Feedback control system using optical incremental position encoder with dual sinusoidal intensity patterns
US6232594A · kind A · utility
Assignee
Inventors
Key dates
| Filing date | Jun 22, 1999 |
| Grant date | May 15, 2001 |
| Priority date | — |
| Expiry date | Jun 22, 2019 |
Classification
- Technology area (CPC G)Physics
- CPC primaryG01D5/34
- WIPO fieldMeasurement
- WIPO sectorInstruments
Abstract
A feedback control system has two sinusoidal quadrature position feedback signals generated by photosensitive detectors that sense light reflected from (or transmitted through) position encoding strips that have a reflectance (or transmissivity) that varies sinusoidally along the length of the strip. The system may have one position encoding strip, with two photosensors offset along the length of the strip to provide a ninety degree phase offset. Alternatively, the system may have two strips that are offset in phase by ninety degrees. An error signal is produced directly within the servo loop without requiring computation of ARC-SIN or ARC-COSINE. The error signal is continuous, and position error is not sensitive to photosensor gain.
Source: USPTO / EPO open patent data. Objective bibliographic and citation counts.