SU923657A1 - Rolled stock thickness automatic control method - Google Patents

Description

The invention relates to rolling production, and in particular to methods of automatic control of the thickness of sheet metal, and can be used in automatic control systems for cold and hot rolling mills.

The closest in technical essence and the achieved result to the proposed is a method of controlling the thickness of the car, including measuring the position of the piston of the pressure cylinder, the rolling force, the thickness of the car, determining the deviations of these values from their set values and entering the control actions in the functions of these deviations in the position controller hydraulic piston piston (1].

A disadvantage of this control method is a subjective evaluation ope- _m Rathore arising during the rolling in the mill for the visual determination of quality and disturbing factors affecting the quality of it. Cro

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Moreover, for the stable operation of the strip thickness regulator, it is necessary simultaneously with the change in the equivalent rigidity of the stand to change the gear ratio of the regulator. Since, in the "soft" stand, the control actions both in the position of the piston and in the increment of the rolling force enter the regulator with the same signs, in order to prevent overshoot it is required to reduce the gear ratio of the regulator. In the “hard” stand mode, these control actions have opposite signs, and in order to increase speed (in order to preserve the selected optimal mode of control signal processing) it is required to increase the gear ratio of the regulator.

The purpose of the invention is to improve the quality control of the thickness of the rolling and stabilization of the rolling process.

This goal is achieved by

What in the method of automatic regupiz 92365? four

the thickness of the car, which includes measuring the position of the piston of the hydraulic cylinder of the pressure device, the force of procaviation, the thickness of the car, determining the deviations of these quantities from their specified values — 5, and entering the control actions in the function of these deviations into the regulator of the piston of the cylinder; measure the time of one revolution of the support roll and integrate during this time the deviation of the thickness of the strip at the exit of the stand from the specified value taking into account the sign of the deviation and without taking into account the sign of this deviation compare, modulo _{15, the} integration results, if the modules are equal, increase the equivalent stiffness of the stand in proportion to the integration result, without taking into account the sign of deviation and, accordingly, increase the regulator's transfer ratio ₂ , thickness, and if the modules are not equal, reduce the equivalent rigidity of the stand in proportion to integration without regard to the sign of deviation and, accordingly, ₂₅ reduce the transfer coefficient of the thickness regulator.

It is known that at the steady-state rolling process, the main disturbing factors affecting the quality of the rolled thickness are changes in the thickness and physico-mechanical parameters of the rolled and disturbances caused by the eccentricity of the support rolls. Moreover, during the rolling process, both of them and others can dominate in terms of their effect on the ³⁵ output thickness. It is known that the output thicknesses eliminate perturbations caused by changes tackle, expediently in the "hard" stand when the regulator ⁴⁰ is supplied THICKNESSES positive feedback increment rolling force. The disturbances caused by the eccentric system of the support rolls are effectively eliminated when operating in the “soft” stand mode, i.e. ⁴⁵ Rami regulators, stabilizing force rental * "Key to stand or to have a negative feedback on the increment of the rolling force.

The proposed method allows, by analyzing ⁵⁰ deviations of the output strip thickness in a section equal to the circumference of the support roll, to determine the predominance of that louse of another disturbing factor and select the necessary one! the rigidity of the cage, which provides optimal control of the strip thickness. Change in equivalent stiffness

the cage with a simultaneous corresponding change in the gear ratio of the regulator makes it self-adjusting for disturbing factors, while the output thickness is effectively controlled and the rolling process disturbances are minimized. °

The method is as follows.

The position of the piston of the hydraulic cylinder of the pressure device, the rolling force, the thickness of the rolled steel M, the time of one revolution of the support roll X. '*

Determine the deviation from the specified values of the measured parameters: the position of the piston of the hydraulic cylinder of the pressure device, the rolling force, the thickness of the car.

During the time of one revolution of the support roll, the deviation of the rolled metal thickness from the specified value is integrated

taking into account the sign of deviation b + T

/

and without considering the sign of deviation

/ ^111- / (ί.

Compare the results of the integration modulo

6 ί

If величинаη. ^ ΖΓΠθξ is a given sensitivity threshold), increase the equivalent rigidity of the cage by increasing the positive feedback in the control unit of the hydraulic clamping device for the rolling force increment proportional to the result of integration without taking into account the sign of the deviation and, accordingly, increase the transfer coefficient of the control loop on the input signal.

If P> reduce the equivalent stiffness of the stand by increasing the negative feedback in the control loop of the hydraulic clamping device for incrementing the rolling force is proportional to the result of integration without taking into account the sign of deviation and, accordingly, reduce the transfer coefficient of the loop on the input signal.

The drawing shows a diagram of the device that implements the proposed method.

The device contains a meter 1

rolling forces, unit 2 comparisons, one

which entrance is connected to the exit me

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of the rolling force amplifier 1, and the second is given the rolling force setpoint, inverter 3, whose input is connected to the output of comparator 2, variable resistor 4, the first input of which 5 is connected to the output of comparator 2 and the second to the output of inverter 3, gauge 5 thickness of the rental and block 6 comparison, the first input of which is connected to the outputs of the meter 5 thickness of rolled hire, and the second input is given the specified value of the thickness of the rolled, diode 7, the positive pole of which is connected to the output of the block 6 of comparison, diode 8, negative Kotor entrance o is connected to you · 15 by the flow of the comparison unit 6, the inverter 9, the output of which is connected to the positive input of diode 8, the integrator 10, whose input is connected to the negative input of diode 7 and the output of inverter 9, the integrator 11, whose input is connected to the output of block 6 comparison, the diode 12, the positive pole of which; connected to the output of the integrator 11, a diode 13, the negative pole of which is connected to the 25 output cm of the integrator 11, an inverter 14., whose input is connected to the positive input of the diode 13, a summing amplifier 15, the inverse input of which is connected to the output of the inverter 14 and the negative 30 input of the diode 12 and the direct input is connected to the output of the inverter 10, the relay 16, the coil of which is connected to the output of the summing amplifier 15, the electric motor 17, the armature of which is connected to the output 35 of the integrator 11, and the field winding through the switching contacts of the relay 16 is connected to the source full-time constant voltage, gauge 18 piston position of the hydraulic cylinder, block 19 40

comparison, the first input of which is connected to the output of the piston position gauge 18 of the hydraulic cylinder, and the second input receives the specified value of the piston position, the hire thickness regulator 20, 45 • one input of which is connected to the output of the comparison unit 19, and the second input to the variable resistor 4, electrohydraulic converter 21 whose input ₅₀ is connected to controller 20 vyhodsm strip thickness, the hydraulic cylinder 22, whose input is connected with the output of the electro-hydraulic converter 21, a pulse tacho-generator 23 connected to the support in lkom and gene- Rhatore ₅₅ 24 ,, clock pulse input of which is connected with the output of the pulse tacho-generator 23, and the output -. s. integrators: rami 10 and 11. Regulator 20 consists

from the input resistors 23 and 24 of the variable feedback resistor 25 and the operational amplifier 26 '.

The device works as follows.

Before rolling, the slider of the variable resistor 4 is in the middle position and only a signal of the deviation of the position of the piston of the hydraulic cylinder from its predetermined value is received at the input of the ‘20 thickness regulator. The gauge 5 of the thickness of the rolled product measures the output thickness, which in unit 6 of the comparison was compared with the specified value. The deviations of the thickness of the rolled products arrive simultaneously at the inputs of the integrator 10 and 11, and at the input of the integrator 10 the deviations come through the diodes 7 and 8 and the inverter 9, so that regardless of the sign of the deviation it will always integrate a positive signal, and at the input of the integrator 11 there will be deviations of thickness taking into account their signs, so the output of the integrator 11 can be both positive and negative voltage. A pulse tachogenerator 23 is connected to one of the support rolls of the stand, the output of which is connected to the output of the generator 24 clock pulses. The 24 clock pulse generator generates one pulse when the support roller makes one revolution.

The leading edge of this pulse opens the outputs of the integrators 10 and 11, and the falling edge of this pulse, the integrators 10 and 11 are reset to zero.

Upon receipt of the clock pulse voltage from the output of the integrator 10 is fed to the armature of the motor 17 and simultaneously to the direct input of the summing amplifier 15, at the same time from the output of the integrator 11 through the diodes 12 and 13, as well as the inverter 14, the voltage goes to the inverse of the summing amplifier 15. If these two voltages are equal, then the output of summing amplifier 15 is zero and the coil of relay 16 is de-energized. When this motor 17 rotates in one direction, moving the sliders of variable resistors 4 and 25 in the direction of increasing positive feedback increment rolling force and increase the transmission coefficient of the operational amplifier 26. If the signals at the outputs of the integrators 10 and 11 are not equal, then the output of the summing amplifier 15 will appear. voltage that includes the relay ·

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16. At the same time, the electric motor 17 rotates in the other direction, moving the engines of variable resistors 4 and 25 in the direction of increasing negative feedback for the increment of rolling force and reduction of the transmission coefficient of the operational amplifier 26. With the falling edge of the clock pulse, the integrators 10 and 11 are reset to zero, their outputs are closed and the operation of the device is repeated.

The implementation of the proposed method allows to improve the quality of the rolled strip by longitudinal multiplicity by determining the disturbing factors affecting the output deviation and eliminating the influence of these disturbances by changing the equivalent rigidity of the cage and stabilizing the rolling process, which will make it possible to obtain an economic effect of introducing 220 thousand rubles.

Claims (1)

Claim The method of automatic control of the thickness of the rental, including the measurement of the position of the piston of the hydraulic cylinder of the pressure device, the rolling force eight strip thickness, determining deviations of these values from their desired values and input control actions as a function of these deviations in the controller 5 of the piston gidroiilindra, characterized ^ eat that to improve the quality of regulation rolled thickness and stabilizing the rolling process, is measured during one oboro ¹⁰ that a support roll and is integrated during this time rolled thickness deviation from the set value is compared in absolute value of the integration, if the modules are equal, increase the stiffness vivalentvuyu ¹⁵ eq millstands proportional integration result and exclude the sign of the deviation and hence increase the transmission ratio regulator thickness, and if ke modules 20 are equal, an equivalent stiffness of the cage is reduced in proportion to the integration result and exclude the sign of deviation and correspondingly reduce reredatochny control factor top25 tire.