Encoder scale error compensation employing comparison among multiple detectors
US7126109B2 · kind B2 · utility
Assignee
Inventors
Key dates
| Filing date | Jun 14, 2004 |
| Grant date | Oct 24, 2006 |
| Priority date | — |
| Expiry date | Aug 27, 2024 |
Classification
- Technology area (CPC G)Physics
- CPC primaryG01D5/36
- WIPO fieldMeasurement
- WIPO sectorInstruments
Abstract
An encoder calculates position error values and applies compensation values to encoder position measurements in-situ. The encoder includes a scale and a multi-section detector for detecting a spatially periodic pattern, such as an optical interference pattern, produced by the scale. The detector includes spatially separated first and second sections. A signal processor estimates respective phase values from detector sections and calculates a phase difference reflecting a spatial position error in the scale. A compensation value is calculated from the phase difference and included in the estimate of the scale position to compensate for this spatial position error. The compensation values may be calculated and used on the fly, or calculated and saved during an in-situ calibration operation and then utilized during normal operation to compensate uncorrected measurements.
Source: USPTO / EPO open patent data. Objective bibliographic and citation counts.