JPS589708A - Control device for sheet thickness in rolling mill - Google Patents

Abstract

PURPOSE:To reduce the sheet thickness deviation by on-off controlling the sheet thickness when running in low speed, by detecting said deviation at the exit of a stand to discriminate whether a rolling mill is in high speed running or in low speed one. CONSTITUTION:An automatic sheet thickness control is on-off controlled when a rolling mill is in low speed running, and said thickness controlling system is changed to an integral control when running in high speed. At this time, in on- off controlling, there is caused a time lag in detecting the sheet thickness deviation DELTAH equivalent to the distance between the 2nd stand and a thick-detector 8, but the delay at the 2nd stand is eliminated by bringing the deviation DELTAH to zero or close to zero. On the other hand, these is caused a delay in detecting the deviation DELTAH in integral controlling, and moreover an action, to bring the deviation to zero or close to zero, itself causes the delay because of the integral control. By this reason, the thickness deviation by the integral control of slow response is inevitably large compared with the on-off control, accordingly when running in slow speed, the deviation DELTAH is reduced by the on- off controlling compared with the integral one.

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.

Figure 1 shows an example of conventional rolling equipment with an automatic plate thickness control device biased.
J is the winder, # and ! The electric motor for driving the rolls of the 1st and 7th stands, and the 7tj electric motor! A roll speed control device that controls the speed of
10 is a thickness detector for detecting the thickness of the sheet, 1 is an automatic sheet thickness control device, and 10 is a rolled material.

In the above configuration, in order to roll the plate thickness at the exit side of the second stunt mill to the target plate thickness h.

Plate thickness deviation Δh (target plate thickness h) detected by thickness detector IK
The pull speed of the second stunt roller is adjusted by the automatic plate thickness control device so that the difference between the actual plate thickness and the actual plate thickness is zero or close to zero.

In addition, 1. 2nd stand l and ko are electric motor-tei.

#Yoshi-driven, electric motor-tei,! is controlled by the roll speed control devices 6 and 7, but the roll speed control device 6
, 7 is the roll speed reference VIR based on the pressure storm schedule, -
The electric motor J is driven so that the roll speed becomes faster based on the given reference value.

If you change the speed of the second stand, the tension of the rolled material/Q between the first and first stands will change, and the thickness of the plate on the exit side of the second stand will change. That is, increasing the speed of the second stuntco causes the speed of the first. As the tension between the first stands increases and the thickness of the outlet side of the second stand column decreases, conversely, if the speed of the second stand column decreases, the seventh stand column. The tension between the first stands decreases and the plate thickness on the exit side increases.

FIG. 2 shows the general configuration of the conventional automatic plate thickness control device, in which is is a gain multiplier, /4 is an integrator, /
There is a 7Fi multiplier. 'In such a configuration.

The plate thickness deviation Δh is multiplied by a gain G1 by a gain multiplier 1zFc in order for the automatic plate thickness control system to obtain a stable response.

The gain GK multiplied here is G, -V, RRF
X −X KI...(1)6.

Therefore, V and RNF are the roll speed standard of the second stunt roller, h@ is the target plate thickness, and KIFi is the shadow change coefficient (rate of change in plate thickness when the roll speed is changed).

The output ΔhXG1 of the gain multiplier 13 is further integrated by the integrator 14), and the integrated output 17. is multiplied by the roll speed reference VIRIF of the second stunt roller by the multiplier 17. The output of the multiplier 17 is output as an output jTJRIIF for controlling the roll speed of the second stunt roller. ΔVI
It is output as RmF. Δv,m! Iy is represented by the following formula.

ΔVIRIF −Δ V@X VIRIF
-Song (J) Note that a proportional + integrator may be used as the integrator 16.

In the automatic plate thickness control device as described above, in order to obtain a stable response of the automatic plate thickness control system, the gain multiplier 13 is multiplied by the roll speed standard of 7.11 mF of the second stunt roller. Since there is a certain distance between the second standco and the thickness detector 2, there is a delay in detecting the plate thickness deviation Δh, and this delay time is inversely proportional to the roll speed of the second standco.

In order for the automatic plate thickness control system to obtain a stable response to changes in the detection delay time of plate thickness deviation Δh due to changes in the roll speed of the second stand roller, the gain multiplier lsK is used as the I-roll speed reference for the stand roller. VIRIIF is multiplied.

Therefore, when the roll speed of the second stand 2 is high, the gain of the automatic plate thickness control system is high and the automatic plate thickness control has a quick response. However, when the roll speed of the second stand 2 is low, the automatic plate thickness control system The gain of the thickness control system becomes low, resulting in automatic plate thickness control with slow response.

If the roll speed of the former costanco is fast,
The response to the plate thickness deviation ΔhK is fast, and good automatic plate thickness control can be obtained even when the plate thickness deviation Δh is set to zero or close to zero. The response to Δh is slow and good automatic plate thickness control cannot be obtained.

When rolling a rolled material at low speed in a rolling mill facility, most of the time the leading end of the rolled material is threaded and the tail end of the rolled material is removed. The rate of change in the thickness of the base material (rolled material before rolling) is greater at the leading end and tail end portions of the rolled material than at other rolled material portions, and the plate thickness deviation Δh becomes large under automatic thickness control with a slow response.

This is an automatic plate that has been developed to improve the drawbacks of the above-mentioned prior art, which reduces the plate thickness deviation Δh of the rolled material due to low speed operation of the rolling mill, and enables more efficient plate thickness control. The present invention attempts to provide a thickness control device.

That is, in the apparatus of the present invention, the automatic plate thickness control is turned on and off by 1KL when the rolling mill is operating at low speed.

When the rolling mill is operating at high speed, automatic plate thickness control is switched to integral control. In the case of on-off control, there is a delay in detecting the plate thickness deviation Δh to adjust the distance between the second stand and the thickness detector, but in order to make this plate thickness deviation Δh zero or close to zero, there is a delay in the detection of the thickness deviation Δh. On the other hand, with integral control, there is a delay in detecting the plate thickness deviation Δh, and in order to press this plate thickness deviation h to zero or close to zero, there is also a delay in K due to the integral control. Therefore, integral control, which has a slow response, causes a larger plate thickness deviation than on/off control.

Therefore, if the on/off control is performed during low speed operation of the rolling mill, the plate thickness deviation Δh can be reduced compared to the integral control K.

In addition, in automatic plate thickness control during high-speed operation of a rolling mill, it is possible to reduce the plate thickness deviation Δh by using integral control with a quick response.

FIG. 3 shows an embodiment of the present invention.

In the figure, ko/#i is a gain multiplier, and 2 is an integrator.

1 are multipliers, which are similar to gain multiplier /j, integrator 14 and multiplier 7 of FIG. 2, respectively. Furthermore, the integrator n performs an integration operation at the point where the signal 9 & is input, and when the signal 9 & disappears, it holds the output immediately before it disappears.

An adder is inserted between the integrator and the multiplier.

a#i Multiply the deviation ΔhKG by the gain multiplier to obtain ΔV. Therefore, G is given by the quadratic formula.

G@−x x 1”·=(J) h·ζ Here, the hoa target thickness and Kl are the influence coefficients (rate of change in plate thickness when the roll speed is changed).

-da is an adder that accumulates the output ΔV of the gain multiplier 3. In other words, the cumulative value before addition (previous addition result)
This is done every time the sum of tPCΔV and output V is set.

A roll speed detector detects roll speed failure of the first stand λ.

1 is an off-time calculator which outputs a signal Jfa every time the calculated off-time t1 elapses, samples the output of the speed detector, and calculates the next off-time t1 based on this. When the signal a is output, if the signal f1 is output, the signal 30 is given to the adder 30a from Jθ, and the adder calculates based on Δh at that point. ∆V, ∆maj-,
Add to. The time during which such operations are performed is called on-time, and in the illustrated embodiment, the on-time is extremely short compared to the off-time.

This is the starting point for the next off-time tlo. The off time t1 corresponds to the time from when the rolled material passes through the JO stand λ until it reaches the thickness detector IK, and the off time t1 corresponds to the distance from Atsuko's stand 2 to the thickness detector I and the distance between the 1iE
Calculated based on V snow.

9 is a judge, and the speed setting value VIR1! When F is received, a signal Jfa is generated when it is greater than a predetermined value, and a signal Jfa is generated when it is smaller than the predetermined value.

While the signal λ91 is being generated, the integrator performs an integration operation, and its output is applied to the multiplier via the adder. The operation in this case is similar to that of the conventional control device shown in FIG.

Signal-? While tl is being generated, each time the signal λffa is generated, an addition is performed in the adder 1, and the output thereof is applied to the multiplier 26 via the adder 26. In this case, the output Δvjit of the adder changes in a step-like manner each time an addition is performed, as shown in FIG. 3(b) ItC.

It remains constant until the off-time t1 calculated at that point has elapsed. As a result of changing ΔV in this manner, the thickness deviation ΔhFi suddenly changes as soon as ΔV changes, as shown in FIG. 1 (IL). Tasoshi.

This change is the thickness detector! It is detected after the off time 11 has elapsed. In this way, the on-time and off-time are alternately repeated, and after changing the speed set value VIRIMF once during the on-time, the thickness deviation ΔhK detected at the time 8 elapses from the off-time is used to determine the next value to be used. Control performed by calculating the speed setting value vfi11LIIF is called on/off control.

In the present invention, on/off control is performed during low speed operation, and since no integral element is included in the control system, control with good stability and responsiveness is performed.

As explained above, the automatic plate thickness control device of the present invention performs on/off control of automatic plate thickness control when the rolling mill is operating at low speed, and performs automatic plate thickness control using integral control when the rolling mill is busy operating at high speed. Therefore, compared to the conventional case where the entire speed range is integrally controlled, the plate thickness deviation during low speed operation of the rolling mill can be reduced.

[Brief explanation of the drawing]

Fig. 1 is a schematic diagram showing an example of rolling mill equipment equipped with an automatic plate thickness control device, Fig. 2 is a schematic diagram showing a conventional automatic plate thickness control device, and Fig. 3 is a schematic diagram showing an example of rolling mill equipment equipped with an automatic plate thickness control device. A block diagram showing an example of a plate thickness control device. Fig. 1 (IL) and (b) #i is a graph showing an example of the plate thickness deviation and control output in on/off control. λl... First gain multiplier 1.2J...integrator, J
J...Second gain multiplier, λq...Seventh adder, Co...Co-adder. Lagoon...multiplier, core...2nd stand speed detector,
K: Off-time calculation unit, K9: Judgment unit.

Claims (1)

[Claims] A detector for detecting plate thickness deviation on the outlet side of a stand for rolling rolled material, a determiner for determining whether the rolling mill is in a high-speed operation state @ or a low-speed operation state 9, and an output of the determiner. The receiver is a control system that controls the plate thickness of the rolled material on and off when the rolling mill is in a low-speed operating state @IIc, and the receiver is a control system that controls the thickness of the rolled material on and off when the rolling mill is in a low-speed operating state @IIc, and the receiver is a control system that controls the thickness of the rolled material on and off when the rolling mill is in a high-speed operating state @IIc A plate thickness control device for a rolling mill, comprising: a control system including an integral element for controlling the plate thickness of the rolled material.