JPH0661861A - Encoder signal processing multiplier - Google Patents

Abstract

PURPOSE:To provide an encoder with high resolution without use of a biphase carrier signal with high accuracy by counting a width or a purse signal obtained by comparing either of a phase A or a phase B signal being an incremental signal with a reference triangle wave so as to interpolate a level within one pulse width of the incremental signal. CONSTITUTION:A phase A signal is compared with a reference triangle wave outputted from a reference triangle wave signal generator 107 at a comparator 106. The pulse width of the output pulse from the comparator 106 varies with a signal level (rotating angle). The pulse width is counted by a counter 108. Data representing a position of an incremental signal within one pulse width according to the count of the pulse width are prepared in a ROM as a table. That is, the output of the counter 108 is used for an address. The position data are outputted by a correction arithmetic operation device 111 based on the count of the pulse width (ROM address) by the counter 108 and discrimination of a quadrant by a quadrant discrimination device 110.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a signal processing and multiplying device for an incremental encoder.

[0002]

2. Description of the Related Art In order to improve the control accuracy of a motor for rotating or linear motion incorporated in a robot or a machine tool, a detector capable of instantaneously and accurately measuring the position and speed of these motors is required. ing. An encoder (rotary encoder) is one of such position detectors.
There is. In the case of the increment type, there has been a phase difference detection method or the like as an electric multiplication method for achieving high accuracy.

[0003]

In the phase difference detection method which is the conventional multiplication method, as shown in FIG.
in θ) and B phase (cos θ) (θ: rotation angle to be detected) are multiplied by carrier signals cos ωt and sin ωt, respectively, and the rotation angle is calculated by detecting the phase difference between the obtained output signal and the carrier signal. This can be expressed by the following equation. Asinθ · Bcosωt + Acosθ · Bsinωt = ABsin (ωt + θ) where Asinθ is an A-phase signal, Acosθ is a B-phase signal, and Bsinωt and Bcosωt are carrier signals. As can be seen from this equation, the accuracy of the phase difference between the two carriers, the signal amplitude ratio, and the incremental signal (A
The amplitude ratio of the phase and B phase affected the multiplication factor, that is, the deterioration of accuracy. Therefore, a highly accurate two-phase carrier signal is required. Therefore, an object of the present invention is to provide a high-resolution encoder that is not affected by the accuracy of the amplitude ratio of the incremental signal without using a highly accurate two-phase carrier signal.

[0004]

A reference triangular wave signal generator, and a comparator device for comparing an incremental signal of either the A phase or the B phase with a reference triangular wave signal output from the reference triangular wave signal generator. , A counter device for counting the output pulse width of the comparator device, a table ROM having position data with the output of the counter device as an address, and the quadrant within which a position represented by the output signal of the counter device is within one pulse. And a quadrant judging device for judging whether or not it is present, and the position data on the table ROM is corrected by the output of the quadrant judging device to calculate the position.

[0005]

In order to achieve this object, in the present invention, the width of the pulse signal obtained by comparing one of the A phase and the B phase, which is an incremental signal, with the reference triangular wave is counted to increase the incremental (A phase Or, it interpolates within one pulse of B phase).

[0006]

EXAMPLE FIG. 1 shows an example of the present invention. 101, 10
2, 103 are comparator devices, 103 is a direction discriminating device, 104 is an up / down counter, 105 is a counter value adjusting device, 107 is a reference triangular wave signal generator, 108
Is a counter device, 109 is a clock, 110 is a quadrant determination device, and 111 is a correction calculation device. First, 101-1
The circuit constituted by 05 is a circuit for counting the pulsed encoder output as it is, as is conventional. Whether the up-counting or the down-counting is performed is determined based on the phase relationship of the advance or the delay of the A phase and the B phase.

The interpolation within one pulse of the present invention is 106 to 1
It is realized by a circuit composed of 11. First, the A-phase signal is compared with the reference triangular wave output from the reference triangular wave signal generator 107 by the comparator device 106. The output of the comparator device 106 is as shown in FIG. That is, the pulse width changes according to the signal level (rotation angle). The pulse width is counted by the counter device 108. Data indicating the position within one pulse width of the incremental signal (A phase or B phase) is stored in the ROM as a table according to the counted value of the pulse width. That is, the output of the counter device 108 becomes an address. The pulse width count values are the first quadrant and the second quadrant, and the third quadrant and the fourth quadrant.
Since the quadrants have the same value, the first quadrant and the third quadrant are in the table.
You only need to have quadrant position data. Here, the number of position data that can be held in the table increases as the clock frequency for counting is higher, the rotation speed of the encoder is lower (incremental signal frequency is lower), and the reference triangular wave signal frequency is lower ( Higher resolution). Count value of pulse width (R
OM address), quadrant determination by the quadrant determination device 110, and position data is output by the correction calculation device 111.

That is, in the first quadrant or the second quadrant, if the B phase is negative, the quadrant determining device determines that it is in the first quadrant, and the table is displayed according to the count value (address) of the counter device 108. The position data of the 1st quadrant that they have is output. If the phase B is positive, the quadrant judging device judges that it is in the second quadrant, and the correction arithmetic device adds a numerical value of 90 ° to the position data of the first quadrant on the table and outputs the position data. . If it is in the third quadrant or the fourth quadrant, if the B-phase is positive, the quadrant determining device determines that it is in the third quadrant, and the counter device 108
The third number held in the table according to the count value (address) of
Outputs quadrant position data. If the B-phase is negative, it is judged by the quadrant judging device that it is in the fourth quadrant, and the correction arithmetic device adds a numerical value of 90 ° to the position data of the third quadrant on the table and outputs the position data. . Counter 1
The value of 04 is adjusted by the counter value adjusting device 105 according to the multiplication number within one pulse (for example, the value of the counter 104 is multiplied by 10 when multiplying by 10 within one pulse) and the value of position data output. Know the rotation angle with high accuracy by adding them together. Although the embodiment has been described with respect to a rotary encoder, a linear encoder can be used as well.

[0009]

As described above, according to the present invention, unlike the conventional phase difference detection method, a highly accurate two-phase carrier signal is not used and the amplitude ratio of the incremental signal is not affected. There is an excellent effect that a high resolution encoder can be obtained.

[Brief description of drawings]

FIG. 1 is a block diagram showing a specific embodiment of the present invention.

FIG. 2 is a waveform explanatory diagram of the present invention.

FIG. 3 is a block diagram of a conventional signal processing system.

[Explanation of symbols]

 101, 102 Comparator device 103 Direction discriminating device 104 Up-down counter 105 Counter value adjusting device 106 Comparator device 107 Reference triangular wave signal generator 108 Counter device 109 Clock 110 Quadrant judging device 111 Correction arithmetic device 301 Two-phase carrier signal generator 302, 303 Multiplier 304 Adder 305 Phase difference detection circuit

 ─────────────────────────────────────────────────── ─── Continuation of front page (72) Inventor Yuji Arinaga 2-1, Kurosaki Shiroishi, Hachimansai-ku, Kitakyushu, Fukuoka Prefecture Yasukawa Electric Co., Ltd.

Claims (1)

[Claims] 1. An incremental encoder for detecting a linear or rotational position, comprising a reference triangular wave signal generator,
A comparator device for comparing the incremental signal of either the A phase or the B phase with the reference triangular wave signal output from the reference triangular wave signal generator, and a counter device for counting the output pulse width of the comparator device A table ROM having position data with the output of the counter device as an address, a quadrant judging device for judging in what quadrant the position represented by the output signal of the counter device is in one pulse, and an output of the quadrant judging device By the table R
An encoder signal processing and multiplying device comprising a correction arithmetic device for calculating a position by correcting position data on an OM.