JPS5833706A - Actuator driving circuit - Google Patents

Abstract

PURPOSE:To suppress a stationary error within a specified value without being affected on the performance of an actuator, by converting an output of an integrator into an actuator driving signal. CONSTITUTION:An integrator 10 zeros an integration value I being the output while a correction error E2 is <=0 and increases the value I as time elapses while the error E2 is >0. The value I is applied to an adder 11. The adder 11 adds the error E2 to the value I as a gradually increased error E3, which is applied to a comparator 8. This comparator 8 compares the error E3 with a saw-tooth waveform N and outputs a rotating signal P. Thus, if this error E1 is smaller than a dead band D, the pulse width of driving signals W1, W2, regardless of the elapse of time, is zero and a DC motor 1 is stopped. Thus, the stationary error can be taken to the dead band D or less.

Description

DETAILED DESCRIPTION OF THE INVENTION The present invention relates to an actuator drive circuit that drives an actuator to a target position.

Conventionally, the circuit shown in FIG. 1 has been known as this type of circuit. In this FIG. 1, l is a DC motor,
Rotate shaft 2. This rotational position rItR of the shaft 2 is outputted by a potentiometer 3. tfc
, the target position A of the shaft 2 is given by four tensiometers 4.

A subtracter 5 outputs an error E, which is the absolute value of the difference between the rotational position R and the target position A, and a sign sYt.

The error E1 is sent to a subtracter 6, and the sign S is sent to an amplifier 9. The subtracter 6 subtracts a fixed dead band width D=i from the error E1, outputs the correction error &1,
The signal is sent to comparator 8.

A constant sawtooth waveform N from the sawtooth wave generator l is also input to the comparator 8, and this correction error El is compared with the sawtooth waveform N to output the rotation signal Pt to the amplifier 9. It's becoming a trap.

The amplifier 9 controls the DC motor 11 according to the rotation signal P and the code 8.
Driving signals w, , w, t for driving are output. The DC converter 1 is rotating while the drive signal W1°W is at a high level.

Next, the operation of the actuator drive circuit shown in FIG. 1111 will be described in conjunction with the time chart t- shown in FIG. Second
The symbols in the figure correspond to the symbols of each signal in FIG. The subtracter 5 outputs an error E1 of the rotational position relative to the target position A and a sign 8i. Further, the subtracter 6 subtracts the cine sensitivity band width from the error E1 to obtain a correction error E. Comparator 8 calculates the correction error E! The sawtooth shape Nt is compared, and while the former is larger than the latter, a high-level rotation signal P is output.

The amplifier 9 amplifies the rotation signal P and generates a drive signal W1°WI
At the same time, the rotational direction of the DC motor 1 is controlled according to the symbol S. That is, the rotational position R is set to the target position A.
If larger, the signal S is at a low level and the rotation signal P is the drive signal W! is amplified, and the DC motor l rotates in a direction that decreases the rotational position R.

Conversely, if the rotational position R is smaller than the target position, the drive signal W
1 is generated, and the rotation position Rt is rotated in the direction of increasing.

Therefore, the error Bl and the 14-pulse width of the drive signal W, , W, which is the drive time of the DC motor 1, have a proportional relationship as shown in FIG.

The conventional examples described above have the following drawbacks. The driving time required for the DC motor 1 to rotate includes the third
There is a minimum value indicated by Wo in the figure.

When the /4 pulse width of the drive signals W, , Wl is smaller than this minimum drive time Wo, the DC motor 1 does not rotate. If the error t'Eo corresponding to this minimum drive time W is 1
If the difference E1 is smaller than E, the DC motor l will not rotate.

Therefore, between the rotational position 1iiR and the target position A,
A steady error Eo larger than the width of the dead zone will occur.

The minimum drive time Wo varies depending on the performance of the DC Tanabata 1 and the drive power supply voltage, so there is a steady-state error E.

It will also change depending on the performance of the DC motor 1, etc.

This invention has been developed in view of these points, and has the following features:
It is an object of the present invention to provide an actuator drive circuit in which a steady-state error matches a fixed dead band width and is not dependent on the performance of the actuator.

Embodiments of the actuator drive circuit of the present invention will be described below with reference to the drawings. FIG. 4 is a block diagram showing the configuration of one embodiment. In this figure 4, the first
Parts that are the same as those in the figures are given the same reference numerals and their explanations are omitted.
We will focus on the parts that differ from those in Figure 1.

As is clear from comparing Figure 4 with Figure 1,
In the figure, an integrator 10 and an adder 11 are newly added to the circuit of FIG. 1, and the integrator 10 has a correction error E! is less than O, its output, the integral value IkO
And the correction error E! When is greater than 0, the integral value I- is increased by δ with the passage of time. This integral value is added to an adder 11.

The adder 11 adds the correction error E2 and the integral value, and adds the result to the comparator 8 as a gradual error E3. This comparator 8
compares the incremental error E3 with the sawtooth waveform N and outputs a rotation signal P. Other parts are the same as in FIG.

Next, the operation of the actuator drive circuit of the present invention constructed as described above will be described with reference to the time chart shown in FIG. The symbols in FIG. 5 correspond to the symbols of each part in FIG. Now, as long as the correction error E, is less than or equal to O, the integral value I is 0, and as long as the correction-difference E, exceeds 0, the integral value I increases with time. Incremental error B
, is the sum of the correction error E3 and the integral value 1. The high level of the 3rd rotation signal P is caused by the difference E, which is greater than the sawtooth waveform N. Therefore, the drive signals Ws, Wz
The Noil 2 width tends to increase as long as the error E is greater than the dead band and its sign is constant.

FIG. 6 shows the relationship between the error E1 and the pulse width of the drive signals W, , W. Correction error E! While is less than 0, that is, while the error El is smaller than the dead zone width;
If the pulse width is 0 and the correction error E2 exceeds 0, then
That is, when the error E is larger than the dead zone width, it changes as t, tl, t, . . . over time. Assuming that the minimum driving time is t''Wo, a steady error E occurs in the conventional example shown in FIG.

In the case of the embodiment shown in FIG. 4, the operation is as follows.

If the error E1 is larger than the error E, the DC motor 1 will rotate and the error E! becomes smaller. When the error E1 becomes smaller than the error value, the DC motor 1 does not rotate at time to.

However, as time passes, it changes to tlst2..., so the /4' pulse width of the drive signals Wt, W increases,
After time t3, the DC motor IFi rotates, and the error EIi becomes smaller. When the error E becomes smaller than the dead band width, the drive signal W1. W! The pulse width of is 0
Therefore, the DC motor 1 stops. Therefore, the steady-state error can be reduced to less than the width of the dead zone.

In addition, in the embodiment shown in FIG.
! However, the correction error E is directly connected to the comparator 8, compared with the sawtooth waveform N, the entire rotation signal P is generated, the integral value It is converted to the Noyals deviation, and this is converted into the rotation signal P. A similar effect can be obtained by adding it.

Furthermore, the actuator is not limited to a DC motor, but can also be applied to a pressure-controlled vacuum motor.

As described above, according to the actuator drive circuit of the present invention, the detected position of the actuator and the target value are compared with the comparator, and the output is gradually increased while the sign of the output is constant, and when the sign is reversed, the output is gradually increased. In addition to converting the output of this integrator into a 7-actuator drive signal, the steady-state error can be suppressed to within a certain value without being affected by the performance of the actuator. It is possible.

[Brief explanation of the drawing]

Figure 1 is a block diagram of a conventional actuator drive circuit.
Figure 2 is a waveform diagram of each part to explain the operation of the 7-cut machine drive circuit in Figure 1, and Figure 3 shows the error diagram to explain the operation of the 7-cut machine drive circuit in Figure 1. E1 drive signal W, , W! Figure 4 shows the relationship between pulse width and pulse width.
is a block diagram showing the configuration of an embodiment of the actuator drive circuit of the present invention, and the fifth factor is a block diagram for explaining the operation of the actuator drive circuit of the present invention. It is a diagram showing the relationship between the error B1 and the noggle width of the drive signals Ws and Ws for explaining the operation of the drive circuit.・
Potentiometer, 5, 6... Subtractor, 7... Sawtooth wave generator, 8... Comparator, 9... Amplifier, 10.
... Integrator, 11... Adder. Note that the same reference numerals in the figures indicate the same or corresponding parts. Agent Makoto Kuzuno - Figure 2 2 Figure 4 S 2 Figure 61 Procedural Amendment (1) Dear Commissioner of the Japan Patent Office 1, Indication of the case Patent application Sho! ! No. 8-131983 No. 2, Name of the invention Actiator Drive Garden Path 3, Relationship with the case of the person making the amendment Patent applicant address 2-2-3 Marunouchi, Chiyoda-ku, Tokyo Name (601) Mitsubishi Electric Corporation Representative: Hitoshi Katayama 4, Agent address: 2-2-3-5 Marunouchi, Chiyoda-ku, Tokyo; Subject of amendment; Scope of claims and Detailed description of the invention. 6. Contents of the amendment (13% claim is corrected as shown in the attached sheet. (2) "Sawtooth wave generator 1" on page 2, line 11 is corrected as "sawtooth wave generator 7" 7. Amendment of list of attached documents Claims: One or more claims A subtractor that outputs the error and sign from the position and target value of the actuator, and the correction error from this subtractor is integrated and corrected. An integrator that outputs an integral value of 1o when the error is less than zero and increases with the opening time when the correction error exceeds O, and the drive signal of the actuator is determined by the output of this integrator and the above sign. 2. The actuator drive circuit according to claim 1, further comprising means for outputting an output.

Claims (1)

[Claims] a first subtractor that outputs the error and sign from the actuator position and target value; a second subtractor that subtracts a certain dead zone from the error output from the first subtractor and outputs a correction error; An integrator that integrates the correction error from this second subtractor and outputs an integral value that outputs an integral value that increases with the opening time when the correction error is less than or equal to zero, and when the correction error exceeds 0; An actuator drive circuit comprising means for outputting a drive signal for the actuator based on the code and the result of comparing the output of the device with a predetermined signal.