JPH06203285A - Signal transmitter for position detector - Google Patents

Abstract

PURPOSE:To reduce cost and to improve the degree of freedom for layout by suppressing the number of transmission lines just for one channel and reducing the thickness of a cable. CONSTITUTION:This signal transmitter for position detector is provided with a controller 16 for processing the position data of an object to be detected and magnetic pole detection parts 4a and 4b and further, this device is provided with a position detector 4 for detecting the position data of the object to be detected, up/down counter 5 for up or down counting based on the two phases of sine waves outputted from the position detector 4 corresponding to the position change of the object to be detected, conversion circuit part 6 for converting the counter value counted by the up/down counter 5 or the change amount of the counter value per unit time and a magnetic pole position detecting signal outputted from the magnetic pole detection parts 4a and 4b to serial signals, and transmission line 9 for transmitting the serial signals to the controller 16.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a signal transmission device for a position detector, and more particularly to a device for transmitting and processing signals of three channels of A phase, B phase and serial phase.

[0002]

2. Description of the Related Art Conventionally, in a motor such as a brushless motor, position data of the motor spindle is detected. This data is detected by A, A at the end of the motor spindle.
A magnetic recording medium for B / Z phase detection and a magnetic pole detection magnet for U / V / W phase detection are provided to obtain a position data signal from the magnetic recording medium and a driving position data signal from the magnetic pole detection magnet. It is done by. These data are transmitted to the control device through the cables that bundle the respective transmission paths, and various processing such as feedback control is performed based on these data.

[0003]

However, the apparatus for detecting, transmitting and processing the above data signal has the following problems. That is, since three-phase signals of A phase, B phase, and serial phase (Z, U, V, W phases) are transmitted, the number of transmission lines is large and the cable for bundling them must be thick, resulting in high cost. There is a problem that becomes. Moreover, when the control device is arranged relatively far, the transmission line must be lengthened, which further aggravates the problem. Also, if the cable gets thicker, if the cable is also routed inside the machine body,
The occupying portion of the cable is large, and the swiveling of the cable is restricted outside the machine body, and the supporting member that supports the cable inside and outside the machine body must have a structure with relatively high rigidity. There is also a problem that the degree of freedom in design is limited.

Therefore, the present invention provides a signal transmission device for a position detector, in which the number of transmission lines is set to one channel and the thickness of the cable is reduced, and the cost is low and the degree of freedom in design is improved. The purpose is to

[0005]

In order to achieve the above object, a signal transmission device of a position detector according to the present invention has a control device for processing position data of an object to be detected and a magnetic pole detector, A position detector that detects position data of the detection object; an up-down counter that counts up or down based on a two-phase sine wave output from the position detector according to a position change of the detection object; A conversion circuit unit that converts a counter value counted by the up / down counter, or a variation amount of the counter value per unit time, and a magnetic pole position detection signal output from the magnetic pole detection unit into a serial signal, and the serial circuit. And a transmission line for transmitting a signal to the control device.

[0006]

According to the signal transmission device of the position detector in such means, the position data of each phase of A, B, Z, U, V and W is detected by the position detector, respectively.
Two-phase sine waves of A and B phases are counted up or down by the up / down counter. The counter value or the amount of change in the counter value per unit time and the position data of each of the Z, U, V, and W phases are converted into serial signals in the conversion circuit unit, and transmitted to the control device for transmission. The number of paths can be reduced to one channel, and the thickness of the cable can be reduced.

[0007]

Embodiments of the present invention will be described below with reference to the drawings. FIG. 1 is a schematic side view of a signal transmission device for a position detector showing an embodiment of the present invention, and FIG. 2 is a configuration diagram schematically showing FIG. 1, respectively. It is applied to the robot arm. In FIG. 1, reference numeral 1 denotes, for example, a brushless motor, and a disc-shaped magnetic pole detecting magnet 2 is provided on an end surface of a main shaft 1a of the motor 1. The magnetic pole detection magnet 2 has N poles and S poles alternately magnetized in the circumferential direction and sends out U, V, W phase drive position data. A disk-shaped magnetic recording medium 3 is provided in front of the magnetic pole detecting magnet 2. This magnetic recording medium 3 has an upper step portion in which N poles and S poles are magnetized side by side on the circumference, and an N pole and an S pole are in phase with the upper step portion.
It is provided with a lower stage part in which poles are alternately magnetized on the circumference, and sends position data of the Z, A, and B phases.

The motor 1 has the above A, B, Z, U, V,
A position detector 4 such as an encoder for detecting the W-phase position data is additionally provided. In the case 44 of the encoder 4 (shown by a dotted line to avoid complication of the drawing), the magnetic pole detecting portion is provided at a position facing the magnetizing portions of the magnetic pole detecting magnet 2 and the magnetic recording medium 3. A barrel Hall element 4a and an MR sensor 4b are arranged respectively. The Hall element 4a includes a waveform shaping circuit 4c, an up / down counter 5, a parallel / serial converter 6, a line driver 8, a 5V power source 18, and a ground power source 19 which will be described later. It is attached to the back surface of the base of the signal processing circuit 17 configured by the above. Hall element 4a, MR sensor 4
The output line b is 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 parallel / serial converter 6 which is a conversion circuit unit via an up / down counter 5 which counts up or down, and other phases (Z, The output lines of (U, V, W phases) are directly connected to the parallel / serial converter 6, respectively. The serial signal line 7 from the parallel / serial converter 6 is connected to the line driver 8. The BUS line 10 and the inverted BUS line 11 of this line driver 8
Are bundled in the middle of the encoder cable 9 and connected to the line receivers 14 in the control device 16, respectively. The signal processing circuit 17 is provided with a 5V power source 18 and a ground power source 19, respectively.
8. The ground power supply 19 is connected to the control device 16 via the 5V power supply line 12 and the ground power supply line 13, respectively. The 5V power line 12 and the ground power line 13 are bundled in the encoder cable 9 together with the BUS line 10 and the inverted BUS line 11. The output line of the line receiver 14 in the control device 16 is connected to the serial / parallel converter 15 via the serial signal line 30. From this serial / parallel converter 15, the Z, U, V, W
The phase position data and the counter value can be output in parallel. The control device 16 and the motor 1 are shown in FIG.
As shown in FIG. 3, the motor cable 31 is connected, and the motor 1 can be driven from the control device 16.

The operation of the signal transmission device for the position detector will be briefly described below. When a drive signal is transmitted from the control device 16 to the motor 1 via the motor cable 31 in order to operate the motor 1, the spindle 1a starts rotating, and the magnetic field is changed by the magnetic pole detection magnet 2 and the magnetic recording medium 3. . The change in the magnetic field is detected in the Hall element 4a as U-, V-, and W-phase driving position data. In the MR sensor 4b, Z,
The position data of the A and B phases are detected respectively, and A and B are detected.
The phase is detected as a sine wave. 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. Signal A shaped into these rectangular waves. , B. Is counted up or down by the up / down counter 5, and the counter value counted by the up / down counter 5 is input to the parallel / serial converter 6 as a 16-bit signal. On the other hand, the position data signal U shaped into the rectangular wave. , V. , W. , Z. Are directly input to the parallel / serial converter 6.

FIG. 3 shows the format of the serial signal transmitted from the parallel / serial converter 6 to the control device 16. In this figure, this format uses, for example, a Manchester code of 1 Mbps, and a code 20 indicates a rest space before transmission of various data.
1 is a space 20 followed by a 16-bit counter value transmitted from the up / down counter 5, 22 is a 12-bit empty space following the counter value 21, 23z, 2
3u, 23v and 23w are position data signals U of 1 bit each transmitted from the waveform shaping circuit 4c following the empty space 22. , V. , W. , Z. 24 is a position data signal U. , V. , W. , Z. 8 CRC bits for checking a series of data are shown respectively. Here, the counter value 21, the empty space 22, and the position data signals 23z, 23u, 23v, and 23w constitute 32-bit data, and the rest space 20, the counter value 21, the empty space 22, and the position data signals 23z, 2
One frame is composed of 3u, 23v, 23w and CRC24. This 1-frame serial signal is repeatedly transmitted through the encoder cable 9 in accordance with the detection signals from the Hall element 4a and the MR sensor 4b.
6 is transmitted. This serial signal is converted into a parallel signal by the serial / parallel converter 15 in the control device 16, and this parallel signal (position data signal U.
V. , W. , Z. , 16-bit counter value).

As described above, in the present embodiment, the two-phase sine waves of the A and B phases output from the MR sensor 4b are input to the up / down counter 5 to obtain the counter value. The position data signals of the phases (U, V, W, Z phases) are converted into serial signals in the serial / parallel converter 6 and transmitted to the control device 16, so that the number of transmission paths is 1 channel. In addition, the thickness of the cable can be reduced and the cost can be reduced.

Here, in this embodiment, a part of the encoder cable 9 is wired in the arm of the robot, but since the encoder cable 9 can be made thin as described above. , The portion occupied by the conventional cable 9 can be effectively used for other purposes, and the arm itself can be made thin. Further, outside the robot body, there are less restrictions such as swinging of the cable 9 than before, Moreover, the supporting member for supporting the cable 9 can have a relatively simple structure both inside and outside the robot, so that the degree of freedom in design can be improved.

Further, in this embodiment, the up / down counter 5 is provided and the counter value counted by the up / down counter 5 is transmitted to the serial / parallel converter 6, There is also an effect that the transmission speed does not need to be increased so much and therefore the number of rotations of the motor 1 is not limited.

Although the invention made by the present inventor has been specifically described based on the embodiments, the invention is not limited to the above embodiments, and various modifications can be made without departing from the scope of the invention. Needless to say, for example, in the above embodiment, the up / down counter 5,
Although the parallel / serial converter 6 and the like are provided inside the case 44 of the encoder 4, they may be provided outside the case 44. In this case, for example, the transmission line may be extended by about 30 cm, an encoder signal processing box may be provided in front of the transmission line, and the up / down counter 5, the parallel / serial converter 6 and the like may be arranged in this box.

Further, in the empty space 22 of the format of the serial signal, for example, the case 4 of the encoder 4
It is also possible to carry an alarm signal of temperature rise in 4 and alarm signals of the motor 1 and the encoder 4. In addition, in the empty space 22, for example, how many watts the encoder 4 is mounted on the motor, or how many pulses of A-phase and B-phase signals are generated each time the main shaft 1a makes one rotation are shown. It is also possible to post information.

Further, in the above-mentioned embodiment, although an application example to the arm portion of the robot is described, the present invention is not limited to the arm portion and can be applied to other parts,
Further, it is of course applicable to other devices than the robot. Further, an optical encoder using a code disk, a light receiving element, and a light emitting element is not excluded.

Furthermore, in the use up to now, it has been described that the 16-bit up / down counter value and Z, U, V, W are transmitted as serial signals. The same effect can be expected by transmitting the amount of change and Z, U, V, W as a serial signal. That is, the up-down counter value can be reproduced in the control device by adding together the change amounts received by the control device 16. Note that this example
The effect of reducing the number of transmission bits can also be expected.

[0018]

As described above, according to the signal transmission device of the position detector of the present invention, A, A outputted from the position detector,
The B-phase two-phase sine wave is input to the up / down counter to obtain a counter value, and the counter value or the change amount of the counter value per unit time and the magnetic pole position detection signal of another phase are converted. Since the circuit unit converts the signal to a serial signal and transmits it to the control device, the number of transmission lines can be reduced to one channel and the thickness of the cable can be made thin, so that the cost can be reduced and the design flexibility can be improved. Can be achieved.

[Brief description of drawings]

FIG. 1 is a schematic side view of a signal transmission device of a position detector showing an embodiment of the present invention.

FIG. 2 is a configuration diagram schematically showing FIG.

FIG. 3 is a diagram for explaining the format of a serial signal transmitted from the conversion circuit unit in FIG.

[Explanation of symbols]

 1a Object to be detected 4 Position detector 4a, 4b Magnetic pole detection unit 5 Up-down counter 6 Conversion circuit unit 9 Transmission line 16 Control device

Claims (1)

[Claims] 1. A control device for processing position data of an object to be detected, a position detector having a magnetic pole detector for detecting position data of the object to be detected, and a position detector for detecting a position change of the object to be detected. An up / down counter that counts up or down based on a two-phase sine wave output from the position detector, a counter value counted by the up / down counter, or a change amount of the counter value per unit time. Signal transmission of a position detector including a conversion circuit unit that converts a magnetic pole position detection signal output from the magnetic pole detection unit into a serial signal, and a transmission path for transmitting the serial signal to the control device. apparatus.