JP4988171B2 - Rolling mill control device - Google Patents

Description

The present invention relates to the control equipment of the rolling mill.

  Generally, in rolling control, control is performed so as to keep a plurality of physical states indicating a rolling state at a predetermined level. This physical state includes plate thickness and tension. For the plate thickness, a thickness gauge is placed on the exit side of the rolling mill so that the thickness after rolling becomes the target thickness, and the deviation between the output of the delivery side thickness meter and the target thickness is obtained, and the deviation The control object such as the speed of the rolling mill is controlled so that the value approaches zero. Similarly, for the tension, a tension meter is arranged on the entrance side of the rolling mill so as to achieve the target tension, the deviation between the output of the tension meter and the target plate thickness is obtained, and the rolling mill is set so that the deviation approaches zero. Control the controlled object such as speed.

  Japanese Patent Application Laid-Open No. 2-92411 discloses a technique in which a so-called final stand using a dull roll having a high friction coefficient is used to control the speed of the rolling mill in order to keep the tension at a predetermined target value together with the plate thickness. In the prior art, a thickness gauge is arranged on the exit side of the final stand, and the speed of the rolling mill two steps before the final stand is controlled based on the output of the thickness gauge. On the other hand, a tensiometer is arranged between the last stand and the previous rolling mill, and the speed of the previous rolling mill from the last stand is controlled based on the output of the tensiometer.

JP-A-2-92411

  Thus, when controlling the same control object to control a plurality of physical states indicating the rolling state to be predetermined, for example, when controlling the speed of the rolling mill to maintain a predetermined thickness, the tension Was affected, and there was a problem of leaving the target value. In particular, in the above conventional example, in order to minimize interference, the speed of the rolling mill two steps before the final stand is controlled for the plate thickness, and the speed of the rolling mill one step before the final stand is controlled for the tension. For example, the subject was controlled separately. Therefore, the distance from a measuring device to a target rolling mill becomes long, and the problem that control delay cannot be avoided has arisen.

  The objective of this invention is providing the control apparatus and control method of a rolling mill which eliminate the said problem, reduce the influence of mutual control, and can avoid a control delay further.

  In order to achieve the above object, in the present invention, a first motor rotation control signal for controlling the motor rotation state of a predetermined rolling mill is output based on the input plate thickness value, and the predetermined value is determined based on the input plate thickness value. A second motor rotation control signal for controlling the motor rotation state of the rolling mill upstream from the rolling mill is output, a correction value for correcting the input plate thickness value, and a value calculated based on the input plate thickness value A correction value to be corrected, or a correction value to correct a value for performing an operation on the input plate thickness value is output based on the input tension value, and the second motor rotation control signal is output with respect to the input plate thickness value and The second motor rotation control signal is output based on the correction value.

  Alternatively, instead of this, the first control signal is output to a predetermined rolling mill among the plurality of rolling mills so that the predetermined physical state is controlled to a predetermined value among the plurality of physical states, and the predetermined physical state is different. A second control signal is output to a rolling mill upstream or downstream of the predetermined rolling mill so as to control to a predetermined value, and the second control signal is corrected based on a physical state different from the physical state. Configured.

  According to the present invention, for example, when control is performed so that the tension and the plate thickness are maintained at predetermined values, the influence of mutual control can be reduced, and further, control delay can be avoided.

  The best mode for carrying out the present invention will be described below with reference to the drawings. In order to explain the concept of the present invention in an easy-to-understand manner, a reference example will be described first, followed by a basic concept.

First, a reference example will be described. The plate thickness control and tension control in a cold tandem rolling mill using a dull roll with a high friction coefficient for the final stand has the configuration shown in FIG. Each of the stands 1A (#i stand) to 1C (# i-2 stand) includes work rolls 3A, 3B, 3C and backup rolls 2A, 2B, 2C. In a tandem rolling mill composed of i stands, there are i stands. Each stand has a backup roll 2 (reference numeral 2A,
2B and 2C, collectively referred to as reference numeral 2), work roll 3 (reference numerals 3A, 3B, and 3C are collectively referred to as reference numeral 3), and a motor + motor control device for controlling the speed of the work roll 3. 5 and a rolling-down device + rolling-down control device 4 for controlling the rolling load applied to the rolled material. When the work roll 3A of the final stand (corresponding to #i stand 1A) uses a dull roll having a high surface friction coefficient, the influence on the product surface quality and the product shape are great. Cannot be used for thickness control and tension control. In the reference example in FIG. 2, the control output destination of # i-1 to #i inter-stand tension control unit 20 is set to # i-1 stand speed, and the control output is output to the speed control unit 5B. In addition, as a control output destination of the outlet side thickness control unit 21 using the outlet side thickness gauge 10, # i-2 stand speed 1C is set, and a control output is output to the speed controller 5C.

  Here, the dead time will be described. The dead time in the delivery side plate thickness control unit 21 is as shown in FIG. When the # i-1 stand speed 5B is operated, the plate thickness change occurs immediately below the #i stand 1A. Therefore, the detection dead time is the plate transfer time 51 from directly under the #i stand 1A to the exit side thickness gauge 10. . On the other hand, when the # i-2 stand speed 5C is operated, the plate thickness change occurs immediately below the # i-1 stand 1B, so the detection dead time is the plate from the # i-1 stand 1B directly to the exit side thickness gauge 10. The transfer time 52 is reached.

  Therefore, in the case of the reference example shown in FIG. 2, since the exit side plate thickness control unit 21 performs control using the # i-2 stand 1C speed, the dead time due to plate transfer increases, and the control gain decreases accordingly.

  By installing a plate thickness meter between # i-1 stand 1B to #i stand 1A, or by installing a plate speed meter that can detect the plate speed of the rolled material on the exit side of each stand, # i-1 stand Although it is possible to improve the control response by controlling the thickness of the outlet side of the # i-1 stand 1B by directly measuring the 1B outlet side thickness or using the mass flow equation, the detector is expensive. In addition, the labor for maintaining the detector is increased.

  That is, the concept in the present embodiment will be described. In order to improve the response of the exit side plate thickness control 21, the output side plate thickness measurement value which is an input of the exit side plate thickness control to the # i-2 stand is set to # i-1 to # i-1. The output of #i stand tension control is given as the plate thickness setting value, and the exit side plate thickness control using # i-1 stand as the control output destination and the exit side plate thickness control using # i-2 stand as the control output destination are intentionally interfered. By controlling the tension between # i-1 and #i stands, the tension control between # i-1 and #i stands and the exit side thickness control do not interfere, and the control output to # i-1 stand is possible. Use as much as possible. Therefore, it is not necessary to install a new detector, and the response of the outlet side thickness control 21 can be improved. In addition, by predicting a change in the delivery side plate thickness by the delivery side plate thickness control model and correcting the delivery side plate thickness measurement value which is an input to the delivery side plate thickness control, the delivery side plate thickness control becomes stable even if the control response is increased.

  Therefore, it is possible to improve the plate thickness accuracy on the delivery side of the rolling mill without installing a special detector such as a plate speed meter or a plate thickness meter between the tandem rolling mill stands.

  Next, details will be described with reference to FIG. 2 that are the same as those in the reference example shown in FIG. For an i-stand tandem rolling mill, an exit side thickness control unit 25B that controls the speed of # i-1 stand 1B and an exit side thickness control unit that controls the speed of # i-2 stand 1C. The exit side plate thickness control is performed by two control systems of 25C. Further, for tension control between # i-1 to #i stands, a tension control unit 26A having a control output terminal as a roll speed of the # i-1 stand 1B and an exit side thickness gauge 10 to the exit side thickness control unit 25C. The tension control unit 26B performs tension control using the plate thickness correction amount with respect to the plate thickness measurement result as a control output end.

  Either one or both of the tension control unit 26A and the tension control unit 26B are operated by the tension control method selection unit 28. One or both of the outlet side plate thickness control unit 25B and the outlet side plate thickness control unit 25C are operated by the outlet side plate thickness control output destination selection unit 29.

Further, the plate thickness measurement result H _measure of the _delivery side plate thickness meter 10 which is an input to the delivery side plate thickness control unit 25B and the delivery side plate thickness control unit 25C is corrected by the delivery side plate thickness prediction computation unit 27 and the computation result. Used in thickness control.

FIG. 4 shows an outline of a switching method between the tension control method selection unit 28 and the outlet side plate thickness control output destination selection unit 29. The tension between # i-1 to #i stands is classified into the upper limit of tension, upper limit of tension, upper reset value of tension, lower reset value of tension, lower limit of tension, lower limit of tension, and tension control unit 26A and tension control unit 26B. Perform the switching process. When the actual tension T _measure exceeds the upper limit tension or lower limit tension as shown in the time t ₁ to the time t ₂ in FIG. 4, the tension control method selection unit 28 operates the tension control unit 26A (control gain is set to 0). On the other hand, the operation of the tension control unit 26B is stopped (the control gain is set to 0). As a result, the tension control unit 26A calculates the deviation between the actual tension value T _measure and the target tension value T _{ref i-1} which is the output of the tension meter, and the motor 5B of the # i-1 stand 1B so that this deviation becomes smaller. An operation amount ΔM _26A for operating is calculated and output.

Similarly, if the actual tension T _measure exceeds the upper limit or lower limit of tension from time t ₁ to time t ₂ in FIG. 4, the outlet side thickness control output destination selection unit 29 operates the outlet side thickness control unit 25C. (The control gain is set to 1.0). On the other hand, the outlet side thickness control unit 25 is stopped (the control gain is set to 0). As a result, the operation amount ΔM _25B output from the exit side plate thickness control unit 25B becomes 0, so the motor 5B is controlled by the operation amount ΔM _26A output from the tension control unit 26A.

As already described, if it exceeds the tension actual T _{its measure} tension limit or tension lower limit, the output of the tension control unit 26B is stopped, the tension actual sum value H _T becomes t _0, as the numerical 2B , the sum of the predicted correction value H _e for outputting the side thickness prediction calculation section 27 exits the sheet thickness results H _{its measure} is the output of the thickness gauge. Therefore, delivery side thickness control unit 25C calculates the difference between the predicted correction value H _e value obtained by adding the plate thickness results H _{its measure} in (H _measure + H _e) and leaving the target plate thickness H _{ref i-2,} this deviation The operation amount ΔM _25C of the motor 5C of the # i-2 stand 1C is output so that becomes smaller. The motor 5C is controlled by the operation amount ΔM _25C .

  In this way, the tension control unit 26A directly controls the # i-1 stand speed to control the tension. In this case, if the control output is output to the #i stand by the exit side plate thickness control unit 25B, it interferes with the tension control unit 26B. = 0, the control output of the exit side thickness control unit 25B is held, and interference with the exit side thickness control is prevented.

Tension performance is controlled by the tension control unit 26A, as from the time t ₂ in FIG. 4 of the time t _3, When tension actual T _{its measure} is returned to between the tension limit and tension on the reset value or tension lower and under tension reset value The tension control method selection unit 28 stops the tension control unit 26A (sets the control gain to 0), and operates the tension control unit 26B (sets the control gain to 1.0). Here, the outlet side plate thickness control output destination selection 29 selects the outlet side plate thickness control unit 25B and the outlet side plate so that the gain of the outlet side plate thickness control unit 25B is relatively smaller than the gain of the outlet side plate thickness control unit 25C. The thickness control unit 25C is operated. Thus, delivery side thickness control unit 25B calculates the delivery side thickness results H _{its measure} and the sum of the predicted correction value _{H e (H measure + H e} ) targeted delivery side thickness value H _{ref i-1} of the deviation, the The operation amount ΔM _25B of the motor 5B of the # i-1 stand rolling mill 1B is output with a gain smaller than 1.0 so that the deviation becomes smaller. As described above, since the operation amount output from the tension control unit 26A is 0, the operation amount ΔM _26B is added to the motor 5B as it is.

At the same time, if the actual tension T _measure is between the upper tension limit and the upper tension reset value or between the lower tension limit and the lower tension reset value from time t ₂ to time t ₃ in FIG. Operates the tension controller 26B (control gain 1.0). Tension control unit 26B calculates a tension actual T _{its measure} and the target tension value T _{ref i-2} of the deviation, and outputs to calculate the thickness correction value H _T as the deviation decreases. Therefore, the thickness sum value H _T, the sum of the predicted correction value H _e and thickness results _{H measure (H T + H e} + H measure) is, by delivery side thickness control output destination selecting section 29, the exit side thickness controller 25C Is output. Delivery side thickness control unit 25C calculates a target delivery side thickness value H _{ref i-2} of the deviation between the value thickness results are corrected _{(H T + H e + H} measure), as the deviation is small, the operation amount Calculate and output ΔM _25C . Incidentally, the plate thickness correction value H _e, has been described as a value for correcting the thickness results H _{its measure,} as long as it has the same function, for example, correcting the plate thickness value H _{ref i-2} target output The correction value may be a correction value for correcting the deviation from the target outlet plate thickness value H _{ref i-2} .

As described above, the tension control unit 26B corrects the exit side plate thickness measurement result of the exit side plate thickness meter 10 to the exit side plate thickness control unit 25C, but this becomes the tension control unit 2B output, which is output as the tension control 2B output. Is a correction amount to the measured value of the outlet side plate thickness. When the actual tension is higher than the set value, the tension control 2B output is on the minus side, but the exit side plate thickness control unit 25C recognizes that the exit side plate thickness record is thin (deviation is minus side). Control is performed so that the detected value becomes the plus side and the input of the outlet side thickness control unit 25C becomes zero. As a result, since the detection result by the exit side thickness gauge 10 becomes thicker, the exit side thickness control unit 25B operates in a direction to increase the speed of the # i-1 stand 1B, resulting in a decrease in the actual tension and the target. Head for tension.

Since the tension actual T _{its measure} is the output H _T 0 of tension on becomes smaller than the reset value (or the tension actual T _{its measure} is greater than under tension reset value), tension control unit 26B, the delivery side thickness controller 25C out An offset error is not generated with respect to the measurement value of the side plate thickness meter 10, which matches the input to the output side plate thickness control unit 25B.

  Here, the exit side plate thickness measured by the exit side plate thickness meter 10 has an offset error corresponding to the output of the tension control unit 26B, but this is a correction amount at a level where there is no problem in product quality. For example, when a plate thickness accuracy of 5 μm is required, a product quality problem does not occur if a correction amount of about 0.5 μm is used.

When the outlet side thickness measurement value in the outlet side thickness gauge 10 fluctuates and the outlet side plate thickness control unit 25B operates to remove it, the speed of the # i-1 stand 1B changes, and # i-1 #I The tension between stands changes. The # i-1 to #i stand tension fluctuations can only be controlled by # i-1 stand speed, and the exit side plate thickness control 25B and # i-1 to #i stand tension control do not interfere with each other. When the tension between # i-1 to #i stands fluctuates, by changing the target plate thickness setting of the exit side plate thickness control unit 25C, the # i-1 stand exit side plate thickness is changed. As a result, #i By controlling the tension between the -1 to #i stands, it is possible to prevent interference between the outlet side thickness control unit 25B and the tension control between the # i-1 to #i stands.

  FIG. 5 shows details of the outlet side thickness prediction calculation unit 27. In the exit side thickness control unit, the plate transfer time from # i-1 stand 1B or #i stand 1A where the thickness changes to the exit side thickness gauge 10 is required, and the plate thickness detection is delayed, so the integral control gain is large. There is a problem that cannot be done. Therefore, the control gain of the outlet side thickness control can be increased by predicting the amount of change in the outlet side thickness from the output side thickness control output and removing it from the measurement result of the outlet side thickness gauge 10.

From the control outputs (ΔM _25B , ΔM _25C , to be precise, the motor rotational speed command value obtained by integrating these) of the outlet side thickness control units 25B and 25C, the thickness change amount is calculated by the plate thickness change prediction units 30B and 30C. Predict. This calculates a predicted correction value H _e based on the prediction. In this case, since the mass flow constant law is established between the speed and the plate thickness, the change in the exit side plate thickness is predicted using the mass flow equation. By adding this predicted value to the measurement result of the delivery side thickness gauge 10, even if the thickness variation due to the control is before reaching the delivery side thickness gauge 10, the estimated delivery side thickness value is determined by the delivery side thickness control. Since the plate thickness correction can be taken into account, it is possible to increase the exit side plate thickness control gain. However, when the plate thickness controlled by the exit side plate thickness control is in a state that can be measured by the exit side plate thickness gauge 10, it is not necessary to consider the plate thickness variation due to the control, so the predicted value of the plate thickness variation is subtracted. There is a need. Therefore, plate thickness transfer 31B and 31C are provided, and the output is subtracted from the plate thickness change prediction units 30B and 30C.

  FIG. 6 shows an operation explanatory diagram of the outlet side plate thickness prediction calculating unit 27. When the measured plate thickness at the exit side thickness gauge 10 changes stepwise, the exit side plate thickness predicted value (by predicting and correcting the exit side plate thickness change by the plate thickness change prediction unit 30B from the control output by the exit side plate thickness control ( (Exit side thickness control input) is obtained. When the plate thickness corrected by the control reaches the exit side thickness gauge 10, the measured plate thickness is reduced correspondingly, and the estimated exit side plate thickness is also reduced. This is prevented by the output of the plate thickness transfer 31B. In consideration of the output of the plate thickness transfer section 31B, the predicted output side plate thickness is as shown by the thick dotted line in FIG. 6, and the correction of the plate thickness variation due to the plate thickness control output can be offset.

  Using the output of the outlet side thickness prediction calculation unit 27 to correct the measured value of the outlet side thickness in the outlet side thickness gauge 10 and using it in the outlet side thickness control units 25B and 25C, the output of the integral control output due to dead time is exceeded. Therefore, it is possible to increase the integral control gain of the outlet side plate thickness control units 25B and 25C, and to increase the control response.

  In this way, it is possible to greatly increase the control response of the outlet side plate thickness control and improve the plate thickness accuracy. In addition, when this method is used, a special detector such as an inter-stand plate speedometer, which is required when mass flow plate thickness control is applied, is unnecessary.

FIG. 3 is a detailed view of the overall device and the outlet side plate thickness control unit. Reference example for comparing and explaining the concept of this embodiment. Explanatory drawing of the detection dead time in delivery side plate | board thickness control. FIG. 4 is a detailed view showing tension control and plate thickness control switching. The figure which shows the detail of delivery side plate | board thickness prediction. Explanatory drawing of delivery side plate | board thickness prediction.

Explanation of symbols

  25B, 25C... Outlet side plate thickness control unit, 26A, 26B... Tension control unit, 27... Outlet side plate thickness prediction calculation unit, 28.

Claims (1)

Means for inputting the tension value and thickness value of the rolled material;
First sheet thickness control means for outputting a first motor rotation control signal for controlling a motor rotation state of a predetermined rolling mill based on the input sheet thickness value; and the predetermined rolling based on the input sheet thickness value. Second sheet thickness control means for outputting a second motor rotation control signal for controlling the motor rotation state of the rolling mill upstream from the mill, and the first sheet thickness control means based on the input tension value; An output side thickness control output destination selection means for operating one or both of the second thickness control means; and
First tension control means for outputting a third motor rotation control signal for controlling the motor rotation state of the predetermined rolling mill based on the input tension value, and controlling the motor rotation state of the upstream rolling mill. Second tension control means for outputting a correction value for correcting the input plate thickness value based on the input tension value, and the first tension control means and the second tension based on the input tension value. Tension control method selection means for operating any one of the control means,
When the tension value exceeds a tension upper limit value or a tension lower limit value, the delivery-side plate thickness control output destination selection unit stops the first plate thickness control unit and operates the second plate thickness control unit. The second motor rotation control signal is output, and the tension control method selection means operates the first tension control means to output the third motor rotation control signal,
When the tension value is between the tension upper limit value and the tension lower limit value, the delivery-side plate thickness control output destination selection unit operates the first plate thickness control unit to output the first motor rotation control signal. And outputting the second motor rotation control signal by causing the second plate thickness control means to operate at a lower control gain than when the tension value exceeds the tension upper limit value or the tension lower limit value. The tension control method selection means is configured to operate the second tension control control means to output the correction value .

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