JP2008243081A - Process control method and system - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To stably control a process having a characteristic such as plate thickness control in a rolling equipment. <P>SOLUTION: In this process control method for controlling a process 31 having an influence coefficient correlated to an input variable A among the input variables A and B, feedback control including integral control based on a controlled variable 38 from a status variable 33 of the target process is applied to the input variable B. When a control output 60 for the feedback control is obtained based on a first integral output 58 from a first integrator and a second integral output 59 from a second integrator obtained by selectively using the first integrator 55 and the second integrator according to the status of the first input variable, as to a constant region wherein the first input variable is kept constant, influence of the control output in the previous constant region on the following constant region is reduced, so that more stable control can be carried out. <P>COPYRIGHT: (C)2009,JPO&INPIT

Description

  The present invention relates to a process control technique that can be used as suitable for sheet thickness control in cold rolling, for example.

  FIG. 7 schematically shows the configuration of a conventional general sheet thickness control system in a rolling facility (cold rolling facility). The rolling equipment 1 includes a rolling mill 2 and is rolled out by pressing a material to be rolled (steel strip) 4 fed from an entry side tension reel 3 with upper and lower work rolls 5 and 5 in the rolling mill 2. A side tension reel 6 is used for winding. In such a rolling process, the rolling reduction is determined by the rolling load applied to the material 4 to be rolled by the work rolls 5, 5, thereby giving the sheet thickness after rolling of the material 4 to be rolled. Here, the rolling reduction is a reduction rate of the thickness of the material 4 to be rolled by rolling. Sheet thickness control in the rolling process can be performed as control of the rolling load that correlates with the rolling reduction. However, the control of the rolling load is inferior in response. Therefore, in practice, plate thickness control is performed as control of the distance between the upper and lower work rolls 5 and 5 (work roll interval) that correlates with the rolling load.

  The work roll interval control in the plate thickness control is performed by the input side plate thickness control unit 8 based on the input side plate thickness measured by the input side plate thickness meter 7 (incoming plate thickness results), and by the output side plate thickness meter 9. Combining the delivery side plate thickness control performed by the delivery side plate thickness control device 10 based on the measured delivery side plate thickness (delivery side plate thickness results) and the reduction acceleration / deceleration correction performed by the reduction acceleration / deceleration correction device 11 based on the rolling speed. Do it. That is, the control output of each of the inlet side plate thickness control, the outlet side plate thickness control, and the reduction acceleration / deceleration correction is input to the hydraulic reduction control device 12, and the hydraulic reduction control device 12 receives this and the interval between the upper and lower work rolls 5 and 5 is increased. adjust.

  The rolling mill 2 is provided with a speed control device 13 so that it can be operated by changing the rolling speed from a stopped state to a maximum speed determined in terms of equipment. The change of the rolling speed is necessary, for example, at the time of rolling start work and rolling end work in one-pass rolling. In other words, in rolling, a rolling start operation is required in which the material to be rolled 4 is caught in the work roll 5 at the start of rolling in one pass, and a rolling end operation for extracting the material 4 from the work roll 5 at the end of rolling in one pass. It is necessary to reduce the rolling speed at the start of rolling and at the end of rolling. The change pattern of the rolling speed related to the start and end of such rolling is generally as shown in the upper part of FIG. 8, and the change pattern of the rolling load in this case is as shown in the lower part of FIG.

  The change of the rolling speed is also required when performing the joint welding of the material 4 to be rolled during rolling. The plate joint welding is an operation of welding a subsequent rolled material fed from the rolled material coil updated by the entry side tension reel 3 to the preceding rolled material. A steel strip reservoir (not shown) called a looper is provided to allow rolling to continue even during such plate joint welding operations. It can be rolled during welding operations. However, because there is a limit to the length of the material to be rolled that can be stored in the steel strip reservoir, rolling during plate splicing work must be performed at a low speed, and the steel strip reservoir can be reduced to a lower rolling speed. Can be reduced. Such a change pattern of the rolling speed accompanying the joint welding is as shown in the upper part of FIG. 9, for example.

  The rolling speed as described above correlates with the friction coefficient between the work roll 5 and the material 4 to be rolled, and the friction coefficient decreases as the rolling speed increases. The friction coefficient correlates with the rolling load, and the larger the friction coefficient, the larger the rolling load is required. Therefore, if the work roll interval is the same, the required rolling load increases as the rolling speed decreases (FIG. 10). In addition, the influence coefficient of the work roll interval (the coefficient indicating how much the thickness of the exit side changes when the work roll interval is changed by one unit) correlates with the rolling speed, and the influence coefficient of the work roll interval increases as the rolling speed increases. Becomes larger (FIG. 11).

  For these reasons, the work roll interval for setting the exit side plate thickness of the material to be rolled 4 to the target plate thickness is an amount determined according to the rolling speed. Therefore, it is necessary to adjust the work roll interval according to the rolling speed, and for that purpose, the reduction acceleration / deceleration correction is performed by the reduction acceleration / deceleration correction device 11. FIG. 12 shows an outline of the reduction acceleration / deceleration correction device 11. The reduction / acceleration / deceleration correction apparatus 11 includes a speed / reduction position conversion unit 14. The speed / rolling position converting means 14 is a graph or tabular form that displays the rolling speed / working roll interval information relating the working roll interval necessary for setting the delivery side plate thickness to the target plate thickness at a certain rolling speed with the rolling speed. The rolling speed (actual rolling speed or command rolling speed) 15 provided from the speed control device 13 is converted into work roll intervals based on the rolling speed / work roll interval information. Here, the rolling speed / work roll interval information is classified by the steel type of the material to be rolled, the entry side plate thickness setting, and the exit side plate thickness setting, and is created from past rolling record data. The work roll interval output from the speed / rolling position converting means 14 is set to a differential system, the control gain is set by the gain setting unit 16, and further added by the adder 17. (Interval change command) 18 is output to the hydraulic pressure reduction control device 12.

  A certain amount of error is unavoidable in the feed-forward plate thickness control by the reduction acceleration / deceleration correction device 11 as described above. Therefore, in order to suppress this error, the exit side plate thickness control which is feedback control is performed by the exit side plate thickness control device 10. In FIG. 13, the outline | summary of the exit side board thickness control apparatus 10 is shown. The delivery side plate thickness control device 10 sets a control gain (integral gain) with a gain setting unit 19 to the delivery side plate thickness deviation obtained from the delivery side plate thickness from the delivery side plate thickness meter 9 and the delivery side plate thickness setting value, and further an integrator. By performing the integration operation at 20, the work roll interval operation amount is output as the control output 21.

  The upper-stage rolling speed change pattern in FIG. 9 is, for example, the case of the rolling speed change accompanying the plate welding as described above. From the high-speed portion where the rolling is performed at a constant speed while maintaining the rolling speed V1, A reduction part where rolling is performed while gradually decelerating to the rolling speed V2, a low speed part where rolling is performed at a constant speed while maintaining the rolling speed V2, and rolling is performed while gradually accelerating from this low speed part to the rolling speed V1. And a high-speed portion that is rolled at a constant speed while maintaining the rolling speed V1.

  When the reduction / acceleration / deceleration correction and the outlet side thickness control as described above are performed when the rolling speed changes in such a pattern, the change in the operation amount of the work roll interval is as shown in the middle of FIG. The change of the deviation (deviation of the delivery side plate thickness with respect to the delivery side plate thickness setting value) is as shown in the lower part of FIG.

  In the decelerating portion, the necessary rolling load increases as the rolling speed decreases, so the reduction acceleration / deceleration correction operates in the direction of narrowing the work roll interval. During this time, the exit side plate thickness control is also performed. However, in the example shown in the figure, since the exit side plate thickness deviation hardly occurs, the control output amount of the exit side plate thickness control is small.

  If the shift is made to the low speed portion through such a deceleration portion, and the change in the thickness deviation of the outlet side in the direction in which the plate thickness becomes thicker in the low speed portion, the outlet side thickness control operates in the direction of narrowing the work roll interval. In this case, as described above, the influence coefficient is small in the low speed portion. For this reason, the control output with respect to the work roll interval of the outlet side plate thickness control becomes relatively large. In other words, the work roll interval closing direction control output for eliminating the thickness direction exit side plate thickness deviation at the low speed portion is the work roll interval closing direction control for eliminating the same direction of thick direction exit side plate thickness deviation at the high speed portion. It becomes larger than the output. In this state, the operation proceeds to the constant speed rolling at the high speed portion at the same rolling speed as before the deceleration through the acceleration portion where the work roll interval opening direction operation is performed by the reduction acceleration / deceleration correction. In this case, if there is no other disturbance, the work roll interval is the same as before the start of deceleration. However, in the case of the rolling speed change pattern of FIG. 9, the integration time in the integration control in the delivery side thickness control becomes longer than the transition time from the low speed part to the high speed part. The influence of the relatively large work roll interval closing direction control output by the control remains after the shift to the high speed section. And the actual work roll interval becomes narrower than necessary due to the influence of the low speed part remaining, and for a while after the transition from the low speed part to the high speed part, the exit side plate thickness deviation increases in the direction of thinness. That is, the plate thickness of the material to be rolled becomes thin.

  The plate thickness control system in the above rolling equipment can be generalized as a process control system as shown in FIG. The control target process 31 of the process control system includes an input amount A (first input amount) and an input amount B (second input amount). In the control target process 31, a physical phenomenon 32 corresponding to the input amount B is generated and a state amount 33 is output. The input quantity B is correlated with the input quantity A, and the input quantity B is changed according to the input quantity A in order to make the state quantity deviation (deviation between the state quantity 33 and the target state quantity) equal to or less than a certain value. There is a need. Further, for example, an influence coefficient related to the state quantity 33 such as an influence coefficient indicating the degree of change of the state quantity 33 per unit change of the input quantity B is correlated with the input quantity A, and becomes larger as the input quantity A becomes larger, for example. In this way, it changes according to the input amount A.

  The feedback control (FB control) device 34 performs FB control on such a control target process 31. The FB control device 34 includes an integrator 35 and a gain setting unit 36. The gain setting unit 36 sets a control gain to the control amount 38 selected from the state amount 33 by the control amount selecting unit 37, and the integrator 35. The control output amount 39 is generated by the integration operation according to, and the control output amount 39 is added to the input amount B to perform the FB control. In terms of correspondence with the above-described sheet thickness control system, the physical phenomenon 32 is a decrease in sheet thickness of the material to be rolled by rolling, the input amount A is the rolling speed, and the input amount B is the work roll interval. The state quantity 33 includes an exit side plate thickness, an entrance side tension, an exit side tension, a rolling load, and the like. The control amount 38 selected by the control amount selector 37 is an exit side plate thickness deviation.

  The relationship between the input amount A, the control amount 38, and the control output amount 39 is shown in FIG. The upper row shows the change in the input amount A, the middle row shows the change in the control amount 38, and the lower row shows the change in the control output amount 39. The control amount 38 moves as indicated by a dotted line when there is no FB control, and moves as indicated by a solid line according to the control output amount 39 when the FB control is performed.

  FIG. 15 shows a process control system in a case where feedforward control (FF control) such as reduction acceleration / deceleration correction in the above-described plate thickness control system is added to the process control system of FIG. The FF control device 41 performs FF control for changing the input amount B according to the input amount A. By adding such FF control, the relationship among the input amount A, the control amount 38, and the control output amount (the control output amount 39 and the control output amount of the FF control) becomes as shown in FIG.

  Assume that a disturbance amount 42 is added to the process 31 to be controlled in the process control system of FIG. Here, in the case of the above-described plate thickness control system, the disturbance amount 42 is a change in the entry side plate thickness or a change in rolling load due to mechanical factors. FIG. 16 shows the control operation when there is such a disturbance amount 42. The first stage shows the change in the disturbance amount 42, the second stage shows the change in the input amount A, the third stage shows the change in the control amount 38, and the fourth stage shows the change in the control output amount 39. The input amount A increases from the A1 steady region kept constant at A1 and changes to the A2 steady region kept constant at A2. Further, the disturbance amount 42 is generated in the A1 steady region and then continuously added with the same magnitude. The influence coefficient of the disturbance amount 42 on the state quantity 33 is different in the A1 steady region and the A2 steady region, and is assumed to be large in the A1 steady region and small in the A2 steady region, for example. In this case, the control amount 38 changes as indicated by a dotted line when there is no control, and changes as indicated by a solid line when FF control and FB control are performed.

  The FB control for removing the influence of the disturbance amount 42 starts in a state where the input amount A is in the A1 steady region, but the control output amount 39 of the FB control in the A1 steady region has an influence coefficient of the disturbance amount 42 of A1. Since it is relatively large in the steady region, it is large compared to the A2 steady region. Accordingly, when the input amount A becomes the A2 steady region, the control output amount 39 of the FB control with respect to the disturbance amount 42 decreases. However, since there is a time delay due to the integral control in the FB control, the A2 steady region to the A2 steady region. For some time after the transition to, the influence of the FB control in the A1 steady region remains, so that the control output amount 39 becomes larger than the control output amount actually required in the A2 steady region. The control amount 38 becomes large.

  In addition, about the plate | board thickness control and process control in the above rolling equipment, the example disclosed by patent document 1-patent document 4, for example is known.

JP 2003-170210 A Japanese Patent Application Laid-Open No. 09-314211 Japanese Patent Laid-Open No. 03-62201 JP 08-48226 A

  As described above, in the sheet thickness control in the rolling equipment, the work roll interval that gives the exit side sheet thickness after rolling is correlated with the rolling speed, and the influence coefficient such as the work roll distance is correlated with the rolling speed. When the rolling speed changes, due to the integral control in the FB control, the influence of the control output amount at the high speed part (or low speed part) when shifting from the high speed part (or low speed part) to the low speed part (or high speed part) Therefore, there is a problem that a large variation is caused in the outlet side plate thickness.

  This is as follows in the case of process control in which sheet thickness control in a rolling facility is generalized. That is, the control target process has an input amount A and an input amount B, the input amount B giving the state amount of the control target process correlates with the input amount A, and the influence coefficient in the input amount B or disturbance correlates with the input amount A When the input amount A changes, due to the integration control in the FB control, for example, the control output amount in the region where the influence coefficient is small when the input amount A is shifted from the region where the influence coefficient is small to the region where the influence coefficient is large The influence of the control output amount across regions with different influence coefficients causes large fluctuations in the control amount, and the stability of the control is impaired. It is to invite.

  The present invention has been made in the background as described above. For example, a process control method that enables more stable control of a process having characteristics such as sheet thickness control in a rolling facility is provided. And to provide a process control system for executing such a process control method.

  In order to solve the above problems, in the present invention, a process having a first input quantity and a second input quantity and having an influence coefficient correlated with the first input quantity is set as a control target, and In the process control method in which feedback control including integration control based on a control amount from a state quantity is performed on the second input quantity, the first integrator and the second integrator are connected to the first integrator. The control output of the feedback control is obtained from the first integration output from the first integrator and the second integration output from the second integrator obtained by using them according to the state of the input quantity. Thus, with respect to the steady region where the first input amount is kept constant, the control output in the preceding steady region can be suppressed from affecting the subsequent steady region.

  In this way, by using the first integrator and the second integrator in accordance with the state of the first input quantity, the control output of the feedback control is performed across the regions where the state of the first input quantity is different. By suppressing the influence of the force quantity, the control instability problem in the control target process, that is, the influence coefficient for the state quantity of the control target process is correlated with the first input quantity. When the control output amount of feedback control affects regions with different states, it can effectively eliminate the problem that the control amount fluctuates and the control stability is lost. Can be increased.

  According to the present invention, in the process control method as described above, the first integrator performs an integration operation in the steady region, while integrating when the first input amount changes. When the integration operation in the change region is stopped, the first integration output at the time of the integration operation stop is continuously output, and the first integration output when the integration operation is stopped is the first integration output. When the change region ends, the first integration output at that time is changed to the integration of the second integrator. Is added to a term to perform zero clearing to set the integral term of the first integrator to 0, and the second integrator performs an integration operation in the change region while entering the steady region. And the integration operation is stopped , During the integration operation is stopped in the constant region so that cause continues to output the second integrated output of the integrating operation stop time.

  By doing in this way, the stability improvement effect of the above control by separate use of a 1st integrator and a 2nd integrator can be exhibited more effectively.

  In the present invention, in the process control method as described above, the dead band is set to the control amount with a dead band width corresponding to the change in the influence coefficient accompanying the change in the first input amount.

  As described above, the control amount can be correlated with the influence coefficient by setting the dead bandwidth corresponding to the influence coefficient to the control quantity, and thereby, the control output quantity spans the regions where the states of the first input quantity are different. Can be suppressed even more effectively.

  The setting of the dead band as described above is effective only for stabilizing the control as described above. Therefore, in the present invention, in order to solve the above-described problem, a process having a first input quantity and a second input quantity and having an influence coefficient correlated with the first input quantity is set as a control target, and In a process control method in which feedback control including integral control based on a control amount from a state amount is performed on the second input amount, according to a change in an influence coefficient accompanying a change in the first input amount By setting the dead band to the control amount with the dead band width, it is possible to suppress the influence of the control output amount of the feedback control over the region where the state of the first input amount is different. It is a feature.

  The process control method as described above is particularly suitable for controlling the rolling process. Therefore, in the present invention, for the process control method as described above, the process to be controlled is a rolling process.

  A process control system used for executing the process control method as described above includes a variable feedback control device provided with the first integrator and the second integrator for the feedback control, And an integrator operating means for performing an operation for separately using one integrator and the second integrator based on a determination result for the first input amount, and The configuration includes a dead band setting device for setting.

  According to the present invention as described above, more stable control is possible for control of a process having characteristics such as sheet thickness control in a rolling facility, for example.

  Hereinafter, modes for carrying out the present invention will be described. FIG. 1 shows a configuration of a process control system according to the first embodiment. The process control system of this embodiment is basically the same as the process control system of FIG. 15 described above, and a variable FB control device 51 is provided instead of the FB control device 34 in FIG. 15 and an FB control correction device 52 is provided. It differs in that it is provided. Therefore, hereinafter, the variable FB control device 51 and the FB control correction device 52 will be mainly described, and the other components are denoted by the same reference numerals as in FIG. 15 and the above description is incorporated.

  The variable FB control device 51 is configured so that the FB control based on the state quantity 33 which is the output of the control target process 31 can be corrected by the FB control correction device 52 according to the input amount A. A setter 54, a first integrator 55, a second integrator 56, and an integration amount changer 57 are provided.

  In order to correlate the control amount 38 with the influence coefficient, the dead band setting unit 53 sets the dead band width generated by the FB control correction device 52 according to the change in the influence coefficient accompanying the change in the input amount A as described later. Based on the dead band, the control amount 38 is set. The gain setting unit 54 sets a control gain (integral gain) to the control amount 38 for which the dead band is set.

  The first integrator 55 and the second integrator 56 are used depending on the state of the input amount A. That is, the first integrator 55 performs an integration operation in a steady region where the input amount A is kept constant and outputs a first integration output 58, and the second integrator 56 changes the input amount A. The integration operation is performed in the change region (decrease region or increase region), and the second integration output 59 is output. Then, the first integrated output 58 and the second integrated output 59 are added to obtain the control output amount 60 of the variable FB control device 51.

  The integration amount changer 57 operates in the change region, and increases or decreases the first integration output 58 in accordance with the change of the input amount A. That is, the integration amount changer 57 increases or decreases the first integration output 58 by setting an integration amount change gain according to an influence coefficient that changes with a change in the input amount A.

  FIG. 2 shows an outline of the control operation of the variable FB control device 51. The first stage is the change in the input amount A, the second stage is the change in the control output amount 60 of the variable FB control device 51, the third stage is the change in the second integrated output 59, and the fourth stage is the integration. A change in the first integral output 58 in which the integral amount change gain is set by the amount changer 57 is shown. The input amount A is linearly decreased in the decreasing region from the A1 steady region that is maintained at A1 and then moved to the A2 steady region that is maintained and maintained in A2, and further linearly increased in the increasing region. Then, it changes so that it may move to A1 stationary region again.

  In such a change in the input amount A, the first integrator 55 performs an integration operation in the steady region (A1 steady region, A2 steady region), and the input amount A changes in the change region (decrease region, increase region). When entering, the integration operation is stopped, and while the integration operation in the change region is stopped, the first integration output 58 at the time of the integration operation stop is continuously output. While the first integrator 55 stops the integration operation in the change region, the integration amount changer 57 sets the integration amount change gain according to the change of the influence coefficient according to the change of the input amount A. When the first integration output 58 is decreased or increased and the change region is completed, the first integration output 58 at that time is added to the integration term of the second integrator 56 to thereby add the first integration output 58. Zero clear is performed to set the integral term of the unit 55 to zero. Here, in the example of FIG. 2, the influence coefficient has a positive correlation with the input amount A. Therefore, the first integrated output 58 decreases in the decreasing region of the input amount A, and the first integrated output 58 increases in the increasing region of the input amount A.

  On the other hand, the second integrator 56 performs the integration operation in the change region, stops the integration operation when the input amount A enters the steady region, and stops the integration operation when the integration operation is stopped in the steady region. The integration output 59 (this is an output obtained by adding the first integration output 58 at the end of the change region as described above) continues to be output.

  The FB control correction device 52 functions to correct the FB control in the variable FB control device 51 in accordance with the input amount A. As shown in FIG. 3, the integrator operation means 61, the input amount change determination means 62, the dead amount A band amount setting unit 63 and an integral amount changing gain calculating unit 64 are provided.

  The integrator operation means 61 performs an operation for using the first integrator 55 and the second integrator 56 as described above in cooperation with the input amount change determination means 62. That is, the input amount change determination means 62 determines whether the input amount A is in a steady state or a change state, and the integrator operation means 61 performs a separate operation based on the determination result. FIG. 4 shows an example of the flow of processing in the separate operation by the cooperation of the integrator operation means 61 and the input amount change determination means 62 as an example. First, in step 101, a process for determining the state of the input amount A is performed. The determination result of step 101 is divided into three: no change (steady region), change start (change region start), and change end (change region end). If there is no change, the process proceeds to step 102. In step 102, the integration operation of the second integrator 56 is stopped while allowing the first integrator 55 to perform the integration operation. If the change starts, the process proceeds to step 103. In step 103, the integration operation of the first integrator 55 is stopped, while the second integrator 56 is allowed to perform the integration operation. If the change has ended, the process proceeds to step 104. In step 104, the first integration output 58 at the end of the change is added to the second integrator 56 to clear the first integrator 55 to zero.

  The dead band amount setting means 63 generates a dead band width 65 corresponding to the change in the influence coefficient accompanying the change in the input amount A and provides it to the dead band setting unit 53. The dead band width 65 is generated by the dead band amount setting means 63 by, for example, prepared input amount A / influence coefficient / dead band width correspondence data (data relating to the correspondence between the input amount A, the influence coefficient, and the dead band width). ) Can be used.

  The integration amount change gain calculation means 64 generates an integration amount change gain 66 according to the change of the influence coefficient accompanying the change of the input amount A and provides it to the integration amount changer 57. The generation of the integration amount change gain 66 by the integration amount change gain calculation means 64 is performed using, for example, the input amount A / influence coefficient correspondence data prepared beforehand (data relating to the correspondence between the input amount A and the influence coefficient). Can do.

  The FB control by the variable FB control device 51 and the FB control correction device 52 as described above improves the stability of control for the process 31 to be controlled. As described above, the control target process 31 has the characteristic that the input amount A and the input amount B correlating with the input amount A, and the influence coefficient for the state amount 33 correlates with the input amount A. As the control output in (for example, the A2 steady region) affects the subsequent steady region (for example, the A1 steady region), the control output 38 temporarily affects the control amount across regions with different influence coefficients. I have the problem of large fluctuations. The FB control by the variable FB control device 51 and the FB control correction device 52 effectively solves such a problem in the control target process 31 and improves the stability of the control.

  Such stabilization of control is first brought about by setting a dead band by the dead band setting unit 53. That is, by setting the dead band width corresponding to the influence coefficient to the control amount 38, the control amount 38 can be correlated with the influence coefficient, whereby the control output amount 39 affects the region where the state of the input amount A is different. This can be effectively suppressed, and the stability of the control can be improved. More specifically, by setting the dead band width corresponding to the influence coefficient to the control amount 38, the control amount 38 is correlated with the influence coefficient, so that the control output amount is spread over different regions of the input amount A. It is possible to effectively suppress a situation in which the control amount due to the influence of 39 fluctuates greatly and this can improve the stability of the control.

  Further, in addition to the improvement in control stability due to the dead band, the input amount A can be obtained by using the first integrator 55 and the second integrator 56 according to the state of the input amount A as described above. It is possible to further effectively suppress the influence of the control output amount 39 over the regions having different states, thereby further improving the stability of the control.

  FIG. 5 shows an example of the control operation in the case where the disturbance amount 42 is added to the control target process 31 in the process control system according to the first embodiment, and corresponds to FIG. In FIG. 5, the variation of the control amount is improved compared to the case of FIG.

  FIG. 6 shows a configuration of a process control system according to the second embodiment. The process control system of this embodiment is a case where the process control system according to the first embodiment is applied to rolling equipment. That is, the process control system of the present embodiment is a plate thickness control system in which a rolling process is a process to be controlled. The rolling equipment 1 to be controlled by the plate thickness control system of the present embodiment is the same as the rolling equipment 1 of FIG. 7 described above. The plate thickness control system of this embodiment is basically the same as the plate thickness control system of FIG. 7, and includes a variable output side plate thickness control device 71 instead of the output side plate thickness control device 10 of FIG. The difference is that a side plate thickness control correction device 72 is added.

  The variable delivery side plate thickness control device 71 has the same configuration as that of the variable FB control device 51 in FIG. 1, and performs the variable FB control as described above with the delivery side plate thickness as the control amount 38 in FIG. The variable delivery side plate thickness control correction device 72 has the same configuration as that of the FB control correction device 52 of FIG. 1, and performs the FB control based on the delivery side plate thickness in the variable delivery side plate thickness control device 71 in the same manner as described above. Correct according to speed.

  As described above, by using the variable delivery side plate thickness control device 71 and the variable delivery side plate thickness control correction device 72, the stability of the thickness control in the rolling facility 1 can be further improved.

  As mentioned above, although the form for implementing this invention was demonstrated, these are only typical examples, This invention can be implemented with various forms in the range which does not deviate from the meaning. For example, in the above embodiment, the setting of the dead band according to the influence coefficient on the control amount and the use according to the input amount of the integrator are combined, but the present invention is not limited to this. It is also possible to employ a configuration in which one of setting and use of an integrator is used.

It is a figure which shows the structure of the process control system of 1st Embodiment. It is a figure which shows the outline | summary of the control action of a variable FB control apparatus. It is a figure which shows the structure of FB control correction apparatus. It is a figure which shows the flow of the process in the use of an integrator. It is a figure which shows the example of the control action in the process control system by 1st Embodiment. It is a figure which shows the structure of the process control system of 2nd Embodiment. It is a figure which shows the structure of the conventional general plate | board thickness control system. It is a figure which shows the pattern of the change of a rolling speed, and the change of a rolling load. It is a figure which shows the change of a work roll space | interval manipulated variable, and the change of an exit side plate | board thickness deviation in relation with the change pattern of a rolling speed. It is a figure which shows the relationship between a rolling speed and a required rolling load. It is a figure which shows the relationship between a rolling speed and an influence coefficient. It is a figure which shows the structure of a reduction acceleration / deceleration correction apparatus. It is a figure which shows the structure of a delivery side plate | board thickness control apparatus. It is a figure which shows the structure of the general process control system corresponding to a plate | board thickness control system. It is a figure which shows the structure of a process control system when FF control is added to the process control system of FIG. FIG. 16 is a diagram showing a control operation when there is a disturbance amount in the process to be controlled in the process control system of FIG. 15.

Explanation of symbols

31 Control target process 33 State variable 38 Control variable 51 Variable FB controller 53 Dead band setting device 55 First integrator 56 Second integrator 57 Integration amount changer 58 First integration output 59 Second integration output 60 Control output 61 Integrator operation means

Claims (8)

A process having a first input quantity and a second input quantity and having an influence coefficient correlated with the first input quantity is set as a control target, and includes integration control based on a control quantity from the state quantity of the control target process. In a process control method configured to perform feedback control on the second input amount,
From the first integration output from the first integrator and the second integrator obtained by using the first integrator and the second integrator according to the state of the first input quantity. By obtaining the control output of the feedback control by the second integral output, the control output in the preceding steady region affects the succeeding steady region for the steady region where the first input amount is kept constant. A process control method characterized in that it is possible to suppress this.   While the first integrator performs the integration operation in the steady region, the integration operation is stopped when entering the change region where the first input amount changes, and during the integration operation stop in the change region, The output of the first integral output when the integration operation is stopped is continued to be output, and the first integration output during the stop of the integration operation is changed according to the change of the influence coefficient according to the change of the first input amount. When the change region ends, the first integration output at that time is added to the integration term of the second integrator, thereby integrating the first integrator. Zero clear is performed to set the term to 0, and the second integrator is allowed to perform integration operation in the change region, while the integration operation is stopped when entering the steady region, and the integration operation is stopped in the steady region. During the integration operation stop Process control method according to claim 1, characterized in that as cause continues to output the second integrated output at.   3. The process control according to claim 1, wherein a dead band is set to the control amount with a dead band width corresponding to a change in an influence coefficient accompanying a change in the first input amount. 4. Method.   The process control method according to claim 1, wherein the process to be controlled is a rolling process. A process including a first input amount and a second input amount, the process having an influence coefficient correlated with the first input amount as a control target, and feedback including integration control based on the control amount from the state amount of the control target process. In a process control method configured to perform control on the second input amount,
By setting a dead band to the control amount with a dead band width corresponding to a change in an influence coefficient accompanying a change in the first input amount, the feedback control is performed across regions where the states of the first input amount are different. A process control method characterized by suppressing the influence of the control output amount.   The process control method according to claim 5, wherein the process to be controlled is a rolling process. A process control system used to execute the process control method according to any one of claims 1 to 4,
For the feedback control, there is provided a variable feedback control device provided with the first integrator and the second integrator, and the use of the first integrator and the second integrator. A process control system comprising an integrator operation means for performing an operation based on a determination result for the first input amount. A process control system used for executing the process control method according to claim 5 or 6,
A process control system comprising a dead band setting device for setting the dead band.

Images