JPS6289110A - Stop position control device for motor - Google Patents

Abstract

PURPOSE:To eliminate the need for high-priced encoder and to always stop the final shaft at the fixed position by setting a gear ratio of the motor shaft and the final shaft with a gear ratio setting device, correcting it in accordance with the gear ratio in the stop position command circuit and setting the target stop position by the output of the position detecting device. CONSTITUTION:The gear ratio of a final shaft 17 and a motor shaft is set by a gear ratio setting device 19 beforehand, the fixed position stop command is given to a stop position command circuit 16, and then, the stop position data are converted and outputted to the gear ratio fold data. The output of the stop position command circuit 16, when the presetting pulse is outputted from a sequence counter circuit 14, is loaded to a counter circuit 12. When the output of a counter circuit 12 comes to be the clamping value or below of a clamping circuit 15, the clamping circuit 15 converts the output of the counter circuit 12 to the digital analog as it does, outputs it to an inverter device 3, the speed of a motor 1 is reduced, when the value of the counter circuit 12 comes to be zero, the speed command comes to be zero and the motor is stopped at the target point.

Description

DETAILED DESCRIPTION OF THE INVENTION [Field of Industrial Application] The present invention relates to a motor stop position control device for stopping a motor that drives a main shaft of a machine tool at a fixed position.

[Conventional technology]

FIG. 2 is a block connection diagram showing a conventional motor stop position control device. In the figure, 1 is the motor, 2 is an orientation speed command circuit that commands a low fixed speed, and 3 is a speed command given from the outside. An inverter device for motor control as a speed control circuit that controls the speed of the motor 1 by voltage; 4 is a circuit that is directly connected to the shaft of the motor 1 and outputs N1 pulses in one rotation; and a circuit that outputs N1 pulses in one rotation; Encoder with two circuits that output one pulse, 5°6.7
is a switch that changes the speed given to the inverter device 3;
8 is a frequency-voltage converter (hereinafter referred to as an F/V converter) that converts the output pulses of the encoder 4 into voltage; 9 is an F/V converter;
A comparator 10 compares the output voltage of the V converter 8 with the voltage applied to the inverter device 3 and outputs a signal of 11 lbel when they match. 11 is a setting device that sets the entire entry angle from the orientation speed to the position loop; 12 is the pulse generator 1
0 is an N-bit counter circuit that counts the output pulses, 13 is a judgment circuit that compares the output data of the counter circuit 12 and the output of the setting device 11 and determines that they match, and 14 is a switch depending on the input condition. 5, 6. A sequence counter circuit that sequentially closes any one of 7 and presets the counter circuit 12, and 15 is a clamp circuit that clamps the output of the counter circuit 12 to a certain level and has a digital-to-analog conversion function. It is.

Next, the operation will be explained. When a fixed position stop command is not given from the outside, the sequence counter circuit 14 closes the switch 5, an external speed command is given to the inverter #3, and the motor 1 is driven at a speed corresponding to this speed command. rotates. At this time, from the encoder 4, as shown in FIG.
N1 phase pulses P+ and P2 are output for each rotation of the motor shaft of motor 1, and as shown in FIG. 3C, one C phase pulse P is output at a specific position during one rotation.
3 is output.

Next, when a fixed position stop command is given at the time of construction shown in FIG. 3, the sequence of the sequence counter circuit 14 is 1.
Step forward to open switch 5 and close switch 6. Then, the speed command from the orientation speed command circuit 2 is given to the inverter device 3, and the motor 1 is decelerated to the speed according to this command. Here, the comparator 9 compares the outputs of the orientation speed command circuit 2 and the F/V converter 8, and when the speed of the motor 1 matches the orientation speed command 2, it outputs a signal of 11 lb. Next, the output of comparator 9 is 11'
When the C-phase pulse P3 of the encoder 4 further rises, the sequence of the sequence counter circuit 14 advances by one step, and the counter circuit 12 is preset. At this time, the counter circuit 12 reads N-bit external stop position data and outputs this value. The pulse generator 10 generates a pulse P as shown in FIG.
4, and this output is given to the counter circuit 12, which subtracts the value of the stop position data.

The determination circuit 13 compares the output data of the counter circuit 12 and the data output from the setter 11, and if the values match, the sequence of the sequence counter circuit 14 is further advanced by one step, and the switch 6 is turned on at time point (3) in FIG.
, and close switch 7. Therefore, the inverter device 3 is supplied with the output voltage of the clamp circuit 15 which clamps the output of the counter circuit 12 at a certain value and converts it into digital-to-analog. At this time, the counter circuit 12 is subtracted by the pulse output from the encoder 4, and when the output of the counter circuit 12 becomes less than the clamp value of the clamp circuit 15, the clamp circuit 15 directly converts the output of the counter circuit 12 into a digital-analog signal. It is converted and output to the inverter device 3 for motor speed control, and the motor 1 is decelerated according to the output of the counter circuit 11.
When the value of the counter circuit 12 becomes zero, the speed command becomes zero and the motor 1 stops at the target stopping point.

[Problems that the invention is supposed to solve]

Since the conventional positioning control device is configured as described above, the encoder 4 for the speed detector, which is directly connected to the motor 1, requires a circuit that generates one pulse per rotation of the motor shaft at a specific position. 4 is expensive, and when this motor 1 is used to drive the main shaft of a machine tool, the gear ratio between the motor shaft and the main shaft that performs positioning is 1.
: If it were not 1, there would be a problem that the stop position of the spindle would shift every time it was oriented.

This invention was made to solve the above-mentioned problems, and it does not require an expensive encoder, and even if the gear ratio is other than 1:1, the final shaft such as the above-mentioned main shaft for positioning can be used. An object of the present invention is to obtain a stop position control device for a motor that can always stop the motor at a fixed position.

[Means for solving problems]

The motor stop position control device according to the present invention sets the gear ratio between the motor shaft and the final shaft of the motor using a gear ratio setter, and further multiplies the external stop position data by the set gear ratio in the stop position command circuit. By doing so, the stop position of the final shaft is calculated, and the count value of the counter circuit that counts the number of revolutions of the motor is corrected according to the above gear ratio based on the calculated output, and the target stop position is set to the final shaft side. The setting is based on the output of a position detector installed at the

[Effect]

The position detector in this invention outputs the target stop position to be positioned as a specific position during one rotation of the final axis detected by the position detector related to the final axis, the motor speed is detected by an encoder, and the motor speed is detected by an encoder. When a fixed position stop command is applied from the outside while the motor is rotating, a counter circuit counts down the number of rotations of the motor, the output of this counter circuit becomes zero, and the specific position of the final axis is detected. This acts to stop the motor at that specific position.

〔Example〕

An embodiment of the present invention will be described below with reference to the drawings. 1st
In the figure, 16 is a stop position command circuit that multiplies the stop position data by the gear ratio to determine and output the stop position of the final axis; 17;
is the final axis for which you want to perform stop positioning, and 18 is 1 of the final axis 17.
A position detector that outputs a pulse at a specific position during rotation, 19
is a gear ratio setting device consisting of a switch that sets the gear ratio between the motor shaft (rotating shaft) and the final shaft. The same blocks as those shown in FIG. 2 are designated with the same reference numerals.
The redundant explanation will be omitted.

Next, the operation will be explained. If no fixed position stop command is input, the same operation as before is performed.

At this time, encoder 4 outputs 1 as shown in FIG.
Tachometer N 1 pulse P1. P is output. Next, when a fixed position stop command is given, the sequence of the sequence counter circuit 14 advances by one step, the switch 5 is opened, and the switch 6 is closed. By this operation, an orientation speed command is given to the inverter device 3, and the motor 1 is decelerated to the speed of this command. Here, the comparator 9 compares the output of the orientation speed command circuit 2 and the output of the P/V converter 8, and when the speed of the motor 1 matches the orientation speed command, outputs a signal of %1 lebel. Next, when the rising edge of this signal and the rising edge of H/L/S is input to the sequence counter circuit 14, the sequence is started. It advances one step and outputs a preset pulse to the counter circuit 12.

On the other hand, the gear ratio between the final shaft 17 and the motor shaft is set in advance by the gear ratio setter 19, and when a fixed position stop command is given to the stop position command circuit 16, the stop position data is converted into data multiplied by the gear ratio. Convert and output. For example, if the final shaft 17 rotates once and the motor shaft rotates twice, a value obtained by doubling the stop position data given from the outside is output. Further, the output of the stop position command circuit 16 is loaded into the single force counter circuit 12 when a preset pulse is output from the sequence counter circuit 14.

When a reset pulse is given by the sequence counter circuit 14, the counter circuit 12 first outputs a value obtained by multiplying the externally given stop position data by the gear ratio. Ru. The determination circuit 13 compares the output data of the counter circuit and the data output by the setter 11, and if the values match, the sequence of the sequence counter circuit 14 is further advanced by one step, the switch 6 is opened, and the switch 7 is closed. Therefore, the inverter device 3 includes a counter circuit 1.
The output voltage of the clamp circuit 15 is provided by clamping the output of 2 at a certain value and converting it from digital to analog. At this time, the counter circuit 12 is subtracted by the pulse output from the encoder 4, and when the output of the counter circuit 12 becomes less than the clamp value of the clamp circuit 15, the clamp circuit 15 outputs the output of the counter circuit 12 as it is.
Digital-to-analog conversion and inverter device 3
The motor 1 is decelerated in accordance with the output of the counter circuit 12, and when the value of the counter circuit 12 becomes zero, the speed command becomes zero and the motor 1 stops at the target point.

〔Effect of the invention〕

As described above, according to the present invention, since the encoder for detecting the speed of the motor and the position of the axis to be positioned can be detected by a position detector such as a proximity switch, positioning can be performed with respect to the motor axis. The gear ratio with the desired shaft is 1:
Even if it is not 1, it is possible to stop at a fixed position. Furthermore, it is no longer necessary to provide a circuit for outputting one pulse per revolution at a specific position in the speed detection encoder directly connected to the motor, resulting in an inexpensive product.

[Brief explanation of drawings]

Fig. 1 is a block connection diagram showing a motor stop position control device according to an embodiment of the present invention, Fig. 2 is a block connection diagram of a conventional stop position control device, and Fig. 3 is a block connection diagram and a signal waveform diagram of each part. , FIG. 4 is a time-speed characteristic diagram of the motor. 1 is a motor, 2 is an orientation speed command circuit, 3 is an inverter device, 4 is an encoder f, 5.6.7 is a switch, 8
is an F/V converter, 9 is a comparator, 10 is a Nihals generator, 1
1 is a setting device, 12 is a counter circuit, 13 is a judgment circuit,
14 is a GX sequence counter circuit, 15 is a clamp circuit, 16 is a stop position command circuit, 17 is a final axis, 18 is a position detector, and 19 is a gear ratio setter. In addition, in the figures, the same reference numerals indicate the same or equivalent parts.

Claims (1)

[Claims] A motor that rotates based on an external speed command is decelerated to the command speed based on a fixed position stop command, and the number of rotations of this motor is subtracted from the external stop position data in a counter circuit, so that the output of this counter circuit becomes zero. In the motor stop position control device that stops the motor at the target stop position when A stop position command circuit that calculates the stop position of the final axis by multiplying the gear ratio of A motor stop position control device, characterized in that the motor stop position is corrected according to the gear ratio.