Shock Resistance of a Disk-Drive Assembly Using Piezoelectric Actuators with Passive Damping

Abstract

Current dual-stage actuator design uses piezoelectric patches only without passive damping. In this paper, we propose a dual-stage servo system using enhanced active-passive hybrid piezoelectric actuators. The proposed actuators will improve the existing dual-stage actuators for higher precision and better shock resistance, due to the incorporation of passive damping in the design. Finite element analyses of different types of piezoelectric actuators in a disk arm assembly under external shock are reported. In the analysis, the viscoelastic damping layers in the hybrid actuator are modeled with the Prony series, which parameters are determined from dynamic frequency data of nomograph. In the simulation, a shock impulse of 175 g, 1 ms half sine is applied at one end of the base while the other end of the base is fixed. The responses of the disk arm assembly with different configurations of the piezoelectric actuators are evaluated and compared. The simulation results show that the enhanced active-passive hybrid actuator design would reduce the residual vibration in in-plane motion induced during the shock, resist lift-off motion, and relief the impact damage while the head slaps.Index Terms -hard disk drive, dual-stage servo system, piezoelectric actuator, active-passive hybrid, shock resistance