Control performance comparison of PZT microactuator driven by voltage and current amplifiers in HDD dual-stage systems

In this paper, we investigate the effect of voltage and current amplifiers for PZT microactuators on the control performance of dual-stage servo systems in hard disk drives (HDDs), where the PZT microactuator is used as a secondary actuator and works together with the primary actuator of voice coil motor (VCM). First, the PZT microactuator's behavior in terms of motion linearization and frequency responses is experimentally studied and compared when it is driven by a conventional voltage amplifier and a charge or current amplifier. It is found that the PZT microactuator with current amplifier has less hysteresis than with voltage amplifier and its first resonance is relatively smaller. Inspired by this difference, the control performance of the dual-stage servo systems in track-seeking and track-following is then compared between the two driving methods for the PZT microactuator.