JPS5916613A - Controlling device of sheet thickness - Google Patents

Abstract

PURPOSE:To increase the effect of automatic sheet thickness control, by changing the drooping characteristics of a speed controller to the prescribed one at the timing of outputting a speed correcting signal of an automatic sheet thickness controller to the speed controller. CONSTITUTION:When automatic sheet-thickness control is turned ON, a timing- generating circuit 22 excites a relay 23 to close a contact 23a, and then an output of an automatic sheet-thickness controller 21 is introduced to a speed controller 32. At the same time, as the circuit 22 excites a relay 36, a circuit which controls drooping characteristics is changed from circuits 34-36b to circuits 35- 36a. That is, when the automatic sheet thickness control is turned ON, the dropping characteristic-controlling circuit is changed to the exclusive circuits 35-36b. Accordingly, the drooping characteristic is also determined without taking into consideration about sheet breakage containing the case of no-breakage by previously conforming it to the functional conditions of the automatic sheet thickness control.

Description

DETAILED DESCRIPTION OF THE INVENTION The present invention relates to an automatic plate thickness control device mainly applied when cold rolling a metal strip.

Conventionally, there has been a device of this type as shown in FIG.

In the figure, (1) is an unwinding machine, and the metal strip (2) unwound from this unwinding machine (1) is transferred to the first stand rolling table (4) via the entrance guide roll (3). The plate thickness is reduced by the rolling effect, and then the NQ, two-stand rolling table (
Step 5), where the thickness of the sheet is further reduced by the rolling effect to the desired thickness, and the sheet is wound up by the winder (7) via the exit guide roll (6). (8) is an electric motor that drives the 1-stand rolling table (4);
) is supplied with power by a power supply device (9) that controls the rotation speed. That is, by attaching a rotation speed detector (not shown) to the electric motor (8) and feeding back the rotation speed, the power supply device (9) can control the rotation speed to a desired speed.
carried out by This control controls the speed of the metal strip (2) passing through the one-stand rolling table (4). The two-stand rolling table (5) is also equipped with a similar circuit (not shown), and similar drive control is performed.

Therefore, both the one-stand rolling table (4) and the two-stand rolling table (5) are driven by speed control.

A thickness gage 00 is installed on the exit side of the two-stand rolling table (5) to monitor that the metal strip (2) has exactly the desired thickness. This thickness meter 00 generates a difference between a desired target plate thickness value, which is a set value, and the thickness of the metal strip (2), which is a measured value, that is, a plate thickness deviation signal 0υ. This plate thickness deviation signal 0]) is input to the automatic plate thickness control device 0'4. The automatic plate thickness control device (2) produces a plate thickness deviation signal of 0◇
This is a P, PI or PID type controller which receives as input, and its output α→ is input to the power supply device (9) of the one-stand rolling table (4). .

Hereinafter, the operation of automatic plate thickness control will be explained using the automatic plate thickness control device 0.
The case where the path is a P-type controller will be explained. Assume now that the polarity of the plate thickness deviation signal 0]) is a negative sign. That is, in this case, the thickness of the metal strip (2) on the exit side of the two-stand rolling table (5) is smaller than the desired thickness. In this case, the output α of the plate thickness control device (a) has a positive sign, that is, a control signal in the direction of increasing the speed of the one-stand rolling table (4). Therefore, 1-stand rolling table (4)
Since the speed of the Arashi two-stand rolling table (5) increases and the speed of the Arashi two-stand rolling table (5) remains constant, the tension in the metal strip (2) between the two rolling tables (4) and (5) decreases. This leads to an increase in the thickness of the metal strip (2) on the exit side of the two-stand rolling table (5) due to rolling phenomena.

As a result, the plate thickness deviation signal α approaches zero, and the desired plate thickness is obtained.

Although the above description has been made for the case where the automatic plate thickness control device 0 is a P-type controller, the control operation is the same even if it is a PI or PID type. However, the PI type is used for the purpose of zeroing the steady-state deviation, and the D type element is added for the purpose of compensating for the detection dead time delay that occurs between the two-stand rolling table (5) and the thickness gauge OQ. It is.

As explained above, the control output a of the automatic thickness control device α is input to the power supply device (9) that controls the speed of the IVhl stand rolling table (4). Therefore, the power supply (
The speed control performed in 9) requires control performance that changes the speed completely following the control output 03.

However, the above requirements are generally not met.

This is because the speed control system has a drooping characteristic that is independent of the automatic plate thickness control system.

For example, as shown in Japanese Patent Application No. 56-208651, the need for drooping characteristics in a rolling mill as shown in FIG. 1 is extremely strong from the viewpoint of preventing sheet breakage.

However, from the viewpoint of automatic plate thickness control, the speed control system has the disadvantage that it does not sufficiently follow the speed change command issued by the automatic plate thickness control device, reducing the control effect.

This invention was made in order to eliminate the drawbacks of the conventional ones as described above, and the drooping characteristic of the speed controller is adjusted to the desired drooping characteristic at the timing of outputting the speed correction signal of the automatic plate thickness control device to the speed controller. The purpose of the present invention is to provide a device that increases the effectiveness of automatic plate thickness control by changing the thickness of the plate.

An embodiment of the present invention will be described below with reference to the drawings. Second
The figure is a schematic control block diagram of an embodiment of the present invention corresponding to FIG.
generates a drooping characteristic control signal αY in addition to the speed correction signal α1 outputted to the speed controller, and outputs both of the above-mentioned signals to the power supply device (9).

Figure 8 shows the above-mentioned signal delivery part in detail, and the hatched parts in the figure are parts of the automatic plate thickness control device (a) and the power supply device (9), that is, the speed control function. Show parts.

In Figure 8, Q◇ is P type (or PI, PID
(type) controller, (2) is an automatic plate thickness control "on" timing generation circuit, (28a) is a relay energized by this timing generation circuit, and (28a) is the a contact point of (28a) in this relay). Also, 0 is the reference speed generation circuit, (2) is the speed controller,
) is the speed detection signal, kabura is the conventional droop characteristic control circuit, (
(to) is the droop characteristic control circuit when the automatic plate thickness control is turned on, (to) is the relay, (86a) is the a contact of the relay (to), (8
6b) is the b contact of the relay (g). Further, θ1) represents a current controller, and (6) represents a current detection signal.

In FIG. 8, a known example of speed control that has been implemented in the past is a cascade type speed control circuit consisting of 0.times.I.times.G1X1 and . Among these, the drooping characteristics are controlled by the circuit (goods). In other words, the output signal of the speed controller (which is the input signal to the current controller 0) is:
Since it can be treated as a current signal within the speed control response range, this output signal is input to the speed controller through the multiplier circuit (b) to generate a so-called drooping characteristic in which the speed decreases as the current increases. It has become.

In the present invention, in addition to the above-mentioned conventional known example, a circuit for generating drooping characteristics is constructed from (opening) in FIG.
The feature is that it switches to In other words, the automatic plate thickness control "on" timing generation circuit) excites the relay @, closes the contact (28a), and leads the output of the automatic plate thickness controller Q0 to the speed controller). At the same time, the tie generating circuit (a) and the relay (b) are also excited, so the circuit for controlling the drooping characteristic is switched from circuit (i)-(86b) to circuit (g) (85a). That is, when automatic board thickness control is "on", the circuit for controlling drooping characteristics is also switched to a dedicated circuit ()-(86b). Therefore, this drooping characteristic can be determined in advance, including zero (that is, no drooping characteristic), with almost no consideration given to board breakage, in accordance with the functional convenience of automatic board thickness control.

Therefore, unlike the conventional device shown in Figure 1, the automatic plate thickness control function and drooping characteristic function do not operate completely independently and separately, but the drooping characteristic function is based on the automatic plate thickness control function. By subordinating them, precise control can be achieved.

In the above embodiments, the case where there are two rolling stands is shown, but the present invention can be similarly applied to cases where there are eight or more rolling stands.

Further, although the above embodiments have shown application to feedback type plate thickness control, the present invention can be applied to feedforward type plate thickness control in exactly the same manner.

As described above, according to the present invention, the drooping characteristic of the speed controller is changed to the desired drooping characteristic at the timing when the speed correction signal of the automatic sheet thickness control device is output to the speed controller. This has the effect of increasing the effect of thickness control and thereby improving the accuracy of product plate thickness.

[Brief explanation of drawings]

FIG. 1 is a simplified block diagram of a conventional plate thickness control device, FIG. 2 is a simplified block diagram of an embodiment of the present invention, and FIG. 8 is a detailed block diagram of the signal delivery portion in FIG. 2. (1)...Rewinder, (2)...Metal band, (3)...
・Entry side guide roll, (4)... 1-stand rolling table,
(5)... Two-seat rolling table, (6)... Exit guide roll, (7)... Winder, (8)... Drive motor, (9)... Power supply device , H...thickness gauge, 0])・
...Plate thickness deviation signal, 0 proverb...Automatic plate thickness control device, 0.
・・Automatic plate thickness control signal, α → ・・Droop characteristic control signal,
Qη...controller, (a) 00. timing generation circuit,
)...Relay, (28a)...A contact, 01)...
・・Reference speed generation circuit, in) ・・Speed controller, (g)
...speed detection signal, (b), ni)...drooping characteristic control circuit, (to)...relay, (86a) ”・A contact,
(86b) ・B contact, @η...Current controller, (6)
...Current detection signal In the figures, the same reference numerals indicate the same or corresponding parts. Agent Makoto Kuzuno

Claims (1)

[Claims] An electric motor that drives a rolling table for rolling a material to be rolled, a speed controller that controls the speed of this electric motor, first and second drooping characteristic control circuits that arbitrarily determine drooping characteristics of this speed controller,
A plate thickness controller which inputs a deviation signal between the thickness of the material to be rolled and the target plate thickness and derives a speed correction signal that makes the deviation signal zero; A plate thickness controller characterized by comprising a timing generation circuit that controls the timing of output to the controller and selectively utilizes the first or second drooping characteristic control circuit according to the timing.