Constant velocity servosystem wtih high positional accuracy
US4988932A · kind A · utility
Assignee
Inventors
Key dates
| Filing date | Oct 10, 1989 |
| Grant date | Jan 29, 1991 |
| Priority date | — |
| Expiry date | Oct 10, 2009 |
Classification
- Technology area (CPC G)Physics
- CPC primaryG11B7/26
- WIPO fieldAudio-visual technology
- WIPO sectorElectrical engineering
Abstract
The present servosystem positions a movable member such as an optical head over a rotating disk with a constant velocity and high positional accuracy by utilizing a fast analog feedback loop that is controlled by a slower digital loop. The analog feedback loop locks the speed of the movable member to the speed of the rotating disk in a spiral recording track. The progress of the movable member is constantly monitored with the digital loop. A velocity error of known magnitude and direction is introduced into the system. When the error exceeds a preset limit an error of the known magnitude but of the opposite direction is introduced. The servosystem thus zig-zags about the desired position with small velocity changes to provide a substantially constant velocity system with high positional accuracy.
Source: USPTO / EPO open patent data. Objective bibliographic and citation counts.