Performance evaluation using laser doppler vibrometer sensing technique on advanced lead magnesium niobate-lead titanate piezoelectric-material-based microactuator for hard drive head

Abstract

This paper presents a microactuator for a dual-stage actuator (DSA) of hard disk drive (HDD) based on a lead magnesium niobate-lead titanate (PMN-PT) piezoelectric material and a comparative evaluation of its performance versus that of a traditional lead zirconate titanate (PZT) microactuator using the laser Doppler vibrometer (LDV) sensing technique. PZT microactuator technology has commonly been implemented in the read/write (R/W) magnetic head of HDD. It has a significant function, that is, it moves the magnetic head rapidly and accurately. In order to achieve both accurate positioning control on data tracks and high-speed access across another data track, advanced high-performance actuators and servo control technologies are necessary. An actuator with a wide stroke travel range is essential for HDD as it gives a high-speed access performance. In this study, we focused on comparing the proposed dual-stage PMN-PT head-based actuator with the existing PZT actuator that were mounted on a commercial head gimbal assembly (HGA) using an LDV to determine whether the proposed device could be a worthy replacement of the traditional PZT microactuator. Our experimental results show that the proposed PMN-PT microactuator provided more than twofold improvement in the stroke travel of the R/W magnetic head. Moreover, its dynamic behavior was suitable for assembling a high-density HDD in the future for big data storage without any needs to redesign the HGA nor to costly invest in new assembling machines in a production line. The comparative data of dynamic and static behaviors of PMN-PT versus PZT obtained in this study may be put to good use by sensor designers. Moreover, for many cyber-physical system designers, our data may make them take interest in PMN-PT as a better-performing sensor and an actuator for their systems.