JPH0723582A - Motor control circuit - Google Patents

Abstract

PURPOSE:To obtain a motor control circuit which easily realizes an inexpensive device for driving more than one shaft of motor smoothly at a constant speed. CONSTITUTION:When two shafts of master and slave motors 16a 16b are driven simultaneously at same set speed Vs, the feedback speed control circuit for the slave motor 16b is provided with subtractors 20, 21 for feeding back the rotational speed signal of the master motor 16a.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a motor control circuit for synchronously driving a motor having two or more axes and a plurality of axes at the same rotational speed.

[0002]

2. Description of the Related Art FIG. 4 shows an example of a uniaxial motor control circuit. FIG. 4A is a circuit diagram thereof, and FIGS. 4B and 4C are waveform diagrams of an adder output and a motor speed. Is shown. In the figure, 11 is a subtractor for obtaining the difference between the speed set value Vs and the rotation speed of the motor detected by a tacho-generator described later, 12 is an adder for adding the output of the subtractor 11 and the speed set value Vs, 15 is the output V of the adder 12
driver for driving a motor based on s', 16
Is a motor, and 17 is a tacho-generator that is directly connected to the motor 16 and detects the rotation speed thereof, and together with the subtractor 11 and the adder 12, constitutes a feedback circuit for controlling the rotation speed of the motor 16.

Further, FIG. 5 shows a biaxial drive mechanism for vertically moving a driven body mounted on a support frame by synchronously driving two motors at the same rotation speed.
That is, the ball screw 31 that is rotated by the two motors 16a and 16b via the gear boxes 30a and 30b.
The support base 32 is attached to a and 31b, and the support base 3
The driven body 33 attached to the No. 2 is moved up and down. The motors 16a and 16b are provided with the motor control circuits shown in FIG. 4, respectively, and are driven synchronously at the same rotation speed. . In FIG. 5, 1
Reference numerals 7a and 17b are tacho-generators similar to those shown in FIG.

Next, the operation of the configuration according to FIG. 4 will be described. The speed set value Vs is input to the driver 15 through the subtractor 11 and the adder 12, and the driver 15 drives the motor 16
To rotate. When the motor 16 rotates, a signal proportional to the rotation speed is generated from the tacho generator 17 directly connected to the motor 16 and input to the input of the subtractor 11,
As shown in FIGS. 4B and 4C, the input signal of the driver 15 gradually decreases from 2Vs at the start of driving, and becomes constant when the rotation speed of the motor 16 becomes equal to the speed setting value Vs.

If, for some reason, the rotation speed of the motor 16 becomes faster than the speed setting value Vs, the subtracter 1
The output of 1 becomes a negative value, and the input signal V of the driver 15
Since s'is smaller than the speed setting value Vs, the motor 1
6 is to be decelerated, and returns to the speed setting value Vs. On the contrary, when the rotation speed of the motor 16 becomes faster than the speed setting value Vs, the output of the subtractor 11 becomes a positive value and the input signal Vs ′ of the driver 15 becomes larger than the speed setting value Vs. 16 is to be accelerated and returns to the speed set value Vs.

Here, even if there are a plurality of motors 16 as shown in FIG. 5, the speed is independently controlled by the configuration shown in FIG. The rotation is controlled at the same speed.

[0007]

In the conventional motor control circuit, since each motor 16 is independently controlled as described above, even if the motors 16 having two or more axes are simultaneously driven at the same rotation speed, all the motors 16 are controlled. Since the loads of the motors 16 are not exactly the same, fluctuations in the rotation speed occur due to load imbalance, mechanical system variations, and the like.

Since the speed fluctuation is feedback-controlled, it immediately stops after a delay of the response time of the control system, but the speed fluctuations of the respective motors are independent of each other, and as a result, the respective motors are dispersed. Will move to. In a drive mechanism in which motors of two or more axes must always move at the same rotation speed, such speed fluctuation is a problem, and in order to prevent the drive mechanism from being affected by speed fluctuation, , Considerable measures are needed.

The present invention has been made to solve the above problems, and an object thereof is to obtain a motor control circuit that can always drive a plurality of motors having two or more axes at the same rotational speed. .

[0010]

A motor control circuit according to a first aspect of the present invention sets one motor as positive when driving motors of two or more axes based on the same speed set value, and With the motor as a subordinate, a synchronization means for inputting a positive motor rotational speed signal to a feedback circuit for controlling the subordinate motor rotational speed to synchronize the subordinate motor rotational speed with the positive motor rotational speed is provided. It is a thing.

The motor control circuit according to claim 2 is
When driving motors of two or more axes based on the same speed setting value, one motor is positive and the other motor is slave, and the positive motor rotation speed is fed to the feedback circuit of the rotation speed control of the slave motor. A synchronizing means for inputting a signal to synchronize the rotation speed of the subordinate motor with the rotation speed of the positive motor, and the rotation speed control of the subordinate motor when the speed difference between the positive and subordinate motors is smaller than a set value. And a dead zone circuit for blocking the input of a positive motor rotation speed signal to the feedback circuit.

[0012]

In the motor control circuit according to the first aspect of the present invention, when two or more axes of motors are simultaneously driven at the same rotation speed, one motor is positive and the other motors are secondary, and the secondary motors are secondary. When the rotation speed of the slave motor is faster than the rotation speed of the positive motor by inputting the rotation speed signal of the positive motor to the feedback circuit of the rotation speed control of the slave motor to control the rotation speed of Reduces the rotation speed of the slave motor, and conversely, when the rotation speed of the slave motor becomes slower than the rotation speed of the positive motor, accelerates the rotation speed of the slave motor to reduce the rotation speed of the slave motor. The rotation speed is synchronized with the rotation speed of the positive motor.

Further, in the motor control circuit according to the second aspect of the present invention, a dead band near the set speed is provided in the feedback circuit for controlling the rotation speed of each motor so that the fluctuation range is small with respect to the set speed. By not correcting the speed, the motor rotates on the contrary without changing the speed, so that smooth movement can be obtained.

[0014]

EXAMPLES Example 1. The first embodiment of the present invention will be described below. FIG. 1 is a configuration diagram of a motor control circuit according to the first embodiment. This motor control circuit is used when driving two or more motors simultaneously at the same rotation speed.
One motor is positive and the other motor is slave, and by inputting the rotation speed signal of the positive motor to the feedback circuit of the rotation speed control of the slave motor to control the rotation speed of the slave motor, It is intended to control the rotation speed of the motor.

In the figure, the positive first motor has the same numeral as the numeral shown in FIG. 4 followed by the letter a, and the subordinate second motor has the same structure. , A code in which the letter b is added after the number shown in FIG.

In the figure, 11a and 11b are the first speed setting values Vs and the first values detected by the tachogenerators 17a and 17b.
And subtracters 12a and 12b for obtaining the difference between the rotational speeds of the second motors 16a and 16b, respectively.
adder for adding the output of b and the speed setting value Vs respectively, and 15a, 15b for motors 16a, 16b, respectively.
For driving the motor, 16a and 16b are motors,
Reference numerals 17a and 17b are tacho-generators that are directly connected to the motors 16a and 16b and detect the rotation speeds thereof, respectively.
Is a subtracter for obtaining the difference between the rotation speeds of the first and second motors detected by the tacho generators 17a and 17b, and 21 is a subtractor for obtaining the difference between the output Vsb 'of the adder 12 and the subtractor 20. , Its output becomes a speed command to the driver 15b which drives the second motor 16b.

That is, the configuration of FIG.
6a is a positive motor, and the second motor 16b is a subordinate motor, the control circuit of the first motor 16a is the same as the conventional control circuit, but the control circuit of the second motor 16b is 17b and subtractor 11 and adder 1
The speed control feedback circuit consisting of 2b is connected to the motor 1
Subtractor 20 that takes the difference between the rotation speed signal of the motor 2 and the rotation speed signal of the motor 2, and subtraction that takes the difference between the output signal of the subtractor 20 and the output Vsb 'of the adder 12b that is the speed control signal of the motor 2. Vessel 21 is newly added.

Next, the operation of the first embodiment having the above configuration will be described. First motor 16a and second motor 16
When the speeds of b are the same, the output of the subtractor 20 becomes zero, so the output of the subtractor 21 is the output Vsb ′ of the adder 12b.
(At this time, Vsb '= Vs) comes out as it is. Therefore, the rotation speed of the second motor 16b is the speed setting value V
It remains as it is.

Now, for some reason, the second motor 16b
, The output signal of the subtractor 20 has a positive value, the output of the subtractor 21 subtracts the value of the subtractor 20 from the output signal of the adder 12b. It will be a good thing. That is, since the rotation speed command value for the second motor 16b becomes smaller than the original speed command value, the second motor 16b decelerates.

The speed of the second motor 16b is the first
When the speed becomes equal to the speed of the motor 16a, the second motor 16b continues to rotate at the speed command value of the second motor 16b. On the contrary, when the speed of the second motor 16b becomes slower than the speed of the first motor 16a, the output signal of the subtractor 20 has a negative value, and therefore the output of the subtractor 21 is
It is the output signal of 2b minus the value of the subtractor 20. That is, since the rotation speed command value for the second motor 16b becomes larger than the original speed command value, the second motor 16b accelerates. Then, the speed of the second motor 16b becomes equal to the speed of the first motor 16a.

Although the first embodiment describes the control circuit for a biaxial motor, it goes without saying that it can be applied to a control circuit for a multiaxial motor.

Therefore, according to the first embodiment, when the two motors 16a, 16 are simultaneously driven at the same rotational speed, one motor 16a is positive, the other motor 16b is subordinate, and the subordinate motor 16b is subordinate. To control the rotation speed of
By inputting the rotation speed signal of the positive motor 16a to the feedback circuit of the rotation speed control of the slave motor 16b, the rotation speed of the slave motor 16b is positive.
If the rotation speed of the slave motor 16b is slower than that of the positive motor 16a, the rotation speed of the slave motor 16b is reduced. The rotational speed of the subordinate motor 16b is increased by increasing the rotational speed of the positive motor 16a.
Can be synchronized with the rotation speed of.

Example 2. Next, FIG. 2 is a configuration diagram according to a second embodiment of the present invention. The second embodiment is the same as the first embodiment.
However, while the rotational speed signal of the positive motor 16a is fed back only to the subordinate motor 16b, the positive motor 16a
Similarly, the rotation speed signal of the corresponding motor 16b is fed back to a. When the motor has only two axes, the rotation speed signals of the mutual motors are fed to the feedback circuit for controlling the rotation speed of each motor. By inputting, it is intended to mutually control the rotation speeds of the motors.

In FIG. 2, reference numerals 20a and 20b denote subtractors 2 and 1 for the first and second motors 16a and 16b, respectively.
1a and 21b are the first and second motors 16 respectively.
The subtractor for a and 16b is similar to the feedback circuit for speed control of the second motor 16b in the configuration of FIG.
A subtractor 20a for taking the difference between the rotation speed signal of the first motor 16a and the rotation speed signal of the second motor 16b is provided in a feedback circuit for speed control of the first motor 16a, and an output signal of the subtractor 20a. And a subtracter 21a for taking the difference between the speed control signal of the first motor 16a and the speed control signal of the first motor 16a are newly added. By inputting, the mutual rotation speeds of the motors are controlled. Others are the same as in FIG.

Next, the operation of the second embodiment having the above configuration will be described. First motor 16a and second motor 16
When the speeds of b are equal, the output of the subtractor 20a becomes zero, so the output of the subtractor 21a is the output V of the adder 12a.
sa 'comes out as it is. Therefore, the first motor 1
The rotation speed of 6a remains the speed setting value Vs.

Now, for some reason, the second motor 16b
, The output signal of the subtractor 20a becomes a negative value, the output of the subtractor 21a is the output signal of the adder 12a from the subtractor 2a.
The value of 0a is subtracted. That is, since the rotation speed command value for the first motor 16a becomes larger than the original speed command value, the first motor 16a accelerates. Then, the speed of the second motor 16b is equal to that of the first motor 16a.
When the speed becomes equal to, the first motor 16a continues to rotate again with the speed command value of the first motor 16a.

On the contrary, when the speed of the second motor 16b becomes slower than the speed of the first motor 16a, the subtracter 20
Since the output signal of a has a positive value, the output of the subtractor 21a is the output signal of the adder 12a minus the value of the subtractor 20a. That is, since the rotation speed command value for the second motor 16b becomes smaller than the original speed command value, the first motor 16a decelerates. Then, the speed of the second motor 16b becomes equal to the speed of the first motor 16a.

The operation of the second motor 16b is the same as that described above, and the second motor 16b is operated.
Becomes slower than the first motor 16a, the first motor 16a accelerates and the second motor 16b decelerates to equalize the speeds. The second motor 16b is the first motor 16
When it becomes faster than a, the first motor 16a decelerates and the second motor 16b accelerates to equalize the speeds.

Therefore, according to the second embodiment, when the motors have only two axes, the mutual rotation speed signals of the motors are input to the feedback circuit for controlling the rotation speeds of the respective motors. Further, it is possible to synchronize with the rotation speed of the other motor, and it is possible to simultaneously drive the two-axis motors at the same rotation speed.

Example 3. Next, FIG. 3 is a configuration diagram according to a third embodiment of the present invention. In the third embodiment, the first motor 16a and the second motor 16 are the same as those in the first and second embodiments described above.
If there is a slight difference in speed of b, the control circuit works to correct it, whereas if the feedback loop gain of the control circuit is high, the rotation speed of the motor to which speed correction is applied is hunting. Because there is a possibility that
In order to prevent this, if the fluctuation of the speed is slight, it is left as it is, and the speed is corrected only when the fluctuation is large.

That is, in the configuration shown in FIG. 3, the absolute value detector 2 for detecting the absolute value of the output of the subtracter 20 for obtaining the difference between the speeds of the first and second motors is different from the configuration of FIG.
2, a comparator 23 that compares the absolute value of the speed difference with the dead zone set value, and operates based on the output of the comparator 23 to control the output of the subtractor 20 to the subtractor 21. A switching means 24 is added so that when the speed difference between the positive motor and the slave motor is smaller than a set value, the positive motor rotation speed signal to the feedback circuit for controlling the rotation speed control of the slave motor is added. It forms a dead zone circuit that blocks input. The switching means 24 is an analog switch or a gate circuit.

Next, the operation of the third embodiment having the above configuration will be described. In the third embodiment, similar to the first embodiment, the rotation speed of the subordinate motor 16b is set to the positive motor 1.
It can be synchronized with the rotation speed of 6a. That is,
When the speeds of the first motor 16a and the second motor 16b are substantially equal to each other and the output of the subtractor 20 is smaller than the dead zone set value, the output from the comparator 23 turns off the switching means 24 and the subtractor 21 outputs Output is adder 12b
Output Vsb '(at this time, Vsb' = Vs) is directly output. Therefore, the rotation speed of the second motor 16b remains the speed setting value Vs, and speed correction is not performed.

Now, for some reason, the second motor 16b
When the speed difference between the speed of the first motor 16a and the speed of the first motor 16a becomes larger than the dead zone set value, the absolute value of the output of the subtractor 20 becomes larger than the dead zone set value, and accordingly the output of the comparator 23 is determined. Since the switching means 24 is connected and the output of the subtractor 20 is sent to the subtractor 21, the subtractor 21 drives the speed signal of the value obtained by subtracting the value of the subtractor 20 from the output signal of the adder 12b. 15b, and the speed of the second motor 16b is corrected.

In this case, when the speed of the second motor 16b is faster than the speed of the first motor 16a, the output signal of the subtractor 20 changes from zero to a positive value, so that the switching means 24 is connected. As a result, the output of the subtractor 21 becomes the output signal of the adder 12b minus the value of the subtractor 20. That is, since the rotation speed command value for the second motor 16b becomes smaller than the original speed command value, the second motor 16b decelerates.

On the contrary, when the speed of the second motor 16b becomes slower than the speed of the first motor 16a, the subtracter 20
Since the output signal of is a negative value, the switching means 24
Is connected, the output of the subtractor 21 becomes the output signal of the adder 12b minus the value of the subtractor 20. That is, since the rotation speed command value for the second motor 16b becomes larger than the original speed command value, the second motor 16b accelerates. Then, the speed of the second motor 16b becomes equal to the speed of the first motor 16a.

As described above, when there is a difference in speed between the first motor 16a and the second motor 16b, the output of the subtractor 20 changes from zero to a positive or negative value. Only the absolute value is taken out and compared with the dead zone set value by the comparator 23. When the speed difference is smaller than the dead zone set value, the switching means 24 is turned off, and the second motor based on the rotation speed signal of the first motor 16a. The speed correction of 16b is not performed, and the switching means 24 is connected only when the speed difference becomes larger than the dead zone set value, and the speed correction is performed.

Therefore, according to the third embodiment, by providing the dead band in the vicinity of the set speed in the feedback circuit for controlling the rotation speed of each motor, the speed correction is performed when the fluctuation width is small with respect to the set speed. By avoiding this, the motor rotates on the contrary without changing the speed, so that smooth movement can be obtained.

[0038]

As described above, according to claim 1 of the present invention, when two or more axes of motors are driven based on the same speed set value, one motor is set to be positive and the other motors are set to be positive. As a slave, since a rotation speed signal of the positive motor is input to the feedback circuit for controlling the rotation speed of the slave motor, a synchronization unit for synchronizing the rotation speed of the slave motor with the rotation speed of the positive motor is provided. When the rotation speed of the slave motor becomes faster than the rotation speed of the positive motor, the rotation speed of the slave motor is reduced, and conversely, the rotation speed of the slave motor becomes slower than the rotation speed of the positive motor. In this case, the rotational speed of the secondary motor can be synchronized with the rotational speed of the positive motor by accelerating the rotational speed of the secondary motor, and it is necessary to drive two or more axes of motors simultaneously at the same speed and smoothly. Device with , There is an effect that can be produced easily and inexpensively.

According to the second aspect of the invention, when two or more axes of motors are driven based on the same speed setting value, one motor is set to be positive and the other motor is set to be slave, and the slave motor is rotated. Inputting the rotation speed signal of the positive motor to the speed control feedback circuit to synchronize the rotation speed of the subordinate motor with the rotation speed of the positive motor, and the speed difference between the positive and subordinate motors is the set value. When it is smaller, the dead band circuit for blocking the input of the positive motor rotation speed signal to the feedback circuit for controlling the rotation speed of the subordinate motor is provided. By not performing the correction, the motor rotates on the contrary without changing the speed, so that it is possible to obtain the smooth motion.

[Brief description of drawings]

FIG. 1 is a circuit diagram of a motor control circuit according to a first embodiment of the present invention, in which a rotation speed signal of a positive motor is given to a feedback circuit for rotation speed control of a slave motor.

FIG. 2 is a circuit diagram of a motor control circuit according to a second embodiment of the present invention, in which rotation speed signals of two-axis motors are given to a feedback circuit for rotation speed control of a counterpart motor. .

FIG. 3 relates to a second embodiment of the present invention, in which a dead zone of speed change is provided in a motor control circuit for giving a positive motor rotation speed signal to a feedback circuit for controlling the rotation speed of a secondary motor. It is a circuit of the motor control circuit.

FIG. 4 is a circuit of a conventional motor control circuit.

FIG. 5 is a configuration diagram showing a biaxial drive mechanism that vertically drives a driven body attached to a support frame by driving two motors synchronously at the same rotation speed.

[Explanation of symbols]

 11a Subtractor 11b Subtractor 12a Adder 12b Adder 13 Subtractor for the first motor 16a 14 Subtractor for the first motor 16a 15a Driver 15b Driver 16a First motor 16b Second motor 17a Tachometer 17b Tachometer 20 Subtractor 20a Subtractor 20b Subtractor 21 Subtractor 21a Subtractor 21b Subtractor 22 Absolute value detector 23 Comparator 24 Switching means

Claims (2)

[Claims] 1. When driving two or more axes of motors based on the same speed set value, one motor is positive and the other motor is secondary, and a feedback circuit for controlling the rotation speed of the secondary motor is positive. Input the rotation speed signal of the motor of
A motor control circuit comprising a synchronizing means for synchronizing the rotation speed of a subordinate motor with the rotation speed of a positive motor. 2. When driving motors of two or more axes based on the same speed set value, one motor is positive and the other motor is slave, and a feedback circuit for controlling the rotational speed of the slave motor is positive. Input the rotation speed signal of the motor of
Synchronizing means for synchronizing the rotation speed of the slave motor with the rotation speed of the positive motor, and a positive means for the feedback circuit of the rotation speed control of the slave motor when the speed difference between the positive and slave motors is smaller than a set value. A motor control circuit including a dead zone circuit that blocks input of a motor rotation speed signal.