Linear and rotary multitrack absolute position encoder and methods using the same
OwnerPhilip M. Johnson, David K. Johnsoninventors
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Abstract
Optical Position Encoders and methods using the same are described. In embodiments, the optical position encoders include a multitrack Hybrid Cyclic Binary Code-2 (HCBC-2) encoded scale and an Optical Readout Assembly (ORA), where the ORA provides absolute position optical readout and automatic physical alignment to the scale. Linear optical position encoders, rotary optical position encoders, and methods of measuring the position of ORA relative to a scale using such encoders are also described.
Claims21
An optical absolute position encoder, comprising:
- a scale comprising a substrate comprising a first region encoded with a hybrid cyclic binary code 2 (HCBC-2);
- and
- an optical readout assembly (ORA);
- wherein:
- said first region encoded with said HCBC-2 comprises:
- a first sub-region comprising a first multitrack array of hybrid cyclic binary code (HCBC) patterns;
- a second sub-region comprising a second multitrack array of HCBC patterns, the second multitrack array being a reflection and complement of the first multitrack array;
- the ORA comprises at least one light source configured to emit light pulses onto said HCBC-2 encoded scale;
- and
- said ORA is configured to measure at least a portion of light reflected by said HCBC-2 scale and determine a position of said HCBC-2 scale relative to said ORA.
A method of measuring the absolute position of a scale relative to a readout assembly, comprising:
- emitting light pulses from a light source, said light pulse being incident on a scale, the scale comprising a first region encoded with a hybrid binary cyclic code 2 (HCBC-2);
- detecting, with an optical readout assembly (ORA) at least a portion of said light pulses reflected by said scale, and generating at least one sensor signal;
- and
- calculating, with a controller, a position of the scale relative to said readout assembly, based on said at least one sensor signal;
- wherein:
- the first region encoded with said HCBC-2 scale comprises:
- a first sub-region comprising a first multitrack array of hybrid cyclic binary code (HCBC) patterns;
- and
- a second sub-region comprising a second multitrack array of HCBC patterns, the second multitrack array being a reflection and complement of the first multitrack array.
Dependencies are inferred from the claim text.