POSITION DETECTING DEVICE AND METHOD FOR PRODUCING A MARKING ARRANGEMENT FOR A POSTION DETECTING DEVICE

• US 20130200886A1
• Filed: 04/20/2010
• Published: 08/08/2013
• Est. Priority Date: 04/20/2010
• Status: Active Grant

• Current Assignee: Hamilton Bonaduz AG (Hamilton Company)
• Original Assignee: Hamilton Bonaduz AG (Hamilton Company)
• Inventors: Kirste, Vinzenz, Kppel, Claudio Gian
• Granted Patent: US 9,041,385 B2
• Time in Patent Office: Days
• US Class Current: 324/207.22
• CPC Class Codes: G01B 7/003 for measuring position, not involving coordinate determination coordinate measuring G01B7/004
• CPC Class Codes: G01D 5/2455 with incremental and absolute tracks on the same encoder
• CPC Class Codes: G01D 5/2492 Pulse stream
• CPC Class Codes: G01D 5/34792 with only digital scales or both digital and incremental scales
• CPC Class Codes: Y10T 29/49764 with testing or indicating

Abstract

The present invention provides a position detecting device for detecting a positional relationship between a first component (10) and a second component (12), comprising a marking arrangement (14) which is provided on the first component (10) and has an absolute track (18) and an incremental track (20), the absolute track (18) having a plurality of absolute markings (22) from which a binary absolute code sequence (B) can be read, and the incremental track (20) having a plurality of incremental markings (24) which are associated with the absolute markings (22) and from which an alternating incremental sequence (I) can be read, and a sensor arrangement (16) which is provided on the second component (12) and is configured to scan the absolute markings (22) and the incremental markings (24; 24), wherein the absolute code sequence (B) is formed from a first and a second De Bruijn sequence (B1, B2) of order N which follow one another, the second De Bruijn sequence (B2) being a cyclic shift of the first De Bruijn sequence (B1), and wherein the first De Bruijn sequence (B1) ends with a first subsequence (Ua) of length N−1 and contains a second subsequence (Ub) of length N−1 which is identical to the first subsequence (Ua) and is shifted relative to the first subsequence (Ua) by an uneven number of places, and wherein the second De Bruijn sequence (B2) is shifted cyclically relative to the first De Bruijn sequence (B1) such that it ends with the second subsequence (Ub).

Claims

1. Position detecting device for detecting a positional relationship between a first component (10;

10a) and a second component (12;

12a), comprising;

a marking arrangement (14;

14a) which is provided on the first component (10;

10a) and has an absolute track (18;

18a) and an incremental track (20;

20a), the absolute track (18;

18a) having a plurality of absolute markings (22;

22a) from which a binary absolute code sequence (B) can be read, and the incremental track (20;

20a) having a plurality of incremental markings (24;

24a) which are associated with the absolute markings (22;

22a) and from which an alternating incremental sequence (I) can be read, and

a sensor arrangement (16;

16a) which is provided on the second component (12;

12a) and is configured to scan the absolute markings (22;

22a) and the incremental markings (24;

24a),

characterised in that the absolute code sequence (B) is formed from a first and a second De Bruijn sequence (B1, B2) of order N which follow one another, the second De Bruijn sequence (B2) being a cyclic shift of the first De Bruijn sequence (B1),

in that the first De Bruijn sequence (B1) ends with a first subsequence (Ua) of length N−

1 and contains a second subsequence (Ub) of length N−

1 which is identical to the first subsequence (Ua) and is shifted relative to the first subsequence (Ua) by an uneven number of places,

in that the second De Bruijn sequence (B2) is shifted cyclically relative to the first De Bruijn sequence (B1) such that it ends with the second subsequence (Ub).

2. Position detecting device according to claim 1,

characterised by an electronic control means (30) which is connected to the sensor arrangement (16;

16a) to receive a first sensor signal corresponding to a scanning of the absolute track (18;

18a), a second sensor signal corresponding to a scanning of the incremental track (20;

20a) and a third sensor signal corresponding to a detected relative position between two successive incremental markings (24;

24a), and which is configured to determine the positional relationship between the components (10, 12;

10a, 12a) on the basis of the first sensor signal, the second sensor signal and the third sensor signal.

3. Position detecting device according to claim 2,

characterised in that the electronic control means (30) comprises a memory means (32) in which an absolute position value, formed by N+1 bits, is stored, the electronic control means (30) setting N bits of the absolute position value according to the first sensor signal and setting one bit of the absolute position value according to the second sensor signal.

4. Position detecting device according to claim 1, characterised in that the sensor arrangement (16;

16a) is configured to detect exactly N successive absolute markings (22;

22a).

5. Position detecting device according to claim 1, characterised in that the scanning of the marking arrangement (14;

14a) is based on a magnetic interaction between the sensor arrangement (16;

16a) and the absolute markings (22;

22a) and/or the incremental markings (24;

24a).

6. Position detecting device according to claim 1,

characterised in that the position detecting device is configured to detect a linear displacement position between the components (10, 12).

7. Position detecting device according to claim 1,

characterised in that the position detecting device is configured to detect a rotational position between the components (10a, 12a).

8. Position detecting device according to claim 7,

characterised in that the absolute track (18a) and the incremental track (20a) revolve fully around an axis of rotation A of the components (10a, 12a), a beginning of the second De Bruijn sequence (B2) adjoining an end of the first De Bruijn sequence (B1) and a beginning of the first De Bruijn sequence (B1) adjoining an end of the second De Bruijn sequence (B2).

9. Method for producing a marking arrangement (14;

14a) for a position detecting device for detecting a positional relationship between a first component (10;

10a) and a second component (12;

12a), the position detecting device comprising a sensor arrangement (16;

16a) for scanning the marking arrangement (14;

14a), in particular for a position detecting device according to any one of the preceding claims, the method comprising the following steps;

provision of an initial De Bruijn sequence (B0) of order N (S1),

identification of a first subsequence (Ua) of length N−

1 and of a second subsequence (Ub) of length N−

1 which are identical to one another and occur within the initial De Bruijn sequence (B0), shifted relative to one another by an uneven number of places (S2),

provision of a first De Bruijn sequence (B1) of order N by cyclically shifting the initial De Bruijn sequence (B0) so that the first De Bruijn sequence (B1) ends with the first subsequence (Ua) (S3),

provision of a second De Bruijn sequence (B2) of order N by cyclically shifting the initial De Bruijn sequence (B0) so that the second De Bruijn sequence (B2) ends with the second subsequence (Ub) (S4),

provision of an absolute code sequence (B) by linking the first De Bruijn sequence (B1) and the second De Bruijn sequence (B2) (S5),

provision of an absolute track (18;

18a) from a plurality of absolute markings (S6;

22;

22a) encoding the absolute code sequence (B), and

provision of an incremental track (20;

20a) from a plurality of incremental markings (24;

24a) which are associated with the absolute markings (22;

22a) and encode an alternating incremental sequence (I) (S6).

10. Position detecting device for detecting a positional relationship between a first component (10;

10a) and a second component (12;

12a), preferably a position detecting device according to claim 1, comprising;

a marking arrangement (14;

14a) which is provided on the first component (10;

10a) and has an absolute track (18;

18a) and an incremental track (20;

20a), the marking arrangement (14;

14a) being obtainable by a method according to claim 9, and

a sensor arrangement (16;

16a) which is provided on the second component (12;

12a) and is configured to scan the absolute markings (22;

22a) and the incremental markings (24;

24a).