Lowering the Hump of Sensitivity Functions for Discrete-Time Dual-Stage Systems

摘要

This brief is concerned with servo loop design in the discrete-time domain that aims to achieve a low-hump sensitivity function for dual-stage hard disk drive (HDD) systems. Sensitivity functions for the discrete-time dual-stage systems are analyzed on the basis of the Bode integral theorem. A 3-dB sensitivity function hump is achieved in simulation for the discrete-time dual-stage actuation system with a piezoelectric (PZT) microactuator (MA) using the H{sub}∞ loop shaping method and the proposed linear matrix inequality (LMI) approach. Additionally, implementation is done for the PZT MA dual-stage system and a sensitivity function/with the magnitude lower than 3 Db being achieved.