Shaft angle encoder with rotating off-axis interference pattern
US5138154A · kind A · utility
Assignee
Inventor
Key dates
| Filing date | Apr 4, 1990 |
| Grant date | Aug 11, 1992 |
| Priority date | — |
| Expiry date | Apr 4, 2010 |
Classification
- Technology area (CPC G)Physics
- CPC primaryG05G2009/04759
- WIPO fieldMeasurement
- WIPO sectorInstruments
Abstract
A shaft angle encoder adapted for use in a hand-held gyroscope has a motor at the core of the gyroscope suspended by two pairs of orthogonal gimbals to provide two-degrees-of-freedom for the inner gimbal. Power is provided to the motor through conductive elements in the bearings without limting the range of motion of the gyroscope. An electro-optical shaft angle encoder for detecting the rotation of the inner gimbal with respect to the outer gimbal includes an optical pattern mounted along a cylindrical portion of the inner gimbal about the axis of rotation of the inner gimbal and in alignment with one of the outer gimbal bearings. A light source and a rotational phase plate are mounted to the outer gimbal and aligned with this optical pattern and a light path is provided through the optical pattern, the rotational phase plate, and the outer gimbal bearing. The rotational phase plate interferences with the image of the optical pattern so as to create an image which rotates about the axis of the outer gimbal bearing as a function of the rotation of the inner gimbal with respect to the outer gimbal. This image is detected by a quadrature sensor mounted on the outer housing which dete…
Source: USPTO / EPO open patent data. Objective bibliographic and citation counts.