JPS59162787A - Controlling method and device for motor - Google Patents

Abstract

PURPOSE:To adjust the rotating speed of a motor accurately at a high speed by dividing a speed command value into a fixed value and adjustable variable value, and employing the sum or difference thereof. CONSTITUTION:Starting/stopping speed command value setting means, speed command value retrieving and calculating means, variable value supplying means in a speed command value with variable value adjusting means, fixed value supplying means, comparing means for comparing and outputting the speed command value from the speed command value retrieving and calculating means with the rotating speed from the rotating speed detecting means of a motor, and motor driving means for controlling the deviation to a small value on the basis of an input from the comparing means.

Description

[Detailed Description of the Invention] [Field of Application of the Invention] The present invention relates to a method for controlling an electric motor and a control device thereof, and particularly a method for adjusting the rotation speed by changing a speed command value that gives the rotation speed of the electric motor. The present invention relates to a method of controlling an electric motor and a control device thereof.

[Prior art]

In a conventional electric motor control device of this type, when adjusting the rotational speed of the electric motor, the rotational speed of the electric motor can be adjusted by making the entire speed command value that gives the rotational speed variable.

However, when the speed command value is read in by a microcomputer, if the number of bits handled is constant, if the speed command value becomes a large value, it will be difficult to maintain accuracy as an adjustment value, and if the number of bits is increased, , the time required to capture the command value increases, and if the command value is captured while the motor is rotating,
It had drawbacks such as interfering with speed control.

[Purpose of the invention]

The present invention eliminates the drawbacks of the above-mentioned conventional techniques and provides a method for controlling an electric motor, which can adjust the rotational speed of the electric motor with high precision and high speed, and a control device directly used for carrying out the method. Its purpose is to

[Summary of the invention]

A method for controlling an electric motor according to the present invention is a method for controlling an electric motor that changes a speed command value related to the rotational speed of the electric motor and controls the rotational speed of the electric motor so as to approach the speed command value. As the command value, a value related to the sum or difference between the fixed value part and the variable value part, which are divided into a fixed value part and an adjustable variable value part, is used, and the speed command value is changed by the variable value part. It was designed to be controlled.

Furthermore, the configuration of the electric motor control device according to the present invention is such that the electric motor changes a speed command value related to the rotational speed of the electric motor and controls the rotational speed detected by the rotational speed detection means of the electric motor so as to approach the speed command value. In the control device, a variable value partial supply means for a speed command value comprising a start, stop and speed command value setting means, a speed command value search and calculation means, a variable value adjustment means, and a fixed value partial supply means. , a comparison means for comparing and outputting the rotational speed from the rotational speed detection means of the electric motor and the speed command value from the speed command value search and calculation means, and control to reduce the deviation based on the input from the comparison means. and an electric motor driving means.

In addition, the present invention divides the speed command value of the electric motor into a fixed value part given by the ROM of a microcomputer and a variable value part that can be adjusted from the outside, and controls the sum or difference thereof as the speed command value. It was designed to do so.

FIG. 1 is an overall configuration diagram clearly showing the electric motor control device according to the present invention.

That is, the entire system is an electric motor control device that changes a speed command value related to the rotational speed of the electric motor and controls the rotational speed detected by the rotation detection means of the electric motor so as to approach the speed command value.

It is started by the stop/speed command setting means, and one of the speed command values related to data of several types of speed patterns is set.

Then, based on this set speed command, the speed command value search and calculation means searches the fixed value partial supply means and the variable value partial supply means, and calculates the sum of the fixed value part and the variable value part, or , perform calculations to calculate the difference between the fixed value part and the variable value part, thereby creating the speed command value,
The comparison means compares the speed command value of the motor with the rotation speed of the electric motor detected by the rotation speed detection means of the electric motor, and outputs the result to the motor drive means.

The electric motor driving means controls the rotational speed so as to approach the speed command value by controlling the electric motor to reduce the deviation based on the input.

Note that the variable value portion supply means stores the adjusted variable value from the variable value adjustment means, and the speed command value search and calculation means corresponds to the variable value portion of the speed command value based on the speed command. The above calculation is performed by selectively inputting a variable value.

[Embodiments of the invention]

DESCRIPTION OF THE PREFERRED EMBODIMENTS An embodiment of a method for controlling an electric motor according to the present invention, together with an embodiment of a control device thereof, will be described with reference to the drawings.

First, FIG. 2 is a schematic diagram of an electric sewing machine controlled by an embodiment of the present invention.

That is, the power of the electric motor 1 is transmitted to the pulley 3. The electric motor 1 is transmitted to the sewing machine 5 via the belt 2, and the electric motor 1 is controlled by operating a foot pedal 9 and a setting switch 8A provided on the controller 8, and the sewing machine rotation speed at that time is as follows. This is the output from the speed generator 4 connected to the main shaft of the sewing machine 5.

Therefore, during manual sewing, the foot pedal 9 generates a speed command value according to the amount of pedal depression, and during automatic sewing, the foot pedal 9 generates commands to start and end sewing of the sewing pattern given by the setting switch 8A. In this case, the sewing machine 5 starts when the foot pedal 9 is depressed, and stops in the neutral position.

The setting switch 8A described above has the following two functions.

(1) Selection of automatic sewing 2 manual sewing.

Selection of several automatic sewing patterns.

Here, the sewing speed data is called a speed command value, which is created by calculation with a fixed value part stored in ROM and a variable value part stored in RAM, which will be described later.

Next, FIG. 3 is a control circuit diagram of a motor control device according to an embodiment of the present invention, and FIG. 4 is a flowchart of variable value adjustment in a motor control method according to an embodiment of the present invention. FIG. 5 is a block diagram of a delay circuit according to an embodiment of the control device, and FIG. 6 is a timing chart.

The speed generator 4 serves as a rotation speed detection means for the electric motor 1, the setting switch 8A, and the pedal switch 9 serve as start, stop, and speed command setting means, and the CR circuit (1) 10...
+1)12. Comparator (1) 13...(n) 15
corresponds to a variable value adjustment means, the motor drive circuit 16 corresponds to a motor drive means, 17 is a microcomputer, the controller (CPU) 8 is a speed command value search and calculation means, a comparison means, R,0M18
corresponds to fixed value partial supply means, and RAM 19 corresponds to variable value partial supply means.

P1 to PIn are input ports of the controller 8, and PO is an output port of the step signal.

Further, in FIG. 4, C+-C represents the calculated value of the delay time counter in the RAM 19 mentioned above.

In the above configuration, when a speed command is inputted to the controller 8 of the microcomputer 17 by a command from the pedal switch 9 and the setting switch 8A, the microcomputer 17 inputs the speed command value corresponding to the command and the speed generator. The electric motor 1 is controlled so that the output becomes close to that of the motor 4.

Here, the first value as the fixed value part of the speed command value is
It is stored in the ROM 18, and the second
The value is stored in RA, M19 by the procedure shown in FIG.

First, a step signal is output from the output port PO of the controller 8.

This step signal is generated by a variable delay time CR circuit (1).
10 to (n) 12, and after a predetermined time has elapsed, the waveform is shaped by the comparators (1) 13 to (n) 15, and the input port P■ of the controller 8 is input.
1-P1. This is what is entered in the .

Then, the controller 8 calculates the delay time from when the output port PO outputs the step signal to when the step signal is input to the input ports PII to PI by setting the counter in the RAM 19 to 1.
It is measured and memorized by increasing the value in increments.

The delay time measured by the method described above becomes the second value described above as the variable value portion of the speed command value.

Therefore, the sum or difference between the above-mentioned first value and this second value becomes the speed command value subjected to predetermined adjustment.

That is, the second value is added to the first value, or the fixed value portion is maximized and the second value is subtracted from it.

FIG. 5 shows an example of the configuration of the delay circuit section, each of which has a capacitor. FIG. 6 is a timing chart showing the operation of the delay circuit section (a).
) to (d) correspond to (a) to (d) in FIG.

That is, when a step signal as shown in FIG. 6(a) is output from the output port PO of the controller 8 in the microcomputer 17, the potential of the capacitor Cd+ becomes -.

gradually increases as shown in Figure 6 (1b), and the potential ■. is the threshold voltage V of comparator (1) 13
When the voltage exceeds th, a signal appears at the input port P11 of the controller 8 as shown in FIG. 6(C).

The signal shown is input. The delay time during this time is 1 as shown in the figure.
．． becomes.

Similarly, the signal shown in FIG. 6(e) is input to the input port PI2, and the delay time during this time is t2 as shown in the figure.

Note that the same effect can be achieved even if the above-mentioned charging circuit is used as a discharging circuit.

As described above, according to this embodiment, the speed command value is the sum or difference between the first value as the fixed value part and the second value as the variable value part. When importing the command value, it is only necessary to import the second value, that is, the adjustment amount, which greatly reduces the time spent importing the speed command value. Even if the speed command value is imported while the sewing machine is running, the speed It does not interfere with control.

Unfortunately, due to the structure of the microcomputer, the size of data that it can handle is limited to 4 to 8 bits, that is, 15 to 255, but this can be used only for the second value as the variable value part. However, the effect of improving the accuracy of the speed command value can be expected.

Furthermore, the delay circuit section of the device can be configured with a very simple circuit consisting of one capacitor, one variable resistor, and one comparator for each channel, which has an advantageous effect in terms of productivity. It is.

Next, FIG. 7 is a flowchart of variable value adjustment in a control method according to another embodiment.

That is, this embodiment relates to a case where the speed command value is taken in when the sewing machine is stopped.

As the number of types of speed command values to be retrieved increases, the time required to retrieve the speed command values cannot be ignored, and if high accuracy of the rotational speed is required, such as during automatic thread trimming, it may become a problem to control the rotational speed. This embodiment can deal with this problem.

As shown in FIG. 7, first, at the start of speed command value capture, it is determined that the pedal switch 9 is off and the sewing machine 5 is in a stopped state.

The speed command value is not taken in when the sewing machine is rotating, and the speed command value is taken in only when the sewing machine is stopped.

In other words, once the pedal switch 9 is turned off to stop the sewing machine 5, and then the pedal switch 9 is turned on to rotate the sewing machine 5, the controller 8 controls the speed using the adjusted speed command value. .

The above control procedure makes it possible to adjust the rotational speed of the sewing machine without hindrance to speed control even if the types of speed command values increase.

Although the embodiments described above relate to the control of an electric motor in an electric sewing machine, the present invention is not limited to such electric motors, but can broadly be applied to a speed command value that gives the rotational speed of the electric motor. This can be effectively used to control an electric motor in which the rotational speed is adjusted by making the rotation speed variable.

〔Effect of the invention〕

According to the present invention, it is possible to provide a method for controlling an electric motor and a control device therefor, which make it possible to adjust the rotational speed of an electric motor with high precision and high speed. be able to.

[Brief explanation of the drawing]

FIG. 1 is an overall configuration diagram of an electric motor control device according to the present invention, FIG. 2 is a schematic configuration diagram of an electric sewing machine controlled by an electric sewing machine according to an embodiment of the present invention, and FIG. FIG. 4 is a control circuit diagram of a control device for an electric motor according to an embodiment of the present invention.
FIG. 5 is a flowchart of variable value adjustment in a motor control method according to an embodiment of the present invention; FIG. 5 is a delay circuit block diagram according to an embodiment of the control device; FIG. 6 is a timing chart diagram; The figure is a flowchart of a control method according to another embodiment. DESCRIPTION OF SYMBOLS 1... Electric motor, 4... Speed generator, 8... Controller, 8A... Setting switch, 9... Pedal switch, 10~l2-CR circuit (1)~(n), 13~
15... Comparators (1) to (n), 16... Motor drive circuit, 17... Microcomputer, 18
...RAM. 19...RAM, PO...output port, P11~P
1. ...Input port, Rt "l'L-...Variable resistor, Cd+~Cd,... Capacitor. Agent: Patent attorney Kosaku Fukuda (and one other person) 1・"'1 Second, Fig. 3 Figure 4 Figure 5 Figure 8\ Figure 6

Claims (1)

[Claims] 1. In a method of controlling an electric motor, the speed command for the rotational speed of the electric motor is changed so that the rotational speed of the electric motor approaches the speed command value by changing the speed command value related to the rotational speed of the electric motor. As a value, a value related to the sum or difference between the fixed value part and the variable value part, which are divided into a fixed value part and an adjustable variable value part, is used, and the speed command value is changed by the variable value part for control. A method for controlling an electric motor, characterized in that: 2. A method for controlling an electric motor according to claim 1, wherein the speed command value is changed by the variable value portion while the electric motor is rotating. 3. A method for controlling an electric motor according to claim 1, wherein the speed command value is changed by the variable value portion while the electric motor is stopped. 4. Start, stop, and speed command settings in an electric motor control device that changes the speed command value related to the rotational speed of the electric motor and controls the rotational speed detected by the motor rotational speed detection means so as to approach the speed command value. means, a speed command value search and calculation means, a variable value partial supply means for the speed command value having a variable value adjustment means, a fixed value partial supply means, a rotation speed from the rotation speed detection means of the electric motor, and the above. An electric motor comprising a comparison means for comparing and outputting a speed command value from a speed command value search and calculation means, and a motor drive means for controlling to reduce a deviation based on input from the comparison means. control device. 5. In the device described in claim 4, the variable value adjusting means is a step signal delaying means, and the step signal delaying means is constituted by a charging circuit or a discharging circuit including a capacitor and a variable resistor, and a comparator, The adjustable variable value portion in the variable value portion supplying means is configured such that its charging time or discharging time is varied by the variable resistor, and the time is obtained by counting the time using a counter. A control device for an electric motor.