KR20010017302A - Appratus for controlling roll separation force utilizing adaptive fuzzy control in a twin roll strip caster - Google Patents

Abstract

PURPOSE: A device for controlling pressure by using adaptive fuzzy control in an instrument for manufacturing a film of two rolls type is provided to cope rapidly with the change of the process, which isn't managed in the PID control, by using an adaptive fuzzy controller. CONSTITUTION: The device includes a roll repelling power sensor(306), the target value of the roll repelling power, a PID control instrument(303), an error of the roll repelling power, an adaptive fuzzy control instrument and a casting speed target value. The roll repelling power sensor(306) senses the repelling power of the roll generated in manufacturing a film. The first calculating instrument calculates an error of the target value of the roll repelling power and the real value of the roll repelling power sensed in the roll repelling power sensor(306). The PID control instrument(303) inputs the error of the roll repelling power and calculates the corrected value of the casting speed to reduce the error. The adaptive fuzzy control instrument controls and applies the fuzzy control rule and infers the casting speed correcting portion. The second calculating instrument adds the target value of the casting speed and the correcting portion output from the PID control instrument(303) and the adaptive fuzzy control instrument and corrects the casting speed target value.

Description

Rolling force control device using adaptive purge control in twin roll type sheet manufacturing equipment {APPRATUS FOR CONTROLLING ROLL SEPARATION FORCE UTILIZING ADAPTIVE FUZZY CONTROL IN A TWIN ROLL STRIP CASTER}

The present invention relates to a method of controlling the rolling force of the thin plate by controlling the repulsive force of the roll in a twin-roll thin plate manufacturing apparatus for casting the thin plate directly from the molten metal, and more specifically to the change of the process using an adaptive purge controller The present invention relates to a pressure reduction force control apparatus and method using adaptive purge control in an apparatus capable of actively replacing a two-roll type thin sheet manufacturing apparatus.

In general, in the production of a double roll type thin plate, when the repulsive force of the roll is not controlled, the repulsive force of the roll changes due to the fluctuation of the molten metal 103 or the change in the coagulation ability due to the surface condition of the roll. The internal organization of the compartment becomes uneven. In addition, the cold rolled tissue promotes non-uniformity of grains. In addition, if the repulsive force of the roll changes irregularly, the wear of the edge dam nip is uneven.

In addition, when the molten metal 209 is injected between the roll 207 and the roll 208 in the case of casting by a twin roll-type thin plate manufacturing apparatus, the repulsive force of the roll decreases when the speed of the roll increases if the roll gap is constant. The slower the roll, the greater the repulsive force of the roll.

Here, the roll gap means the distance of the roll nip 212 which is the minimum distance between the two rolls 207 and 208, which is the actual thickness of the sheet to be cast. By using these characteristics, the repulsive force of the roll generated during casting is observed. When the repulsive force of the roll is larger than the desired value, the casting speed 213 is increased, and when it is lower than the desired value, the casting speed 213 is slowed to decrease the rolling force of the thin plate. Can be controlled to the desired value.

Therefore, in the related art, as shown in FIG. 2, the repulsive force of the roll generated during sheet metal casting is measured by the roll repulsive force sensor 205, and the measured value 204 of the roll repulsive force and the target value 201 of the roll repulsive force And the casting speed correction value 206 for causing the error 202 to be zero in the PID controller 203 is added to the casting speed target value 207 to obtain the main speed control loop ( By applying the target speed to the target speed 208, the casting force is made while the roll repulsion force maintains the target value.

However, in the actual casting situation in which the process control is performed, the process characteristics change according to the change of casting variables and the external situation of the casting. In this case, a static PID controller having a fixed gain is used as in the conventional method. In this case, proper control is not achieved. In addition, in order to obtain a desired control, there is an inconvenience in that the characteristic of the PID controller, that is, the gain, needs to be changed whenever the characteristic of the process changes.

SUMMARY OF THE INVENTION The present invention has been made to solve the above-described problems, and an object thereof is to provide an adaptive purge control in a double roll type thin plate manufacturing apparatus capable of quickly coping with a process change not handled by PID control using an adaptive purge controller. It is to provide a reduction force control device using.

1 is a schematic view showing the configuration of a twin roll thin plate casting apparatus.

2 is a block diagram showing a reduction force control loop using a conventional PID control.

3 is a block diagram showing a reduction force control loop using adaptive purge control according to the present invention.

4 is a block diagram showing the configuration of an adaptive purge controller used in the reduction force control loop of the present invention.

* Description of the symbols for the main parts of the drawings *

304: adaptive purge controller 401: roll repulsion error

402: singleton purge unit 403: inference unit

404: non-fuzzy block 407: fuzzy control rule based system

As a constitutional means for achieving the above object of the present invention, the present invention is to measure the repulsive force of the roll during sheet casting to correct the target casting speed of the circumferential speed control loop according to the error from the target value In the pushing force control device using the adaptive purge control,

Roll repulsive force sensing means for detecting the repulsive force of the roll generated during sheet casting,

First calculating means for calculating an error between the roll repulsion target value and the roll repulsive force measured value detected by the roll repulsive force detecting means;

PID control means for receiving the roll reaction force error and calculating a correction value of the casting speed to reduce the error;

An adaptive purge control means for inferring a casting speed correction component by applying a roll repulsion force error to a fuzzy control rule by applying a roll repulsion force error input to each control cycle to an adaptive purge rule;

And a second calculating means for correcting the main speed target value by adding the correction amount output from the PID control means and the adaptive purge control means to the target value of the casting speed.

Hereinafter, with reference to the accompanying drawings will be described in detail the configuration and operation of the present invention.

3 is a control configuration diagram of a twin-roll thin plate manufacturing apparatus having a reduction force control device according to the present invention, the reduction force control device according to the present invention is installed on the back of the fixed roll 311 is fixed to the fixed roll 311 The roll repulsion force sensor 306 for measuring the applied repulsive force, a first operator 321 for calculating an error between the roll repulsion force target value and the actual roll repulsion force detected by the roll repulsion force sensor 306, and the first operator. PID controller 303 for outputting a roll reaction force correction value with a fixed gain so as to reduce the reaction force error calculated in step 321, and the fuzzy control rules learned while learning the process characteristic change of the twin-roll type sheet manufacturing apparatus. An adaptive purge controller 304 for outputting a roll reaction force correction value corresponding to the reaction force error calculated from the one-operator 321, and a correction value output from the PID controller 303 to a target value 308 of a predetermined casting speed. 307 and adaptive purge controller 304 A second operator 322 for outputting a target value of the corrected casting speed by adding a correction value 316 outputted from the second and a fixed roll 311 at a corrected casting speed output from the second operator 322; It is composed of a circumferential speed control loop 309 for controlling the moving roll 31 to rotate.

The adaptive purge controller 304 may further include a fuzzy equalizer 402 for converting an error value of the roll repulsive force output from the first operator 321 into a proper language variable according to its magnitude, and an output from the fuzzy equalizer 402. An inference unit 403 for inferring how to correct the casting speed by applying a fuzzy control rule to the language variable, and a language variable output as the result inferred by the inference unit 403 into a correction value of the actual casting speed. Casting speed correction from the non-fuge section 404 and the repulsion error (e) Control rule for inferring the Factor vector from the equation ) Is made up of a fuzzy control rule unit 407 for adjusting to an optimum value.

In the present invention, as shown in Fig. 4, the fuzzy control rules are set to seven (θ1 to θ7), and the membership function thereof is as indicated by reference numeral 408 in Fig. 4.

As shown in FIG. 4, the fuzzification method uses a singleton method, the defuzzification method uses a center average method, and the inference method. Use the product method.

In the above, the fuzzy is to convert the input variable represented by the number into a language variable (fuzzy variable), the adaptive purge controller 304 according to the present invention is the repulsive force error (e) output from the first operator 321 is It becomes an input variable expressed as a number, and converts the input repulsion error (e) into language variables such as "negative big, negative medium, negative small, zero, positive small, positive medium, positive big" according to its size. . This is done in the purge unit 402.

Next, the inference unit 402 applies the language variable to the control rule 407 composed of "IF, THEN" to infer a language variable that determines how the casting speed occurs when the repulsion error is a certain degree. For example, if the reaction force error (e) is "negative big", it means that the actual roll reaction force is much larger than the target value in view of the target value 301 and the actual roll reaction force value 305 of the roll reaction force. In order to lower the actual roll repulsion to the target, you will need to speed up the roll. Thus, the inferred result can be a language variable "very fast." The result output from the inference unit 402 is defusified numerically by the non-fuzzy unit 404 again.

According to Wang, Li-Xin in "Adaptive Fuzzy Systems and Control", the deceptive function of the conclusion is irrelevant as long as the shape is symmetrical, but only the values of θ1 to θ7 corresponding to the center value mean the main meaning. In the present invention, the center values θ1 to θ7 of the membership function 408 for the repulsive force error (e) may be fixed or used without using an adaptive algorithm after initial values are set by an experienced worker. Is 0 and then the factor vector to be adjusted at every control period ( ) Can be automatically adjusted to the optimal value from the equation of change, or a combination of both methods can be used.

In the present invention The initial value of is set based on the experience of the operator. In this case, since the initial value of the output value for each roll is empirically determined, the transient period of the adaptive purge controller 304 is reduced according to the appropriateness of this value.

In the fuzzy control rule 407 of FIG. 4, the conclusion section set by the operator's experience as described above is θ1 = 0.0003, θ2 = 0.0002, θ3 = 0.0001, θ4 = 0.0, θ5 = -0.0001, θθ6 = -0.0002, θ7 =- 0.0003.

And, every control period is the adaptive control rule 406 shown in FIG. Substituting the reaction force error (e) into ) And the factor vector ( ) Plus the newly adjusted factor vector ( ) Therefore, in each control cycle, the correction vector of the casting speed for the reaction force error is adjusted as described above. Inferred by the fuzzy control rule 407 with

And, the output of the inference unit 403 ( ) In the non-fuzzy section 404 As shown in the figure, the casting speed correction value is converted into a number representing the casting speed correction value, which is the output of the adaptive purge controller 304. From here, (= [ξ1, ξ2, ..., ξ7]) is obtained from the membership function 408 according to the control rule, and is a factor corresponding to the output of seven Gaussian functions for each repulsion error. Is Is the factor vector to be adjusted, and Υ is fuzzy controller adaptation gain, set to 0.0003.

In this way, the adaptive purge controller 304 learns about the characteristics of the process system that are changing by using the real-time error from the target roll repulsion force.

When the steady state is reached, the repulsive force error e will in theory be zero, and therefore, the output of the PID controller 303 will be theoretically zero. On the contrary, the adaptive purge controller 304 takes over all the control characteristics, resulting in all the outputs of the controller. This can be expressed as the adaptive purge controller 304 learned the characteristics of the process.

Accordingly, the adaptive purge controller 304 has a characteristic that the gain of the controller continuously changes during the casting process by the twin roll type sheet casting machine. That is, by detecting and learning the characteristics of the twin-roll thin sheet manufacturing apparatus from the control side in real time and outputs a casting speed correction value corresponding thereto using the fuzzy adaptation rule 406.

The output of the adaptive purge controller 304 is input to the second operator 322 together with the output value of the PID controller 302 and added to the target casting speed target value 308. The casting speed target value to which the correction amount is added is applied to the circumferential speed control loop 309 so that the casting speed of the fixed roll 311 and the moving roll 312 is corrected.

The present invention, as described above, by using the adaptive purge controller in conjunction with the PID controller in the process of constantly controlling the pressing force of the non-uniform thin plate produced in the process of manufacturing the thin plate by varying the casting speed according to the repulsive force of the roll Even if changes in casting variables and changes in process characteristics due to external conditions of casting occur, it is possible to anticipate and cope with them in advance, thereby controlling the rolling force of the sheet more consistently, thereby making the quality of the sheet produced more consistent. There is an excellent effect that can uniformly wear the edge dam.

Claims (1)

In the pressing force control device using adaptive purge control in a twin-roll type sheet manufacturing apparatus for correcting the target casting speed of the circumferential speed control loop by measuring the repulsive force of the roll during thin sheet casting and an error with the target value, Roll repulsive force sensing means for detecting the repulsive force of the roll generated during sheet casting, First calculating means for calculating an error between the roll repulsion target value and the roll repulsive force measured value detected by the roll repulsive force detecting means; PID control means for receiving the roll reaction force error and calculating a correction value of the casting speed to reduce the error; An adaptive purge control means for inferring a casting speed correction component by applying a roll repulsion force error to a fuzzy control rule by applying a roll repulsion force error input to each control cycle to an adaptive purge rule; Adaptive purge control in a double-roll type thin sheet manufacturing apparatus, comprising: a second calculation means for correcting a main speed target value by adding a correction amount output from the PID control means and the adaptive purge control means to a target value of a casting speed; Pressing force control device using.