Contact-Induced Vibration in Dual-Stage Hard Disk Drive Servo Systems and Its Compensator Design

Abstract

This paper presents the experimental observation results of contact-induced vibration (CIV) and its compensator design in dual-stage hard disk drive servo systems, where the vibration is caused by the continuous contact of read/write head and recording media. Consistent relationships between the center frequencies and magnitudes of the vibration modes and the tested fly height, rotation speed, and track position are clearly observed and analyzed. It reveals that the CIVs excite and amplify only the resonance modes of the system. In consequence, the so-called PQ method is adopted to perform the compensator design. As such, the relative contributions to system output from the voice coil motor and lead-zirconium-titanate actuator subsystems can be well assigned in the frequency domain. The remarkable performance of the well-designed compensator is demonstrated by simulation.