Flying Height Control with Gap Capacitance Servo in Near-Field Optical Disk Drives
| Autor: | Hsing-Cheng Yu, 余興政 |
|---|---|
| Rok vydání: | 2002 |
| Druh dokumentu: | 學位論文 ; thesis |
| Popis: | 90 In order to overcome the diffraction limit of conventional optical disk drives, the flying pickup head in near-field optical disk drives enables the slider to fly at a stable spacing above the disk surface, thereby substantially increasing storage capacity and density. Hence, enhancing control performance to improve focusing speed and accuracy is required. To sense flying height in control experiments, a gap capacitance servo measures capacitance variation between the pickup head and disk surface and process voltage signals out of the capacitor by demodulation. Sliding mode control inherited with robust properties can deal with model uncertainty and disturbances. Therefore, a DSP control card executes a sliding mode control algorithm to compensate the vibration of the optical disk surface and achieve a stable flying height for the pickup head. |
| Databáze: | Networked Digital Library of Theses & Dissertations |
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