JPH10240304A - Controller - Google Patents

Abstract

PROBLEM TO BE SOLVED: To suppress the occurrence of the pull-back phenomenon of PID signals even when output signals exceed a limit value by the abnormal change of a target value and input signals by changing an integrated arithmetic result so as to match the PID signals with the limit value when the peak of the PID signals is detected. SOLUTION: Integrated output In, proportional output Pn and differentiated output Dn PID computed in a PID computation part 29 based on the target value SVn and the input signals PVn are outputted to a change amount calculation part 31, the PID signals Pn+In+Dn are outputted to a timing judgement part 33 and further, target value differentiated output Dsvn is outputted to an output limiter processing part 35. Also, an integration change part 53 is connected to the PID computation part 29, is provided with a function for performing an arithmetic operation for attaining the value of the output signals MV outputted from the output limiter processing part 35 when a timing is outputted from the timing judgement part 33 and changing the integrated arithmetic result in the PID computation part 29 and changes the arithmetic processing so as to limit the PID signals.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a control device for performing proportional (P), integral (I) and differential (D) calculations, so-called PID calculations, and in particular, suppresses the occurrence of overshoot due to a large change in target value. It relates to improvement of a control device.

[0002]

2. Description of the Related Art Conventionally, as a control device of this type, FIG.
The speed type PID configuration shown in FIG.

In this configuration, a control deviation En obtained by subtracting an input signal PVn from a target value SVn by a subtractor 1 is added to a proportional change calculator 3 and an integral change calculator 5, and the input signal PVn is differentiated. In addition to the minute operation unit 7, the change operation outputs ΔPn and ΔIn are added by an adder 9, and the addition unit 11 subtracts the change operation output ΔDn from the added output to obtain a PID change signal ΔPIDn obtained by speed / In addition to the position shape converter 13, the PID change signal ΔPIDn and the PID signal PID (n−1) at a point before (time point n−1) before this PID change signal ΔPIDn
To calculate a PID signal PIDn from the PID signal PI
Dn is output to the output signal (operation amount) M via the output limiter 15.
Vn is output to the control target side. In the drawings, () is omitted from (n-1) (the same applies hereinafter).

Further, when the PID signal PIDn is out of the limit value of the output limiter 15, ie, exceeding the upper limit value MH or the lower limit value ML, the conversion control unit 17 controls the PID change signal .DELTA.PIDn by the amount exceeding the limit value ML or MH. The speed / position shape conversion unit 13 is controlled so as to omit.
The control device having the speed-type PID configuration has a configuration in which even if the PID signal PIDn greatly changes due to a change in the target value SVn or the like,
The output limiter 15 limits the output value within the limit values MH to ML, and the conversion control unit 17 controls the speed / position type conversion unit 13, so that the input signal PVn exceeds the target value SVn due to excessive integration. , So-called overshoot is suppressed.

That is, the speed / position type converter 13 normally performs an operation such as PIDn = PID (n-1) +. DELTA.PIDn PID (n-1) = PIDn, but the PID signal PIDn indicates the limit value MH or ML. When it exceeds, the conversion control unit 17 changes the PID signal PIDn as follows. When PIDn> MH: PIDn = MH, PID (n-
1) = MH When PIDn <ML: PIDn = ML, PID (n−
1) = ML

A control device having a position-type PID structure similar to the speed-type PID structure also has a structure as shown in FIG.
The one provided with an integral control unit capable of arbitrarily changing the integral value is used.

In this configuration, the control deviation En from the subtractor 1 is
Is added to the proportional operation unit 19 and the integration operation unit 21, the input signal PVn is applied to the differentiation operation unit 23, these operation outputs Pn, In, and Dn are added and subtracted by the addition unit 25, and the obtained PID signal PIDn is output to the output limiter 15. As an output signal (manipulation amount) MVn via the PID signal, and the PID signal PIDn at the time point n is output as the limit value MH of the output limiter 15.
Or, when it exceeds ML, the integral control section 27 corrects and controls the integral output In from the integral operation section 21 to MH- (Pn-Dn) or ML- (Pn-Dn).

In this position type PID control device, the integration operation unit 21 is controlled via the integration control unit 27,
Over-integration is suppressed to reduce the amount of input signal PV passing, thereby reducing overshoot for a large change in target value.

That is, the integral operation section 21 of FIG. 9 normally performs an operation such as In = I (n-1) + ΔIn I (n-1) = In, but the PID signal PIDn exceeds the limit value MH or ML. The integration control unit 27 changes the integration value In as follows. When PIDn> MH: In = MH- (Pn-Dn),
When I (n-1) = In PIDn <ML: In = ML- (Pn-Dn),
I (n-1) = In

By the way, each of the above-mentioned control devices has an input signal PVn which does not change stepwise for the following reason.
It has an input differentiation configuration that differentiates only. That is, in this type of control device, as described above, the PID signal PID
The overshoot can be suppressed by changing n and the integral value In. On the other hand, when the differential operation is performed on the control deviation En, if the target value SV is changed stepwise, the PID signal PIDn is once limited. Value MH
Alternatively, after reaching ML, a so-called differential retraction phenomenon in which the retraction is greatly reduced to within the limit value occurs.

FIG. 10 is a diagram for explaining such a differential pullback phenomenon. The dashed line in FIG. 10 indicates that the controller of FIG. 8 or FIG.
This is a target value change response of the PID signal PIDn when the conversion control unit 17 and the integration control unit 27 are not provided when V is changed in a step-like manner. The differential signal is effective and the output signal MVn has a pulse-like shape having a peak A point. It has a waveform. This P
For the ID signal PIDn, the conversion control unit 1 in the configuration of FIG.
7 is the peak limiter of the PID signal PIDn and the output limiter 1
In the configuration shown in FIG.
Changes the integral value In to MH- (Pn-Dn), whereby the PID signal PIDn is equal to the upper limit value MH.

This is equivalent to shifting the peak A point downward to the upper limit value MH by applying a bias to the waveform indicated by the one-dot chain line in FIG. Therefore, when the conversion control unit 17 and the integration control unit 27 are added, the PID signal P
After reaching the upper limit value MH at the timing of changing the target value as shown by the broken line in FIG.
L side), and as a result, the response of the input signal PV is delayed as indicated by the broken line in the figure, so that the input signal PV does not change in a step-like manner. I have.

[0013]

However, in the above-described control device having the input differential PID configuration, although the response to the step change of the target value SVn is improved, it is necessary to suppress the differential pullback phenomenon in other operation situations. There is still room for improvement.

That is, when the PID signal PIDn has the limit value M
When H or ML is exceeded, the speed /
When processing is performed to suppress over-integration by the position shape conversion unit 13 and the integration operation unit 21, as shown in FIG. 11, for example, impulse noise is mixed into the input signal PVn in a stable control state, and PID is generated at the rising edge of the noise. When the calculation result exceeds the upper limit value MH of the output limiter 15 and the PIDn of the PID calculation result matches the upper limit value MH by the correction processing of the integration calculation result, when the noise rises and disappears at the next sample time, In this case, a pull-back phenomenon occurs in which the PID operation result PIDn is pulled back extra by the amount corrected by the correction processing.

Therefore, as shown by the broken line in FIG.
There is a disadvantage that it takes more time until the control is stabilized again as compared with the case of the solid line without the correction processing. Further, the target value SV
Input signal PVn due to an erroneous operation when changing
If the change of the target value SV is repeated in a shorter time than the response time of the above, a problem as shown in FIG. 12 occurs.

For example, the target value SV such that the PID calculation result PIDn becomes smaller than the lower limit value ML at the time point in FIG.
Is changed, the PID calculation result PIDn is changed to the lower limit value ML.
The result of the integration operation is corrected so as to match. afterwards,
When the target value SV is returned to the original target value SV in a short time (time point in FIG. 12), the integral calculation is started from the corrected value, and PI
The D signal PIDn becomes higher than the original value by the integral correction, and the input signal PVn is disturbed extra.

The present invention has been made in order to solve such a conventional drawback, and the PID signal pullback phenomenon occurs even when an output signal exceeds a limit value due to an abnormal change in a target value or an input signal from a control target. It is an object of the present invention to provide a control device capable of suppressing the generation of the control signal.

[0018]

In order to solve such a problem, the present invention obtains an input signal by performing proportional, integral and differential operations on the input signal and the target value so as to match the target value. A control device for outputting an output signal from the PID signal to a control target side, wherein the PID signal exceeds a predetermined limit value and deviates from the proportional and differential change amounts and the integral change amount. When the peak of the PID signal is detected based on the comparison, the integration calculation result is changed so that the PID signal matches the limit value.

According to the present invention, when the above-mentioned peak is detected, an output signal thereof coincides with a value obtained by adding the added value of the proportional, differential and integral changes during the comparison of the changes to the above-mentioned limit value. A configuration for changing the result of the integration operation is also possible.

The present invention also provides a configuration for multiplying the proportional and differential change amounts by a coefficient in the range of "0" to "1" to compare with the integrated change amount, and an integral operation when no peak is detected. In addition, when the PID signal changes to within the limit value due to the stop of the integration operation, the P operation is stopped without stopping the integration operation.
A configuration for calculating the ID signal is also possible.

[0021]

Embodiments of the present invention will be described below with reference to the drawings. FIG. 1 is a block diagram showing an embodiment of a control device according to the present invention. In FIG. 1, P
The ID calculation unit 29 converts the target value SVn and an input signal PVn, which is a measurement value from a control target (not shown), into a predetermined PID.
A PID operation is performed with a constant to output an integral output In, a proportional output Pn, a differential output Dn, a PID signal Pn + In + Dn, and a target value differential output Dsvn at each predetermined sample timing. The change amount calculating unit 31, the timing determining unit 33
And an output limiter 35.

As shown in FIG. 2, for example, as shown in FIG.
Is calculated by an integral operation unit (I) 39 and a proportional operation unit (P) 41 to output an integral output In and a proportional output Pn, and the input signal PVn is inverted by an inverting unit 43 to obtain a differential operation unit. (D) The differential output Dn calculated in 45 is output, and the integration output In, the proportional output Pn, and the differential output Dn are added by the adder 47, and the PID signal Pn + I
In addition to outputting n + Dn, the differential value calculation section 45 calculates the target value SVn and outputs a target value differential output Dsvn to generate a position-type PID calculation configuration. The function of the integral operation unit 39 is changed by an instruction from an integral change unit 53 described later.

Returning to FIG. 1, the change amount calculating section 31 stores and holds the proportional output Pn, the integral output In, and the differential output Dn for each input timing, and also stores the proportional output Pn
(N-1), integral output I (n-1), differential output D (n-
1), and outputs a change amount of each output, that is, an integral change amount ΔIn, a proportional change amount ΔPn, and a differential change amount ΔDn, and is connected to the timing determination unit 33. The coefficient unit 49 outputs an arbitrary coefficient from “0” to “1” in response to an instruction from an input unit (not shown), and is connected to the timing determination unit 33.

The output limit value setting section 51 outputs an upper limit value and a lower limit value (limit value) MH or ML as output limit values set by input means (not shown), and includes a timing judgment section 33 and an output limiter. Processing unit 3
5 is connected. The timing determination unit 33 uses the PID
It has a function of outputting a timing signal relating to the operation and other functions, and has an output limiter processing unit 35 and an integration changing unit 5
3 is connected.

The timing determination section 33 determines whether or not the PID signal Pn + In + Dn, which is the PID calculation result, exceeds the limit value MH or ML from the output limit value setting section 51. , And the value obtained by multiplying the sum of the proportional and differential change amounts ΔPn + ΔDn by the coefficient from the coefficient unit 49 (coefficient × (ΔPn + ΔDn)), and storing the result at least until the next sample. It has a function of outputting a change timing signal to the output limiter processing unit 35 and the integration change unit 53 when the value becomes negative and the amount of change sequentially increases.

That is, as shown in FIG. 3A, when the input signal PVn that increases so as to approach the target value SV does not reach the target value SV, control of the target value SV and the input signal PVn is performed as shown in FIG. Since the deviation is plus (+), the PID signal Pn + In + Dn exceeds the upper limit MH and the output is saturated,
The integral change amount ΔIn increases and the proportional and derivative change amount [coefficient × (ΔPn + ΔDn)] decreases.

Here, when the subtraction result is continuously negative, the condition of ΔIn <−coefficient × (ΔPn + ΔDn) is satisfied, and when the amount of change is large, it is determined that ΔIn + coefficient ×
[ΔPn + ΔDn] <ΔIn−1 + coefficient × [ΔP (n−
1) + ΔD (n−1)] is satisfied,
When these conditions are satisfied, PI exceeding the upper limit value MH
The D signal Pn + In + Dn, that is, the output amount MV before the output limit processing passes the peak point (point P in FIG. 3B),
A change timing signal is output assuming that the state is decreasing toward the upper limit value MH.

The coefficient from the coefficient section 49 changes the temporal timing of the sum ΔPn + ΔDn of the change amounts of the proportionality and the derivative. When the coefficient exceeds “0” and is less than “1”, the upper limit MH is set. Signal Pn +
This indicates that the peak point P of In + Dn (output amount MV) is delayed, and the coefficient “1” does not delay the peak point P. Then, the timing determination unit 33 calculates the peak point P of the PID signal.
Determination points (P1, P2) from the start of the determination to the end of the determination
The function of adding 求 め ΔMV by adding the value of 2) and outputting it to the output limiter 35 is provided.

ΣΔMV can be expressed as follows: ΣΔMV = ΔPn + ΔIn + ΔDn + ΔP (n−1) +
ΔI (n−1) + ΔD (n−1) As will be described later, it is used for changing the integral calculation when the change timing signal is output. Note that the number of additions for the change in the output amount MV before the output limit value processing is not limited to two consecutive times.

The timing determining section 33 has a function of outputting a stop timing signal for stopping the integration operation to the integration changing section 53 when the above condition is not satisfied. However, when the PID signal changes below the upper limit value MH and falls within the upper limit value to the lower limit value MH to ML, for example, when the integration calculation is stopped by the stop timing signal, the timing determination unit 33 integrates the control sample. It has a function of outputting an execution timing signal to perform an operation.

When the PID signal Pn + In + Dn falls below the lower limit ML, the timing determination section 33 determines that the PID signal Pn + I falls below the lower limit ML.
In the same manner, the peak point of (n + Dn) is obtained and the change timing signal is output, while the ΣΔMV from the start to the end of the determination of the peak point is output. It has a function of outputting an execution timing signal when the output amount exceeds the lower limit value ML due to the stop.

The output limiter processing section 35 outputs the PID signal P
When n + In + Dn exceeds the limit value MH or ML, the output signal MV is limited to the limit value MH or ML.
The function of outputting as
3 and the control target. Then, when the timing determination unit 33 outputs the change timing signal, the output limiter processing unit 35 sets the limit value MH or ML to Σ.
It has a function of outputting a value obtained by adding ΔMV as an output signal MV.

When the control device of the present invention configures the differential differentiation type PID control, the output limiter processing section 35 outputs the target value differential output D to the output signal limited to the limit value MH or ML.
svn is added, and the output is output as an output signal after being again limited by the limit value MH or ML, or the target value differential output Dsvn is added to the value obtained by adding ΣΔMV to the limit value MH or ML, and the output is again limited by the limit value MH or ML. It has the function of limiting output.

The integration change section 53 is connected to the PID calculation section 29, and performs an operation such that when the timing is output from the timing determination section 33, the value becomes the value of the output signal MV output from the output limit processing section 35. And has the function of changing the result of the integration operation in the PID operation unit 29. That is, the integration change unit 53 feedback-outputs an instruction signal to stop the integration operation when the stop timing signal is output from the timing determination unit 33, and outputs the limit value MH or ML plus ΣΔMV to the output signal MV when the change timing signal is output. An instruction signal having such a value is feedback-outputted, and when an execution timing signal is output, an instruction signal for performing an integration operation for the control sample is output as feedback.

Next, the operation of the control device having the configuration shown in FIG. 1 will be briefly described. The integral output In, the proportional output Pn, and the differential output Dn PID-calculated by the PID calculator 29 based on the target value SVn and the input signal PVn are sent to the change amount calculator 31, the PID signal Pn + In + Dn is sent to the timing determiner 33, and further to the target value. The differential output Dsvn is output to the output limiter 35.

The proportional output P input to the variation calculator 31
The integrated change amount ΔIn, the proportional change amount ΔPn, and the differential change amount ΔDn are output to the timing determination unit 33 based on n, the integrated output In, and the differential output Dn. In the timing determination unit 33, an arbitrary coefficient from “0” to “1” from the coefficient unit 49 is output from the output limit value setting unit 51 to the limit value M.
H and ML are input.

The timing determining section 33 outputs the PID signal Pn
When + In + Dn exceeds the limit value MH or ML,
From the integral change ΔIn, the proportional and differential change ΔPn +
A value obtained by multiplying the sum of ΔDn by a coefficient [coefficient × (ΔPn + ΔD
n)] is subtracted, and when the subtraction result is negative and the amount of change is sequentially increasing, the PID signal Pn
+ In + Dn is determined to have passed the peak point P in FIG.
The change timing signal is output to the output limiter 35 and the integration changer 53. At this time, タ イ ミ ン グ ΔMV obtained by adding the two changes in the peak point P determination of the PID signal from the timing determination unit 33 is output limiter processing unit 35.
Output to

Even if the PID calculation result exceeds the upper limit value MH, if the control deviation is abnormal or the above condition is not satisfied even if the control state is not abnormal, a stop timing signal is output from the timing determination unit 33. It is output to the limiter processing unit 35 and the integration change unit 53. Further, when the output amount changes below the upper limit value MH and falls within the range from the upper limit value to the lower limit value MH to ML, for example, when the integration operation is stopped by the stop timing signal, the timing determination unit 33.
Output an execution timing signal to the output limiter 35 and the integration changer 53.

As a result, the output limiter 35 outputs a PID signal Pn + In + Dn, which is a PID calculation result.
Is greater than the limit value MH or ML, the output signal MV limited to the limit value MH or ML is output to the control target and the integration change unit 53, and when the change timing signal is output, the limit value MH is output. Alternatively, a value obtained by adding ΣΔMV to ML is similarly output as the output signal MV.

When the stop timing signal is output from the timing determination unit 33, an instruction signal for stopping the integration operation is output from the integration change unit 53 to the PID calculation unit 29, and when the change timing signal is output, the limit value MH is output. Or ML
An instruction signal having a value that becomes an output signal MV to which ΔMV has been added is output to the PID operation unit 29, and when an execution timing signal is output, an instruction signal for performing an integration operation for the control sample is output from the PID operation unit 29. 29. Therefore, based on these instruction signals, the PID calculation unit 29 varies the calculation function of the integration calculation unit 39 shown in FIG. 2, for example, to suppress or stop the over-integration operation, and at the time of outputting the execution timing signal, A PID signal that has been subjected to the integration operation for the minute is output.

As described above, according to the control device of the present invention, the target value S
PID signal P obtained by performing PID operation from Vn and input signal PVn
When IDn exceeds the limit value MH or ML, a value obtained by multiplying a proportional differential change amount ΔPn + ΔDn by a coefficient [coefficient × (ΔPn + ΔDn)] is subtracted from the integral change amount ΔIn. When the peak point of the previous output signal MV is determined, the integral calculation of the PID calculation is changed so that the output amount MV is limited by the limit value MH or ML. It is difficult to pull back and the target value SV
Even if n is erroneously set, if the value is reset to an appropriate value before reaching the peak point of the output signal MVn, the pullback of the PID signal can be quickly stopped.

Further, as a value for changing the result of the integration operation so as to suppress the output signal MVn to the limit value MH or ML, P
Since the change addition value ΣΔMV of the output amount MVn from the start of the determination of the peak point of the ID signal to the end of the determination is a value obtained by adding the limit value MH or ML, the peak determination is performed more efficiently than when the integration is corrected for each sample. Although the start of the correction is delayed by the required time, the difference in output is minimized. That is, in the conventional configuration in which the integration correction is performed for each sample, the output signal becomes smaller than the limit value at the points P1 and P2 as shown by the broken line a in FIG.
When the peak of the signal is determined to be at the point P2, when the integral feedback correction is performed so that the output signal reaches the limit value MH, the output becomes higher than the integral correction for each sample as shown by a dashed line b in FIG. That's a lot added.

Therefore, according to the present invention, the output variation ΣΔMV during peak measurement is calculated, and the output value used for the integral correction calculation when the peak is determined is set to MH + ΣΔMV instead of the limit value MH. As shown by the solid line c in FIG. 3, it is possible to approximate the output movement when the conventional sample-by-sample integration correction is performed. Then, even if the PID calculation result exceeds the limit value MH or ML, the integration calculation is stopped when the output condition of the change timing signal is not satisfied, so that there is an effect of preventing over integration.

Further, the proportional differential change amount ΔPn + ΔDn is multiplied by “1” exceeding the coefficient “0” to obtain a PID signal PID.
Since the peak point of n is determined, the peak point of the PID signal can be arbitrarily delayed, and fine control in which the integration operation output is finely variably adjusted can be performed. further,
PID by integration calculation stop by stop timing signal
When the signal changes from the upper limit value to the lower limit value MH to ML, the integration operation for the control sample is performed, so that the PID signal can be prevented from fluctuating near the limit value MH or ML.

By the way, the above-described PID operation unit 29
The configuration is not limited to the configuration shown in FIG. For example, as shown in FIG. 4, a configuration in which the differential operation unit 45 for differentiating the target value SVn in the configuration of FIG. 2 is omitted is also possible. In addition, PID
As shown in FIG. 5, the arithmetic unit 29 calculates the deviation obtained by subtracting the input signal PV from the target value SV by the subtraction unit 37,
9 to output the integrated output In, and the input signal PVn
Are inverted by an inverting unit 43, respectively, and are operated by a proportional operation unit 41 and a differential operation unit 45 to obtain a proportional output Pn and a differential output D.
n, and outputs the PID signal Pn by adding the integral output In, the proportional output Pn, and the differential output Dn in an adder 47.
A configuration for outputting + In + Dn is also possible.

When the PID operation unit 29 is formed by the configurations shown in FIGS. 4 and 5, the output system of the target value differential term Dsvn from the PID operation unit 29 in FIG. Not be.

Although the configuration of FIG. 1 according to the present invention described above is a form of position type PID control, the present invention can also adopt a speed type PID control configuration as shown in FIG. In FIG. 6, a PID calculation unit 55 performs PID calculation of a target value SVn and an input signal PVn with a predetermined PID constant to perform a proportional change ΔPn, an integral change ΔIn, a differential change ΔDn, and a PID.
PID signal as addition value and target value differential output Dsvn
At a predetermined sample timing, and is connected to the timing determination unit 33 and the output limiter processing unit 35.

That is, the PID operation unit 55 calculates the PID of FIG.
It has a function also as the ID calculation unit 29 and the change amount calculation unit 31, and the PID addition value is changed and calculated by an instruction signal from the addition change unit 73 described later. The specific configuration of the PID calculation unit 55 is, for example, as shown in FIG. 7, the difference obtained by subtracting the input signal PVn from the target value SVn by the subtraction unit 37 and the integration change amount ΔI from the integration calculation unit 57 and the proportional calculation unit 59.
n and the proportional change amount ΔPn, the input signal PVn is inverted by the inverting unit 61 and the differential operation unit 63 outputs the differential change amount ΔDn, and the integral change amount ΔIn, the proportional change amount ΔPn, and the differential change amount ΔDn are calculated. The addition is performed by the addition unit 65,
The PID addition value is output by the integration element 67, the target value SVn is calculated by the differentiation calculation section 63, and the target value differential output Dsvn is output from the integration element 67.

The timing judging section 33 in FIG. 6 has a function similar to that of FIG. 1 described above, and outputs a change timing signal, a stop timing signal and an execution timing signal, and also outputs a PID signal, that is, an output before the output limit. Signal M
The output limiter 35 has a function of outputting the added value ΣΔMV corresponding to the change in V, and the output limiter 35 also has a function similar to that of FIG.

The addition change section 69 includes a timing determination section 33
When the change timing signal is output from the output limiter 35, a function for calculating the value of the output signal MVn output from the output limiter processing unit 35, and a function for changing the addition operation of the PID signal in the PID calculation unit 55 or a stop timing signal When the output is output, the integration operation in the PID operation unit 55 is stopped, and when the execution timing signal is output, the integration operation in the PID operation unit 55 at the timing is executed.

The operation in the speed type PID control configuration as shown in FIG.
9 is the same as the position type PID control configuration of FIG.
Since the effect is the same, the description is omitted.

[0052]

As described above, according to the present invention, a PID signal obtained by performing a proportional, integral and differential operation on an input signal or a target value so as to match the input signal with the target value is transmitted to the control object side. When the PID signal exceeds a predetermined limit value, a peak of the PID signal is detected based on a comparison between the proportional and differential change amounts and the change amount of the integral operation. When the detection is detected, the arithmetic processing is changed so as to limit the PID signal. Therefore, even if the output value exceeds the limit value due to an abnormal change in the input signal or the target value, the occurrence of the pullback phenomenon can be suppressed. In a configuration in which the output signal is changed to a value obtained by adding the addition value of the proportional, differential, and integral change amounts during the detection of the peak to the limit value, the output change when the sample integration is corrected for each sample is: There is an advantage that a closer output change can be expected. Further, the present invention relates to overshoot and the like because the control timing can be varied in a configuration in which the proportional and differential change amounts are multiplied by a coefficient in the range of “0” to “1” and compared with the integral change amount. A delicate operation of the integral term near the output limit value can be performed, and a control response waveform for a target value change such that the output exceeds the limit value can be continuously changed by one coefficient. Further, in a configuration in which the calculation processing is changed so that the integration calculation is stopped when the peak of the PID signal is not detected, there is an effect of preventing excessive integration. Furthermore, when the PID signal changes within the limit value due to the stop of the integration operation, the configuration in which the PID signal is calculated without stopping the integration operation can prevent the PID signal from fluctuating near the limit value.

[Brief description of the drawings]

FIG. 1 is a block diagram showing an embodiment of a control device according to the present invention.

FIG. 2 is a block diagram illustrating a specific configuration of a PID calculation unit in FIG. 1;

FIG. 3 is a diagram for explaining the operation of the control device of FIG. 1;

FIG. 4 is a block diagram illustrating another configuration of the PID calculation unit in FIG. 1;

FIG. 5 is a block diagram illustrating another configuration of the PID calculation unit in FIG. 1;

FIG. 6 is a block diagram showing another embodiment of the control device according to the present invention.

FIG. 7 is a block diagram illustrating a specific configuration of a PID calculation unit in FIG. 6;

FIG. 8 is a block diagram showing a conventional control device serving as a reference of the present invention.

FIG. 9 is a block diagram showing another control device that is a reference of the present invention.

FIG. 10 is a diagram for explaining the operation of the control device of FIG. 8 or 9;

FIG. 11 is a diagram illustrating the operation of the control device of FIG. 8 or 9;

FIG. 12 is a diagram illustrating the operation of the control device of FIG. 8 or 9;

[Explanation of symbols]

 1, 37 Subtraction unit 3 Proportional change operation unit 5 Integral change operation unit 7 Differential change operation unit 9, 11, 25, 47, 65 Addition unit 13 Speed / position type conversion unit 15, 35 Output limiter 17 Conversion control unit 19, 41, 59 Proportional operation unit 21, 39, 57 Integral operation unit 23, 45, 63 Differential operation unit 27 Integral control unit 29, 55 PID operation unit 31 Change amount calculation unit 33 Timing determination unit 35 Output limiter processing unit 43, 61 inverting section 49 coefficient section 51 output limit value setting section 53 integration changing section 67 integration element 69 addition changing section

 ────────────────────────────────────────────────── ─── Continuing on the front page (72) Inventor Masashi Shimada 5-16-6 Kugahara, Ota-ku, Tokyo Inside Rika Kogyo Co., Ltd.

Claims (5)

[Claims] 1. An input signal that is proportional (P) or integral (I) to a target value so as to match the input signal or the target value.
And a control device for outputting an output signal from a PID signal obtained by performing a differential (D) operation to a control target side, wherein the proportional and differential change amounts and the When the peak of the PID signal is detected based on the comparison with the integrated change amount,
A control device for changing the result of the integral (I) calculation so that an ID signal matches the limit value. 2. The method according to claim 1, wherein when the peak is detected, the output signal is equal to a value obtained by adding an addition value of the proportional, differential, and integral changes during the comparison of the change to the limit value. The control device according to claim 1, wherein (I) changing a calculation result. 3. The control device according to claim 1, wherein the proportional and differential change amounts are multiplied by a coefficient in a range of “0” to “1” and compared with the integral change amount. 4. The calculation processing is changed to stop the integration calculation when the peak is not detected.
The control device according to any one of claims 1 to 3. 5. The method according to claim 5, wherein the PID is stopped by stopping the integration operation.
5. The control device according to claim 4, wherein when the signal changes within the limit value, the PID signal is calculated without stopping the integration calculation.