Position/speed detection method and apparatus
US4922175A · kind A · utility
Assignee
Inventors
Key dates
| Filing date | Mar 3, 1989 |
| Grant date | May 1, 1990 |
| Priority date | — |
| Expiry date | Mar 3, 2009 |
Classification
- Technology area (CPC G)Physics
- CPC primaryG01D5/24409
- WIPO fieldMeasurement
- WIPO sectorInstruments
Abstract
Disclosed is a position detecting method and apparatus which are suitable for detecting the position of a moving body on the basis of the output of a position detector for generating two-phase periodic waves having a phase difference of a quarter period, the method comprising the steps of: comparing either one of the two-phase periodic waves with a predetermined reference value having hysteresis to thereby obtain a roughly estimated position for every half period of the one periodic wave; analog-to-digital converting the two-phase periodic waves and a zero-cross value for every sampling period to thereby obtain a finely estimated position; and detecting the position of the moving body on the basis of the roughly estimated position and the finely estimated position while correcting an error due to the hysteresis at the starting point of the roughly estimated position, by use of the relationship between the roughly estimated position and the finely estimated position. According to this method/apparatus, continuity between the roughly estimated position and the finely estimated position can be maintained, so that exact and high-resolution position detection can be performed.
Source: USPTO / EPO open patent data. Objective bibliographic and citation counts.