JPS583763B2 - Automatic plate thickness control device for rolling mills - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION The present invention relates to an automatic plate thickness control device for a rolling mill that rolls a rolled material used in rolling mill equipment to a target thickness.

FIG. 1 is a schematic configuration diagram showing an example of well-known rolling mill equipment equipped with an automatic plate thickness control device, in which 1 is the first stand, 2
is the second stand, 3 is the winder, 4 and 5 are 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; 8 is a second stand 2;
9 is an automatic plate thickness control device, and 10 is a rolled material.

In this configuration, in order to roll the exit side plate thickness of the second stand 2 to the target plate thickness ho, the plate thickness deviation △h (difference between the target plate thickness ho and the actual plate thickness) detected by the thickness detector 8 is reduced to zero. Alternatively, the roll speed of the second stand 2 is adjusted by the automatic plate thickness control device 9 to make it 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 driven by a roll speed control device 6,
The roll speed control devices 6 and 7 are given roll speed standards V1REF and V2REF based on the rolling schedule, and the electric motors 4 and 7 are controlled so that the roll speed becomes equal to the given standards. 5.

Now, when the speed of the second stand 2 is changed, the tension of the rolled material 10 between the first and second stands 1 and 2 changes, and the second stand
The thickness of the exit side of stand 2 changes.

Immediately, when the speed of the second stand 2 is increased, the tension between the first and second stands 1 and 2 increases, and the thickness of the outlet side of the second stand 2 becomes thinner. When the speed is reduced, the tension between the first and second stands 1 and 2 is reduced, and the thickness of the outlet plate becomes thicker.

Figure 2 shows a circuit diagram of a conventional automatic plate thickness control device used in rolling mill equipment as shown in Figure 1.
In the figure, 21 is a gain multiplier, and 22 is an integrator.

In the configuration as described above, the plate thickness deviation Δh is multiplied by the gain G1 by the gain multiplier 21 in order for the automatic plate thickness control system to obtain a stable response.

The gain G1 multiplied here is It will be like this.

Here, V2REF is the roll speed standard of the second stand 2, ho is the target plate thickness, and K1 is the influence coefficient (rate of change in plate thickness when the roll speed is changed).

The output △hXGt of the gain multiplier 21 is integrated by the integrator 22 and becomes the output △ that controls the roll speed of the second stand 2.
It is output as V2REF.

Note that a proportional + integrator as shown in FIG. 3 may be used as the integrator 22 shown in FIG. 2.

Now, if the first and second stands 1 and 2 are accelerated simultaneously, as the speed increases, the friction coefficient becomes smaller, the plastic coefficient of stands 1 and 2 becomes smaller, and the rolling load of stands 1 and 2 becomes smaller. decrease.

Therefore, the thickness of the exit side plates of the stands 1 and 2 becomes thinner rapidly.

On the other hand, the oil film on the roll bearings of stands 1 and 2 becomes thinner due to acceleration, and the gap between the rolls becomes narrower.
, 2, the outlet side plate thickness becomes thinner rapidly.

For the above reasons, even if automatic plate thickness control is not performed, the second
The thickness of the outlet side of the stand 2 becomes thinner rapidly as the speed increases.

Therefore, the exit plate thickness deviation Δh of the second stand 2 generally has a large positive deviation before acceleration, and becomes a negative deviation during acceleration due to acceleration.

In the automatic plate thickness control device shown in Fig. 2, the integrator 2
2 is included, so when the plate thickness deviation Δh is positive, the roll speed reference ΔV2REF is integrated by the integrator 22 in a direction that increases the speed of the second stand 2.

Therefore, since the plate thickness deviation Δh is a large positive deviation until the middle of acceleration, the roll speed reference ΔV2REF outputs a large signal in the speed increasing direction.

However, the signal in the direction of the acceleration force acts in the direction of reducing the thickness of the outlet side of the second stand 2.

Since this signal includes an integrator 22, the integrator 22 integrates in the direction of speed increase unless the plate thickness deviation Δh becomes negative.

Even if the plate thickness deviation △h suddenly becomes negative due to acceleration, the roll speed reference △V output in the direction of the acceleration force.
It takes time to turn 2REF into the deceleration direction.

Furthermore, the integrator 22 helps the plate thickness deviation to suddenly become a negative deviation due to acceleration, and since automatic plate thickness control is installed, the negative deviation at the rolling start portion becomes larger, resulting in undergauge exceeding the desired gauge range. Next rolled material 1
There is a drawback that the 0 off-gauge part becomes long.

Therefore, an object of the present invention is to provide an automatic plate for a rolling mill that eliminates the drawbacks of the prior art described above, reduces the off-gauge portion of the rolled material due to rolling machine acceleration, and thus makes it possible to efficiently control the plate thickness. To provide thickness control device.

More specifically, in order to prevent the acceleration of the stand from promoting undergauge in the automatic plate thickness control, the automatic plate thickness control is set to proportional control during the period when the plate thickness deviation is positive from the start of rolling, so that the plate thickness deviation is reduced. Once the deviation becomes zero or negative, the automatic plate thickness control is switched to integral control (or proportional + integral control). In this case, the control is proportional before switching, so if the switch is made when the plate thickness deviation △h is zero, the output ΔV2REF is zero, and after the switch is integral control (or proportional + integral control), the plate thickness deviation Δh is negative. When this happens, the rolling system is configured to suppress thinning of the plate and reduce undergauge caused by acceleration by issuing a signal to decelerate the stand, that is, to return the plate thickness deviation △h to zero. This provides an automatic plate thickness control device for machines.

FIG. 4 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 which 32 is a proportional device;
34 is a plate thickness deviation detector, 35 is a speed reference detector, 36 is a rolling start detection circuit, and RY is a relay.

In the configuration as described above, the plate thickness deviation Δh is multiplied by the gain G1 by the gain multiplier 1.

Incidentally, this multiplication is as shown in equation (1). The plate thickness deviation detector 34 detects that the plate thickness deviation △h has become zero or negative, and on the other hand, the roll speed of the second stand 2 The speed reference detector 35 detects that the reference V2REF has become below the constant speed reference (speed before rolling start).

Therefore, the rolling start detection circuit 36 is connected to each of the detectors 34.3.
The period from the start of rolling until the plate thickness deviation once becomes zero or negative based on the detected force from 5 (during this period, the relay RY
is ON).

When the relay RY is on, the output of the proportional device 32 is the output △V2REF from the automatic plate thickness control device. When the relay RY is off, the output of the gain multiplier 1 is integrated by the integrator 3, and the output of the integrator 3 is The output is from the automatic plate thickness control device △
V2REF Totoru.

As described above, the rolling start detection circuit 36 detects the period from the start of rolling until the thickness deviation on the exit side of the second stand 2 becomes zero or negative, and during this period, the relay RY of the rolling start detection circuit 36 is activated. In order to turn on the automatic plate thickness control, proportional control is performed based on the action of the proportional device 320 circuit.

Through this proportional control, the speed reference ΔV2REF is outputted in order to control the roll speed of the second stand 2 in the direction of zeroing the thickness deviation Δh in accordance with the thickness deviation Δh.

When the plate thickness deviation rapidly approaches zero due to acceleration, the speed reference △V2REF based on proportional control also approaches zero, and when the plate thickness deviation becomes zero, the relay RY of the rolling start circuit 36 is turned off and automatic plate thickness control is performed using an integrator. This will be done via 22.

Therefore, if integral control is utilized from the start of rolling, the roll speed standard △V2R in the direction of large thickening force even if the plate thickness deviation is near zero.
In contrast to the EF output, this switching does not result in an output that promotes undergauge.

Immediately after switching to the integrator 22, automatic plate thickness control is performed in a direction to reduce undergauge, and this integral control is continued until one rolled material is finished rolling.

FIG. 5 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 denotes a roll spacing control device.

That is, the configuration shown in the fifth figure exemplifies rolling mill equipment in which the roll gap is controlled by the roll gap control device 54 based on the output of the automatic plate thickness control device 9, and the thickness of the plate at the exit side of the stand 2 is set to the target plate thickness. The automatic plate thickness control device 9 includes an integrator (or proportional + integrator) and a proportional device, and has substantially the same configuration as that in FIG. 4.

According to this configuration, in the automatic plate thickness control device 9,
The roll spacing control device 54 outputs S as a roll spacing control output based on the plate thickness deviation Δh, and controls the roll spacing of the stand 2 by matching the roll spacing reference S with the control output ΔS.

In this case as well, in order to prevent the above-mentioned undergauge phenomenon due to acceleration of the stand 2, a method is adopted in which proportional control is performed first and then switched to integral control (or proportional + integral control).

FIG. 6 is a schematic configuration diagram of an automatic board thickness control device according to still another embodiment of the present invention, in which 62 is a rewinder, 66 is a tension control device, and 67 is a drive for the rewinder 62. Each shows an electric motor.

That is, the configuration shown in the sixth figure is a rolling equipment in which the tension of the unwinding machine 62 is controlled by the tension control device 66 based on the output of the automatic thickness control device 9, and the thickness of the sheet at the exit side of the stand 2 is set to the target thickness. The automatic plate thickness control device 9 is equipped with an integrator (or proportional + integrator) and a proportional device, and has substantially the same configuration as that in FIG. 4.

According to this configuration, in the automatic plate thickness control device 9,
A tension control output ΔT is output based on the plate thickness deviation Δh, and the tension control device 76 compares the tension reference T with the control output ΔT to control the unwinding tension of the unwinding machine 62. .

In this case as well, in order to prevent the above-mentioned undergauge phenomenon due to acceleration of the stand 2, a method is adopted in which proportional control is performed first and then switched to integral control (or proportional + integral control).

As described above, according to the present invention, the timing at which the plate thickness deviation shifts from zero to negative is detected and the proportional control is switched to the integral control (or proportional + integral control), so that rolling can be started. Unlike the case where integral control is performed from Since automatic plate thickness control is performed, it is possible to obtain an automatic plate thickness control device for a rolling mill that can reduce the amount of off-gauge of rolled material.

[Brief explanation of the drawing]

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, Fig. 2 is a circuit configuration diagram of a conventional plate thickness control device, and Fig. 3 shows the integrator shown in Fig. 2. FIG. 4 is a circuit diagram of a replaceable proportional + integrator; FIG. 4 is a circuit diagram of an automatic plate thickness control device for a thick rolling machine according to an embodiment of the present invention; FIGS. FIG. 2 is a circuit configuration diagram of an automatic plate thickness control device for a thick rolling machine according to an embodiment of the present invention. 21...gain multiplier, 22...integrator, 32...proportional device, 34...plate thickness deviation detector, 35...speed reference detector, 36...rolling start 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 by controlling the speed of the stand, and a rolling method. detecting means for detecting a first period from the start until the plate thickness deviation output of the thickness detector shifts from zero to a negative value, distinguishing it from a second period thereafter; and detecting the thickness in the first period; a proportional system that proportionally controls the plate thickness control means based on the plate thickness deviation output of the thickness detector; and a proportional system that proportionally controls the plate thickness control means based on the plate thickness deviation output of the thickness detector in the second period; 1. An automatic plate thickness control device for a rolling mill, comprising a control circuit having an integral or proportional+integral system for performing integral control.