SU1503917A1 - Method and system for automatic controlling per cent reduction of strip in rolling mill - Google Patents

Abstract

The invention is intended for use in the reduction control systems of the dressing mills. The purpose of the invention is to improve the quality of the trained strip. Relative compression in the cage is controlled by acting on the pressure device of the cage or tensioning the strip by the deviation of the reduction from the setpoint. In addition, the perturbation compression is adjusted, compensating for the effect of the variable component of the strip thickness variation at the cage entrance on the amount of compression. To do this, by controlling the input thickness, taken into account with regard to the transport delay, and the specified coupling coefficient between the deviation of the input thickness and the amount of movement of the pressing device, a control signal is generated for moving the pressing device. After each movement, the specified coupling coefficient is corrected by the integral of the difference in reduction deviations recorded at the initial and final moments of movement of the pressing device. 2 sec. f-ly, 2 ill.

Description

The invention relates to the automation of the rolling process, in particular, to the regulation of the relative strip reduction in the training mills of sheet rolling production.

“The purpose of the invention is to increase the quality of the strip by reducing the influence of input thickness fluctuations on the reduction value.

Figure 1 shows a block diagram of a strip reduction control system; Fig. 2 shows the execution of the control signal generator.

The method of automatic adjustment of the reduction ratio is as follows.

When a strip is rolled, a continuous measurement of the input thickness of the strip and its relative reduction (in strip speeds at the entrance and exit of the rolling stand) is carried out. The deviation of the relative reduction from a given value is worked out by acting on the stand pressure device (it can also be done by changing the tension of the strip ).

In parallel, a variable component is extracted from the input thickness information signals and used; (taking into account the transport lag) To form an additional (to the control signal from the controller

ate

with so

-four

3150

reduction of the control signal to the stand cage. In the formation of the first additional control pulse, this component is taken with some initially specified ratio between the relative deviation of the input thickness and the amount of reduction (K .. -tgtTT) Formil

Each subsequent control pulse is conducted according to the corrected coupling coefficient K. For this, the control pulse is fixed at the beginning and end of the current control pulse. | (in the process of working out the mismatch) deviations of the relative reduction results corresponding to these moments from the setpoint: Ua.r and l /.r.-

According to the integral of the difference of the fixed values, the coefficient KQ is corrected, according to which the just-worked control pulse is formed, and the control pulse following it forms according to this corrected coupling coefficient. Next, the process is repeated, providing adjustment with a period and line by adjusting the coupling coefficient between the deviation of the strip thickness and the amount of movement of the pressure device depending on the function

(Lou.r- Z p.r) -sign,

| where

V

I.l

 moving speed on

-

press device. The use of correlation between: signals of the input reduction thickness ensures the independence of the regulating effect from the influence of random disturbances.

The system implementing the proposed method contains pulse sensors.

I and 2 speed lanes connected

with them, reduction gauge 3, comparison element 4, whose reduction setting j is set to the input, reduction regulator 5 (with an impact on the stand press device), meter 6 of the input strip thickness with high-pass filter 7 at the output and tracking unit 8 connected inputs to the outputs of the sensor 1 and the filter 7. The output of the node 8 tracking through the divider 9 (the second input of which is set to the input thickness H), the multiplier 10, the adder

II and the nonlinear element 12 is connected

- JO

15 20

25 30

35

- x

7

with the input of the i3 model of the pressure device, the output of which through the divider 14 is connected to the second input of the adder 1 1. The second input of the controller 5 is connected to the output of the reference element 4. The same output is connected by the combined inputs of the 1.5 and 16 memory elements, the control inputs of which are connected to the two outputs of the control signal generator 17. The outputs of the memory elements 15 and 16 through the adder 18 and the key 19, controlled from the third output of the imaging device 17, are connected to the integrator 20. The output of the integrator 20 is connected to the input of the adder 21, to the second input of which the initial coupling coefficient K is set between the relative deviation the input thickness is L tl / N strip and the displacement of the pressure device of the stand. The output of the adder 21 is connected via the green 22 of the module's split module to the second input of the divider 14, a. through the second nonlinear element

23- with the second input of the multiplier 10, Connection of the outputs of the reduction regulator 5 and of the non-linear element 12 with the node

24 pressure control device. the cage is filled through the adder 25.

The shaper 17 of the control signals (figure 2) consists of single vibrators 26-30 and elements OR 31-33. The inputs of the one-shot 26-24 combined and connected to the input of the node, the outputs of the single-shot in pairs 26-27, 28-29, 27-29 through the elements OR 31-33 are connected respectively to the third, second and first outputs of the node 17.

five

0

I

The system works as follows.

The deviation of the strip thickness from the technological rating at the entrance of the stand is measured by a thickness gauge 6, the output of which is fed to the input of the high-pass filter 7, which passes only a variable thickness component to its output. The signal 4 Nl / goes to the input of the nodule 8 tracking, according to the signal of the sensor 1 pulse, the frequency at the output of which is proportional to 1 speed of the strip and the output of the stand.

The unit 8 performs a delay in the output of the 4 N filter 7 to the input of the divider 9 for the duration of the strip from the meter 6 to the mill stand. Divider 9, carried out the division

citant K; great

Signal DN on the installation of the thickness N of the roll, generates a signal proportional to the relative deviation of the strip thickness, which is fed to the first input of the multiplier 10. The second input of the multiplier 10 from the output of the nonlinear element 23 receives a signal of the technological coefficient S

 I

 i

the degree of relative deviation of the thickness of the roll and the amount of movement of the pressure device necessary to compensate for the effect of this disturbance on the reduction of metal. The signal, proportional to the coefficient, forms the adder 21, the first input of which receives the initial, roughly approximate value of the coefficient K, and the second input, a correction correction from the output of the integrator 20. The output signal of the nonlinear element 23 sets the desired direction of movement of the stand press device As in the general case, the deviation of the input thickness deviation is ambiguous due to the direction of movement of the pressure device and depends on the parameters of the cage and the strip. If signal

Tn n

exceeds the width of the zone

the insensitivity of the nonlinear element 12, then the control unit 24 of the pressing device through the adder 25 from the output of the element 12 receives a signal for specifying the speed of movement. And it simultaneously arrives at the input of model 13, the transfer function of which is identical to the transfer function of the pressing device. The output signal of model 13, proportional to the current position of the pressure device L S, is fed to the first input

35

40

The former 17 forms the leading edge of the positive current at its input (by a signal cutting the adjusted part or by the falling edge of the signal negative pulse which is outputted by the output input of the memory element 15 to the reverse input of the memory element. On the fixed end of the control end the output 2 of the former forms a pulse, the incoming control input of the element 16 pa These signals of the former, for example, with a positive signal input, the elements 15 and 6 of the memory are written, respectively, following the value of the deviation of reduction from k: lud ... p, which was governed by a pressure device (and according to

divider 14, on the second input of which 4 $ is perturbed in thickness), and

D.U.r, which is fixed at the control point.

the signal is proportional to the value of the technological module

output ratio of node 22 in the module module. The signal proportional to the coefficient K. is fed to the input of the node 22 from the output of the adder 21. At the moment when the output signal of the divider 14 is equal to the output signal of the multiplier 10, the signal at the output of the element 12 will become zero, the pressure device will stop and change the signal model 13 output - testing

.

15 0 5

0

five

0

the perturbation over the input thickness is over,

When the thickness of the rolled stock changes, the operation of the circuit is repeated. In this case, at the output of the nonlinear element 12, during each working out, a sign signal is generated, which sets the direction of movement of the pressing device during the working out. This signal is fed to the input of the control signal generator 17 (FIG. 2), which generates pulse write control signals to the memory elements 15 and 16, as well as key control 19.

The output of meter 3 at comparison node 4 is compared to avg. by jaw, and the deviation signal from its output goes through the reduction controller 5 and the adder 25 to the control device control unit 24 in order to test the deviation, as well as to the information inputs of the elements 15 and 16.

The former 17 generates a leading edge on the leading edge of the positive signal (at a signal leading the adjusted section) or on the falling edge of the negative signal, which from the output 3 of the former forms a post to the control input of the memory element 15. According to the signal fixing the end of the regulation, the output 2 of the driver 17 generates a pulse arriving at the control input of the memory element 16. These signals of the imaging unit 27, for example, with a positive signal at the input, memory elements 15 and 6, respectively, record the following values of the deviation of the reduction from the setpoint: Lud..p, which had a regulating effect on the actuator of the pressing device (and corresponding

$ 4 perturbed by thickness), and

50

55

DUr, which is fixed at the end of the regulation.

In the other direction of movement of the pressing device, in the process of working out, the former 7 changes the address of the recording of the loop values, responsibly to the memory elements 6 and 15, and thus sets the sign signal Sign V, (V c, is the speed of the pressing device).

The output signals of elements 15 and 16 are fed to the inputs from mmator 18, the output of which is determined by the output

Uf8 G§.p J n.p) Sign VH.

The integration of the output signal of the adder 18 is carried out by the signal from the output G of the former 17, which is formed in it by the one-oscillator 30 to the trailing edge of the one-oscillator 27 or 28. The signal 19 closes the switch 19, connecting for a pulse duration t on output 1 output of the subtractor 18 to the input of the integrator 20. The output signal of the integrator 20 begins to change in accordance with the expression

- with

and

Cho, -1

, - 11 (dh p-4hn, p) .Sign V ,,

where T is the integrator time constant 20.

The output signal of the integrator 20 is supplied to the second input of the adder 21, correcting the initial set transfer coefficient Kd. So, if .р / 37 п, р РИ movement of the pressure device up (there was an overshoot), then the output signal of the adder 21 decreases and decreases, which determines the duration and direction of movement of the pressure device for working out perturbations along the thickness of the subwoofer.

The proposed solution allows to increase the dynamic ACCURACY speed of working out the misalignment of reduction caused by fluctuations of the input thickness, and ultimately to obtain a band of higher quality (the control accuracy increases by 30-50%).

Claims (2)

1. A method of automatically controlling the relative reduction of the strip in a rolling mill, including regulating the reduction by acting on the pressure device of the stand in accordance with the magnitude of the mismatch between the result of measuring the relative reduction and its setting, characterized in that, in order to increase the quality of the strip, control the thickness of the strip in front of the cage; determine the variable component of the thickness of the strip, according to the magnitude of this component, taking into account the transport lag of the strip from Eren its thickness to stand and the ratio between the communication 0 five 0 five 0 5 jg 5 the deviation of the strip thickness and the magnitude of the movement of the pressure device corrects the impact on the pressure device, and in the adjustment process periodically adjusts the coupling coefficient between the deviation of the strip thickness and the magnitude of the movement of the pressure device depending on the function iC-STg.p - Zlr) Sign Vfi.y dt, where 4 ar and dp are, respectively, deviations of the reduction from the predetermined technology before and after the regulating action on the pressure device; Vj is the speed of movement of the pressure device. 2. An automatic control system of relative strip reduction in a rolling mill, containing a divider, multiplier, key, two memory elements, pulse speed sensors of the strip, installed before and after the stand, a relative reduction gauge connected to them, the output of which is connected through the comparison element with the output of the regulator of the contact connected with the control unit. drive, for example, a pressure device,. characterized in that, in order to increase the quality of the strip, a series / thickness / strip extender connected to it, a filter and a tracking unit connected to the speed sensor installed up to the stand, the multiplier, the first sum, torus and the first nonlinear element, the second input of the first divider is connected to the output of the tracking unit as well as the second nonlinear element connected by the output to the second input of the multiplier, the second divider connected by the output to the second input of the first adder, the pressure device model block connected between the output of the first nonlinear element and the first input of the second divider, the signal extraction module of the module connected by the output to the second input of the second divider, the second adder whose output is connected to the inputs of the second nonlinear element and module extension node signal, third adder, integrator, and driver. signals, the first the output of which is connected to the control input of the key, the second and third outputs to the control inputs of the memory elements, and the input to the output of the first nonlinear element, the second inputs of the memory elements are connected to the output of the reference element, and their outputs through the third adder to the information input of the key, the output of which through the integrator is connected to the first input of the second adder, the second input of which is the input of the setpoint of the initial coupling coefficient between the deviation of the input thickness and the amount of movement of the pressing device, When the output of the first nonlinear element is coupled to node (control pressure device. figure 1 Fi.g out Out, 2 Out /