Plant variation compensation for piezoelectric microactuator in dual-stage servo of disc drives

Abstract

A method and system for providing plant variation compensation for a microactuator in a dual-stage servomechanism of a disc drive. The method includes performing indirect adaptive filtering to identify plant variation in the microactuator, and tuning a compensator for the microactuator based on the plant variation. The indirect adaptive filtering can be performed using a two-stage process, including a first stage of adaptive modeling for the dual-stage servomechanism and a second stage of generating an indirect mode-reference inverse for the microactuator. A combined process can alternatively be employed. The microactuator can be a piezoelectric microactuator which forms a PZT system. The dual-stage servomechanism also includes a coarse actuator such as a voice coil motor.

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