Feed forward compensation for repeatable head position error in a disc drive

摘要

Method and apparatus for reducing repeatable runout signals in a servo position error (SPE) signal of a disc drive actuator. During track following, a measurement estimate is obtained through the sampling and accumulating of data from the SPE over a mechanical revolution of the drive, the measurement estimate providing a characterization of the repeatable runout signal in the servo position error signal. A correction estimate is updated by the measurement estimate, and the correction estimate is added to the servo position error signal to provide an adjusted servo position error signal. The disc drive uses the adjusted servo position error signal to generate a correction signal for adjusting the position of the actuator. The measurement estimate is reset after each update of the correction estimate and a new measurement estimate is generated during each subsequent rotation of the disc drive during track following mode.