Compact, long-range absolute position transducer with an extensible compact encoding
US6157188A · kind A · utility
Assignee
Inventor
Key dates
| Filing date | Aug 31, 1998 |
| Grant date | Dec 5, 2000 |
| Priority date | — |
| Expiry date | Aug 31, 2018 |
Classification
- Technology area (CPC G)Physics
- CPC primaryG01D5/2073
- WIPO fieldMeasurement
- WIPO sectorInstruments
Abstract
A compact, long-range inductive absolute position transducer system has two members movable relative to each other and includes a code track transducer and at least one fine wavelength transducer. The two members include a read head member and a scale member. The phase difference between the phase angles of two fine wavelength transducers may be used to generate an intermediate wavelength. Alternatively, the phase difference between the phase angles of one fine wavelength transducer and the code track transducer may be used to generate an intermediate wavelength. The code track includes sequential n-bit code words. Each sequential code word identifies an absolute position of one member with respect to the other with a first resolution. Each intermediate wavelength includes an integer number of code words greater than or equal to one. Using this relationship, the intermediate wavelength is used to identify the start position (start bit) of the appropriate code word. A fine track transducer is then used to define an absolute position of the read head member relative to the scale member to a second, finer resolution.
Source: USPTO / EPO open patent data. Objective bibliographic and citation counts.