JP3436052B2 - Control device - Google Patents

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 derivative (D) operations, so-called PID operations, and particularly to suppressing the occurrence of overshoot due to a large change in target value. Regarding improvement of a control device.

[0002]

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

In this configuration, the subtraction unit 1 adds the control deviation En obtained by subtracting the input signal PVn from the target value SVn to the proportional change calculation unit 3 and the integral change calculation unit 5, and the input signal PVn is differentially changed. In addition to the minute calculation unit 7, the change calculation outputs ΔPn and ΔIn are added by the addition unit 9, and the PID change signal ΔPIDn obtained by subtracting the change calculation output ΔDn by the addition unit 11 from the added output is used as the speed / In addition to the position-type conversion unit 13, the PID change signal ΔPIDn and the PID signal PID (n-1) before this one time point (n-1 time point)
PID signal PIDn is calculated from
Dn is output signal (manipulation amount) M via the output limiter 15.
Vn is output to the control target side. In the drawings, () is omitted from (n-1) (hereinafter the same).

Moreover, when the PID signal PIDn exceeds the limit value of the output limiter 15, that is, exceeds the upper limit value MH or the lower limit value ML, the conversion controller 17 exceeds the limit value ML or MH of the PID change signal ΔPIDn. The speed / position type conversion unit 13 is controlled so as to cut off.
Even if the PID signal PIDn changes greatly due to the change of the target value SVn,
The output limiter 15 limits it 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 overintegration. The occurrence of so-called overshoot is suppressed.

That is, the speed / position type conversion unit 13 normally performs an operation such as PIDn = PID (n-1) + ΔPIDn PID (n-1) = PIDn, but the PID signal PIDn sets 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 PIDn <ML: PIDn = ML, PID (n−
1) = ML

Further, as shown in FIG. 9, a controller having a position type PID structure similar to the speed type PID structure is also shown in FIG.
The one provided with an integral control unit capable of arbitrarily changing the integral value is used.

This configuration has a control deviation En from the subtraction unit 1.
To the proportional calculation section 19 and the integral calculation section 21 and the input signal PVn to the differential calculation section 23, and the calculation outputs Pn, In and Dn are added and subtracted by the addition section 25, and the obtained PID signal PIDn is output limiter 15 Is output as an output signal (manipulated amount) MVn via the PID signal PIDn at the time point n and the limit value MH of the output limiter 15 is changed.
Alternatively, when it exceeds ML, the integral control unit 27 corrects and controls the integral output In from the integral calculating unit 21 to MH- (Pn-Dn) or ML- (Pn-Dn).

Also in the control device of this position type PID configuration, the integral calculation unit 21 is controlled via the integral control unit 27,
The over-integration is suppressed to reduce the overshoot amount of the input signal PV, and the overshoot is reduced for a large target value change.

That is, although the integral calculator 21 of FIG. 9 normally performs a calculation such as In = I (n-1) + ΔIn I (n-1) = In, the PID signal PIDn exceeds the limit value MH or ML. In the meantime, the integral control unit 27 changes the integral 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 control devices described above has an input signal PVn that does not change stepwise for the following reasons.
It has an input differential configuration that differentiates only. That is, in this type of control device, as described above, the PID signal PID
Although the overshoot can be suppressed by changing n or the integral value In, when the target deviation SV is changed stepwise when the control deviation En is differentiated, the PID signal PIDn is once limited. Value MH
Alternatively, after reaching ML, a so-called differential pullback phenomenon occurs in which the pullback is greatly pulled back within the limit value.

FIG. 10 is a diagram for explaining such a differential pullback phenomenon. The dashed-dotted line in FIG. 10 indicates that the control device of 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 steps, and the differential operation is effective and the output signal MVn has a pulse shape having a peak A point. It has a waveform. This P
With respect to the ID signal PIDn, the conversion control unit 1 in the configuration of FIG.
7 outputs the peak A point of the PID signal PIDn Limiter 1
The upper limit value MH of 5 is suppressed, and in the configuration of FIG.
Change the integrated value In to MH- (Pn-Dn), so that each PID signal PIDn becomes equal to the upper limit value MH.

This is equivalent to biasing the waveform indicated by the alternate long and short dash line in FIG. 10 and translating the peak point A downwardly to the upper limit value MH. Therefore, the PID signal P when the conversion control unit 17 and the integration control unit 27 are added
As shown by the broken line in FIG. 10, IDn reaches the upper limit value MH at the timing of changing the target value and then suddenly moves in the reverse direction (lower limit value M
Since the response of the input signal PV is delayed as indicated by the broken line in the figure as a result, the input differential structure is provided to differentiate the input signal PV that does not change stepwise. There is.

[0013]

However, although the control device of the input differential type PID configuration described above improves the response to the stepwise change of the target value SVn, it suppresses the differential pullback phenomenon in other operating situations. There is room for further improvement.

That is, the PID signal PIDn is limited to the limit value M.
When H or ML is exceeded, the speed /
When the position-type conversion unit 13 and the integration calculation unit 21 perform processing to suppress overintegration, as shown in FIG. 11, for example, impulse noise is mixed into the input signal PVn in the stable control state, and PID occurs at the rising portion 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 is made equal to the upper limit value MH by the correction process of the integral calculation result, when the noise rises and disappears at the next sampling time, In addition, a pullback phenomenon occurs in which the PID calculation result PIDn is pulled back by the amount corrected by the correction process.

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

For example, the target value SV at which the PID calculation result PIDn becomes less than the lower limit value ML at the time point in FIG.
Is changed, the PID calculation result PIDn is set to the lower limit value ML.
The integral calculation result is corrected so that afterwards,
When the target value SV is returned to the original target value 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 amount, and the input signal PVn is excessively disturbed.

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

[0018]

In order to solve such a problem, the present invention obtains proportional, integral and derivative operations with respect to an input signal and a target value so as to match the input signal with the target value. A control device that outputs an output signal from the PID signal to the controlled object side, and when the PID signal exceeds a predetermined limit value and is out of the integrated change amount,
When the peak of the PID signal is detected based on the result of subtracting the added value of the proportional and differential change amounts ,
The above-mentioned integral calculation result is changed so that the output signal matches the limit value.

The present invention is also directed to those proportional and differential variables.
Apply a coefficient in the range of "0" to "1" to the added value
It is also possible to employ a configuration in which the integral change amount is subtracted.

When the above peak is not detected, the integral calculation
Configuration that changes the above calculation processing to stop
When the calculation is stopped, the PID signal changes to the above limit value.
At this time, the PID signal is calculated without stopping the integral calculation.
It is also possible to have a configuration.

[0021]

BEST MODE FOR CARRYING OUT THE INVENTION 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 sets the target value SVn and the input signal PVn, which is a measured value from a control target (not shown), to a predetermined PID.
The PID calculation is performed with a constant and the integrated output In, the proportional output Pn, the differential output Dn, the PID signal Pn + In + Dn, and the target value differential output Dsvn are output at every predetermined sample timing. The change amount calculation unit 31, the timing determination unit 33
And the output limiter processing unit 35.

In the PID calculator 29, the subtractor 37 subtracts the input signal PVn from the target value SVn as shown in FIG.
Is calculated by the integral calculation unit (I) 39 and the proportional calculation unit (P) 41 to output the integral output In and the proportional output Pn, and the input signal PVn is inverted by the inverting unit 43 to differentiate it. (D) The differential output Dn calculated by 45 is output, and the integrated output In, the proportional output Pn, and the differential output Dn are added by the adder 47 to add the PID signal Pn + I.
In addition to outputting n + Dn, it has a position type PID calculation configuration that calculates the target value SVn by the differential calculation section 45 and outputs the target value differential output Dsvn. The integration calculation unit 39 has its calculation function changed according to an instruction from the integration changing 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 at each input timing, and the previous proportional output Pn.
(N-1), integral output I (n-1), differential output D (n-
The difference from 1) is calculated, and the change amount of each output, that is, the integral change amount ΔIn, the proportional change amount ΔPn, and the differential change amount ΔDn are output, and is connected to the timing determination unit 33. The coefficient section 49 outputs an arbitrary coefficient exceeding “0” to “1” according to an instruction from an input means (not shown), and is connected to the timing determining section 33.

The output limit value setting unit 51 outputs the upper limit value and the lower limit value (limit value) MH or ML as the output limit value set by the input means (not shown), and the timing judgment unit 33 and the output limiter. Processing unit 3
Connected to 5. The timing determination unit 33 uses the PID
The output limiter processing unit 35 and the integration changing unit 5 have a function of outputting a timing signal related to calculation and other functions.
Connected to 3.

The timing determination unit 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 unit 51. , A value [coefficient × (ΔPn + ΔDn)] obtained by multiplying the sum of proportional and differential changes ΔPn + ΔDn by a coefficient from the coefficient unit 49 is subtracted (compared), and the result is stored at least up to the next sample, and the subtraction result is It has a function of outputting a change timing signal to the output limiter processing unit 35 and the integration changing unit 53 when the amount of change becomes negative and the amount of change gradually 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 as shown in FIG. 3B. Since the deviation is plus (+), the PID signal Pn + In + Dn exceeds the upper limit value MH side and the output is saturated,
The amount of change in integration ΔIn increases, and the amount of change in proportional and differential [coefficient × (ΔPn + ΔDn)] changes in the direction of decrease.

Here, if the subtraction result becomes continuously negative, the condition of ΔIn <−coefficient × (ΔPn + ΔDn) is satisfied, and if the amount of change is large, ΔIn + coefficient ×
[ΔPn + ΔDn] <ΔIn-1 + coefficient × [ΔP (n−
1) + ΔD (n-1)], and
When these conditions are satisfied, PI exceeding the upper limit value MH
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),
The change timing signal is output because it is in a state of decreasing toward the upper limit value MH.

By the way, the above-mentioned coefficient from the coefficient section 49 is for varying the timing in time of the sum ΔPn + ΔDn of the proportional and derivative changes, and when the coefficient exceeds “0” and less than “1”, the upper limit value MH is reached. PID signal exceeding Pn +
The peak point P of In + Dn (output amount MV) is delayed, and the coefficient “1” indicates a state where it is not delayed. Then, the timing determination unit 33 determines the peak point P of the PID signal.
Determination points (P1, P
It has a function of adding the value of 2) to obtain ΣΔMV, and outputting it to the output limiter processing unit 35.

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

Further, the timing judgment section 33 has a function of outputting a stop timing signal for stopping the integral calculation to the integration changing section 53 when the above-mentioned condition is not satisfied. However, when the PID signal changes so as to fall below the upper limit value MH and fall within the upper limit value to the lower limit value MH to ML due to the stop of the integration calculation by the stop timing signal, the timing determination unit 33 integrates the control sample. It has a function of outputting an execution timing signal so as to perform an operation.

When the PID signal Pn + In + Dn drops below the lower limit value ML, the timing judgment section 33 drops the PID signal Pn + I below the lower limit value ML.
Similarly, the peak point of n + Dn is obtained and the change timing signal is output, while ΣΔMV from the start of the determination of the peak point to the end of the determination is output, and the stop timing signal is output when the above condition is not satisfied, and the integration calculation is performed. It has a function of outputting the execution timing signal when the output amount changes by exceeding the lower limit value ML due to the stop.

The output limiter processing unit 35 receives 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.
Has a function of outputting as, and the integration changing unit 5
3 and the controlled object. Then, the output limiter processing unit 35 sets the limit value MH or ML to Σ when the change timing signal is output from the timing determination unit 33.
It has a function of outputting a value obtained by adding ΔMV as an output signal MV.

When the deviation limiter type PID control is configured by the control device of the present invention, 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 re-limited with the limit value MH or ML and output as an output signal, or the target value differential output Dsvn is added to the value obtained by adding ΣΔMV to the limit value MH or ML and re-outputted with the limit value MH or ML. It has the function of limiting and outputting.

The integral changing unit 53 is connected to the PID calculating unit 29, and performs an operation such that when the timing is output from the timing determining unit 33, the value of the output signal MV output from the output limiter processing unit 35 is obtained. It has a function of changing the integration calculation result in the PID calculation unit 29. That is, the integration changing unit 53 feeds back an instruction signal for stopping the integration calculation when the stop timing signal is output from the timing determination unit 33, and outputs the output signal MV obtained by adding ΣΔMV to the limit value MH or ML when outputting the change timing signal. An instruction signal having such a value is fed back and further, at the time of outputting the execution timing signal, an instruction signal for performing an integral operation for the control sample is fed back and output.

Next, the operation of the control device having the above-mentioned configuration of FIG. 1 will be briefly described. The integral output In, the proportional output Pn, and the differential output Dn, which are 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 signals Pn + In + Dn are sent to the timing determiner 33, and the target value The differential output Dsvn is output to the output limiter processing unit 35.

The proportional output P input to the change amount calculating section 31
Based on n, the integrated output In, and the differential output Dn, the integrated change amount ΔIn, the proportional change amount ΔPn, and the differential change amount ΔDn are output to the timing determination unit 33. In the timing determination unit 33, any coefficient from the coefficients “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 determination unit 33 determines the PID signal Pn.
When + In + Dn exceeds the limit value MH or ML,
From the integral change amount ΔIn, the proportional and derivative change amount ΔPn +
A value obtained by multiplying the sum of ΔDn by a coefficient [coefficient × (ΔPn + ΔD
n)] is subtracted, and the subtraction result becomes negative and the amount of change gradually increases, the PID signal Pn
It is judged that + In + Dn has passed the peak point P of FIG. 3B,
The change timing signal is output to the output limiter processing unit 35 and the integration changing unit 53. At this time, the output limiter processing unit 35 obtains ΣΔMV from the timing determination unit 33, which is the sum of two changes in the peak point P determination of the PID signal.
Is output to.

Further, even if the PID calculation result exceeds the upper limit value MH, if the control deviation is abnormal, or if the above condition is not satisfied even if the control deviation is not in an abnormal state, the timing determination unit 33 outputs a stop timing signal. It is output to the limiter processing unit 35 and the integration changing unit 53. Furthermore, when the output amount changes below the upper limit value MH to fall within the upper limit value to the lower limit value MH to ML due to the stop of the integral calculation by the stop timing signal, the timing determination unit 33.
Outputs the execution timing signal to the output limiter processing unit 35 and the integration changing unit 53.

As a result, from the output limiter processing section 35, the PID signal Pn + In + Dn which is the 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 changing unit 53, while 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, the integration change unit 53 outputs an instruction signal to stop the integration calculation to the PID calculation unit 29. When the change timing signal is output, the limit value MH is output. Or Σ in ML
When the instruction signal having a value that becomes the output signal MV to which ΔMV is added is output to the PID operation unit 29, and when the execution timing signal is further output, the instruction signal for performing the integration operation for the control sample is the PID operation unit. It is output to 29. Therefore, based on these instruction signals, the PID operation unit 29 changes the operation function of the integration operation unit 39 shown in FIG. 2, for example, to suppress or stop the overintegration operation, while at the same time outputting the execution timing signal, the sample concerned. The PID signal obtained by the integral calculation of the minutes is output.

As described above, the control device of the present invention has the target value S
PID signal P calculated by PID from Vn and input signal PVn
When IDn exceeds the limit value MH or ML, the value obtained by multiplying the proportional change amount ΔPn + ΔDn by a coefficient [coefficient × (ΔPn + ΔDn)] is subtracted from the integrated change amount ΔIn, and the PID signal, that is, the output limit When the peak point of the previous output signal MV is discriminated, the integration operation of the PID operation is changed so that the output amount MV limited by the limit value MH or ML is changed. It becomes 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 the peak point of the output signal MVn is reached, the PID signal can be pulled back quickly.

Moreover, P is a value for changing the result of the integral calculation so that the output signal MVn is limited to the limit value MH or ML.
Since the added value ΣΔMV of the change in 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 the value added to the limit value MH or ML, the peak determination can be performed more than when the integration correction is performed for each sample. Although the start of correction is delayed by the time required, the difference in output can be minimized. That is, in the conventional configuration in which the integral correction is performed for each sample, the output signal becomes as shown by the broken line a in FIG. 3 and becomes smaller than the limit value at the time points P1 and P2.
When the peak of the signal is determined to be the P2 point, and the integral feedback correction is performed so that the output signal becomes the limit value MH at this point, the result becomes as indicated by the alternate long and short dash line b in FIG. It means that many people have joined.

Therefore, in the present invention, the change amount ΣΔMV of the output 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 movement of the output when the conventional sample-by-sample integration correction is performed. Even if the PID calculation result exceeds the limit value MH or ML, the integral calculation is stopped when the output condition of the change timing signal is not satisfied, so that there is an effect of preventing overintegration.

Further, the proportional differential change amount ΔPn + ΔDn is multiplied by a coefficient “0” and multiplied by “1” to obtain the PID signal PID.
Since the peak point of n is discriminated, the peak point of the PID signal can be arbitrarily delayed, and fine control by finely variably adjusting the integral operation output can be performed. further,
PID by stopping integration calculation 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 wandering in the vicinity of the limit value MH or ML.

By the way, the PID calculator 29 described above is
The configuration is not limited to that shown in FIG. For example, as shown in FIG. 4, a configuration is possible in which the differential operation unit 45 that differentiates the target value SVn in the configuration of FIG. 2 is omitted. Furthermore, PID
As shown in FIG. 5, the calculation unit 29 integrates the deviation obtained by subtracting the input signal PV from the target value SV by the subtraction unit 37 into the integration calculation unit 3.
9 and outputs the integrated output In, and the input signal PVn
Are inverted by the inversion unit 43, and the proportional output Pn and the differential output D are calculated by the proportional operation unit 41 and the differential operation unit 45.
n is output, and the integrated output In, the proportional output Pn, and the differential output Dn are added by the adder 47 to obtain the PID signal Pn.
A configuration for outputting + In + Dn is also possible.

When the PID computing unit 29 is formed with the configurations of FIGS. 4 and 5, the output system of the target value differential term Dsvn from the PID computing unit 29 in FIG. 1 is eliminated and the deviation differential type PID control configuration is adopted. Don't

Although the above-described configuration of FIG. 1 according to the present invention is in the form of position type PID control, the present invention is also possible with a velocity type PID control configuration as shown in FIG. In FIG. 6, the PID calculator 55 performs a PID calculation of the target value SVn and the input signal PVn with a predetermined PID constant to obtain a proportional change amount ΔPn, an integral change amount ΔIn, a differential change amount ΔDn, PID.
PID signal that is the added value and target value differential output Dsvn
Is output for each predetermined sample timing, and is connected to the timing determination unit 33 and the output limiter processing unit 35.

That is, the PID calculation unit 55 uses the PID of FIG.
It has a function that also serves 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 an addition change unit 73 described later. For example, as shown in FIG. 7, the PID calculation unit 55 has a specific configuration in which the subtraction unit 37 subtracts the input signal PVn from the target value SVn to calculate the deviation from the integration calculation unit 57 and the proportional calculation unit 59.
n and the proportional change amount ΔPn are output, the input signal PVn is inverted by the inversion unit 61, and the differential change amount ΔDn is output from the differential operation unit 63. The integrated change amount ΔIn, the proportional change amount ΔPn, and the differential change amount ΔDn are output. Addition is performed by the addition unit 65,
The integrating element 67 outputs the PID addition value, the target value SVn is calculated by the differential calculating section 63, and the target value differential output Dsvn is output from the integrating element 67.

The timing judgment unit 33 in FIG. 6 has the same function as in FIG. 1 described above, and in addition to the function of outputting the change timing signal, the stop timing signal and the execution timing signal, the PID signal, that is, the output before the output limit. Signal M
It has a function of outputting the added value ΣΔMV of the change in V, and the output limiter processing unit 35 also has the same function as that of FIG. 1 described above.

The addition changing unit 69 is the timing judging unit 33.
When the change timing signal is output from the output limiter processing unit 35, the output timing MVn output from the output limiter processing unit 35 is calculated, and the addition operation of the PID signal in the PID calculation unit 55 is changed, and the stop timing signal is changed. It has a function of stopping the integral calculation in the PID calculating unit 55 when it is output, and executing the integral calculation in the PID calculating unit 55 at the timing when the execution timing signal is output.

The operation in the speed type PID control configuration as shown in FIG. 6 is performed by the PID calculating section 55 and the addition changing section 6
Other than 9 is the same as the position type PID control configuration of FIG.
The effect is also the same, so the description is omitted.

[0052]

As described above, according to the present invention, the PID signal obtained by performing proportional, integral and differential operations on the input signal and the target value so as to match the input signal to the target value is transferred to the controlled object side. a control apparatus for outputting an output signal, when the PID signal exceeds a predetermined limit value, the
From the integral change, add the proportional and derivative changes
The peak of the PID signal is detected based on the result of the subtraction, and when this peak is detected, the output signal is the above-mentioned limit value.
Since the integral calculation result is changed so that it matches with, it is possible to suppress the occurrence of the pullback phenomenon even if the output value exceeds the limit value due to an abnormal change in the input signal or the target value .
For example, the output change when the modified every sample integration, there is an advantage output change closer can be expected. Further, in the present invention, with respect to the added value of the proportional and derivative change amounts, "0"
In the configuration in which the coefficient in the range of “1” is multiplied and subtracted from the integral change amount, the control timing can be varied, so that a delicate operation of the integral term near the output limit value related to overshoot or the like can be performed. It becomes possible, and it becomes possible to continuously change the control response waveform with respect to the target value change such that the output exceeds the limit value by one coefficient. Further, when the peak of the PID signal is not detected, change the processing to stop the integral operation, furthermore, when the PID signal by the stop of the integral operation is changed to the limit value, the without stopping the integral operation Prevents over-integration in the configuration that calculates the PID signal
However, it is possible to prevent the PID signal from wandering around the limit value.

[Brief description of 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 showing a specific configuration of a PID calculation unit in FIG.

FIG. 3 is a diagram illustrating an operation of the control device of FIG.

FIG. 4 is a block diagram showing another configuration of the PID calculation unit in FIG.

5 is a block diagram showing another configuration of the PID calculation unit in FIG.

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

7 is a block diagram showing a specific configuration of a PID calculator of FIG.

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

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

FIG. 10 is a diagram illustrating an operation of the control device of FIG. 8 or FIG.

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

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

[Explanation of symbols]

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

─────────────────────────────────────────────────── ─── Continuation of the front page (72) Inventor Masashi Shimada 5-16-6 Kugahara, Ota-ku, Tokyo Rika Kogyo Co., Ltd. (56) Reference JP-A-6-102902 (JP, A) JP-A 4-138501 (JP, A) JP 59-32629 (JP, A) (58) Fields investigated (Int. Cl. ⁷ , DB name) G05B 11/00-13/04

Claims (3)

(57) [Claims] 1. Proportional (P) and integral (I) to the input signal and the target value so that the input signal matches the target value.
And the differential (D) controller which outputs an output signal from the PID signal obtained by calculation to the controlled object side, under circumstances in which the PID signal exceeds a predetermined limit value, before
From the integral change amount, add the added value of the proportional and derivative change amounts.
A control device, wherein when the peak of the PID signal is detected based on the result of the subtraction, the integral (I) calculation result is changed so that the output signal matches the limit value. 2. Comparing the added value of the proportional and differential changes
And multiply by a coefficient in the range of "0" to "1" to change the integral
The control device according to claim 1, wherein the control device subtracts from the amount. 3. The product when the peak is not detected.
The calculation process is changed to stop the minute calculation, and the integration
When the calculation is stopped, the PID signal changes within the limit value.
The PID signal without stopping the integration calculation
The control device according to claim 1, which calculates