Title:
ACTIVE MAGNETIC BEARING SYSTEM FOR IMPROVED SERVO CONTROL
Document Type and Number:
WIPO Patent Application WO2000063888
Kind Code:
A3
Abstract:
Apparatus and method for controlling position of a head (120) in a disc drive (100), the head supported by a rotary actuator (110) which is in turn magnetically levitated by an active magnetic bearing assembly (112). A servo control circuit (16) applies current to an actuator coil (113) to rotate the actuator and an active magnetic bearing control circuit (168) applies currents to bearing coils (208) to levitate the actuator. When an external disturbance is applied to the actuator, the active magnetic bearing control circuit provides a bearing translation (BT) signal to the servo control circuit to adjust the current applied to the actuator coil to compensate for the disturbance. Contrawise, when the servo control circuit initiates a seek operation, a seek expectancy (SE) signal is provided to the active magnetic bearing control circuit to adjust the currents to the bearing coils to compensate for the resulting torque forces on the actuator.
Inventors:
ELL TRAVIS E
Application Number:
PCT/US2000/010462
Publication Date:
January 24, 2002
Filing Date:
April 19, 2000
Export Citation:
Assignee:
SEAGATE TECHNOLOGY LLC (US)
International Classes:
F16C32/04; F16C39/06; G11B5/48; G11B5/55; G11B5/588; G11B5/596; G11B21/02; (IPC1-7): F16C39/06; F16C32/04; G11B5/48; G11B5/55
Foreign References:
| EP0819861A2 | 1998-01-21 | |||
| US5808839A | 1998-09-15 |
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