Method and apparatus for feedforward repeatable runout compensation in a selected frequency range
US6859341B2 · kind B2 · utility
Assignee
Inventors
Key dates
| Filing date | Mar 25, 2003 |
| Grant date | Feb 22, 2005 |
| Priority date | — |
| Expiry date | Aug 5, 2023 |
Classification
- Technology area (CPC G)Physics
- CPC primaryG11B5/59627
- WIPO fieldAudio-visual technology
- WIPO sectorElectrical engineering
Abstract
For runout compensation in a data handling system, a servo feedback loop is configured to control a head position relative to a corresponding disc surface. Operation of the feedback loop is complicated by a repeatable error in the head position having energy at harmonics of the spindle rotation frequency. Also, the feedback loop has a gain with a frequency sensitivity in a target frequency range. A feedforward controller generates an output injected into the feedback loop based on an error-indicative input. This defines a feedforward closed-loop transfer function, between the loop output and the feedforward controller input. The feedforward controller prevents the frequency sensitivity from substantially varying the feedforward closed-loop transfer function gain and phase within the target frequency range, thus reducing computational burden.
Source: USPTO / EPO open patent data. Objective bibliographic and citation counts.