JP2009199220A - Parameter adjusting device and adjusting method - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To surely increase/decrease manipulated variables for necessary times at executing auto tuning of a control device. <P>SOLUTION: A parameter adjusting device 1 includes: an AT executing part 3 for generating a limit cycle for repeatedly outputting manipulated variables MV having a constant amplitude to a control object; an increase/decrease detecting part 4 for detecting an increase/decrease range of process variables PV corresponding to the output of the manipulated variables MV; an AT completion propriety determining part 5 for determining that auto tuning can be completed when stop of amplification of the increase/decrease range of the process variables PV and stop of attenuation of the increase/decrease range can be separately confirmed; and a PID parameter value calculating part 7 for calculating a PID parameter based on a response of the process variables PV corresponding to the output of the manipulated variables MV to set the PID parameter in a PID control device 2. The AT executing part 3 and the PID parameter value calculating part 7 complete the auto tuning after the auto tuning is determined to be in a state allowing completion. <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 a control device such as a PID based on a response of the controlled object according to the output of the manipulated variable The present invention relates to a parameter adjusting apparatus and an adjusting method having an auto-tuning function for adjusting the control parameters of the control.

  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.

JP 2006-106925 A

  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. However, in the case of a conventional AT in which the operation amount is moved up and down by the number of times designated in advance, the number of operations of the operation amount may be insufficient in a higher-order control target.

  As a countermeasure for this, a method in which the operator determines and sets the required number of times of vertical movement is also used, but specialized judgment is required of the operator. In addition, the number of up and down movements required for the operation amount may change depending on the conditions for starting the AT. That is, even if the operator sets the number of up / down movements, the number of up / down movements may be insufficient.

  SUMMARY An advantage of some aspects of the invention is to provide a parameter adjustment device and an adjustment method capable of moving an operation amount up and down by a required number of times more reliably than in the past.

The present invention generates a limit cycle that repeatedly outputs a manipulated variable having a constant amplitude to a controlled object, and calculates a control parameter of a control device based on the response of the controlled object according to the output of the manipulated variable. In the parameter adjustment device having a function, an auto-tuning executing means for generating the limit cycle, a vertical movement detecting means for detecting a vertical movement width of the control amount according to the output of the operation amount, and a vertical movement of the control amount Auto-tuning completion determination unit that determines that the auto-tuning can be completed when the stop of the width amplification and the stop of the attenuation of the vertical movement width can be confirmed separately, and the output of the operation amount Parameter value calculating means for calculating a control parameter based on a control amount response according to the The Ningu execution means and the parameter value calculation means, after the auto-tuning completion determination means determines that the possible completion status auto tuning is obtained by such finishing the auto-tuning.
Further, in one configuration example of the parameter adjustment device of the present invention, the number of times of vertical movement of the control amount is defined in advance after the auto-tuning completion determination unit determines that the auto-tuning can be completed. A vertical movement count determination means for notifying completion of auto-tuning when the number of vertical movements has elapsed, wherein the auto-tuning execution means ends the limit cycle when receiving the notification of completion of auto-tuning, and calculates the parameter value The means is configured to calculate and set the control parameter when the auto-tuning completion notification is received, and finish the auto-tuning.
Further, in one configuration example of the parameter adjusting device of the present invention, parameter calculation starts when the number of vertical movements of the control amount has reached a predetermined number of vertical movements after starting the auto-tuning. A number of times of vertical movement that performs notification, and the parameter value calculation unit receives the parameter calculation start notification, and each time a response of a control amount necessary for calculating the control parameter is obtained, Calculation and setting are performed.

In addition, the parameter adjustment method of the present invention includes an auto-tuning execution procedure for generating the limit cycle, a vertical motion detection procedure for detecting a vertical movement width of the control amount according to the output of the manipulated variable, and an increase / decrease of the control amount. Auto-tuning completion determination procedure for determining that the auto-tuning can be completed when the stop of the dynamic width amplification and the stop of the attenuation of the vertical movement width can be confirmed separately; A parameter value calculation procedure for calculating a control parameter based on a response of a control amount according to an output and setting the control parameter, and after determining that auto-tuning can be completed in the auto-tuning completion determination procedure The auto-tuning is finished.
Further, in one configuration example of the parameter adjustment method of the present invention, the number of times of vertical movement of the control amount is defined in advance after determining that the auto-tuning can be completed in the auto-tuning completion determination procedure. A procedure for determining the number of times of vertical movement when the number of times of vertical movement has elapsed, and a step of determining the number of times of vertical movement, wherein the auto tuning execution procedure ends the limit cycle when the notification of completion of auto tuning is performed, and the parameter value The calculation procedure is such that when the auto-tuning completion notification is made, the control parameter is calculated and set to finish the auto-tuning.
Further, in one configuration example of the parameter adjustment method of the present invention, the parameter calculation is started when the number of vertical movements of the control amount has reached a predetermined minimum number of vertical movements after the auto-tuning is started. The parameter value calculation procedure includes the control parameter every time a response of a control amount necessary for calculating the control parameter is obtained after the parameter calculation start notification is performed. Is calculated and set.

  According to the present invention, when the amplification of the vertical movement width of the controlled variable is stopped and the attenuation of the vertical movement width of the controlled variable is confirmed separately, the vertical movement waveform with a stable controlled variable is obtained. Since the auto-tuning is terminated after judging that it has been obtained, there is no shortage of the number of vertical movements of the manipulated variable even in the case of higher-order control objects, which is more necessary than before in the auto-tuning of control equipment. The operation amount can be moved up and down by the number of times.

  Further, in the present invention, after the start of auto-tuning, the control amount response necessary for calculation of the control parameter can be obtained from the time when the predetermined number of vertical movements of the control amount has passed the predetermined minimum number of times of vertical movement. Control parameters are calculated and set each time, so even if there is a situation where auto tuning must be terminated for some reason, There is a high probability that is already set. As a result, in the present invention, when auto-tuning is interrupted, it is possible to reduce the probability of wasting time and labor required for the limit cycle until then.

[Principle of Invention 1]
FIGS. 1 to 5 are diagrams for explaining the principle of the present invention, and FIGS. 1 to 3 and FIG. 5 are waveform diagrams showing examples of changes in the control amount PV according to the operation amount output during AT execution. FIG. 4 is a diagram illustrating an example of a multi-loop temperature control system. 1 to 3, SP is a set value. FIG. 1 shows an example in which the vertical movement width of the controlled variable PV is stabilized while being amplified in accordance with the manipulated variable output that moves up and down, and FIG. 2 shows an example in which the vertical movement width of the controlled variable PV is stabilized while being attenuated. 3 shows an example in which the control amount PV immediately stabilizes after AT starts.

  In the example of FIG. 4, the temperature inside the firing furnace 10 is controlled by temperature controllers 13-1 to 13-5. The temperature sensors 12-1 to 12-5 measure the temperatures of the zones Z1 to Z5 heated by the heaters 11-1 to 11-5, respectively. The temperature controllers 13-1 to 13-5 calculate the manipulated variables so that the temperatures measured by the temperature sensors 12-1 to 12-5 respectively match the set values. The electric power devices 14-1 to 14-5 supply electric power corresponding to the operation amounts output from the temperature controllers 13-1 to 13-5 to the heaters 11-1 to 11-5, respectively. In the example of FIG. 4, only zone Z1, Z3, Z5 (temperature controller 13-1, 13-3, 13-5) is performing AT.

  FIG. 5A shows an example in which the temperature PV3 of the zone Z3 of the firing furnace 10 moves up and down according to the operation amount output from the temperature controller 13-3 during AT execution, and FIG. 5B shows the temperature controller. An example is shown in which the temperature PV1 of the zone Z1 of the firing furnace 10 moves up and down according to the operation amount output from 13-1. In FIGS. 5A and 5B, SP3 is a temperature setting value of the zone Z3, and SP1 is a temperature setting value of the zone Z1. 5A and 5B show that the center point of the vertical movement of the temperature PV1 of the zone Z1 is not stable due to the effect of the temperature PV3 of the zone Z3 and the on / off of the heater 11-1, and the temperature PV1 This shows an example in which the amplitude of movement slightly repeats amplification and attenuation.

  In the case of a higher-order control object, the reason why the number of up / down movements of the operation amount MV in the conventional AT is insufficient is that a plurality of up / down movements of the operation amount MV are required until the state of up / down movement of the control amount PV is stabilized. For this reason, it is difficult to assume in advance the number of vertical movements required for the operation amount MV. In principle, the stable up-and-down movement of the control amount PV is approximately constant in amplitude and period depending on the controlled object. Here, depending on the start condition of the AT, the vertical movement width of the control amount PV gradually increases while the vertical movement width of the control amount PV gradually attenuates. The inventor noticed that there are cases in FIG. 2 approaching a stable vertical movement while continuing, and in FIG. 3 starting from a situation close to a condition where it is easy to obtain a stable vertical movement of the control amount PV.

  More importantly, for example, in the multi-loop temperature control system (zone control system) shown in FIG. 4, there is a case where the AT is activated simultaneously in a plurality of zones having some temperature interference even if it is not an adjacent zone. As shown in FIG. 5B, the inventor has noted that the vertical movement width of the control amount PV may be slightly amplified and attenuated depending on the relationship between the time constants.

  Assuming all cases shown in FIGS. 1 to 4, 5 </ b> A, and 5 </ b> B, amplification of the vertical movement width of the control amount PV is stopped and attenuation of the vertical movement width of the control amount PV is stopped. If it can be confirmed separately that the operation amount MV has stopped, it can be determined that a stable up-and-down movement waveform of the control amount PV by the required number of up-and-down movements of the manipulated variable MV has been obtained and AT is terminated. The inventor has conceived that it is effective. In other words, it is not realistic to try to detect a stable vertical movement waveform of the control amount PV. It is confirmed separately that the continuation of only the amplification and the continuation of only the attenuation are finished. "It is a limit cycle waveform detection method that is sufficiently practical for general-purpose control equipment." Note that “separately confirm” means confirming the stop of the vertical movement width of the control amount PV after confirming the stoppage of the vertical movement width of the control amount PV, or amplifying the vertical movement width of the control amount PV. This means that after confirming the stop, the damping stop of the vertical movement width of the control amount PV is confirmed.

[Principle of Invention 2]
As described above, when the AT is terminated after confirming that the vertical movement width of the control amount PV has stopped amplifying or stopped, a case is assumed in which the number of vertical movements of the manipulated variable MV increases. When the number of times of operation amount MV increases and decreases, when AT is interrupted for some reason, a situation in which it is unavoidable to end in the middle is likely to occur. In the case of confirming whether the vertical movement width of the control amount PV is stopped or attenuated, the vertical movement of the control amount PV is approaching an ideal state at a stage before confirmation can be made even if complete confirmation cannot be obtained. Therefore, if the PID parameter value is calculated and stored step by step as an intermediate determination after the minimum number of times of vertical movement of the control amount PV is obtained, when the AT is interrupted, The inventor has focused on reducing the probability that motion is wasted.

[First Embodiment]
Hereinafter, embodiments of the present invention will be described with reference to the drawings. FIG. 6 is a block diagram showing the configuration of the parameter adjustment apparatus according to the first embodiment of the present invention. This embodiment corresponds to Principle 1 of the invention described above.
The parameter adjustment apparatus 1 includes an AT execution unit 3 that generates a limit cycle for repeatedly outputting an operation amount MV having a constant amplitude to a control target, and a vertical movement width (peak-to-peak) of the control amount PV according to the output of the operation amount MV. ), And when the stop of amplification of the vertical movement width of the control amount PV and the stop of attenuation of the vertical movement width can be confirmed separately, the situation is such that the AT can be completed. When the AT completion determination unit 5 and the AT completion determination unit 5 determine that the AT can be completed, the number of vertical movements of the control amount PV exceeds a predetermined number of vertical movements. There is a vertical movement number determination unit 6 that performs AT completion notification, and a PID parameter value calculation unit 7 that calculates a PID parameter based on a response of the control amount PV according to the output of the operation amount MV and sets the PID parameter in the PID control device 2. .

  FIG. 7 is a diagram showing an example of a temperature control system to which the parameter adjusting device 1 and the PID control device 2 of the present embodiment are applied. In the example of FIG. 7, 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 parameter adjustment device 1 and the PID control device 2 are provided inside the temperature controller 100.

Hereinafter, operations of the parameter adjustment device 1 and the PID control device 2 will be described. FIG. 8 is a flowchart showing the operation of the parameter adjusting apparatus 1, and FIG. 9 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 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 parameter adjustment device 1 and the PID control device 2.

  For example, when the AT function is activated in accordance with an operator instruction (step S1 in FIG. 8), the AT execution unit 3 generates a limit cycle (step S2). That is, when the control amount PV is larger than the set value SP, the AT execution unit 3 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 object, and is repeatedly performed every fixed operation cycle. Thus, a limit cycle in which the amplitude of the manipulated variable MV is constant as shown in FIG. 9 occurs. In the case of the example in FIG. 7, it goes without saying that the output destination of the manipulated variable MV is the power regulator 114.

Next, the vertical movement detection unit 4 detects the vertical movement width of the control amount PV (step S3). The vertical movement detection unit 4 detects the maximum deviation absolute value detected when the deviation (SP−PV) between the set value SP and the control amount PV becomes a positive value (when the control amount PV is smaller than the set value SP). | Era | = | SP-PV | is detected, and the maximum deviation absolute value detected when the deviation (SP-PV) becomes a negative value (when the control amount PV is larger than the set value SP). | Erb | = | SP-PV | is detected. Then, the vertical movement detection unit 4 calculates the vertical movement width ΔPV of the control amount PV by the following equation.
ΔPV = | Era | + | Erb | (1)

  Then, the vertical movement detection unit 4 notifies the value of the vertical movement width ΔPV of the control amount PV to the AT completion availability determination unit 5 and the vertical movement number determination unit 6. Further, the vertical motion detector 4 detects an extreme value deviation Er which is a deviation (SP-PV) between the set value SP and the extreme value of the control amount PV, and the deviation (SP-PV) immediately before the extreme value deviation Er. The PID parameter value calculation unit 7 is notified of the operation amount switching elapsed time Th that is the time from the time when the positive / negative is reversed to the time when the extreme value deviation Er is obtained. Needless to say, the maximum deviation absolute value | Er | is the absolute value of the extreme deviation Er.

  The vertical motion detection unit 4 operates at a constant operation cycle, but the calculation of the vertical motion width ΔPV is not limited to each operation cycle. As shown in FIG. 9, the vertical movement width ΔPV is calculated when the maximum deviation absolute value | Era | is detected after the maximum deviation absolute value | Erb | is detected, or the maximum deviation absolute value | Era | Is detected when the maximum deviation absolute value | Erb | is detected.

Subsequently, the AT completion availability determination unit 5 determines whether or not the AT can be completed from the latest vertical movement width ΔPV _n and the previous vertical movement width ΔPV _n−1 (step S4). First, AT completion judging unit 5, when the proportion of the most recent vertical movement width Pv _n for vertical movement width Pv _n-1 of the immediately preceding satisfy equation (2), vertical movement width of the control amount PV is amplified (That is, it is determined that the attenuation of the vertical movement width has stopped).
ΔPV _n / ΔPV _n-1 > 1-ξ (2)

  ξ is a margin for detecting the vertical movement width amplification and attenuation, for example, 0.05. The detection of the amplification of the vertical movement width with the margin ξ means that the situation in which the vertical movement width of the control amount PV continues to attenuate is stopped and no further attenuation is detected. .

Further, AT completion judging unit 5, when the proportion of the most recent vertical movement width Pv _n for vertical movement width Pv _n-1 immediately preceding satisfies the equation (3), vertical movement width of the control amount PV is attenuated (That is, it is determined that amplification of the vertical movement width has stopped).
ΔPV _n / ΔPV _n-1 <1 + ξ (3)
The detection of the attenuation of the vertical movement width with the margin ξ means that the situation in which the vertical movement width of the control amount PV continues to be amplified stops and is no longer amplified.

  If at least one of Expression (2) and Expression (3) has not been established between the AT start time and the present time, the AT completion propriety determination unit 5 determines that the AT is not in a state where the AT can be completed (Step S1). NO in S4). If it is determined that it is not possible to complete the AT, the process returns to step S2. In this way, the processing of steps S2 to S4 is repeatedly executed at regular intervals. This operation cycle may normally be the same as the control cycle of the PID control device 2.

  Then, the AT completion propriety determination unit 5 determines that the expression (2) is established between the AT start time and the present time and detects the attenuation stop of the vertical movement width of the control amount PV, and then the expression (3) is established and controlled. When the stop of amplification of the vertical movement width of the amount of PV is detected, or after the stop of amplification of the vertical movement width of the control amount PV is detected from the AT start time to the present time, the attenuation stop of the vertical movement width of the control amount PV is detected. If so, it is determined that the situation is such that the AT can be completed (YES in step S4).

  In the case of the example in FIG. 1, the vertical movement width of the control amount PV gradually amplifies and approaches a stable vertical movement, so equation (2) is established at the beginning of AT and the vertical movement width of the control amount PV is established. Is detected, and then the expression (3) is established, and the amplification stop of the vertical movement width of the control amount PV is detected. In the case of the example in FIG. 2, since the vertical movement width of the control amount PV gradually attenuates and approaches a stable vertical movement, the stop of amplification of the vertical movement width of the control amount PV is detected at the beginning of AT. Thereafter, the stop of the attenuation of the vertical movement width of the control amount PV is detected. In the case of FIG. 3 and FIG. 5 (B), it will be materialized in order of Formula (2) and Formula (3) or Formula (3) and Formula (2) according to the situation at that time.

  If it is determined that the AT can be completed, the AT completion availability determination unit 5 outputs an AT completion availability notification signal to the up / down movement number determination unit 6 and the PID parameter value calculation unit 7 (step S5).

  Subsequently, the up / down movement number determination unit 6 has passed a predetermined number of up / down movements (usually about three times) from the time when the AT completion notification signal is received until the present time. It is determined whether or not (step S6). If the predetermined number of vertical movements has not elapsed, the process proceeds to step S7 and the limit cycle is continued. The continuation of the limit cycle in step S7 and the detection of the vertical movement width in step S8 are the same as the processes in steps S2 and S3, respectively. In this way, the processes in steps S6 to S8 are repeatedly executed at regular operation cycles.

  The vertical movement number determination unit 6 determines that the number of vertical movements of the control amount PV has passed a predetermined number of vertical movements from the time when the AT completion notification signal is received to the present time (YES in step S6) ), And outputs an AT completion notification signal to the AT execution unit 3 and the PID parameter value calculation unit 7 (step S9).

  The AT execution unit 3 that has received the AT completion notification signal ends the limit cycle. The PID parameter value calculation unit 7 that has received the AT completion notification signal calculates a PID parameter (step S10). FIG. 10 is a waveform diagram for explaining the operation of the PID parameter value calculation unit 7.

  The PID parameter value calculation unit 7 sets a set value as information necessary for calculating the PID parameter value between the reception time of the AT completion notification signal and the reception time of the AT completion notification signal (t7 in FIG. 10). A first extreme value deviation Er1 which is a deviation between SP and the latest extreme value of the control amount PV; a second extreme value deviation Er2 which is a deviation between the set value SP and the second new extreme value of the control amount PV; The first manipulated variable switching elapsed time Th1, which is the time from the time t5 when the sign of the deviation is reversed immediately before the first extreme value deviation Er1 to the time t6 when the first extreme value deviation Er1 is obtained, the second The second operation amount switching elapsed time Th2, which is the time from the time t3 at which the sign of the deviation is reversed immediately before the extreme value deviation Er2 to the time t4 at which the second extreme value deviation Er2 is obtained, is expressed as a vertical movement detection unit 4. Is getting from.

Then, the PID parameter value calculation unit 7 and the information acquired from the vertical motion detection unit 4 and calculation coefficients α, β, γ (for example, α = 1, β = 1, γ = 1), the PID parameter is calculated as follows (step S10).
Pb = 100.0α | Er2-Er1 | / {0.9 (AU-AL)} (4)
Ti = β (Th1 + Th2) (5)
Td = 0.21γ (Th1 + Th2) (6)

  The PID parameter value calculation unit 7 sets the calculated proportional band Pb, integration time Ti, and differentiation time Td 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.

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 it to the control target for each control cycle as in the following equation.
MV = (ζ / Pb) {1+ (1 / Tis) + Tds} (SP−PV) (7)
In Expression (7), s is a Laplace operator, and the constant ζ is 100, for example. As in the case of 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.

  As described above, in the present embodiment, when it is possible to separately confirm that the amplification of the vertical movement width of the control amount PV is stopped and the attenuation of the vertical movement width of the control amount PV is stopped, Since it is judged that a stable PV vertical movement waveform has been obtained and auto-tuning is terminated, there is no shortage of the number of vertical movements of the manipulated variable MV even in the case of a higher-order control target, which is more reliable than before. The operation amount MV can be moved up and down as many times as necessary.

[Second Embodiment]
Next, a second embodiment of the present invention will be described. This embodiment corresponds to Principle 2 of the invention described above. Also in the present embodiment, the configuration of the parameter adjustment device 1 and the PID control device 2 is the same as that of the first embodiment, and will be described using the reference numerals in FIG. FIG. 11 is a flowchart showing the operation of the parameter adjustment apparatus 1 of the present embodiment.

  The processing in steps S1 to S3 in FIG. 11 is the same as that in the first embodiment. Next, the up / down movement number determination unit 6 has passed the minimum number of up / down movements (for example, a maximum and a minimum of 2 each) between the AT start time and the current time. It is determined whether or not (step S11). If the predetermined minimum number of vertical movements has not elapsed, the process proceeds to step S4. The processing in step S4 is the same as that in the first embodiment.

  In this way, as in the first embodiment, the processes of steps S2, S3, S11, and S4 are repeatedly performed at regular operation cycles, and the minimum vertical movement with a predetermined number of vertical movements of the control amount PV is performed. When the number of times has elapsed (YES in step S <b> 11), the vertical movement number determination unit 6 outputs a parameter calculation start notification signal to the PID parameter value calculation unit 7.

Receiving the parameter calculation start notification signal, the PID parameter value calculation unit 7 calculates the PID parameter, and sets the calculated PID parameter in the PID control device 2 (step S12). The process of step S12 is the same as that of step S10.
Next, the processes in steps S4 to S10 are the same as those in the first embodiment. After the AT completion enable / disable determining unit 5 outputs the AT completion possible notification signal, until the up / down motion count determining unit 6 outputs the AT completion notification signal, the loop of steps S6 to S8 is performed as in the first embodiment. Is repeated.

  In this way, in the present embodiment, the PID parameter is calculated and set in the PID control device 2 after the minimum number of vertical movements of the control amount PV is obtained. Even if a situation that must be terminated occurs, the probability that a PID parameter close to an ideal value has already been set in the PID control device 2 increases. As a result, in the present embodiment, when the AT is interrupted, it is possible to reduce the probability of wasting time and effort required for the limit cycle until then.

  12 to 15 are waveform diagrams showing the situation of PID parameter calculation in the present embodiment. In the example of FIG. 12 that approaches the stable vertical movement while the vertical movement width of the controlled variable PV gradually amplifies, the PID parameter value is changed when the maximum and minimum of the controlled variable PV have passed twice each from the AT start time. An example is shown in which the AT is completed when the calculation is started and the PID parameters are calculated four times in total. In the case of the example of FIG. 13 that approaches the stable vertical movement while the vertical movement width of the control amount PV gradually attenuates, an example in which the AT is completed when the PID parameter is calculated four times in total is shown.

  In the example of FIG. 14 in which the control amount PV immediately stabilizes after the start of AT, an example is shown in which AT is completed when the PID parameter is calculated once. In the example of FIG. 15 in which the vertical movement width of the control amount PV is slightly amplified and attenuated, an example is shown in which the AT is completed when the PID parameter is calculated twice.

  The parameter adjusting device 1 and the PID control device 2 described in the first and second embodiments are realized by a computer having a CPU, a storage device, and an interface, and a program for controlling these hardware resources. Can do. 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 control device such as PID.

It is a wave form diagram which shows the example of the change of the control amount according to the operation amount output at the time of auto tuning execution. It is a wave form diagram which shows the other example of the change of the control amount according to the operation amount output at the time of auto-tuning execution. It is a wave form diagram which shows the other example of the change of the control amount according to the operation amount output at the time of auto-tuning execution. It is a figure which shows the example of the temperature control system of a multi loop. It is a wave form diagram which shows the other example of the change of the control amount according to the operation amount output at the time of auto-tuning execution. It is a block diagram which shows the structure of the 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 parameter adjustment apparatus and PID control apparatus of FIG. 6 are applied. It is a flowchart which shows operation | movement of the 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 wave form diagram for demonstrating operation | movement of the PID parameter value calculation part of the parameter adjustment apparatus which concerns on the 1st Embodiment of this invention. It is a flowchart which shows operation | movement of the parameter adjustment apparatus which concerns on the 2nd Embodiment of this invention. It is a wave form diagram which shows the condition of the PID parameter calculation in the 2nd Embodiment of this invention. It is a wave form diagram which shows the condition of the PID parameter calculation in the 2nd Embodiment of this invention. It is a wave form diagram which shows the condition of the PID parameter calculation in the 2nd Embodiment of this invention. It is a wave form diagram which shows the condition of the PID parameter calculation in the 2nd Embodiment of this invention.

Explanation of symbols

  DESCRIPTION OF SYMBOLS 1 ... Parameter adjustment apparatus, 2 ... PID control apparatus, 3 ... AT execution part, 4 ... Vertical motion detection part, 5 ... AT completion availability determination part, 6 ... Vertical motion frequency determination part, 7 ... PID parameter value calculation part.

Claims (6)

It has a function of auto-tuning that generates a limit cycle that repeatedly outputs a manipulated variable with a constant amplitude to the controlled object and calculates a control parameter of the control device based on the response of the controlled object according to the output of the manipulated variable In the parameter adjustment device,
Auto tuning execution means for generating the limit cycle;
Vertical movement detecting means for detecting the vertical movement width of the control amount according to the output of the operation amount;
Auto-tuning completion availability determination means for determining that the auto-tuning can be completed when the stop of the vertical movement width of the control amount and the stop of the attenuation of the vertical movement width can be confirmed separately; ,
Parameter value calculation means for calculating a control parameter based on a control amount response according to the output of the manipulated variable and setting the control parameter in a control device;
The parameter adjustment device, wherein the auto tuning execution means and the parameter value calculation means finish the auto tuning after the auto tuning completion determination unit determines that the auto tuning can be completed. The parameter adjustment device according to claim 1,
Further, after the auto-tuning completion determination unit determines that the auto-tuning can be completed, an auto-tuning completion notification is issued when the number of vertical movements of the control amount exceeds a predetermined number of vertical movements. Equipped with a means for determining the number of times of vertical movement,
The auto tuning execution means ends the limit cycle when receiving the auto tuning completion notification,
The parameter adjustment device is characterized in that the parameter value calculation means calculates and sets the control parameter when receiving the auto-tuning completion notification and finishes the auto-tuning. The parameter adjustment device according to claim 1,
Furthermore, after starting the auto-tuning, it comprises a vertical movement number determination means for notifying the start of parameter calculation when the number of vertical movements of the control amount has passed a predetermined minimum number of vertical movements,
The parameter value calculating means calculates and sets the control parameter every time a response of a control amount required for calculating the control parameter is obtained after receiving the parameter calculation start notification. Adjustment device. It has a function of auto-tuning that generates a limit cycle that repeatedly outputs a manipulated variable with a constant amplitude to the controlled object and calculates a control parameter of the control device based on the response of the controlled object according to the output of the manipulated variable In the parameter adjustment method,
Auto tuning execution procedure for generating the limit cycle;
A vertical movement detection procedure for detecting the vertical movement width of the control amount according to the output of the operation amount;
Auto-tuning completion determination procedure for determining that the auto-tuning can be completed when the stop of the vertical movement width of the control amount and the stop of the attenuation of the vertical movement width can be confirmed separately; ,
A parameter value calculation procedure for calculating a control parameter based on a response of a control amount according to the output of the manipulated variable and setting the control parameter,
A parameter adjustment method, comprising: determining that the auto-tuning can be completed in the auto-tuning completion determination procedure, and ending the auto-tuning. The parameter adjustment method according to claim 4, wherein
Further, after determining that the auto-tuning can be completed in the auto-tuning completion determination procedure, the auto-tuning completion notification is performed when the number of vertical movements of the control amount exceeds a predetermined number of vertical movements. It has a procedure for judging the number of vertical movements.
The auto-tuning execution procedure ends the limit cycle when the auto-tuning completion notification is performed,
The parameter value calculation procedure is characterized in that when the auto-tuning completion notification is made, the control parameter is calculated and set to finish the auto-tuning. The parameter adjustment method according to claim 4, wherein
Furthermore, after starting the auto-tuning, it comprises a procedure for determining the number of times of up / down movement for notifying the start of parameter calculation when the number of up / down movements of the controlled variable has passed a predetermined minimum number of up / down movements,
The parameter value calculation procedure is characterized in that the control parameter is calculated and set every time a control amount response necessary for calculating the control parameter is obtained after the parameter calculation start notification is performed. Parameter adjustment method.

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