Suppression of cross-track vibrations using a self-sensing micro-actuator in hard disk drives

Abstract

In this study we utilize the self-sensing capabilities of piezoelectric micro-actuators in hard disk drives (HDD) to actively suppress in-plane resonance modes of the suspension in an HDD. The self-sensing circuit is based on a tunable capacitance bridge that decouples the control signal from the sensing signal in the micro-actuator. A hybrid modeling technique based on a realization algorithm and least-squares optimization for continuous-time systems is used to model the single-input dual-output system. An analog controller was computed using standard $$H_{\infty}$$ -controller design tools and reduced in order using model reduction routines. Experimental implementation using analog filter design shows the effectiveness of the proposed method in reducing the main sway modes of the suspension.