JP2810610B2 - Transmission method of encoder signal - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

The present invention relates to a method for transmitting an encoder signal, and more particularly, to a method for transmitting an absolute encoder signal.

[0002]

2. Description of the Related Art Conventionally, in a motor such as a brushless motor, position data of a motor main shaft is detected. This data is detected by A,
A magnetic recording medium for detecting B and Z phases and a magnet for detecting magnetic poles for detecting U, V and W phases are provided, and a position data pulse signal from the magnetic recording medium and a driving position data signal from the magnetic pole detecting magnet are respectively provided. It is done by getting. Here, the A and B phases are output signals of a pulse generator that generates 90-degree phase pulses of n pulses per one rotation of the motor spindle according to the rotation direction, and the Z phase is one pulse per one rotation of the motor spindle. It is defined as the output signal of the origin pulse generator to be generated. The U, V, and W phases are defined as output signals of a magnetic pole detection signal generator that generates a pulse corresponding to the magnetic pole position of the field magnet of the motor. These data are transmitted to a control device via cables that bundle transmission lines, and various processes such as feedback control are performed based on the data.

[0003]

However, the device for transmitting the data signal has the following problems. That is, when the position detector is a so-called absolute encoder that detects the absolute position of the motor spindle,
Since four-channel signals of A-phase, B-phase, serial-phase (Z, U, V, W-phase) and absolute counter value are transmitted, the number of transmission lines is large, and the cable for bundling them must be thick. There is a problem of high cost. In addition, when the control device is disposed at a relatively long distance, the transmission path must be lengthened, which further increases the problem. Also, when the cable becomes thicker, if the cable is also routed inside the machine body,
Since the occupied portion of the cable is large, and outside of the machine main body, the swaying of the cable and the like is restricted, and the support member for supporting the cable inside and outside the machine main body must have a relatively high rigidity structure. There is also a problem that the degree of freedom in design is limited.

Accordingly, the present invention provides a method of transmitting an encoder signal in which the number of transmission paths is reduced to one channel and the thickness of a cable is reduced, and the cost is reduced and the degree of freedom in design is improved. Aim.

[0005]

In order to achieve the above object, a method for transmitting an encoder signal according to the present invention comprises: a rotating body, that is, a rotation amount of a motor and a Z phase within a predetermined time obtained from phases A and B; And position data composed of U, V, and W phases (hereinafter, simply referred to as position data) by a first sampling method.
The serial signal obtained by, in the rotation amount serial signal, 1 calibration by superimposing divided every predetermined number of bits in the serial signal by the second sampling the output of the absolute counter indicating the absolute position of the rotating body
Constitute a serial signal Rakuta, the superimposed 1 Calibration
Multiple characters obtained by updating the serial signal of the tractor
Is transmitted to the control device through a one-channel transmission path.

[0006]

According to the method of transmitting an encoder signal in such a means, the detected position data is transmitted in a predetermined time.
It is converted into a serial signal indicating the amount of shift . On the other hand, the counter value of the absolute counter is also a serial signal, divided for the serial signal of the position data every predetermined number of bits
And it is superimposed on the serial signal of one character by Rukoto
No. is composed, and a plurality of keys obtained by updating the character
Characters are transmitted to the controller. Therefore, the number of transmission paths can be reduced to one channel and the thickness of the cable can be reduced. In particular, in the present invention, the absolute count
Serial signal from the data
Is embedded in a single character.
The transmission time is reduced.
It is supposed to be.

[0007]

Embodiments of the present invention will be described below with reference to the drawings. FIG. 1 is a schematic perspective view of a signal transmission device to which an encoder signal transmission method according to an embodiment of the present invention is applied, and FIG. 2 is a configuration diagram schematically showing FIG. , Is applied to the arm part of the robot. In FIG. 1, reference numeral 1 denotes, for example, a brushless motor, and a disk-shaped magnet 2 for detecting magnetic poles is provided on an end surface of a main shaft 1 a of the motor 1. The magnetic pole detecting magnet 2 has N and S poles alternately magnetized in the circumferential direction, and sends out U, V, and W phase driving position data. A disk-shaped magnetic recording medium 3 is provided in front of the magnetic pole detecting magnet 2. The magnetic recording medium 3 has an upper portion in which the N pole and the S pole are magnetized side by side on the circumference one by one, and an N pole and an S pole having the same phase as the upper portion are formed on the circumference. And a lower portion that is alternately magnetized to transmit the Z, A, and B phase position data.

[0008] The motor 1, the above A, B, Z, U, V,
An absolute encoder 4 for detecting the W-phase position data and the absolute position data of the motor is provided. In the case 44 of the encoder 4 (indicated by a dotted line to avoid complicating the figure), the Hall element 4a is located at a position facing the magnetized portion of the magnetic pole detecting magnet 2 and the magnetic recording medium 3. , An MR sensor 4b, and a Hall element 4a includes a waveform shaping circuit 4c, a multiplying + direction detecting circuit 40, an up / down counter 5, a parallel / serial converter 6, and a communication control unit 5, which will be described later.
0, an absolute counter 43, a parallel-serial converter 44 on the absolute counter side, CRC bit adders 51 and 52, a line driver 8, a 5V power supply 18, and a ground power supply 19, which are attached to the back of the base of the signal processing circuit 17. . The output lines of the Hall element 4a and the MR sensor 4b are connected to a waveform shaping circuit 4c for shaping the waveform into a rectangular wave as shown in FIG. The output lines of the A and B phases of the waveform shaping circuit 4c are connected to a quadruple pulse + direction detection circuit 40 for converting the pulse into a quadruple pulse and an up / down signal, respectively. A communication control unit 50 for transmitting an output line of the circuit 40, a clear signal, and a sampling instruction signal;
Are connected to a 6-bit up / down counter 5 that counts up or down according to the advance or delay of the AB phase. The output line of the up / down counter 5 is connected to the parallel / serial converter 6, and the output lines of the other phases (Z, U, V, W phases) are directly connected to the parallel / serial converter 6, respectively. Have been.

The output line of the quadruple pulse + direction detection circuit 40 is also connected to a 24-bit absolute counter 43. The output line of the absolute counter 43 and the output line of the communication control unit 50 are It is connected to the parallel / serial converter 44 on the counter side. The output line of the parallel-serial converter 44 is connected to the parallel-serial converter 6, and the output line of the CRC bit adder 51 for error detection is also connected to the parallel-serial converter 6. ing. Then, the serial signal line 7 from the serial converter 6
Are connected to the line driver 8.

The BUS line 10 and the inverted BUS line 11 of the line driver 8 are connected to a line receiver 14 in a control device 16, respectively. The signal processing circuit 17 and the control device 16 are provided with 5V power supplies 18 and 41 and ground power supplies 19 and 42, respectively.
The power supply line 12 and the ground power supply line 13 are connected to each other. These 5V power line 12 and ground power line 13
Are bundled together with the BUS wire 10 and the inverted BUS wire 11 in the encoder cable 9. The encoder cable 9 is appropriately supported by a support member (not shown).

The output line of the line receiver 14 in the control unit 16 is connected to a serial / parallel converter 15 via a serial signal line 30, and the serial / parallel converter 15 outputs the Z, U, V, W-phase position data,
An up-down counter value, an absolute counter value, and a CRC bit for error detection can be output in parallel. The output line of the up / down counter value of the serial / parallel converter 15 performs an AB phase regenerator 45, and error detection is performed on all output lines of the Z, U, V, W phase position data and the counter value and the CRC bit. The counter value of the absolute counter is connected to the error detector 48 and the serial / parallel converter 46, respectively. The control device 16 and the motor 1 are connected by a motor cable 31 as shown in FIG. 1 so that the control device 16 can drive the motor 1. Although the above-mentioned device is provided with a backup power supply for power failure countermeasures, it is omitted to avoid complicating the drawing.

Next, the operation of the signal transmission device will be described.
This will be briefly described below. When drive power is supplied from the control device 16 to the motor 1 via the motor cable 31 to operate the motor 1, the main shaft 1a starts rotating, and the magnetic field is changed by the magnetic pole detecting magnet 2 and the magnetic recording medium 3. . This change in the magnetic field is caused by U,
It is detected as V and W phase drive position data. In the MR sensor 4b, the position data is detected as Z, A, and B phase position data, and the A and B phases are detected as sine waves. These data signals Vu, Vv, Vw,
Vz, Va, and Vb (see FIG. 2) are input to the waveform shaping circuit 4c and shaped into a rectangular wave. The signals A and B shaped into these rectangular waves are converted into four-fold pulses and up-down signals in a four-fold pulse + direction detection circuit 40, and these four-fold pulses and up-down signals are converted into 6-bit up-down signals. It is input to the counter 5 and counted up or down by the up / down counter 5.

In the present embodiment, the up / down counter 5 samples a counter value at regular time intervals according to a first sampling signal from the communication control unit 50. When the sampled counter value is loaded into the parallel / serial converter 6, the counter value is cleared according to a clear signal from the communication control unit 50. Therefore, the sampled counter value becomes a value corresponding to the amount of rotation of the motor within a certain time.

These counter values are input to the parallel-to-serial converter 6 as 6-bit signals b _{0 to} b ₅ , while the position data signals U, V, W, and Z shaped into rectangular waves are: The signals are directly input to the parallel / serial converter 6.

On the other hand, the quadruple pulse and the up / down signal are also input to an absolute counter 43, and the absolute counter 43 samples a counter value in accordance with a second sampling signal from the communication control unit 50. It has become. The count value from the absolute counter 43 is input to the parallel-to-serial converter 44 on the absolute counter side as 24-bit signals ad0 to ad23, and the parallel-to-serial converter 44 outputs the signals as shown in FIG. A serial signal ad of the format is transmitted.

In the figure, reference numeral 80 denotes a rest space before data transmission, 83 denotes a start bit following the space 80 to notify the start of transmission, and 81 denotes a start bit 8
2 transmitted from the absolute counter 43 following 3
A 4-bit absolute counter value and 82 indicate 6-bit CRC bits for checking a series of data (for performing error checking) following the absolute counter value 81, and one frame is composed of 70 bits. ing. Here, the CRC bit 82 is added to the data signal by a signal from the CRC bit adder 52 for error detection. And this serial signal ad
Is input to the parallel / serial converter 6 and superimposed together with the 6-bit up / down counter value and the position data signals U, V, W, Z.

The up / down counter value, the position data signals U, V, W, Z and the absolute counter value ad are subjected to parallel / serial conversion in the parallel / serial converter 6, and the parallel / serial converter 6 outputs the data shown in FIG. A serial signal having a format as shown in FIG.

In FIG. 1, reference numeral 20 denotes a rest space before transmission of various data, reference numeral 21 denotes a start bit following the space 20 to notify the start of transmission, and reference numeral 22 denotes a start bit 21 followed by a signal 6 transmitted from the up / down counter 5.
The up / down counter value of the bit, U, V, and 23 transmitted from the waveform shaping circuit 4c following the counter value 22
W and Z position data signals, 24 are U, V, W and Z position data signals 23 followed by a parallel / serial converter 44
The absolute counter value ad shown in FIG. 3 (c) transmitted from the controller is transmitted, and reference numeral 25 is a 4-bit CRC bit for checking a series of data. Here, the above-mentioned
Absolute consisting of 70 bits per frame
The counter value ad is divided and superimposed on each bit.
The CRC bit 25 is added to the data signal by a signal from a CRC bit adder 51 for error detection, and includes a rest space 20, a start bit 21, an up / down counter value 22, and a position data. Signal 23, absolute counter value ad24, C
One character is constituted by the RC bit 25.
As the code, for example, a Manchester code is used.

The serial signal of one character is repeatedly transmitted to the line driver 8 and the encoder cable 9 while updating the transmission data in accordance with the detection signals from the Hall element 4a and the MR sensor 4b, as shown in FIG. The data is transmitted to the control device 16 through the control unit 16. This signal, as described above, the sampling signal from the communication control unit 50, it signals der sampled at regular intervals in accordance with clear signal, in particular, a frame 70 of bits Abusoryu
The counter value ad is divided and superimposed on each bit.
Tei Runode, signal amount as compared with the prior art has become greatly reduced, thus with a storage capacity can be reduced, so that can be shortened transmission time.

The serial signal is received by the line receiver 14 in the control device 16 via the encoder cable 9. This serial signal is converted into a parallel signal by the serial / parallel converter 15 and the U-, V-, W-, and Z-phase position data U ', V',
W 'and Z' are sent to subsequent processing as they are. On the other hand, the 6-bit up / down counter value is input to an AB phase regenerator 45, and the AB phase generation circuit 47 reproduces the position signals A 'and B'. Furthermore, absolute counter value ad is input to the serial-parallel converter 46, an absolute counter value ad _'0 to AD' ₂₃ parallel converted by 24-bit is obtained in the serial-to-parallel converter 46.

The error detector 48 can detect an error from the transmitted CRC bit 25. In FIG. 2, the signals to be reproduced are denoted by 'such as A', B ', U', V ', W', Z ', ad', which are the signals A, B, U,
Since V, W, Z, and ad have a transmission delay, they are attached to distinguish them.

[0022] Thus, in the present embodiment, the position data to a serial signal, the serial signal, 1 bi and the output of the absolute counter 43 into a serial signal
Is divided and superimposed on each unit , and the one
A plurality of characters updating the serial signal Yarakuta
Is transmitted to the control device 16 through the one-channel transmission line 9, so that the number of transmission lines can be minimized and the thickness of the cable can be reduced, so that the cost can be reduced.

[0023]

As described above, according to the encoder signal transmission method of the present invention, the position data is converted into a serial signal, and the output of the absolute counter is divided into serial signals by this predetermined number of bits. Since a plurality of characters obtained by updating the serial signal of one character formed by the superimposition are transmitted to the control device through the transmission channel of one channel, the amount of transmission data is increased.
, The transmission time can be shortened, the number of transmission lines can be minimized, and the thickness of the cable can be reduced. Therefore, cost reduction and improvement in design flexibility can be achieved.

FIG. 4 is a block diagram schematically showing a signal transmission apparatus to which an encoder signal transmission method according to another embodiment of the present invention is applied, in which the same components as those described in the previous embodiment are used. Are denoted by the same reference numerals, and description thereof is omitted here.
The signal transmission device to which the encoder signal transmission method of this embodiment is applied is different from that of the previous embodiment in that a delay circuit 60 for delaying the time of sampling 1, a subtraction circuit 61, A latch circuit 62 for latching only the 6 bits is provided, and the difference between the outputs of the absolute counter 43 is used as the A-phase and B-phase position signals.

It is needless to say that the same effect as in the previous embodiment can be obtained even with this configuration.

Although the invention made by the inventor has been specifically described based on the embodiments, the present invention is not limited to the above embodiments, and various modifications can be made without departing from the gist of the invention. Needless to say, for example, in the above embodiment, the encoder 4 is
, But may be separated. Further, the transmission path can be constituted by an optical fiber.

In the above embodiment, U, V,
Although an example is described in which the W and Z phase signals are superimposed on the serial signal and transmitted, the present invention may simply transmit the A and B two phases and the absolute counter value by the above method.

Further, in the above embodiment, an example of application to the arm of the robot is described. However, the present invention is not limited to the arm, but can be applied to other parts. Of course, it can be applied to other devices.

[0029]

As described above, according to the encoder signal transmission method of the present invention, the position data is converted into a serial signal, and the output of the absolute counter is superimposed on the serial signal as a serial signal. Since the serial signal is transmitted to the control device via a one-channel transmission line, the number of transmission lines can be minimized and the thickness of the cable can be reduced, so that cost reduction and design flexibility can be improved. I can do it.

[Brief description of the drawings]

FIG. 1 is a schematic perspective view of a signal transmission device to which an encoder signal transmission method according to an embodiment of the present invention is applied.

FIG. 2 is a configuration diagram schematically showing FIG. 1;

FIG. 3 is a diagram for explaining a format of a transmitted serial signal.

FIG. 4 is a configuration diagram schematically illustrating a signal transmission device to which an encoder signal transmission method according to another embodiment of the present invention is applied.

[Explanation of symbols]

 4 Absolute encoder 9 Transmission path 16 Controller 43 Absolute counter

Claims (2)

(57) [Claims] 1. The amount of rotation of a rotating body within a certain time is
A serial signal obtained by the first sampling is converted to a serial signal, and the output of the absolute counter indicating the absolute position of the rotating body is added to the rotation amount serial signal in the second sampling.
To generate a one-character serial signal by dividing it into a serial signal for each predetermined number of bits and superimposing it.
And update the superimposed serial signal of one character.
A method for transmitting an encoder signal, wherein the plurality of obtained characters are transmitted to a control device through a one-channel transmission path. 2. An absolute counter according to claim 1.
Is divided by 1 bit into 1 character
Encoder signal characterized by being superimposed within
No. transmission method.