JP2018151182A - SINGLE-TRACK TYPE Nbit ABSOLUTE ENCODER - Google Patents

Abstract

PROBLEM TO BE SOLVED: To obtain accurate encoder angle data even when a foreign material adheres to a single-track type Nbit absolute pattern.SOLUTION: A one-track type Nbit absolute encoder converts the read data obtained by simultaneously reading absolute patterns (2) by each light-receiving element (6) of at least three or more light-receiving element sets (20, 7, 21) into first to third angle data (A, B, C), compares first to third angle data (A, B', C') after offset correction, and selects the first angle data (A) composed of the most common angle data as encoder angle data (A).SELECTED DRAWING: Figure 1

Description

  The present invention relates to an absolute encoder, and more particularly to a novel improvement for obtaining an accurate encoder angle data by eliminating an abnormality of an absolute signal using a 1-track type Nbit absolute pattern.

Conventionally used absolute encoders using this type of one-track Nbit absolute pattern include, for example, the configurations disclosed in Patent Document 1 and Patent Document 2, but generally, FIG. 1-track type Nbit absolute encoder shown in FIG.
That is, what is denoted by reference numeral 1 in FIG. 2 is a light source composed of an LED, and below this light source 1 is a one-track Nbit absolute pattern 2 (hereinafter referred to as an absolute pattern) with a slight gap. A rotary code plate 3 having a rotating shaft is provided rotatably.

The absolute pattern 2 is composed of a rotary slit 4 and a mask portion 5, and the slit 4 and the mask portion 5 are arranged in a predetermined pattern.
Below the rotary code plate 3, a light receiving element set 7 made up of a predetermined number of light receiving elements 6 is fixed on a base (not shown) of an absolute encoder 8 through a slight gap.

The read data 9 output from each light receiving element 6 of the light receiving element set 7 is input to an angle data converter 10, and the angle data converter 10 outputs digital encoder angle data B.
Since it is known in advance how many angles the light receiving element group 7 is arranged in advance, if the absolute pattern 2 is normal, the angle data converter 10 sends the encoder angle at that time. Data B is output.

In the above-described state, for example, when a foreign substance 12 such as dust enters the single rotary slit 4 of the absolute pattern 2, the foreign substance 12 closes the rotary slit 4, so that the light from the light source 1 is The slit 12 cannot transmit light, and only one of the light receiving elements 6 cannot be turned on.
Therefore, the encoder angle data B output from the angle data converter 10 becomes NG data Ba different from the encoder angle data B originally output.

JP-A-8-313306 Japanese Patent Laid-Open No. 5-252037

Since the conventional one-track Nbit absolute encoder is configured as described above, the following problems exist.
That is, when the foreign matter 12 is attached to one of the rotary slits 4 of the one-track type Nbit absolute pattern 2 of the rotary code plate 3, when the place is read by the conventional light receiving element 6, read data 9 There is a problem that the encoder and angle data B converted after that become abnormal including the NG data Ba.

  The present invention has been made to solve the above-described problems. In particular, the present invention has been made to obtain an accurate encoder angle data by eliminating an abnormality of an absolute signal using a 1-track type Nbit absolute pattern. An object of the present invention is to provide a track-type Nbit absolute encoder.

  A one-track Nbit absolute encoder according to the present invention is composed of N light receiving elements arranged on the circumference of a one-track Nbit absolute pattern of a rotary code plate, and is arranged at a preset angular position. In the one-track type Nbit absolute encoder configured to read the absolute pattern by the provided light receiving element group and convert it to encoder angle data, the absolute pattern is formed by at least three light receiving elements of the light receiving element group. A plurality of first, second and third angle data converters for converting the read data obtained by simultaneously reading the first and second and third angle data A, B and C; 2, first and second angle offset correctors for performing offset correction of the third angle data; An angle data comparator for comparing a plurality of angle data obtained from the first angle data converter and each angle offset corrector, and each angle data comparator uses the angle data comparator. After the comparison, the first angle data consisting of the largest amount of angle data is selected as encoder angle data, and the first, second, and third light receiving element groups are integrated with each other, or It is the structure made into one of separate bodies.

Since the 1-track Nbit absolute encoder according to the present invention is configured as described above, the following effects can be obtained.
That is, the absolute pattern is composed of N light receiving elements arranged on the circumference of the one-track Nbit absolute pattern of the rotary code plate, and the light receiving element group arranged at a preset angular position. In the 1-track Nbit absolute encoder configured to convert the data into encoder angle data, first, read data obtained by simultaneously reading the absolute pattern by each light receiving element of at least three sets of the light receiving element groups A plurality of first, second, and third angle data converters for converting the second and third angle data A, B, and C, and offset correction of the second and third angle data of the angle data. First and second angle offset correctors to perform, the first angle data converter, and each angle offset correction An angle data comparator for comparing a plurality of angle data obtained from the first angle data comprising the most angle data after the comparison of the angle data by the angle data comparators. Since the encoder angle data is selected and the encoder angle data is selected, it is possible to generate the absolute encoder position data by eliminating the abnormality of the absolute signal, and to improve the reliability of the absolute encoder.
In addition, the first, second, and third light receiving element sets are configured to be integrated with each other or separated from each other, thereby facilitating the assembly and assembly of the plurality of light receiving element sets.

It is a schematic block diagram which shows the 1 track type Nbit absolute encoder of this invention. It is a schematic block diagram which shows the conventional 1 track type Nbit absolute encoder.

  The one-track type Nbit absolute encoder according to the present invention is to obtain an accurate encoder angle data by eliminating the abnormality of the absolute signal using the one-track type Nbit absolute pattern.

A preferred embodiment of a one-track Nbit absolute encoder according to the present invention will be described below with reference to the drawings.
In addition, the same code | symbol is attached | subjected and demonstrated to a part the same as that of a prior art example, or an equivalent part.
A reference numeral 1 in FIG. 1 denotes a light source composed of LEDs, and a rotary code having a one-track Nbit absolute pattern 2 (hereinafter referred to as an absolute pattern) with a slight gap below the light source 1. A plate 3 is rotatably provided.

The absolute pattern 2 includes a rotating slit 4 (white portion) and a mask portion 5 (black portion), and the slit 4 and the mask portion 5 are arranged in a predetermined pattern.
Below the rotary code plate 3, the first, second, and third light receiving element groups 20, 7, and 21 including a predetermined number of light receiving elements 6 are connected to the absolute encoder 8 through a slight gap (see FIG. (Not shown).

  The read data 9 output from each light receiving element 6 of each light receiving element set 20, 7, 21 is input to the first, second, and third angle data converters 30, 10, 31, and each angle data converter. The first angle data A from the first angle data converter 30 among the data converters 30, 10, 31 is directly input to the angle data comparator 40.

The second angle data B from the second angle data comparator 10 is input to the angle data comparator 40 after the angle offset correction is performed by the first angle offset corrector 41.
The third angle data C from the third angle data converter 31 is input to the angle data comparator 40 after the angle offset correction is performed by the second angle offset corrector 42.

Next, the operation will be described.
First, in the configuration of FIG. 1, when the N-bit absolute pattern 2 is simultaneously read by each of the light receiving element groups 20, 7, and 21, the foreign matter 12 adheres to the rotary slit 4 in the substantially central portion of the rotary code plate 3. If the light receiving element 6 of the second light receiving element set 7 corresponding to the foreign matter 12 does not enter the light receiving element 6 or the amount of light is extremely small, the light receiving element 6 generates an error signal NG different from the normal signal. The second angle data B composed of the error signal NG is offset-corrected by the first angle offset corrector 41 and input to the angle data comparator 40 as the second a angle data B ′. That is, since the absolute pattern 2 is simultaneously read by the three or more light receiving element groups 20, 7, and 21, a redundant system is configured.

  The first angle data A from the first angle data converter 30 has no foreign matter 12 in each rotary slit 4 of the rotary code plate 3 corresponding to the first light receiving element set 20, so that each light receiving element 6 Read data 9 is normal, and the first angle data A is directly input to the angle data comparator as a normal value. The angle data described above is position data.

  The third angle data C from the third angle data converter 31 has no foreign matter 12 in each rotary slit 4 of the rotary code plate 3 corresponding to the third light receiving element set 21. The third read data 9 is normal, and the third angle data C is input to the angle data comparator 40 as 3a angle data C ′ after the angle offset is corrected by the second angle offset corrector 42. The

In the angle data comparator 40, the first angle data A, the 2a angle data B ′, and the 3a angle data C ′ are input and compared with each other.
Since the comparison in the above case is A = C ′ ≠ B ′, when the most position data is selected, the first angle data A is output to the outside as the encoder angle data A from the angle data comparator 40. .
That is, since at least three or more sets of light receiving element groups 20, 7, and 21 are set in advance at an angle, the angle at the time of arrangement is known in advance, and the angle is corrected by the angle offset corrector 41. Since the position data having the largest number is selected, the highly accurate absolute encoder angle data A can be obtained.
The light receiving element groups 20, 7, and 21 are provided adjacent to each other in the configuration of FIG. 1, but may be arranged apart from each other by a predetermined distance instead of being arranged adjacent to each other.

The gist of the one-track Nbit absolute encoder according to the present invention is as follows.
That is, with respect to the one-track Nbit absolute pattern of the rotary code plate 3, the light receiving element group (20, 20) is composed of N light receiving elements arranged on the circumference and arranged at a preset angular position. 7, 21), in the one-track type Nbit absolute encoder configured to read the absolute pattern 2 and convert it into the encoder angle data A, at least each of the light receiving element groups 20, 7, 21 receives light. A plurality of first, second, and third angle data converters 30 for converting read data 9 obtained by simultaneously reading the absolute pattern 2 by the element 6 into first, second, and third angle data A, B, and C. , 10, 31 and first and second angle offset correctors 41 for performing offset correction of the second and third angle data B and C of the angle data. 42, an angle data comparator 40 for comparing a plurality of angle data A ′, B ′, C ′ obtained from the first angle data converter 30 and the angle offset correctors 41, 42, The angle data comparator 40 selects the first angle data A composed of the largest number of angle data after the comparison of the angle data A, B ′, C ′ and makes it the encoder angle data. In addition, the first, second, and third light receiving element groups 20, 7, and 21 are configured to be formed integrally with each other or separated from each other.

  The one-track Nbit absolute encoder according to the present invention uses the most angular data obtained after processing using read data from three or more sets of light receiving elements as encoder angle data, so that the absolute pattern on the rotating disk Even when foreign matter is attached to the surface, accurate angle data can be easily obtained.

DESCRIPTION OF SYMBOLS 1 Light source 2 1 track type Nbit absolute pattern 4 Rotating slit 5 Mask part 6 Light receiving element 8 Absolute encoder 9 Reading data 10 2nd angle data converter 12 Foreign material 20 1st light receiving element group 30 1st angle data converter 31 3rd Angle data converter 40 Angle data comparator 41 First angle offset corrector 42 Second angle offset corrector A First angle data (encoder angle data)
B 2nd angle data B '2a angle data C 3rd angle data

Claims (2)

A light-receiving element group (20, 20) composed of N light-receiving elements arranged on the circumference of the one-track Nbit absolute pattern of the rotary code plate (3) and arranged at a preset angular position. 7, 21) In a one-track Nbit absolute encoder configured to read the absolute pattern (2) and convert it into encoder angle data (A),
Read data (9) obtained by simultaneously reading the absolute pattern (2) by the light receiving elements (6) of at least three sets of the light receiving element groups (20, 7, 21) is set to the first, second, and third angles. A plurality of first, second and third angle data converters (30, 10, 31) for converting into data (A, B, C), and second and third angle data ( B, C) from the first and second angle offset correctors (41, 42), the first angle data converter (30) and the angle offset correctors (41, 42). An angle data comparator (40) for comparing the obtained plurality of angle data (A, B ', C'), and
After each angle data (A, B ′, C ′) is compared by each angle data comparator (40), the first angle data (A) consisting of the most angle data is selected and the encoder angle data is selected. A one-track Nbit absolute encoder, characterized in that   The said 1st, 2nd, 3rd light receiving element group (20,7,21) is comprised by either the mutually integrated or separate body shape, respectively. Track type Nbit absolute encoder.

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