JPH0779589A - Electric motor controller - Google Patents

Abstract

(57) [Abstract] [Purpose] To provide an inexpensive motor control device capable of synchronously operating a plurality of control devices. A motor control device 13 is mounted directly on a rotary shaft of a direct drive motor 14 and controls a rotational speed of the rotary shaft according to outputs of angle detection resolvers 11 and 12 for detecting a rotation angle of the rotary shaft. A control device of a motor for controlling, wherein an R / D converter 16 for converting the angle output of the angle detection resolvers 11 and 12 into a digital signal, and an absolute angular position of a rotary shaft based on an output of the R / D converter 16 are set to a predetermined value. It has an angle calculation program 27 for calculating 8-bit digital data for each sampling time, and a position output circuit 24 for transmitting the 8-bit digital data calculated by the angle calculation program 27 to an external device.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a control device for an electric motor such as a direct drive motor used in a manufacturing apparatus or the like. In addition, the present invention relates to a motor control device that outputs a synchronization signal to the external control device with the rotational position of the motor.

[0002]

2. Description of the Related Art Conventionally, in a manufacturing apparatus such as an automatic assembling machine and an automatic packaging machine, a main motor is driven to rotate a main shaft, and a main gear is directly connected to the main shaft via gears, cams, etc. Synchronization was being done.
Here, as the main motor, a servo motor or the like has been used to control the speed of the entire manufacturing apparatus.
A rotation position detector such as a resolver was attached to the servo motor in order to control the rotation speed of the servo motor. On the other hand, generally, a rotary position detector such as a rotary encoder or a resolver is attached to the main shaft, and synchronization timing is set by its output. But,
According to this method, a rotational position detector such as a resolver is required in addition to the resolver attached for controlling the speed of the main motor, resulting in an increase in cost. Further, attaching a resolver or the like to the main shaft is a problem because it makes the entire apparatus large.

As a means for solving the problem, Japanese Unexamined Patent Publication No. Sho.
Japanese Patent No. 249733 describes a method of controlling an injection molding machine by the output of an absolute value pulse encoder mounted for speed control of a servo motor. In the present invention, the output pulse of the pulse encoder is read by the counter and the CPU to control the injection molding machine.

[0004]

However, the above-mentioned prior art has the following problems. That is, since a manufacturing apparatus such as an automatic assembly machine has complicated operations and the like, it is often composed of several units, and each unit is often controlled by a separate controller. Here, a control device such as a sequencer used in an automatic assembly machine or the like operates by a simple on / off input, and cannot read the output of a pulse encoder or the like output at a high cycle. It is also possible to build a sequencer that can read the output of a pulse encoder etc. by mounting a microcomputer etc.,
This is costly and unrealistic. Therefore, in the control of the automatic assembly machine or the like, there is a problem that the output pulse of the pulse encoder for controlling the rotation speed of the servo motor cannot be used in the control device such as the sequencer.

SUMMARY OF THE INVENTION It is an object of the present invention to solve the above problems and to provide an inexpensive motor control device capable of synchronously operating a plurality of control devices.

[0006]

In order to achieve this object, the control device for an electric motor of the present invention includes an angle detector mounted directly on the rotary shaft of the electric motor to detect the rotation angle and position of the rotary shaft. A controller for an electric motor that controls the rotation speed of the rotating shaft according to the output, the R / D converter converting the angle output of the angle detector into a digital form, and the rotating shaft of the rotating shaft based on the output of the R / D converter. It has an angle calculation means for calculating the absolute angular position as digital data of predetermined bits at predetermined sampling times, and an output circuit for transmitting the digital data of predetermined bits calculated by the angle calculation means to an external device. There is. In the motor control device of the present invention, in the motor control device, the angle calculation means has two or more output formats, and one of the two or more output formats of the angle calculation means is selected. It has an output format selection means.

[0007]

The angle detector of the electric motor of the present invention having the above-mentioned structure is directly attached to the rotary shaft of the electric motor to detect the rotation angle of the rotary shaft. Then, the control device for the electric motor controls the rotation speed and the position of the rotation shaft according to the output of the angle detector. The R / D converter also digitally converts the angle output of the angle detector. Also, the angle calculation means,
Based on the output of the R / D converter, the absolute angular position of the rotary shaft is calculated as digital data of predetermined bits at predetermined sampling times. The output circuit also transmits the predetermined bit of digital data calculated by the angle calculation means to an external device. Further, the angle calculation means has two or more output formats, and the user selects one of the two or more output formats of the angle calculation means by the output format selection means.

[0008]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS A motor control device according to an embodiment of the present invention will be described in detail below with reference to the drawings. FIG. 1 is a block diagram showing the overall configuration of the motor control device. An inverter circuit 17 which is a drive circuit is connected to the direct drive motor 14 by three power lines. The output shaft of the direct drive motor 14 is connected to a one-rotation detection resolver 11 and a multi-pole detection resolver 12, which are encoders for detecting the rotation angle of the direct drive motor 14. A changeover switch 15 is connected to the one-rotation detection resolver 11 and the multi-pole detection resolver 12. Further, the changeover switch 15 is connected to an R / D converter 16 which samples the output of the one-rotation detection resolver 11 or the multi-pole detection resolver 12 at a constant interval and converts it into a digital amount. The R / D converter 16 is
It is connected to the CPU 20 via the I / O circuit 25.

The inverter circuit 17 is connected via an I / O circuit 25 to a CPU 20 which controls the entire system. The internal configuration of the inverter circuit 17 includes a rectifier circuit that converts an AC voltage supplied from the main power supply into a DC voltage, a base drive control circuit that receives a command from the CPU 20 and controls a current value supplied to the direct drive motor 14, and a base drive. It is composed of an inverter that converts a direct current into an alternating current according to a command from the control circuit. The CPU 20 has
RO that stores the I / O circuit 25, control program, etc.
M21, RAM2 for temporarily storing detected data and the like
2 and the communication port 23 are connected. Also, CP
A position detection circuit 24 for outputting a synchronization timing or the like at every predetermined sampling time is connected to U20. An external device such as a handy terminal or a computer 26 is connected to the communication port 23. The ROM 21 also stores an angle calculation program 27.

Next, the operation of the motor controller having the above structure will be described. It is generally known that the output accuracy of a resolver is not very high due to variations such as coil winding. The applicant of the present application has proposed a method in which the single-revolution detection resolver 11 and the multipole detection resolver 12 are used in combination in order to improve the output accuracy of the resolver.
No. 25161 proposed. The same method is used in the motor control device of this embodiment, but a detailed description thereof will be omitted here.

In the control device of the direct drive motor 14, in order to give a synchronizing signal to each sequencer which is a control device of each part of the automatic assembly machine, (1) the rotation angle which is the absolute position of the rotation shaft of the direct drive motor 14 is set. Method of giving (absolute position output), (2) Method of giving an upper limit value and a lower limit value of the rotation angle of the rotary shaft of the direct drive motor 14 and giving an ON or OFF signal when within the range (range output) Two types of output methods can be selected. Here, the details of each output method will be described later. Output selection and setting of upper limit and lower limit are RC-2
This is done by sending a signal to the 32C communication port 23 by the handy terminal or the computer 26. First, the output selecting method and the setting method of the upper limit value and the lower limit value will be described with reference to the flowchart of FIG.

First, an external terminal such as a computer 26 reads the received data stored in the RAM 22 via the CPU 20 (S21). Next, as shown in FIG. 7, when the content of the parameter number 63 of the received data is 0, it is determined that the absolute position output has been selected, and the process proceeds to the next flowchart (S22, YES). If the content of the parameter number is not 0, it is determined that range output has been selected (S22, NO), and the parameter number is incremented by 1 (S22).
23). Therefore, the user can select either absolute position output or range output as the output format of the position output circuit 24 by changing the content of the parameter number 63. As a result, any output format can be selected according to each sequencer, which is convenient.

Next, with the parameter number 64, the upper limit value of the range output output at the port 0 of the position output circuit 24 is input. Finally, by pressing the carriage return CR (S24), the received data becomes R as the upper limit value of port 0.
It is stored in the AM 22 (S25). Next, with the parameter number 65, the lower limit value of the range output output at the port 0 of the position output circuit 24 is input. Finally, by pushing the carriage return CR (S26), the received data is stored in the RAM 22 as the upper limit value of the port 0 (S2).
7). Next, it is confirmed whether the data input is completed,
If the data input is completed, the program ends (S28, YES). If the data input is not completed, the process proceeds to S23, and the upper limit value and the lower limit value of the range output of the port 1 are set by the next parameter number 65. Since the position output circuit 24 of this embodiment has eight ports, it can output eight range outputs. That is, it is possible to transmit eight different range outputs to each sequencer, which facilitates synchronous control of an automatic assembly machine or the like.

Next, a specific method for outputting the absolute position will be described. A method of detecting the absolute position of the rotary shaft of the direct drive motor 14 by the angle calculation program 27 will be described with reference to the flowchart of FIG. When the rotating shaft of the direct drive motor 14 makes one rotation by the combination method of the one-rotation detecting resolver 11 and the multi-pole detecting resolver 12 of the present embodiment, the CPU 20 makes R
5 via the I / O converter 25 and the I / O circuit 16
Receive 40671 pulses (S1). Next, the current position pulse count obtained by counting the number of pulses from the origin position is divided by the value set by the parameter, that is, the current position pulse count is divided by 2n (S2).

Next, the value obtained by frequency division is output as a binary code to the position output circuit 24 (S3). In the angle calculation program 27 of this embodiment, 212 = 4096
Since the frequency is divided by, the resolution is 360 degrees * 4096 /
540672 = 2.73 degrees. For example, if the current position of the rotary shaft of the direct drive motor 14 is 12
When it is 0 degree, the output of each port of the position output circuit 24 is 120 * 540672 / (40) as shown in FIG.
96 * 360) = 44 is represented by a binary code. The angle calculation program 27 is executed at a predetermined sampling time by a main program (not shown), and thus the position output circuit 2 is executed at a predetermined sampling time.
The output of each port of 4 is changed. In the present embodiment, the case where the position output circuit 24 has eight output ports has been described, but it is also possible to increase the resolution by further increasing the number of ports and realize precise synchronization control. is there.

Next, a method of outputting the range output will be described with reference to the flowchart of FIG. First, the upper limit value and the lower limit value are compared, and if the upper limit value is smaller than the lower limit value (S11, NO), the current position is not smaller than the lower limit value (S14, NO), and the current position is smaller than the upper limit value. In the case (S15, NO), the output of the port is turned on (S1).
6). When the current position is smaller than the lower limit value (S1
4, YES), the output of the port is turned off (S17).
Although the current position is not smaller than the lower limit value (S14, N
O), if the current position is greater than or equal to the upper limit value (S15, YES), the output of the port is turned off (S1).
7). For example, the upper limit is 200,000 and the lower limit is 40.
In the case of 10,000, the output of the output port is (b) in FIG.
As shown in. Here, the shaded area indicates that the output is on.

Next, the upper limit value and the lower limit value are compared, and if the upper limit value is greater than or equal to the lower limit value (S11, Y
ES), if the current position is greater than or equal to the lower limit value (S12, YES) and the current position is less than the upper limit value (S13, YES), the output of the port is turned on (S16). When the current position is smaller than the lower limit value (S12, NO), the output of the port is turned off (S1).
7). Although the current position is not smaller than the lower limit value (S1
2, YES) and if the current position is greater than or equal to the upper limit value (S13, NO), the output of the port is turned off (S17). For example, when the upper limit value is 400,000 and the lower limit value is 200,000, the output of the output port is as shown in FIG. Here, the shaded area indicates that the output is on.

As described in detail above, according to the motor control means of this embodiment, the R / D converter 16 for digitally converting the angle output of the angle detector every predetermined sampling time, and the R / D converter. Angle calculation program 27 for calculating the absolute angular position of the rotation axis as 8-bit digital data based on the output of the above, and a position output circuit for transmitting the 8-bit digital data calculated by the angle calculation program 27 to an external device. Since it has 24 and
Since a sequencer-readable synchronization signal can be transmitted to a plurality of sequencers such as an automatic assembly machine, it is possible to provide an inexpensive motor control device. Further, in the motor control means of this embodiment, the angle calculation program 27 has two types of output formats: absolute position output and range output, and
One of the two output formats of the angle calculation program 27
Since it has a communication port 23 for selecting one,
Since the output format can be selected according to the specifications of the sequencer used, it is possible to select the optimum synchronization signal output format for the entire automatic assembly machine system.

Although the motor control device of the present invention has been described in detail based on the embodiments, the present invention is not limited to the above embodiments and various modifications can be made. For example, in this embodiment, two resolvers are used as the angle detector of the rotary shaft of the direct drive motor 14, but an optical encoder may be used instead of the resolvers. Also, if accuracy is not a concern, then 1
It is also possible to use individual resolvers. Although only one ON-state output is described as the range output in the present embodiment, it is also possible to output two or more ON-states in order to obtain two or more timings.

[0020]

As is apparent from the above description, according to the motor control device of the present invention, the R / R that digitally converts the angle output of the angle detector at every predetermined sampling time is used.
An angle calculation means for calculating the absolute angular position of the rotation axis as digital data of predetermined bits based on the outputs of the D converter and the R / D converter, and the digital data of predetermined bits calculated by the angle calculation means are transmitted to an external device. Since it has an output circuit for controlling the sequencer, a sequencer-readable synchronization signal can be transmitted to a plurality of sequencers such as an automatic assembly machine, so an additional angle detector is not required, and it is inexpensive and space-saving. It is possible to provide a control device for the electric motor. Further, in the motor control means of the present invention, the angle calculation means has two or more output formats of the absolute position output and the range output, and at least one of the two or more output formats of the angle calculation means is selected. Since it has a selection means,
Since the output format can be selected according to the specifications of the sequencer used, it is possible to select the optimum synchronization signal output format for the entire automatic assembly machine system.

[Brief description of drawings]

FIG. 1 is a block diagram showing a configuration of a motor control device that is an embodiment of the present invention.

FIG. 2 is a first flowchart showing the operation of the motor control device.

FIG. 3 is a second flowchart showing the operation of the motor control device.

FIG. 4 is a third flowchart showing the operation of the motor control device.

FIG. 5 is a data diagram showing an output example of range output.

FIG. 6 is a data diagram showing an output example of absolute position output.

FIG. 7 is a data diagram showing parameters such as output format selection.

[Explanation of symbols]

 11 1-Revolution Detection Resolver 12 Multi-Pole Detection Resolver 13 Motor Controller 14 Direct Drive Motor 16 R / D Converter 20 CPU 21 ROM 22 RAM 23 Communication Port 24 Position Output Circuit 27 Angle Calculation Program

[Procedure amendment]

[Submission date] October 15, 1993

[Procedure Amendment 1]

[Document name to be amended] Statement

[Name of item to be corrected] 0003

[Correction method] Change

[Correction content]

[0003] as a means to solve the problem, JP-A-6
In 1 -249733, JP-the output of the absolute value pulse encoder attached to a speed control of a servo motor, a method of controlling the injection molding machine is described. In the present invention, the output pulse of the pulse encoder is read by the counter and the CPU to control the injection molding machine.

[Procedure Amendment 2]

[Document name to be amended] Statement

[Correction target item name] 0012

[Correction method] Change

[Correction content]

First, the received data stored in the RAM 22 is read out via the CPU 20 (S21). next,
As shown in FIG. 7, when the content of the parameter number 63 of the received data is 0, it is determined that the absolute position output has been selected, and the process proceeds to the next flowchart (S22, YES).
If the content of the parameter number is not 0, it is determined that range output has been selected (S22, NO), and the parameter number is incremented by 1 (S23). Therefore, the user can change the contents of the parameter number 63 to change the position output circuit 2
As the output format of No. 4, either absolute position output or range output can be selected. As a result, any output format can be selected according to each sequencer, which is convenient.

[Procedure 3]

[Document name to be amended] Statement

[Correction target item name] 0013

[Correction method] Change

[Correction content]

Next, with the parameter number 64, the upper limit value of the range output output at the port 0 of the position output circuit 24 is input. Finally, by pressing the carriage return CR (S24), the received data becomes R as the upper limit value of port 0.
It is stored in the AM 22 (S25). Next, with the parameter number 65, the lower limit value of the range output output at the port 0 of the position output circuit 24 is input. Finally, by pressing the carriage return CR (S26), the received data is stored in the RAM22 as the lower limit value of the port 0 (S2
7). Next, it is confirmed whether the data input is completed,
If the data input is completed, the program ends (S28, YES). If the data input is not completed, the process proceeds to S23, and the upper limit value and the lower limit value of the range output of the port 1 are set by the next parameter number 65. Since the position output circuit 24 of this embodiment has eight ports, it can output eight range outputs. That is, it is possible to transmit eight different range outputs to each sequencer, which facilitates synchronous control of an automatic assembly machine or the like.

[Procedure amendment 4]

[Document name to be corrected] Drawing

[Name of item to be corrected] Figure 5

[Correction method] Change

[Correction content]

[Figure 5]

Claims (2)

[Claims] 1. A control device for an electric motor, which controls the rotational speed and the position of the rotational shaft according to the output of an angle detector which is directly attached to the rotational shaft of the electric motor and detects the rotational angle of the rotational shaft. An R / D converter that digitally converts the angle output of the angle detector, and an angle calculation that calculates the absolute angular position of the rotary shaft as digital data of predetermined bits at predetermined sampling times based on the output of the R / D converter. A control device for an electric motor, comprising: a means and an output circuit for transmitting a predetermined bit of digital data calculated by the angle calculation means to an external device. 2. The motor control device according to claim 1, wherein the angle calculation means can calculate digital data of two or more output formats, and one of the two or more output formats of the angle calculation means. A control device for an electric motor having an output format selection means for selecting one of the two.