JPH0714527B2 - Automatic thickness control device - Google Patents

Description

Description: TECHNICAL FIELD The present invention relates to a working process such as rolling equipment, and to an apparatus for automatically controlling the product thickness of the process.

[Background of the Invention]

In processing processes such as rolling equipment, extremely strict accuracy is required for the finished thickness of the product. Therefore, several thickness control devices have been conventionally proposed. These thickness control devices are roughly classified into three technologies as described below. However, for convenience of description, the following description will be limited to rolling equipment, but the same applies to other similar technologies.

First, as a first technique, a thickness gauge is provided on the exit side of the rolling mill, and a reduction command is given to the reduction control device of the rolling mill for a time proportional to the deviation between the detected value of the thickness gauge and the target thickness. The effect of the command is transmitted from the rolling mill to the thickness gauge by the transfer of the material to be rolled, the control is suspended for a transfer time, the deviation from the target thickness is obtained again, and the control is repeated. Thickness control (hereinafter AG
(Abbreviated as C) is well known since ancient times. But,
In this method, as described above, there is a physical distance between the control point (rolling mill) and the negative feedback signal detection point (thickness gauge), and as a result, when this forms a control system, a significantly large dead time is generated. Since it is a system including it, it becomes a big obstacle to the realization of continuous control and high-sensitivity control with high gain, and it is hardly practically used at present.

Next, as the second method, a well-known control is the Gesimeter AG.
It is C. This method is disclosed in Japanese Examined Patent Publication No. 29-2385, and in particular, since the thickness fluctuation is detected as a change in rolling load directly under the rolling mill, it is not necessary to consider the transfer dead time observed in the sampling AGC at all. It has the advantage of being good, and enables continuous control, which is the greatest drawback of sampling AGC. However, in this method, since the variation in the thickness of the material to be rolled is detected as the change in the rolling load, the rolling load cell is required to have high accuracy, but generally the accuracy for the load cell cannot be satisfied. In addition, there is a process of dividing the rolling load by the elastic modulus peculiar to the rolling mill converted to the thickness, and this elastic modulus depends on the magnitude of the rolling load to be set, the plate width of the rolled material to be rolled, etc. Since it changes subtly, it cannot be a reliable method for achieving the accuracy of AGC. In addition, the reduction command signal as a proportional signal of the thickness deviation detected as the rolling load depends on the response performance peculiar to the reduction control device, and the response performance of the gauge meter AGC is virtually regulated by the response performance of the reduction control device. It is also well known to be done.

The third method to eliminate these drawbacks is the prediction method AG
C is known (eg registered utility model No. 1183239
issue). This method detects the thickness change of the base material with a thickness gauge on the entrance side of the rolling mill, calculates the deviation between this detection value and the target thickness, and synchronizes with the transfer of the material to be rolled directly under the rolling mill. The deviation is intended to be removed, and since most of the thickness disturbance of the material to be rolled is the variation of the base material thickness, it can be said to be excellent. However, even in this control, the oil film of the rolling mill bearing portion generated immediately below the rolling mill, and the thickness fluctuation caused by the change of the rolling load due to the change of the friction coefficient in the rolling material and the roll contact portion Therefore, this correction also takes the form of a programmed reduction correction for the rolling speed, and a complete strip thickness control can be achieved. Is still incomplete.

[Object of the Invention]

An object of the present invention is to eliminate such drawbacks of the prior art, and to provide an automatic control device that can bring the plate thickness deviation from the target thickness as close to zero as possible.

[Outline of Invention]

In order to achieve the above object, the present invention, a plate speed detector for detecting the moving speed of the material to be rolled on the inlet side and the outlet side of the rolling stand, and to detect the thickness of the material to be rolled on the inlet side and the outlet side. From the thickness detector, the target moving speed of the material to be rolled on the inlet side and the outlet side and the set value of the target thickness and the detected amount, the mass conservation law of the material to be rolled on the outlet side and the inlet side of the rolling stand. And a second arithmetic means for compensating the neutral velocity of the rolling stand on the basis of the correction amount. The automatic plate thickness control device is characterized by

Example of Invention

 Next, an embodiment of the present invention will be described with reference to the drawings.

First, the principle of the present invention will be described. That is,
The present invention is based on the application of the law of conservation of mass in the rolling process, and is based on the fact that the entrance side mass velocity of the rolling mill is equivalent to the exit side mass velocity.

Generally, it is well known that the moving speed of the material to be rolled on the exit side of the rolling mill is faster than the neutral point speed of the rolling mill by the advanced rate. Since the advanced rate can be calculated mathematically as seen in Japanese Patent Application No. 52-97840, the following correlation can be obtained using the value of the advanced rate.

That is, the rolling mill speed (this value is the neutral point velocity in the rolling mill, which is usually given as the target speed value of the automatic speed control device of the rolling mill) is V _M , and the entrance / exit side velocity of the rolling mill is V _DO , respectively. , V _EO and the advanced ratio is f, the rolling mill speed V
_{Since M} is known and the advance rate f is also quantitatively given by the theoretical formula and adaptive correction, if it is known, V _DO = (1 + f) V _M ...... (1) Given in.

Here, h ₀ is the outlet target plate thickness, H ₀ is the inlet target plate thickness, and r is the rolling reduction. However, the rolling reduction r = (H ₀ −h ₀ ) / H ₀
Is defined by

Further, since the mass conservation law is always established on the output side and the input side of the rolling mill, the well-known relationship of V _EO × H ₀ = V _DO × h ₀ (3) is obtained.

Now, if there is no thickness variation in the material to be rolled, the formula (3) is always established and stable rolling continues, but generally, the variation in the longitudinal direction of the peculiar thickness of the material to be rolled and the roll of the rolling mill It is customary that the bite portion is often affected by the oil film of the bearing portion and the friction coefficient. Then, these thickness fluctuations occur immediately when the target plate thickness H _{0 on the} entrance side is accompanied by the deviation ΔH, and H ₀
Changes to + ΔH and affects the equality correlation of equation (3).
That is, the rolling mill entrance speed V _E becomes (V _EO + ΔV _E ) and acts to maintain the mass flow before the fluctuation. On the other hand, the amount of change in output speed ΔV _D required to maintain the output thickness h at the target plate thickness h ₀ is (V _EO + ΔV _E ) × (H ₀ + ΔH) = (V _DO + ΔV _DO ) × h ₀ …
(4) If the above is satisfied, the correlation of equation (3) is substituted into equation (4), and if ΔV _E × ΔH ≈ 0, then V _EO · ΔH + ΔV _E · H ₀ = V _DO · h ₀ If you organize this, Becomes Therefore, by operating the rolling mill exit side speed by the amount shown in the above equation (5), the exit side thickness h can be maintained at the target plate thickness h ₀ .

Next, the basic idea of the present invention described above will be described in more detail with reference to FIG.

In FIG. 1, the material 2 to be rolled is rolled via the plate speed detectors 3a and 3b, which are arranged to face each other on the left and right, the thickness gauges 4a and 4b, and the rolling mill 1. In the figure, V _EO is the target plate speed on the incoming side, V
_DO exit side target plate speed, H ₀ is the entry side target thickness, h ₀ denotes the target thickness side _{out, V E, V D, H} , h is shows the actual values corresponding to each of these setting values There is. Entry side plate thickness H is addition point 10 and entry side plate speed V _E
Subtracts the set values H ₀ and V _EO from the actual values at the addition points 11 to calculate the deviations ΔH and ΔV _E between them, and calculates the respective multipliers 21
And 22, the input side target plate thickness H ₀ and the input side target plate speed V _EO signal are multiplied, and through the adder 12 and the divider 23, the above (5)
Form the right side of the expression.

This output side plate speed correction amount ΔV _DO is added at the addition point 13 with the difference between the output side target plate speed V _DO and its actual plate speed V _D. The correction amount relating to the outlet plate speed V _D obtained by this addition is converted by the corrector 33 into a correction amount corresponding to the rolling mill speed, that is, the neutral point speed, based on the equation (1). That is, from the equation (1), considering that the advanced rate f is generally sufficiently smaller than 1 (for example, about 0.03 to 0.08), V _M = V _DO / (1 + f) ≈ (1-f) V _DO holds. To do. Therefore, in the corrector 33, the correction amount related to the outlet plate speed V _D is multiplied by (1-f) to be converted into a correction amount corresponding to the neutral point speed, and the correction amount is given to the addition point 14. To the addition point 14, the target rolling speed V _M and the output of the speed detector 32, which is a pulse generator or speed generator connected to the rolling mill drive motor 31, are fed back as a negative feedback signal, and a constant speed control system is set. Is forming. The output side plate speed V _D has this closed loop in the minor loop, and the output side target plate speed V _DO and the multiplier 21
Is used as a command value, and a constant speed control system in which the outgoing plate speed V _D is used as a negative feedback signal is formed. Therefore, the compensator 33 has
Arranging a proportional integrator for the purpose of offset compensation can be easily considered as an application example.

Further, the output side thickness deviation (output of the addition point 15) is given to a rolling reduction device (not shown) of the rolling mill 1 via the integrator 34. This is based on the premise that the above equation (5) holds, ΔV _E
ΔH ≈ 0 is set, but it is generally for compensating that it has a definite finite value and that the offset due to the measurement or control error of other sensors and arithmetic units affects the output side plate thickness. is there.

In the prior art, as described above, it is known that the roll-outside thickness variation is caused by the oil film thickness of the roll bearing portion and the sudden change in the friction coefficient of the rolled material against the material to be rolled. , I needed a program control corresponding to this. This program correction amount is generally a correction function that depends on a single or small number of independent variables such as rolling speed or rolling load, and it is difficult to construct a control system that perfectly matches the actual rolling conditions. Atsuta However, if the present invention is applied, the mass conservation law shown in the equation (3) is always established, and the thickness change immediately below the roll is
Since it can be grasped as a change in speed immediately, it is possible to perform correction control by detecting an online status, which is not possible with conventional program control, and it is possible to positively correct the thickness change in the acceleration / deceleration section. Become. Further, the loop for giving the output side thickness change to the adder 13 via the coefficient unit 35 is caused by the offset or accuracy of each device constituting the control system in the above correction, or the control constant, the estimation error of the influence coefficient. The deviation is compensated with a forcing and responsiveness, and a change in the outlet plate thickness h that accompanies a change in the oil film, friction coefficient, etc. peculiar to the rolling mill is also responsive. The thickness of the exit side h ₀
The rate of change of the delivery side speed V _DO due to the change (∂V _DO / ∂h ₀₎
Is given. Furthermore, since it varies from moment to moment depending on the corrector 33, the coefficient unit 35, and the rolling behavior, it may be considered as an application to constantly calculate this online and control it dynamically.

In these series of control processes, the correction output of the addition point 12 should be corrected after the measurement point strictly reaches immediately below the roll of the rolling mill 1, so that the correction of the signal of the plate speed detector 3a is performed. A delay circuit 37 which can be obtained as a value is provided. However, this can be omitted in high speed rolling.

The above description exemplifies the case where the material to be rolled is rolled from the left side to the right side in FIG. 1. However, in the case where the rolled material is rolled from the right side to the left side, the rolling machine 1 is used as a target axis, and the left-right correlation is Think of it as reversing.

Next, FIG. 2 shows a specific embodiment of the automatic plate thickness control device based on the above principle. In FIG. 2, the same or overlapping parts as in FIG. 1 are designated by the same reference numerals, and detailed description thereof will be omitted.

The thickness of the material 2 to be rolled, the detection of the speed, and the feedback are the same as in FIG. 1, but these set values are given by the setter 5. Normally, a control computer is used as the setting device 5, but there is no difference in principle even if individual setting devices are provided. Further, the rolling mill speed V _M and the advance rate f are output to the input side target strip speed V _EO and the output side target strip speed V _DO , and an arithmetic circuit corresponding to the equations (1) and (2) is output. It can be easily considered to provide it. That is, FIG. 3 shows a concrete example of the rolling mill speed command from the setting device 5X.
V _M , the advanced rate function (1 + f), and the reduction rate function (1-r) are given, and these are output through the multipliers 24 and 25 to the output side target plate speed V _DO.
And a process of generating the entry target plate speed V _EO .

Further, in FIG. 2, the addition point 16 is separated from the addition point 13 for the purpose of adding the command signal, but there is essentially no difference from the addition point 13 in FIG.

On the other hand, reference numeral 36 is separated from the adder 14 by applying an automatic speed control device (ASR), but forming the negative feedback speed control system is essentially the same as that part in FIG. Is.

Furthermore, addition points 10 to 15, multipliers 21 and 22, divider 23, corrector 33, integrator 34, coefficient unit 35, setting device 5, delay circuit 37.
It is also feasible to replace the control computer with the above.

In addition to the non-contact type speedometer, the plate speed detectors 3a and 3b are contacted by a low inertia touch roller to the material to be rolled, and the pulse power generator is driven by the rotational force. Is possible.

In the above description, the rolling equipment has been described for the sake of convenience, but it is also applicable to processes such as film and paper making, and the rolling equipment is not particularly limited.

As described above, the thickness variation caused by the characteristics of the rolling mill mainly in the acceleration / deceleration region, which could not be removed even by the prediction method AGC, or the thickness variation during acceleration or deceleration, which is an unstable region of rolling, is significantly improved. It becomes possible to do.

As described above, the present invention can be easily applied to existing equipment by adding only a few speed detectors and arithmetic circuits, and is economically advantageous.

〔The invention's effect〕

As described above, according to the present invention, it is possible to eliminate the drawbacks of the prior art and provide an automatic control device that can bring the plate thickness deviation with respect to the target thickness as close to zero as possible.

[Brief description of drawings]

FIG. 1 is a block diagram showing the principle of the present invention, FIG. 2 is a block diagram showing a specific embodiment of the present invention, and FIG. 3 is a block diagram showing an example of a control computer. 1 ... Rolling mill, 2 ... Rolling material, 3a, 3b ... Strip speed detector, 4a, 4b ... Thickness gauge, 5,5X ... Setting device, 10-16 ...
Addition point or adder, 21,22 …… Multiplier, 23 …… Divider, 24,25 …… Multiplier, 31 …… Rolling machine drive motor, 32…
… Speed generator or pulse generator, 33 …… Compensator or
PI controller, 34 …… Integrator, 35 …… Coefficient unit, 36 …… Automatic speed controller (ASR), 37 …… Delay circuit, V _EO …… Incoming target plate speed, V _DO …… Outgoing target Plate speed, V _E …… Actual track speed on entry side, V _D
…… Outgoing actual plate speed, H ₀ …… Incoming target plate thickness, h ₀ …… Outgoing target plate thickness, H …… Incoming actual plate thickness, h …… Outgoing actual plate thickness, V _M
…… Rolling mill speed command signal (neutral point speed), f …… advance rate, r …… reduction rate.

Claims (1)

[Claims] 1. A plate speed detector for detecting a moving speed of a material to be rolled on an inlet side and an outlet side of a rolling stand, and a thickness detector for detecting a thickness of a material to be rolled on the inlet side and the outlet side. From the set values of the target moving speed and the target thickness of the material to be rolled on the entry side and the output side and the respective detected amounts, based on the law of conservation of mass of the material to be rolled on the outlet side and the inlet side of the rolling stand, the rolled material An automatic plate thickness comprising: a first calculation means for calculating a correction amount of the moving speed on the exit side of the rolling mill; and a second calculation means for correcting the neutral point speed of the rolling stand based on the correction amount. Control device.