JPH08237978A - Fixed position stop controller for motor - Google Patents

Abstract

PURPOSE: To shorten the time required for stopping a plurality of motors at predetermined positions. CONSTITUTION: First motor 10 having higher flywheel effect out of two motors is stopped freely and a position detection signal θ1 , detected through a position sensor 11 and a position detector 12, is delivered through a switching contact 32A to an adder 31. The adder 31 operates the sum of a position command signal θ2 * being set by a stop position setter 23 for the second motor 20 having lower flywheel effect and the position detection siqnal θ1 to produce a position command signal θ2 ** which is then delivered to a position regulator 24. According to a control signal from the position regulator 24, the second motor 20 stops at a position shifted by a distance corresponding to the position command signal θ2 * from the stopping position of the first motor 10 corresponding to the position detection signal θ1 . When the switching contact 32A is opened, the first and second motors 10, 20 can be stopped at individual positions.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a fixed-position stop control device for an electric motor, which maintains a predetermined relative position when stopping two sets of electric motors.

[0002]

2. Description of the Related Art When processing a large work piece attached to a machine tool, the work piece is driven by the cooperative work of a plurality of electric motors, for example, two electric motors. The position must always keep a predetermined value. FIG. 3 is a situation diagram showing a case where two electric motors are operated while maintaining a predetermined relative position. Reference numeral 2 is a workpiece to be mounted on a machine tool, and 10 is a first workpiece for driving the workpiece 2. In a machine tool, it is an electric motor for driving a spindle. Reference numeral 20 is also a second electric motor for driving the workpiece 2 and is a sub-axis driving electric motor in a machine tool, but generally the capacity of the main-axis driving electric motor is larger than the capacity of the sub-axis driving electric motor. In a machine tool, both electric motors 10 and 20 drive the work piece 2 in cooperation with each other, but the synchronous operation must be performed so that the relative angle between the first electric motor 10 and the second electric motor 20 is always constant. I won't. Therefore, the first electric motor 10 is provided with a fixed position stop control device to stop the first electric motor 10 at a preset predetermined position, but the second electric motor 20 is also provided with a separate fixed position stop control device. 2 electric motor 2
If 0 is stopped at a position set by deviating from the stop position of the first electric motor 10 by a predetermined angle, the relative angles of both electric motors will always be constant due to the synchronous operation.

FIG. 4 is a circuit diagram showing a conventional example of a fixed position stop control device when the two electric motors are operated with the relative positions kept at a predetermined value. In the conventional circuit shown in FIG. 4, the first electric motor 1 includes a position sensor 11 and a position detector 12.
The stop position of 0 is detected, and the position detection signal θ ₁ is output.
On the other hand, the stop position setter 13 outputs a position command signal θ ₁ ^* that commands the position at which the first electric motor 10 should stop. The position adjuster 14 detects the position detection signal θ ₁ and the position command signal θ.
Input ₁ ^* and and output a control signal that makes the deviation between both inputs zero. The f / V converter 15 converts this control signal into a voltage command signal and supplies the voltage command signal to the inverter 16 to stop the first electric motor 10 at a predetermined position according to the output of the inverter 16.

The second motor 20 also inputs the position detection signal θ ₂ obtained by the position sensor 21 and the position detector 22 and the position command signal θ ₂ ^* set by the stop position setter 23 to the position adjuster 24. The position adjuster 24, the f / V converter 25, and the inverter 26 operate so that the second electric motor 20 stops at the position where the deviation between both inputs becomes zero. Here, the position command signal θ ₂ ^* set by the stop position setter 23 belonging to the second electric motor 20 and the stop position setter 1 belonging to the first electric motor 10 are set.
If a predetermined angle difference is provided between the position command signal θ ₁ ^* and the position command signal θ ₁ ^* , the first electric motor 10 and the second electric motor 2
0 means to stop with a predetermined relative angle maintained.

[0005]

When stopping an electric motor at a predetermined position, a series of fixed position stop control operations of "starting → braking → position control → stop" are performed on the electric motor. When performing synchronous operation with the relative angle of the two motors being constant, as in the case of the main shaft driving motor and the sub-axis driving motor, the fixed-position stop devices of the respective motors are operated separately and the predetermined position is set. Have stopped. By the way, a large-capacity electric motor has a large flywheel effect, and a load driven by the electric motor also has a large flywheel effect. Therefore, if the large-capacity electric motor and the small-capacity electric motor are simultaneously given the series of fixed-position stop control commands of start-up → braking → position control → stop, the large-capacity electric motor takes a longer time to stop at a predetermined position. . Here, when the main shaft driving electric motor and the sub shaft driving electric motor of the machine tool are taken as an example, the former generally has a larger capacity than the latter.
That is, there is a drawback in that the start-up / shutdown time becomes long and the operating rate of the machine tool is reduced.

Therefore, an object of the present invention is to reduce the time required to stop a plurality of electric motors at predetermined positions.

[0007]

In order to achieve the above-mentioned object, a fixed position stop control device for an electric motor according to the present invention comprises a position detector for detecting the electric motor position, and a stop position setter for setting the electric motor stop position. A position controller for inputting a deviation between a position detection signal output by the position detector and a position command signal output by a stop position setting device, and outputting a control signal for making the deviation amount zero; In a fixed-position stop control device for an electric motor, which comprises a control device for controlling the electric motor to stop at a predetermined stop position in accordance with a control signal output by the position detection signal output by the position detector belonging to the first electric motor. The second electric motor is provided with an adder for adding to the position command signal of the second electric motor, and the addition calculation result output by this adder and the position detection signal output by the position detector belonging to the second electric motor. The deviations shall be entered into the position regulator belonging to the second motor.

Alternatively, the position detection signal output by the position detector belonging to the first electric motor, which has a large sum of the flywheel effect of the electric motor and the flywheel effect of the load, is output by the first electric motor whose total flywheel effect is smaller than that of the first electric motor. The second electric motor is provided with an adder for adding to the position command signal of the second electric motor, and the deviation between the addition calculation result output by the second electric motor and the position detection signal output by the position detector belonging to the second electric motor. Is input to the position adjuster belonging to the second electric motor.

[0009]

According to the present invention, when the stop positions of the two electric motors are determined, if the relative positions of the two electric motors are the predetermined values, it is not necessary to strictly determine the stop positions of the individual electric motors. The stop position of the electric motor is not defined, and the second electric motor is stopped at a position deviated from the first electric motor by a predetermined angle. That is, one of the two motors
Only the stand is stopped at a predetermined position by the fixed position stop control.
If the total flywheel effect of the electric motor and its load is greater, the free stop is performed, and if the smaller total flywheel effect is used, the fixed-position stop control is performed to stop at the predetermined position. .

[0010]

FIG. 1 is a circuit diagram showing a first embodiment of the present invention. A first electric motor 1 shown in the circuit of the first embodiment of FIG.
0, second electric motor 20, position sensors 11 and 21, position detectors 12 and 22, stop position setters 13 and 23, position adjusters 14 and 24, f / V converters 15 and 25, and inverter 1
The names, applications, and functions of 6 and 26 are the same as in the case of the conventional example circuit described above with reference to FIG.

In the circuit of the first embodiment shown in FIG. 1, the second electric motor 2 is used.
The fixed position stop control device belonging to 0 is provided with an adder 31, and the fixed position stop control device belonging to the first electric motor 10 is provided with three sets of switching contacts 32A, 32B, 32 which operate simultaneously.
Provide C. The switching contacts 32B and 32C are normally closed to the position adjuster 14 to detect the position detection signal θ ₁ and the position command signal θ.
_The fixed position stop control operation is performed by giving ₁ ^* , but when controlling the relative angle of the first electric motor 10 and the second electric motor 20 at the time of stop to a predetermined value, these switching contacts 32B and 3 are used.
Since 2C is opened, the fixed-position stop control device of the first electric motor 10 does not operate and is in free stop. At this time, the switching contact 32A, which is normally open, is closed to give the position detection signal θ ₁ detected by the position detector 12 to the adder 31.

The above-mentioned switching contact 32A is connected to the adder 31.
While the position detection signal θ ₁ detected by the position detector 12 belonging to the first electric motor 10 is input via the second electric motor 2
The position command signal θ ₂ ^* set by the stop position setter 23 belonging to 0 is input. The adder 31 calculates the sum of these two values and inputs the calculated result, θ ₂ ^**, to the position adjuster 24 as a new position command signal. Thus the second electric motor 2
Only the fixed position stop control device belonging to 0 will operate.

Here, one having a larger total flywheel effect of the electric motor and the load driven by the electric motor is defined as free stop, and the smaller one is stopped by the fixed position stop control operation at a position deviated from the larger electric motor by a predetermined angle. If so, the fixed position stop control operation operation time can be shortened. FIG. 2 is a circuit diagram showing a second embodiment of the present invention, and shows a case where two electric motors always stop at a predetermined relative angle. In the circuit of the second embodiment of FIG. 2, the first electric motor 10 freely stops,
In a case where the second electric motor 20 is stopped at a predetermined relative angle from the electric motor 10, the first electric motor 10 that freely stops is not provided with a fixed position stop control device, and detection is performed by the position sensor 11 and the position detector 12. The circuit for applying the position detection signal θ ₁ to the adder 31 is permanently installed.

[0014]

According to the present invention, when two electric motors are stopped at a predetermined position, one electric motor is stopped at a free position and the other electric motor is stopped by the operation of the fixed position stop control device. The stopped electric motor is stopped at a predetermined relative angle. With such a configuration, the former electric motor with a large flywheel effect is set to free stop, and the latter electric motor is stopped at a position of a predetermined relative angle from the former by the fixed position stop control. The effect that can shorten is obtained. Further, when the two electric motors always stop at a predetermined relative angle, it is not necessary to install a fixed position stop control device on the electric motor on the free stop side.・ The effect that the price can be reduced is also obtained.

[Brief description of drawings]

FIG. 1 is a circuit diagram showing a first embodiment of the present invention.

FIG. 2 is a circuit diagram showing a second embodiment of the present invention.

FIG. 3 is a situation diagram showing a case where two electric motors are operated while maintaining a predetermined relative position.

FIG. 4 is a circuit diagram showing a conventional example of a fixed position stop control device when the relative position of two electric motors is maintained at a predetermined value for operation.

[Explanation of symbols]

 2 Workpiece 10 First electric motor 11,21 Position sensor 12,22 Position detector 13,23 Stop position setter 14,24 Position adjuster 15,25 f / V converter 16,26 Inverter 20 Second electric motor 31 Addition 32A, B, C switching contact

Claims (2)

[Claims] 1. A position detector for detecting an electric motor position, a stop position setter for setting a motor stop position, a position detection signal output by the position detector, and a position command signal output by the stop position setter. A position adjuster for inputting the deviation and outputting a control signal for making the deviation amount zero, and a control device for controlling the electric motor to stop at a predetermined stop position in accordance with the control signal output by the position adjuster are provided. In the fixed position stop control device for the electric motor, the second electric motor is provided with an adder for adding the position detection signal output from the position detector belonging to the first electric motor to the position command signal of the second electric motor. The constant of the electric motor characterized in that the deviation between the addition calculation result output by the second electric motor and the position detection signal output by the position detector belonging to the second electric motor is input to the position adjuster belonging to the second electric motor. Position stop control device. 2. A position detector for detecting an electric motor position, a stop position setter for setting a motor stop position, a position detection signal output by the position detector, and a position command signal output by the stop position setter. A position adjuster for inputting the deviation and outputting a control signal for making the deviation amount zero, and a control device for controlling the electric motor to stop at a predetermined stop position in accordance with the control signal output by the position adjuster are provided. In the fixed position stop control device for the electric motor, the total flywheel effect is the position detection signal output by the position detector belonging to the first electric motor having a large sum of the flywheel effect of the electric motor and the flywheel effect of the load. The second electric motor is provided with an adder for adding to the position command signal of the second electric motor, which is smaller than the electric motor, and the addition operation result output by the adder and the position belonging to the second electric motor A fixed position stop control device for an electric motor, characterized in that a deviation from a position detection signal output by the detector is input to a position adjuster belonging to the second electric motor.