Method for determining the position of a first moving component relative to a second component and device for applying said method

• US 7,476,843 B2
• Filed: 12/23/2005
• Issued: 01/13/2009
• Est. Priority Date: 12/23/2005
• Status: Expired due to Fees

• Current Assignee: Delphi Technologies, Inc. (BorgWarner Incorporated)
• Original Assignee: Delphi Technologies, Inc. (BorgWarner Incorporated)
• Inventors: Wright, C. David
• Primary Examiner(s): NGUYEN, SANG H
• Application Number:
  US11/317,744
• Publication Number:
  US 20070146730A1
• Time in Patent Office: 1,117 Days
• Field of Search: 356/614, 356402-408, 356617-620, 250/231.13, 250/231.14, 250/231.18, 250/214.1, 250/241.R, 250/237.G, 250/231.11, 250/227.11
• US Class Current: 250/231.13
• CPC Class Codes: G01D 5/347 using displacement encoding scales

Abstract

A method for determining the position of one of two components in relative motion with respect to each other, using optical means, comprises:

• • directing at least one light beam emitted by a light source attached to one component towards a diffractive support attached to the second component, calculated and manufactured for generating an optical signal indicative of the positioning of said support, the optical signal being produced by the diffractive support in transmission and/or in reflection, and the optical signal including information indicative of its quality;
  • detecting and reading at least one optical code formed by said signal, which corresponds to a unique position of the diffractive support relatively to the beam; and
  • assigning a position to each detected optical code.

Claims

1. A method for determining the position of one of two components in relative motion, with respect to each other, using optical means and consisting of:

directing at least one light beam emitted by a light source attached to a component towards a diffractive support attached to the second component, calculated and manufactured in order to generate an optical signal indicative of the positioning of said support, wherein the optical signal is produced by the diffractive support in transmission and/or in reflection, and wherein the optical signal includes information indicative of its quality;

detecting and reading at least one optical code formed by said signal, which corresponds to a unique position of the diffractive support relatively to the beam, and which code includes information indicative of the quality of the signal; and

assessing the quality of the signal;

assigning a position to each detected optical code; and

outputting signal indicative of said position to a user;

wherein each detected and read optical code is compared with electronic codes stored in a memory table for determining the position of the diffractive support; and

wherein each optical code corresponding to a position of the diffractive support includes at least one optical synchronization structure, the detection of which allowing the triggering of the reading phase of the optical signal integrating the code of a position of the diffractive support relatively to the beam.

2. The method according to claim 1, wherein the information indicative of the quality of the signal is a parity code.

3. The method according to claim 1, wherein the information indicative of the quality of the signal is a checksum code.

4. The method according to claim 1, wherein the information indicative of the quality of the signal is a cyclic redundancy.

5. The method according to claim 1, wherein the optical code formed by each optical signal appears as optical structures on the basis of which bits of an electronic code are generated by means for detecting and reading said structures.

6. The method according to claim 5, wherein each detected and read code is submitted to an algorithm for calculating the position of the diffracted support relatively to the beam.

7. The method according to claim 5, wherein the codes defining the position of a component relatively to the other comply, in the order of their succession, with the GRAY code.

8. The method according to claim 1, wherein the diffracted optical code includes at least one starting optical structure and at least one end optical structure delimiting the reading area for the optical signal corresponding to a position of the diffractive support relatively to the beam.

9. The method according to claim 1, wherein each optical code corresponding to an identifiable position includes at least one optical calibration structure used for purposes of diagnosing proper read-out operation.

10. The method according to claim 9, wherein the optical structures consist of at least one light spot, the intensity of which is measured.

11. The method according to claim 10, wherein the variations of luminosity of at least one of the spots forming the optical structures are coded by means of an analog/digital converter, providing binary or grey level read-out.

12. The method according to claim 1, wherein the light source is pulsed according to a frequency controlled by the velocity of the component in motion, read-out being synchronized with the generation of the light beam(s).

13. The method according to claim 1, further comprising the step of determining the angular position of one of the components relatively to the other.

14. The method according to claim 1, wherein the number of optical spots or structures used for coding the angular position is at least equal to 12 in order to provide an angular resolution less than 0.1°

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