JP2009199221A - Pid parameter adjusting device and adjusting method - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a PID parameter adjusting device and adjusting method capable of reducing man hours for parameter adjustment. <P>SOLUTION: The PID parameter adjusting device 1 includes: an AT executing part 4 for generating a limit cycle for repeatedly outputting manipulated variables having a constant amplitude to a control object and for calculating a PID parameter based on a control response corresponding to output of the manipulated variables and an AT coefficient to set the PID parameter in a PID control device 2; an AT information storing part 6 for storing information of the detected control response; an AT coefficient storing part 5 for storing an AT coefficient; an AT resetting signal generating part 9 for generating an AT resetting signal for commanding to reset the PID parameter; and a PID parameter value resetting part 10 for calculating a PID parameter to set the parameter in the PID control device 2 based on stored information of the control response and the AT coefficient stored in the AT coefficient storing part 5 when the AT resetting signal is input. <P>COPYRIGHT: (C)2009,JPO&INPIT

Description

  The present invention relates to a process control technique, and in particular, generates a limit cycle that repeatedly outputs a manipulated variable having a constant amplitude to a controlled object, and the PID of a PID control device based on the response of the controlled object according to the output of the manipulated variable The present invention relates to a PID parameter adjusting device and an adjusting method having an auto-tuning function for adjusting parameters.

  In control devices such as temperature controllers, a limit cycle type auto-tuning (hereinafter referred to as AT) function is widely adopted, and PID parameter values for PID control calculation are automatically determined thereby (for example, Patent Documents). 1). This limit cycle type AT is designed to adjust the PID parameter value by setting an upper limit value and a lower limit value in advance for the manipulated variable MV output to the controlled object, generating a limit cycle with a constant manipulated variable amplitude. It is.

  In the conventional AT disclosed in Patent Document 1, the AT is terminated by generating a limit cycle in which the operation amount moves up and down a designated number of times. The PID parameter value is determined based on the vertical movement width Ah of the control amount PV and the information Th related to the vertical movement time. However, in the conventional AT, strictly speaking, since the estimated value of the PID parameter considered to be the best is calculated based on a small amount of information, an inappropriate PID parameter value may be calculated depending on the control target. .

In this case, after executing AT, the operator manually adjusts the PID parameter while executing control by the control device. However, when manual adjustment is not successful, there is a problem that AT must be executed again.
Conventionally, as a technology for supporting PID parameter adjustment, there is a PID parameter adjustment device disclosed in Patent Document 2. This PID parameter adjusting device creates a control system combining a control algorithm of a control device and a modeling result (formula model) of a control object on the adjusting device, and calculates a simulation result of the control system and an ideal control response characteristic. The difference is given as an evaluation function value, and the simulation of the control system is repeated so that the evaluation function value approaches the optimal value to search for the optimal PID parameter.

JP 2006-106925 A JP 2005-70940 A

In the conventional AT disclosed in Patent Document 1, when the calculated PID parameter is inappropriate and the manual adjustment of the PID parameter by the operator is also unsatisfactory, it is necessary to re-execute the AT, and it takes time for parameter adjustment. There was a problem.
Further, according to the PID parameter adjustment device disclosed in Patent Document 2, it is possible to adjust the PID parameter to an optimum value. However, compared with the case where the AT disclosed in Patent Document 1 is executed, labor and time are reduced. There was a problem that it was much more.

  SUMMARY An advantage of some aspects of the invention is to provide a PID parameter adjustment device and an adjustment method capable of reducing the number of steps for parameter adjustment.

The PID parameter adjusting device according to the present invention generates a limit cycle for repeatedly outputting an operation amount having a constant amplitude to a controlled object, calculates a PID parameter based on a control response and a calculation coefficient corresponding to the output of the operation amount, and generates a PID. Auto-tuning execution means set in the control device; first storage means for storing information on the control response detected by the auto-tuning execution means; second storage means for storing the calculation coefficient in advance; A reset signal generating means for generating a reset signal for instructing resetting of the PID parameter without executing auto-tuning by the auto-tuning executing means; and when the reset signal is input, PI based on the control response information stored in the first storage means and the calculation coefficient stored in the second storage means And calculates the parameters in which and a PID parameter value resetting means for setting the PID control device.
Also, in one configuration example of the PID parameter adjusting device of the present invention, the control response information is information Th regarding the vertical movement width Ah and the vertical movement time of the control amount.
Further, in one configuration example of the PID parameter adjusting device of the present invention, the reset signal generation means may be configured to output the reset signal as the PID parameter value reset when an operation for instructing resetting of the PID parameter is performed. This is output to the setting means.
Further, in one configuration example of the PID parameter adjusting device of the present invention, the second storage unit stores in advance a plurality of sets of the calculated coefficients, and the specified set of calculated coefficients among the plurality of sets is stored in the set. The reset signal generation unit outputs the reset signal to the PID when an operation for changing the designation of the calculation coefficient is performed. This is output to the parameter value resetting means.
Further, in one configuration example of the PID parameter adjusting device according to the present invention, the reset signal generating means may perform the reset signal when an operation of rewriting the calculation coefficient stored in the second storage means is performed. Is output to the PID parameter value resetting means.
Further, in one configuration example of the PID parameter adjusting device of the present invention, when an operation for instructing the update of the calculated coefficient is performed, the control response information stored in the first storage unit and the information Calculation coefficient update means for calculating an update value of the calculation coefficient based on a PID parameter set in the PID control device and updating the calculation coefficient of the second storage means is provided.

Further, the PID parameter adjusting method of the present invention generates a limit cycle that repeatedly outputs a manipulated variable having a constant amplitude to a controlled object, and calculates a PID parameter based on a control response and a calculation coefficient according to the output of the manipulated variable. Auto tuning execution procedure set in the PID control device, information storage procedure for storing the control response information detected in the auto tuning execution procedure in the first storage means, and auto tuning by the auto tuning execution procedure A reset signal generation procedure for generating a reset signal for instructing to reset the PID parameter without executing, and when the reset signal is generated, the reset signal is stored in the first storage means; PID parameter is calculated based on the control response information and the calculation coefficient stored in the second storage means Serial in which and a PID parameter value resetting procedure for setting the PID control device.
In the configuration example of the PID parameter adjustment method of the present invention, the reset signal generation procedure generates the reset signal when an operation for instructing resetting of the PID parameter is performed. .
Further, in one configuration example of the PID parameter adjustment method of the present invention, the second storage means stores in advance a plurality of sets of the calculated coefficients, and the specified set of calculated coefficients among the plurality of sets is stored in the set. It is used in an auto-tuning execution procedure and the PID parameter value resetting procedure, and the reset signal generation procedure generates the reset signal when an operation for changing the designation of the calculation coefficient is performed. Is.
Further, in one configuration example of the PID parameter adjustment method of the present invention, the reset signal generation procedure includes the reset signal when an operation of rewriting a calculation coefficient stored in the second storage unit is performed. Is generated.
Further, according to one configuration example of the PID parameter adjustment method of the present invention, the control response information stored in the first storage unit and the information when the operation for instructing the update of the calculated coefficient is further performed. A calculation coefficient update procedure for calculating an update value of the calculation coefficient based on a PID parameter set in the PID control device and updating the calculation coefficient of the second storage means is provided.

  According to the present invention, information on the control response when auto-tuning is executed is stored, and when the PID parameter is reset, the information on the stored control response is reused. PID parameters can be reset without re-tuning. As a result, in the present invention, it is possible to reduce the man-hours for parameter adjustment as compared with the prior art.

  In the present invention, as the timing for generating the reset signal, when an operation for instructing resetting of the PID parameter is performed, when an operation for changing the designation of a set of calculated coefficients is performed, Three are defined when an operation to rewrite is performed. In particular, when an operation for changing the designation of a set of calculated coefficients is performed, or when an operation for rewriting a calculated coefficient is performed, it is considered that an operation for instructing resetting of PID parameters is performed at the same time, and a reset signal As a result, the convenience of the operator can be improved.

  In the present invention, when an operation for instructing the update of the calculation coefficient is performed, the calculation coefficient is based on the control response information stored in the first storage unit and the PID parameter set in the PID control device. The update value is calculated to update the calculation coefficient of the second storage means. Therefore, if the operator gives an instruction to update the calculation coefficient when good control characteristics are obtained, when the characteristics of the controlled object change slightly and the need for re-execution of auto-tuning occurs, 1 There is a high possibility that good control characteristics can be obtained only by performing auto-tuning once.

[Principle of Invention 1]
The PID parameter value set in the PID control device is a result of AT or a result of manual adjustment by an operator, and the setting process varies. For example, even if it is a PID parameter value obtained by executing AT, the optimum control characteristic is not always obtained, so the PID parameter value is corrected many times by manual adjustment and the control characteristic is confirmed. There are things to do. As a result of confirmation by manual adjustment, if the PID parameter value by the original AT becomes valid, the AT must be re-executed if the PID parameter value by the AT is not recorded. In such a case, the inventor noted that it is possible to reduce the time for performing AT again.

  Information on the control response when the AT is executed, specifically, the vertical movement width Ah (peak-to-peak) of the controlled variable PV and the vertical movement time information Th (approximately half a cycle) are stored. If the device is configured so as to be able to distinguish between “AT execution” and “AT reset”, and the “AT reset” operation is selected, the AT operation is not performed, and the previous AT The inventor has conceived that it is effective to solve the problem if the PID parameter value is reset by reusing the information of the control response when the control is executed. In particular, the significance of storing the control response information instead of storing the PID parameter value itself will be described later. In the above, when the “AT execution” operation is selected, AT is performed as in the conventional case.

[Principle of Invention 2]
As described above, PID parameter values set in the PID control device have various settings. Even if AT has been executed in the past, if the circumstances of setting the current PID parameter value are unknown and it is desired to reliably set the PID parameter value, it is necessary to execute AT again. In the conventional AT disclosed in Patent Document 1, the PID parameter value is calculated by multiplying the control response information by a calculation coefficient for calculating the PID parameter value (hereinafter referred to as an AT coefficient). After changing, AT may be re-executed.

  For example, in a situation where the result of checking the control characteristics after AT execution shows that the PID parameter value by the AT is too responsive to control and there is no allowance for control stability, the AT coefficient is The AT is changed and re-executed. At this time, it is only necessary to operate “AT resetting” with the configuration described in the first principle of the invention, but the calculated PID parameter value is stored as information when the AT has been executed in the past. However, it is not sufficient, and it becomes necessary to store AT coefficients used in the past AT together.

  On the other hand, if information on the control response when executing AT (information Th related to the vertical movement width Ah and vertical movement time of the control amount PV) is stored, this information is universal information related to AT execution. The inventor noted that it is always useful because it is. Then, if information on the control response when the AT is executed is stored in a specially provided storage means, even if the AT coefficient is changed, it is immediately based on the stored control response information. Since the PID parameter value can be corrected, the inventor has conceived that it is effective for solving the problem.

[Principle 3 of the invention]
It is reasonable to understand that the operation of changing the AT coefficient for calculating the PID parameter value is based on the user's intention to correct and reset the PID parameter value by the past AT. Accordingly, when an operation for changing the AT coefficient is performed, it is recognized that the “AT resetting” operation is selected at the same time, and the information of the control response when the AT has been executed in the past is reused. It is more convenient to reset the value.

[Principle of Invention 4]
After AT execution, the PID parameter is manually adjusted while executing the control by the PID control device 2, and when a good control characteristic is obtained by this manual adjustment, the stored control response information (control amount PV of Using the vertical movement width Ah and the vertical movement time information Th), the AT coefficient is calculated backward and updated. In this way, when the characteristic of the controlled object changes slightly and the necessity of AT re-execution occurs, the PID parameter value is calculated by this updated AT coefficient. There is a high possibility that good control characteristics can be obtained only by AT re-execution.

[First Embodiment]
Hereinafter, embodiments of the present invention will be described with reference to the drawings. FIG. 1 is a block diagram showing the configuration of the PID parameter adjusting apparatus according to the first embodiment of the present invention. This embodiment corresponds to the principles 1 to 3 of the invention. The PID parameter adjusting apparatus 1 calculates a PID parameter by an AT execution signal input unit 3 for inputting an AT execution signal for instructing execution of AT and a limit cycle type AT that repeatedly outputs an operation amount MV having a constant amplitude to a control target. Then, the AT execution unit 4 set in the PID control device 2, the AT coefficient storage unit 5 that stores the AT coefficient for calculating the PID parameter value, and the information of the control response when the AT is executed (up and down of the control amount PV) AT information storage unit 6 for storing movement width Ah and vertical movement time information Th), designation change signal input unit 7 for inputting a designation change signal for changing a combination of AT coefficients, and numerical value rewriting for rewriting AT coefficients A numerical value change signal input unit 8 for inputting a signal and an AT reset signal for instructing to reset the PID parameter without executing AT by the AT execution unit 4 AT reset signal generating unit 9 for generating the control response information when the AT reset signal is input and the control response information stored in the AT information storage unit 6 and the AT coefficient stored in the AT coefficient storage unit 5 And a PID parameter value resetting unit 10 that calculates PID parameters and sets the PID parameters in the PID control device 2.

  FIG. 2 is a diagram showing an example of a temperature control system to which the PID parameter adjusting device 1 and the PID control device 2 of the present embodiment are applied. In the example of FIG. 2, a heater 112 and a temperature sensor 113 are installed inside the heat treatment furnace 111. The temperature sensor 113 measures the temperature PV of the air heated by the heater 112. The temperature controller 100 calculates the manipulated variable MV so that the temperature PV matches the set value SP. The power adjuster 114 determines power according to the operation amount MV, and supplies the determined power to the heater 112 through the power supply circuit 115. Thus, the temperature controller 100 controls the temperature in the heat treatment furnace 111. The PID parameter adjusting device 1 and the PID control device 2 are provided inside the temperature controller 100.

Hereinafter, operations of the PID parameter adjusting device 1 and the PID control device 2 will be described. FIG. 3 is a flowchart showing the operation of the PID parameter adjusting apparatus 1, and FIG. 4 is a waveform diagram for explaining the limit cycle type AT used in the present embodiment.
The set value SP is set by the operator and input to the PID parameter adjusting device 1 and the PID control device 2. The control amount PV is detected by a sensor (not shown) and is input to the PID parameter adjusting device 1 and the PID control device 2.

  For example, when the operator instructs execution of AT, AT execution signal input unit 3 inputs an AT execution signal to AT execution unit 4 (YES in step S1 in FIG. 3). Thereby, the AT function is activated, and the AT execution unit 4 generates a limit cycle (step S2). That is, when the control amount PV is larger than the set value SP, the AT execution unit 4 outputs a predetermined operation amount lower limit set value AL to the control target as the operation amount MV, and when the control amount PV is equal to or less than the set value SP. The predetermined operation amount upper limit setting value AU is output as the operation amount MV to the control target until the vertical movement of the operation amount MV reaches a predetermined number of times. Thus, a limit cycle in which the amplitude of the manipulated variable MV is constant as shown in FIG. 4 occurs. In the case of the example in FIG. 2, it goes without saying that the output destination of the manipulated variable MV is the power regulator 114.

Subsequently, the AT execution unit 4 detects a control response according to the output of the operation amount MV, and acquires information on the control response (step S3). In this detection process, the AT execution unit 4 calculates the deviation Er between the set value SP and the control amount PV as in the following equation.
Er = SP-PV (1)

  As shown in FIG. 4, the AT execution unit 4 includes the first maximum deviation absolute value Er1, which is the absolute value of the deviation between the set value SP and the latest extreme value of the control amount PV, and the set value SP and the control amount PV. The second absolute maximum value Er2, which is the absolute value of the deviation from the second new extreme value, and the first maximum absolute deviation value from time t5 when the positive and negative deviations are reversed immediately before the first maximum deviation absolute value Er1. The second maximum deviation absolute value Er2 from the time t3 when the positive / negative deviation of the deviation is reversed immediately before the first manipulated variable switching elapsed time Th1 and the second maximum deviation absolute value Er2 which is the time until the time t6 when Er1 is obtained. The second manipulated variable switching elapsed time Th2 that is the time up to the time t4 when is obtained.

Then, the AT execution unit 4 calculates information Th related to the vertical movement width Ah and the vertical movement time of the control amount PV by the following equation.
Ah = Er1 + Er2 (2)
Th = Th1 + Th2 (3)
This completes the process of step S3.

  The AT execution unit 4 stores the control response information (information Th regarding the vertical movement width Ah and the vertical movement time of the control amount PV) acquired in step S3 in the AT information storage unit 6 (step S4). The AT information storage unit 6 stores control response information over a long period of time. Therefore, it is preferable to use a nonvolatile memory such as an EEPROM (Electronically Erasable and Programmable Read Only Memory) as the AT information storage unit 6.

Next, the AT execution unit 4 sets the PID parameters P0, I0, and D0 as follows using the control response information acquired in step S3 and the AT coefficients α0, β0, and γ0 stored in the AT coefficient storage unit 5 as follows. (Step S5).
P0 = α0Ah (4)
I0 = β0Th (5)
D0 = γ0Th (6)

  Then, the AT execution unit 4 sets the calculated proportional band P0, integration time I0, and differentiation time D0 in the PID control device 2. This completes the process of step S5. The PID control device 2 needs to store the PID parameters for a long time. Therefore, it goes without saying that the PID parameters are stored in a nonvolatile memory such as an EEPROM in the PID control device 2. This completes the AT. Details of the AT are disclosed in, for example, Patent Document 1 and Japanese Patent Application Laid-Open No. 2003-330504.

  The AT coefficient storage unit 5 stores a plurality of sets of AT coefficients in advance, and when an AT coefficient set is designated from the operator via the designation change signal input unit 7, the AT coefficient designated by the operator is stored. Are output to the AT execution unit 4 and the PID parameter value resetting unit 10. The AT coefficient storage unit 5 is also preferably a non-volatile memory such as an EEPROM. In this embodiment, in order to simplify the description, a set of AT coefficients α0, β0, and γ0 that emphasize control responsiveness and a set of AT coefficients α1, β1, and γ1 that emphasize stability are stored in the AT coefficient storage unit 5. Assume that at the time of step S5, a set of AT coefficients α0, β0, γ0 that emphasizes responsiveness has been previously adopted according to the designation from the operator. If the set of AT coefficients α0, β0, and γ0 is important for quick response and the set of AT coefficients α1, β1, and γ1 is important for stability, usually the relationship of α0 <α1, β0 <β1, γ0> γ1 is established. Is set. However, depending on the adjustment know-how, the relationship of α0 <α1, β0 <β1, γ0 <γ1 may be satisfied.

Next, after the AT is completed, the PID control device 2 calculates the operation amount MV based on the set value SP and the control amount PV and outputs the operation amount MV to the control target for each control cycle.
MV = (ζ / P0) {1+ (1 / I0s) + D0s} (SP−PV) (7)
In Expression (7), s is a Laplace operator, and the constant ζ is 100, for example. As in the AT, it goes without saying that the output destination of the manipulated variable MV is the power regulator 114 in the example of FIG.

  Here, as a result of confirming the control characteristics by the PID control device 2, it is assumed that the operator determines that the responsiveness emphasis is excessive and should be changed to the emphasis on stability. The operator can directly correct each parameter value of P, I, and D by manual adjustment, cause the PID control device 2 to execute control again, and check the control characteristics. Then, after correcting the P, I, and D parameter values by manual adjustment and confirming the control characteristics, as a result, the PID parameter values by the AT adopting the stability-oriented AT coefficients α1, β1, and γ1 are set. Suppose you want to. Conventionally, the AT coefficients α1, β1, and γ1 that emphasize stability must be specified and the AT must be re-executed, and the time required until the AT is re-executed and terminated is also required.

  On the other hand, in this embodiment, the operator only needs to specify that the AT coefficients α1, β1, and γ1 that emphasize control stability are adopted. When the designation change signal input unit 7 receives designation from the operator to adopt the set of AT coefficients α1, β1, γ1 (YES in step S6 in FIG. 3), the AT coefficient α1, β1, A designation change signal designating the set of γ1 is output, and the AT reset signal generation unit 9 is notified that the AT coefficient has been changed. The AT coefficient storage unit 5 adopts a set of AT coefficients α1, β1, and γ1 according to the designation from the designation change signal input unit 7, and resets the AT coefficients α1, β1, and γ1 to the AT execution unit 4 and the PID parameter value. It outputs to the part 10 (step S7). Thus, the AT coefficient is changed.

  When receiving the notification that the AT coefficient has been changed from the designation change signal input unit 7 or the numerical value change signal input unit 8, the AT reset signal generation unit 9 considers that the operation of “AT reset” has been selected, An AT reset signal for instructing the PID parameter value resetting unit 10 to reset the PID parameter is output (step S8).

  The PID parameter value resetting unit 10 that has received the AT resetting signal stores control response information (information Th regarding the vertical movement width Ah and vertical movement time of the control amount PV) in the AT information storage unit 6. Whether or not is confirmed (step S9). If the control response information is not stored in the AT information storage unit 6, the AT has not been executed in the past, so the process proceeds to step S2, and the AT is executed as described above.

On the other hand, the PID parameter value resetting unit 10 stores control response information (information Th related to the vertical movement width Ah and vertical movement time of the control amount PV) in the AT information storage unit 6 (in step S9). YES), PID parameters P1, I1, and D1 are calculated as follows from the information on the control response and the AT coefficients α1, β1, and γ1 output from the AT coefficient storage unit 5 (step S10).
P1 = α1Ah (8)
I1 = β1Th (9)
D1 = γ1Th (10)

Then, the PID parameter value resetting unit 10 sets the calculated proportional band P1, integration time I1, and differentiation time D1 in the PID control device 2. This completes the process of step S10, and the PID parameter of the PID control device 2 is corrected. The operation of the PID control device 2 is the same as described above. That is, the PID parameters P0, I0, and D0 in Equation (7) may be replaced with P1, I1, and D1, respectively.
The processes in steps S1 to S10 as described above are repeated as necessary until the operation of the PID parameter adjusting apparatus 1 is completed (YES in step S11).

  Thus, in this embodiment, the AT is re-executed by reusing the information of the control response when the AT has been executed in the past (information Th on the vertical movement width Ah and the vertical movement time of the control amount PV). The PID parameters can be modified without doing so (ie, without taking execution time). The PID parameter value already stored before correction need not be the PID parameter value obtained by the AT, and may be a set value by manual adjustment. Furthermore, the circumstances in which the PID parameter value is set may be unknown.

  Here, in order to help understanding, the difference between the flow of parameter adjustment processing when the conventional AT is used and the flow of processing when the PID parameter adjustment device of the present embodiment is used is shown below.

[Conventional process flow]
(A) The PID parameter adjusting device executes AT → cumulative AT execution count once.
(B) The PID parameter adjustment device calculates the PID parameter using the AT coefficient and the detected control response information.
(C) The PID parameter adjusting device sets the PID parameter in the PID control device.
(D) The operator manually adjusts the PID parameters while executing control by the PID control device.
(E) Manual adjustment is not successful.
(F) The operator changes the AT coefficient.
(G) The PID parameter adjusting device re-executes AT → accumulated AT execution count 2 times.
(H) The PID parameter adjusting device calculates the PID parameter using the changed AT coefficient and the detected control response information.
(I) The PID parameter adjusting device sets the PID parameter in the PID control device.

[Processing flow of this embodiment]
(A) The PID parameter adjustment device executes AT (step S2) → cumulative AT execution count once.
(B) Information on the control response detected by the PID parameter adjusting device is stored (steps S3 and S4).
(C) The PID parameter adjustment device calculates the PID parameter using the AT coefficient and the detected control response information (step S5).
(D) The PID parameter adjusting device sets the PID parameter in the PID control device (step S5).
(E) The operator manually adjusts the PID parameters while executing control by the PID control device.
(F) Manual adjustment is malfunctioning.
(G) The operator changes the AT coefficient (steps S6 and S7).
(H) The PID parameter adjustment device corrects the PID parameter using the changed AT coefficient and the stored control response information (step S10).
(I) The PID parameter adjusting device sets the PID parameter in the PID control device (step S10).

  Comparing the flow of the conventional processing and the flow of the present embodiment, in this embodiment, the PID parameter is corrected by reusing the stored control response information without re-executing the AT. Therefore, the cumulative AT execution time is equivalent to one AT activation, and the man-hours for parameter adjustment can be reduced compared to the conventional case.

  In the present embodiment, the example in which the AT coefficient storage unit 5 stores a plurality of sets of AT coefficients has been described. However, the present invention is not limited to this, and the AT coefficients α, The combination of β and γ may be one set. In this case, when the AT coefficient storage unit 5 receives designation of at least one of the AT coefficients α, β, and γ from the operator via the numerical value change signal input unit 8, the AT coefficient α, β, The coefficient of γ is updated to a coefficient designated by the operator. In this way, the numerical value of the AT coefficient can be freely changed.

  When the combination of the AT coefficients α, β, and γ stored in the AT coefficient storage unit 5 is set as one set, the operator changes the AT coefficients α0, β0, and γ0 set before the step S5. Directly input numerical values for AT coefficients α1, β1, and γ1. When the numerical value change signal input unit 8 receives input of the AT coefficients α1, β1, and γ1 from the operator (YES in step S6 in FIG. 3), the numerical value change signal input unit 8 designates the AT coefficients α1, β1, and γ1 to the AT coefficient storage unit 5 A change signal is output and the AT reset signal generator 9 is notified that the AT coefficient has been changed. The AT coefficient storage unit 5 updates the stored AT coefficients α0, β0, γ0 to the specified AT coefficients α1, β1, γ1 according to the designation from the numerical value change signal input unit 8, and the AT coefficients α1, β1 , Γ1 are output to the AT execution unit 4 and the PID parameter value resetting unit 10 (step S7).

  In the present embodiment, it is assumed that the AT coefficient can be changed. When an operation for changing the AT coefficient is performed, it is recognized that the “AT resetting” operation is selected at the same time. I have to. However, it is assumed that a configuration in which the operator can directly instruct “AT resetting” is also provided. In this case, the designation change signal input unit 7 or the numerical value change signal input unit 8 has changed the AT coefficient with respect to the AT reset signal generation unit 9 even when the change of the AT coefficient is designated by the operator. There is no need to notify. The operator performs an “AT resetting” operation after changing the AT coefficient (steps S6 and S7). When the operator performs an “AT reset” operation, the AT reset signal generation unit 9 outputs an AT reset signal for instructing the PID parameter value resetting unit 10 to reset the PID parameter (step S8). ).

[Second Embodiment]
Next, a second embodiment of the present invention will be described. FIG. 5 is a block diagram showing the configuration of the PID parameter adjusting apparatus according to the second embodiment of the present invention. This embodiment corresponds to Principle 4 of the invention described above. The PID parameter adjustment device 1a according to the present embodiment includes an AT coefficient update signal input unit 11 that inputs an AT coefficient update signal that instructs the PID parameter adjustment device 1 according to the first embodiment to update an AT coefficient. When the AT coefficient update signal is input, the AT coefficient update value is calculated based on the control response information stored in the AT information storage unit 6 and the PID parameter set in the PID control device 2, and AT An AT coefficient updating unit 12 that updates the AT coefficient of the coefficient storage unit 5 is added.

Hereinafter, the operation of the PID parameter adjusting apparatus 1a will be described. FIG. 6 is a flowchart showing the operation of the PID parameter adjusting apparatus 1a. The processing in steps S1 to S11 is the same as that in the first embodiment.
PID parameters P0, I0, and D0 are set in the PID control device 2 by the process of step S5, and the PID control device 2 executes PID control.

  Here, as a result of confirming the control characteristics by the PID control device 2, it is assumed that the control responsiveness is excessively emphasized and the operator determines that the control characteristics should be changed. For the time being, the operator directly corrects the parameter values of P, I, and D by manual adjustment, causes the PID control device 2 to execute control again, and checks the control characteristics. Then, it is assumed that the control characteristics are confirmed by correcting the parameter values of P, I, and D by manual adjustment, and as a result, good control characteristics are obtained.

  In this case, the operator performs an “AT coefficient update” operation. When the operator performs an “AT coefficient update” operation (YES in step S12), the AT coefficient update signal input unit 11 outputs an AT coefficient update signal that instructs the AT coefficient update unit 12 to update the AT coefficient. (Step S13).

Upon receipt of the AT coefficient update signal, the AT coefficient update unit 12 receives control response information (information Th on the vertical movement width Ah and vertical movement time Th of the control amount PV) stored in the AT information storage unit 6 and PID control. Based on the PID parameters P0, I0, D0 set in the device 2, the AT coefficient update values α2, β2, γ2 are calculated as follows (step S14).
α2 = P0 / Ah (11)
β2 = I0 / Th (12)
γ2 = D0 / Th (13)

  Then, the AT coefficient updating unit 12 updates the values of the AT coefficients α0, β0, γ0 stored in the AT coefficient storage unit 5 to the calculated AT coefficients α2, β2, γ2. This completes the process of step S14.

  As described above, in the present embodiment, when good control characteristics are obtained, the stored control response information (information Th related to the vertical movement width Ah and vertical movement time of the control amount PV) is stored. The AT coefficient is used in reverse calculation and updated. As a result, in this embodiment, when the characteristics of the control target change slightly and the need for AT re-execution occurs, the PID parameter value is calculated using the updated AT coefficient. There is a high possibility that good control characteristics can be obtained only by performing AT again.

  The PID parameter adjusting apparatuses 1 and 1a and the PID control device 2 described in the first and second embodiments are based on a computer having a CPU, a storage device, and an interface, and a program for controlling these hardware resources. Can be realized. The CPU executes the processing described in the first and second embodiments in accordance with a program stored in the storage device.

  The present invention can be applied to parameter adjustment of a PID control device.

It is a block diagram which shows the structure of the PID parameter adjustment apparatus which concerns on the 1st Embodiment of this invention. It is a figure which shows one example of the temperature control system to which the PID parameter adjustment apparatus and PID control apparatus which concern on the 1st Embodiment of this invention are applied. It is a flowchart which shows operation | movement of the PID parameter adjustment apparatus which concerns on the 1st Embodiment of this invention. It is a wave form diagram for demonstrating the limit cycle type auto tuning used in the 1st Embodiment of this invention. It is a block diagram which shows the structure of the PID parameter adjustment apparatus which concerns on the 2nd Embodiment of this invention. It is a flowchart which shows operation | movement of the PID parameter adjustment apparatus which concerns on the 2nd Embodiment of this invention.

Explanation of symbols

  DESCRIPTION OF SYMBOLS 1, 1a ... PID parameter adjustment apparatus, 2 ... PID control apparatus, 3 ... AT execution signal input part, 4 ... AT execution part, 5 ... AT coefficient memory | storage part, 6 ... AT information storage part, 7 ... Designation change signal input part , 8... Numerical value change signal input unit, 9... AT reset signal generation unit, 10... PID parameter value reset unit, 11... AT coefficient update signal input unit, 12.

Claims (12)

Auto tuning execution means for generating a limit cycle that repeatedly outputs a manipulated variable having a constant amplitude to a controlled object, calculating a PID parameter based on a control response and a calculation coefficient according to the output of the manipulated variable, and setting the PID parameter in the PID control device When,
First storage means for storing information of the control response detected by the auto-tuning execution means;
Second storage means for storing the calculation coefficient in advance;
A reset signal generating means for generating a reset signal instructing to reset the PID parameter without executing the auto tuning by the auto tuning executing means;
When the reset signal is input, the PID parameter is calculated based on the control response information stored in the first storage unit and the calculation coefficient stored in the second storage unit. A PID parameter adjustment device comprising: PID parameter value resetting means for setting in a control device. The PID parameter adjusting device according to claim 1, wherein
The information on the control response is information Th relating to the vertical movement width Ah and the vertical movement time of the control amount. The PID parameter adjusting device according to claim 1, wherein
The PID parameter adjusting device, wherein the reset signal generating means outputs the reset signal to the PID parameter value resetting means when an operation for instructing resetting of the PID parameter is performed. The PID parameter adjusting device according to claim 1, wherein
The second storage means stores in advance a plurality of sets of the calculated coefficients, and outputs a specified set of calculated coefficients among the plurality of sets to the auto-tuning executing means and the PID parameter value resetting means. Is,
The PID parameter adjustment device, wherein the reset signal generation means outputs the reset signal to the PID parameter value reset means when an operation for changing the designation of the calculation coefficient is performed. The PID parameter adjusting device according to claim 1, wherein
The reset signal generating means outputs the reset signal to the PID parameter value resetting means when an operation of rewriting the calculation coefficient stored in the second storage means is performed. PID parameter adjustment device. The PID parameter adjusting device according to claim 1, wherein
Further, when an operation for instructing the update of the calculated coefficient is performed, the calculated coefficient is based on control response information stored in the first storage unit and a PID parameter set in the PID control device. A PID parameter adjustment apparatus comprising: a calculation coefficient update unit that calculates an update value of the second storage unit and calculates a calculation coefficient of the second storage unit. An auto-tuning execution procedure for generating a limit cycle for repeatedly outputting an operation amount having a constant amplitude to a control target, calculating a PID parameter based on a control response and a calculation coefficient corresponding to the output of the operation amount, and setting the PID parameter in the PID control device When,
An information storage procedure for storing information on the control response detected in the auto-tuning execution procedure in a first storage means;
A reset signal generation procedure for generating a reset signal instructing to reset the PID parameter without executing auto-tuning by the auto-tuning execution procedure;
When the reset signal is generated, the PID parameter is calculated based on the control response information stored in the first storage unit and the calculation coefficient stored in the second storage unit. And a PID parameter value resetting procedure for setting to the control device. The PID parameter adjustment method according to claim 7, wherein
The information on the control response is information Th related to the vertical movement width Ah and the vertical movement time of the control amount. The PID parameter adjustment method according to claim 7, wherein
The reset signal generation procedure generates the reset signal when an operation for instructing resetting of the PID parameter is performed. The PID parameter adjustment method according to claim 7, wherein
The second storage means stores in advance a plurality of sets of calculated coefficients, and uses a specified set of calculated coefficients among the plurality of sets in the auto-tuning execution procedure and the PID parameter value resetting procedure. Is,
In the reset signal generation procedure, the reset signal is generated when an operation to change designation of the calculation coefficient is performed. The PID parameter adjustment method according to claim 7, wherein
The reset signal generation procedure includes generating the reset signal when an operation of rewriting a calculation coefficient stored in the second storage unit is performed. The PID parameter adjustment method according to claim 7, wherein
Further, when an operation for instructing the update of the calculated coefficient is performed, the calculated coefficient is based on control response information stored in the first storage unit and a PID parameter set in the PID control device. A PID parameter adjustment method comprising: a calculation coefficient update procedure for calculating an update value of the second storage means and updating the calculation coefficient of the second storage means.

Images