JPH0156842B2 - - Google Patents

Description

[Detailed description of the invention] [Industrial application field]

The present invention relates to a device for controlling the thickness of a rolled material that eliminates the influence of roll eccentricity on the thickness of a rolled sheet.

[Conventional technology]

Conventionally, in automatic plate thickness control methods for rolling mills,
A method is adopted in which the outlet thickness H of the rolling rolls is indirectly detected by measuring the distance h between the rolls and the rolling force F. This relationship can be expressed by the following equation. H=h+C・F (1) However, H: Roll exit plate thickness h: Roll gap at no load C: Reciprocal of mill elastic modulus F: Rolling force This first equation can be illustrated as shown in Figure 6. It becomes like this.
In Fig. 6, the horizontal axis is the plate thickness, the vertical axis is the rolling force, characteristic curve a is the plastic deformation characteristic of the rolled material, characteristic curve b is the elastic characteristic of the rolling mill, and Hi is the plate thickness at the entrance of the rolling roll. , Ho indicate the exit plate thickness of the rolling roll, respectively. Now, let us consider the case where the outlet thickness of the mill roll is equal to the set value and the mill roll during rolling is eccentric. In this case, the value of the distance h between rolls changes with the eccentricity of the rolls, but since the distance h between rolls is generally detected by the height of the oil column in the reduction cylinder and the amount of movement of the reduction screw, The resulting change in h between rolls cannot be detected. Therefore,
A relationship as shown in FIG. 7 occurs between the actual plate thickness and the detected amount. That is, if the instantaneous value of the change in the distance h between rolls due to roll eccentricity is Δh, the rolling force F increases by ΔF, and the actual plate thickness becomes thinner by Δh ₁ . However, since the measured value of h between rolls does not change, it is detected from the first equation above that the apparent plate thickness has become thicker by Δh ₂ =C・ΔF, and the control device does not perform accurate thickness control and malfunctions. wake up
Note that FIG. 8 shows how the rolling force F varies due to roll eccentricity. In FIG. 8, the chain line is the average value of the rolling force F. Therefore, according to the 1973 special issue of the publication "Siemens Zeitschrift" entitled "Drive Technology and Process Automation in Steel and Rolling Mills", the thickness of the material rolled from the rolling stand can be automatically adjusted. When controlling, the load time roll distance is calculated from the no-load position of the rolling reduction adjustment device and the spring displacement amount of the rolling stand derived from the rolling force measurement value, and one threshold value is set. , rolling force fluctuations within this range are prevented from affecting automatic control. The threshold value for avoiding the influence of rolling force fluctuations caused by roll eccentricity is set using a single counter as the maximum amplitude upper and lower limits of rolling force fluctuations that occur during at least one revolution of the rotating rolling roll. It is created using this method. Only when the rolling force exceeds or falls below this maximum or minimum value is the roll reduction position changed for thickness control purposes. By doing so, it is possible to prevent rolling force fluctuations caused by roll eccentricity from affecting plate thickness control. On the other hand, Japanese Patent Application Laid-Open No. 47-3487 related to the invention of the same applicant
According to Japanese Patent Publication No. 52-1310, in order to detect and process rolling force fluctuations caused by roll eccentricity during operation, multiple threshold values are set, and continuous rolling force fluctuations are set to detect rolling force fluctuations caused by roll eccentricity during operation. I try to match it to the target. Therefore, in this conventional invention, a variable resistor is connected in parallel to the input amplifier of an analog-to-digital converter that processes the measured rolling force, and the resistance value is set to different operating values for each pair connected to the output of the amplifier. A plurality of comparators and an arithmetic logic circuit connected to the comparators are used to change the rolling force according to the amplitude of the rolling force fluctuation at each time. Thereby, only the rolling force changes caused by the rolled material, which exceed the current rolling force fluctuations, are passed to the automatic plate thickness control device. By doing so, it is possible to similarly avoid rolling force fluctuations caused by roll eccentricity from affecting plate thickness control.

[Problem to be solved by the invention]

In any of the above-mentioned conventional techniques, as shown in FIG.
Instead of controlling the plate thickness according to the fluctuation ΔF of
Plate thickness control is performed along the average value F ₀ shown by the chain line. Therefore, as described above, it is possible to prevent rolling force fluctuations caused by roll eccentricity from affecting plate thickness control. However, in any of the above-mentioned conventional technologies, roll-to-roll changes due to roll eccentricity still exist, and therefore the thickness of the product discharged from the roll outlet varies in proportion to the roll-to-roll changes. are doing. Therefore, in any of the above-mentioned conventional techniques, although the problem of controlling the product thickness in an unnecessarily bad direction based on rolling force fluctuations caused by roll eccentricity is solved, Between the rolls due to roll eccentricity from the plate thickness
The problem of eliminating plate thickness variations corresponding to changes has not been solved at all. Therefore, the present invention does not simply avoid giving erroneous operation commands due to roll eccentricity to the automatic control system for the roll distance under load, but also aims to determine the roll eccentricity from the thickness of the product discharged from the roll outlet. The objective is to eliminate plate thickness fluctuations that are caused by roll-to-roll changes.

[Means to solve the problem]

In order to solve such problems, the present invention provides: a load time roll distance adjuster for adjusting the load time roll distance average value according to a load time roll distance command value; 〓A position adjuster that operates the rolling device to adjust the rolling position according to a position command value given in response to the output signal of the regulator, and a load time determined from rolling force fluctuations due to roll eccentricity or spring displacement fluctuations. Between rolls: A roll eccentricity compensation adjuster that forms a roll eccentricity compensation command value according to the change and gives this roll eccentricity compensation command value to a position adjuster; and a roll that is given from this roll eccentricity compensation adjuster to the position adjuster. The present invention is characterized by comprising: a limiter that limits the magnitude of the eccentricity compensation command value; and a threshold device that changes the limit threshold of the limiter in accordance with the amplitude of rolling force fluctuation or spring displacement fluctuation each time.

[Effect]

In the present invention, the rolling force variation ΔF caused by roll eccentricity is actively extracted, and for example, when roll distance decreases due to roll eccentricity, based on the rolling force variation ΔF, The position of the rolls is moved in a direction that increases the distance between the rolls, thereby reducing the distance between the rolls due to roll eccentricity and increasing the distance between the rolls due to the change in the roll position controlled based on the rolling force variation. The position of the rolling rolls was controlled so that the two offsets offset each other, so that the thickness of the plate discharged from the exit of the rolling rolls would not be affected by the eccentricity of the rolling rolls.

【Example】

Next, embodiments of the present invention will be described in detail based on the drawings. FIG. 1 is a block diagram showing one embodiment of the present invention. In FIG. 1, a position adjuster 3 is connected to a load time/roll distance adjuster 1 in a subordinate manner.
At an intermediate addition point, a position command value S ^* is created from the no-load position, that is, the no-load roll interval S ₀ ^* and the loaded roll interval output ΔS ₁ ^* of the regulator 1.
The actual position value S and the actual rolling force value F are measured at the piston 10 of the hydraulically operated rolling down device. Regulator 2
is for creating the roll eccentricity compensation command value ΔS ₂ ^* , and operates not as a rolling force regulator but as a roll eccentricity compensation regulator. The command value C・F ^* of the roll eccentricity compensation regulator 2 is the load time roll distance = actual value h
(or the load time roll interval command value h ^* ) and the position command value S _V ^* which is delayed by the delay device 8 by the characteristic time of the position adjustment system. In addition,
C is the reciprocal of Mill's elastic modulus as mentioned above, and F ^*
is the rolling force command value. The actual spring displacement values C and F are determined by a matching amplifier 7 that copies the spring characteristics of the rolling stand.
Created in The roll eccentricity compensation adjuster 2 likewise acts on the input of the position adjuster 3. Thereby,
The position adjuster 3 receives the roll eccentricity compensation command value ΔS ₂ ^* , and based on it, changes the roll position in the direction opposite to the roll eccentricity, that is, changes in the periodic rolling force F or spring displacement C・F caused by the roll eccentricity. , that is, in order to eliminate the variation between rolls under load,
Perform adjustment operations. However, such a circuit configuration alone does not achieve any improvement in dynamic characteristics. However, the roll eccentricity compensation adjuster 2 is
Since it is not subordinately connected to
Therefore, the roll eccentricity compensation command value ΔS ₂ ^* can be controlled to a value necessary to eliminate periodic fluctuations through control. The control threshold value of the roll eccentricity compensation command value ΔS ₂ ^* is determined by the threshold value device 6 and set by the matching device 5. The threshold value device 6 is configured to calculate the load time roll interval〓actual value h(=S
+C・F), that is, create an average value h ₀ of the actual value h during load and between rolls, and give it to the load and between rolls controller 1. The fluctuations that appear in the actual value h are the fluctuations in the position S and the spring displacement C・
It consists of the residual fluctuation of F. The position variations occur based on the operation of the roll eccentricity compensation adjuster 2, which compensates for roll-to-roll changes caused by roll eccentricity. Furthermore, the threshold value device 6 has the function of automatically adjusting itself to the range of periodic actual value fluctuations. The output h ₀ of the threshold device 6 corresponds to the average value of the input values (S+C·F), and the output E, which is the limiting threshold of the roll eccentricity compensation command value ΔS ₂ ^* , corresponds to the half amplitude peak value of the input fluctuation. As this threshold value device 6, for example,
The circuit configuration disclosed in Japanese Patent No. 47-3487 can be used. Since the inner loop includes automatic position control, the limit threshold value E and the roll eccentricity compensation command value ΔS ₂ ^* represent the same dimension, that is, the same process. Therefore, the roll eccentricity compensation command value ΔS ₂ ^* can be easily limited using the limit threshold E. Considering the pulsations remaining in the actual spring displacement values C and F, the matching device 5 corrects the value E to the value E'. This correction is simple with variable setting correction coefficients. The magnitude of the correction factor is related to the amplification degree of the roll eccentricity compensation regulator 2. The threshold value E', whose value is reduced by the residual pulsation, determines the limit amount of the roll eccentricity compensation command value ΔS ₂ ^* . Accordingly, the roll eccentricity compensation regulator 2 is provided with an operating range in which, on the basis of its inherent regulation characteristics, it only passes through position changes that appear in the controlled elimination of periodic load-time roll-to-roll variations. The operation mode of the automatic control circuit shown in FIG. 1 is as follows. The actual values of the rolling force S and the rolling force F are measured on the piston 10 of the rolling machine. Actual rolling force value F
can be expressed by the following equation, where F ₀ is the average value shown by the chain line in FIG. 8, and ΔF is the variation due to roll eccentricity. F=F ₀ +ΔF (2) From this rolling force actual value F, the spring displacement actual value C·F is formed in the matching amplifier 7. C・F=C(F ₀ +ΔF) (3) Based on the present invention, the rolling roll position (rolling position) of the rolling device is controlled to compensate for roll eccentricity, so the rolling position S is also equal to the average value S It can be expressed as ₀ and the variation ΔS. S=S ₀ +ΔS (4) The actual reduction position value S and the actual spring displacement value C·F are added at the input side of the threshold value device 6. The threshold value device 6 on the one hand creates an average value h ₀ between the rolls from the added value. S+C・F=S+ΔS+C(F ₀ +ΔF)=S ₀ +C
・F ₀ +ΔS+C・ΔF=h ₀ +Δh=h(5) However, h ₀ =S ₀ +C・F ₀ (6) Δh=ΔS+C・ΔF (7) This average value h ₀ is the roll-to-roll command value h ^* The deviation (h ^* − h ₀ ) is the difference between rolls under load 〓
regulator 1. A reduction position command value S ^* is created from the output ΔS ₁ ^* of the roll distance controller 1 during load and the roll distance S ₀ ^* during no load, and is given to the position controller 3. On the other hand, the reduction position command value S ^* is delayed by the characteristic time of the automatic control system and becomes S _V ^* . And this
A subtraction operation is performed between S _V ^* and the average value h ₀ between rolls. S _V ^* −h ₀ = S _V ^* −S ₀ −C・F ₀ = −C・F ₀ (8) Since the average value S ₀ of the rolling position S does not include the variation, it also does not include the variation. It is equal to the delay signal S _V ^* of the lower position command value S ^* that is not present. Then, the average spring displacement value C·F ₀ expressed by the eighth equation is compared with the actual spring displacement value C·F as the spring displacement command value C·F ^* , and the deviation thereof is formed. C・F−C・F ^* =C(F ₀ +ΔF)−C・F ₀ =ΔF (9) This rolling force variation ΔF is given to the roll eccentricity compensation controller 2, thereby changing the roll eccentricity compensation command value ΔS ₂ ^* is formed. This roll eccentricity compensation command value ΔS ₂ ^* is given to the position adjuster 3, and the position adjuster 3 controls the rolling rolls of the rolling device in order to compensate for the variation Δh in the distance between the rolls due to the roll eccentricity. Position is controlled. In this case, the following addition takes place on the input side of the position adjuster 3. S ^* −S − ΔS ₂ ^* = S ^* − (S ₀ + ΔS) − ΔF = (S
^* −S ₀ )−(ΔS+ΔF) When the plate thickness is controlled to be constant, S ^* =S ₀ . Therefore, the position adjuster 3 receives the fluctuation amount ΔF of the rolling force F according to the roll eccentricity from the roll eccentricity compensation adjuster 2.
By giving ΔS + ΔF = 0, it is possible to compensate for the variation ΔF in the rolling force F caused by roll eccentricity, and to keep the distance h between the rolls, that is, the plate thickness H at the exit of the rolls, constant. I can do it. FIG. 9 shows the rolling roll position in the prior art and the rolling roll position in the present invention. That is, Figure A shows the rolling roll position in the prior art,
Figure B shows the position of the rolling rolls in the present invention.
As is clear from FIG. 9, in the prior art, the mill roll position was not controlled in accordance with the roll eccentricity, and therefore the mill roll position was held constant. On the other hand, in the present invention, the position of the rolling rolls is controlled according to the eccentricity of the rolls, and therefore the position of the rolling rolls is controlled to fluctuate according to the eccentricity of the rolls. FIG. 2 shows the configuration of another embodiment of the invention. In FIG. 2, the command value-actual value matching points of the load time roll distance adjuster and the roll eccentricity compensation adjuster are combined into one point. h ^* to h
It is compared with. Here h is h=C・F+S _V ^*
Created by. Furthermore, h ^* = C・F ^* +
Since S ^* holds true, if S ^* = S _V ^* , this comparison is also a comparison between C.F ^* and C.F. In the operating range of the automatic control for roll eccentricity compensation, the output of the load-time roll-to-roll regulator 1 does not change, and therefore the delay is meaningless, so the latter comparison condition is satisfied. The roll eccentricity compensation regulator 2 is designed as a proportional-acting regulator. The load-roll-to-roll regulator 1 is configured as an integral-acting regulator and is connected after the roll eccentricity compensation regulator 2 . The threshold value device 6 automatically adapts its output quantity to periodic fluctuations and serves only to detect roll eccentricity. The magnitude of the limiting threshold is thereby determined. The average value h ₀ of the actual values reproduced in the threshold value device 6 is only an auxiliary variable that is not necessary for the automatic control itself. The limiter 4 has an amplification degree of 1 below the limit threshold,
Reverse the input sign. In this embodiment, _the threshold value device 6 shown in FIG.
1, a comparator 62 that compares the output of this amplifier 61 and the output of a digital-to-analog converter 64, which will be described later, a counter 63 to which the output of this comparator 62 is given, and a digital output of this counter 63 that is converted into an analog value. a digital-to-analog converter 64, and a limiter 65 whose limiting threshold for passing the output of the amplifier 61 is changed by the output of the digital-to-analog converter 64;
Then, by integrating the output of this limiter 65, the difference between rolls is
and an integrator 66 that forms an average value h ₀ . The output of the digital-to-analog converter 64 is supplied to the matching box 5. The operation of the embodiment shown in FIG. 2 is as follows. While the input amount of the limiter 4 does not reach the limit threshold, the input amount of the regulator 1 becomes zero by adding control signals of opposite signs to each other. Therefore, only ΔS ₂ ^* is effective (roll eccentricity compensation automatic control). When the limiting threshold is reached, the direct output coming from regulator 2 becomes so large that regulator 1 receives the input signal and passes it through ΔS ₁ ^* until equilibrium is established again at the input of regulator 2 with feedback S _V ^* . Adjust position S. This eliminates the average value deviation (automatic control between rolls during load). The automatic roll eccentricity detection circuit disclosed in Japanese Unexamined Patent Publication No. 47-3487 can in principle be applied to the threshold device of the present invention. However, as shown in FIG. 3, the input amplifier 12 of the analog-to-digital converter 11 uses the load time roll distance 〓 instead of the spring displacement C・F.
The actual value S+C·F is given. input amplifier 12
Comparators 15 and 16 connected after the circuit check whether the actual value increases or decreases and open or close the logic circuit 17. Logic circuit 17 converts the input signal present at any given time into a pulse train and supplies it to counter 13 .
The count value of counter 13 is fed back to input amplifier 12 via digital-to-analog converter 14. A comparator 19 connected directly or via an amplifier 18 after the input amplifier 12
~24 outputs are direct or timed elements 25, 26
The signal is applied to the arithmetic logic circuit 27 via the . The operating values of the comparators 19 to 24 have step differences for each pair, and are set so that the operating values of the comparators 23 and 24 are the smallest. Output E of logic circuit
, a variable resistor (e.g. digital-to-analog converter) 2 connected in parallel to the input amplifier 12
8 is controlled. These circuits allow analog
The counter 13 of the digital converter 11 copies the average value of the load time and roll time. The amount of roll eccentricity appears at the output E of the arithmetic logic circuit. A disadvantage of this circuit is the operation of the digital-to-analog converter 28 and therefore the associated input amplifier 12.
Based on the change in the degree of amplification, the sensitivity of the comparators 15, 16, 19 to 24, which detect the amount of excess or deficiency of the eccentricity width detected up to that point, changes depending on the size of the roll eccentricity. Therefore, as shown in FIG. 4, the input amplifier 12 has a constant amplification degree, and the comparators 15, 16, 19 to
It is advantageous to provide a matching point upstream of 24 and compare the detected voltage there with the output of the digital-to-analog converter 28. The fixed set value of the comparator corresponds to the amount of deviation from the currently detected eccentricity width. In other words, the operating direction of the comparator is determined according to an increase or decrease in the eccentricity width. In order to perform matching, amplifiers 29 and 30 are provided before the comparators 15, 16, 19-24. An amplifier 31 provides a comparison voltage for matching. A voltage corresponding to the amount of deviation from the eccentricity width appears at the outputs of the amplifiers 29 and 30. The comparator is preferably further provided with a fixed comparison voltage to determine the operating value. The operating value can be determined by changing this voltage or by changing the amplification degree of the amplifiers 29 and 30. As long as a type of comparator that operates by comparison with an input voltage is used, the polarity of the fixed comparison voltage can determine whether the comparator should operate outside or inside the eccentric width. Furthermore, in order to simplify the circuit, an integrator 3 is used instead of the analog-to-digital converter in FIG.
2 is used to calculate the average value of analog operations. The limit threshold values of the limiter 33 for both signal directions are controlled via amplifiers 34 and 35 based on the detected eccentricity width. The output of the amplifier 12 is directly applied to an amplifier 36 connected before the integrator 32 with opposite polarity. While a signal of a magnitude that does not reach the limit threshold of the limiter 33 is output from the amplifier 12, the amplifier 3
The signals at the inputs of 6 cancel and the integrator 32 does not change its output. If the input to the amplifier 12 changes by more than the amplitude of the previously detected variation, the limiter 33 becomes active and continues to integrate until the direct input to the amplifier 36 overcomes and the integrator 32 stores a new average value.

【Effect of the invention】

As explained above, in the present invention, the variation ΔF in rolling force due to roll eccentricity is extracted,
Instead of inputting this variation ΔF into the normal roll position adjustment loop, it is input into a rolling force adjustment loop (roll eccentricity compensation regulator) that operates in parallel with this roll position adjustment loop, and its output is used to correct the roll position. Supplied to the reduction position adjustment loop for use. This makes it possible to eliminate the influence caused by roll eccentricity, and also to control the plate thickness, making it possible to roll with high precision.

[Brief explanation of drawings]

1 and 2 are block diagrams showing different embodiments of the present invention, FIGS. 3 to 5 are circuit diagrams showing different main parts of other embodiments of the invention, and FIG. 6 is a block diagram showing different embodiments of the present invention. Fig. 7 is a characteristic curve diagram showing the relationship between the rolling force of the rolling mill and the plate thickness; Fig. 7 is a characteristic curve diagram showing the relationship between the rolling force of the rolling mill and the plate thickness when the rolling roll is eccentric; Fig. 8 9 is a characteristic curve diagram showing the rolling force of the rolling mill when the rolling roll is eccentric, and FIG. 9 is a characteristic curve diagram of the rolling position of the rolling mill. DESCRIPTION OF SYMBOLS 1... Load time roll distance adjuster, 2... Roll eccentricity compensation adjuster, 3... Position adjuster, 4... Limiter, 5... Matching device, 6... Threshold device.

Claims (1)

[Claims] 1 Load time roll distance adjuster 1 for adjusting the load time roll distance average value (h) according to the load time roll distance command value (h ^* ); The lowering device 10 adjusts the lowering position (S) according to the position command value (S ^* ) given in response to the output signal (ΔS ₁ ^* ) of the regulator 1.
The position adjuster 3 that operates the roll distance under load determined from the rolling force (F) fluctuation or spring displacement (C・F) fluctuation caused by roll eccentricity
Roll eccentricity compensation command value (ΔS ₂ ^* ) according to the change
This roll eccentricity compensation command value (ΔS ₂ ^* ) is formed.
a roll eccentricity compensation adjuster 2 that provides the position adjuster 3 with a limit that limits the magnitude of the roll eccentricity compensation command value (ΔS ₂ ^* ) that is provided from the roll eccentricity compensation adjuster 2 to the position adjuster 3. 4 and the rolling force (F) fluctuation or spring displacement (C.
F) A device for controlling the thickness of a rolled material, comprising: a threshold device 6 that changes the limiting threshold of the limiter 4 in accordance with the amplitude of the fluctuation.