detector. a first control device that outputs a plate thickness control signal via a proportional system, a second control device that outputs a plate thickness control signal via a proportional system based on the output of the thickness detector, and an output of the thickness detector. After the deviation exceeds a certain value until the deviation is detected to be approximately zero, the output of the second control device is
The automatic sheet thickness control device further comprises a switching device that supplies the output of the first control device to the sheet thickness control device at other times.