Design and development of milliactuator embedded suspension for dual stage system in hard disk drives

Abstract

To realize higher track density of HDD, the servo bandwidth should be higher, however, is limited by the mechanical resonances of the arm, coil of the VCM and ball bearing pivot. One approach to overcoming the problem is using dual stage servo system. For this system, we have suggested new milliactuator based on the shear mode of piezoelectric elements to drive the head suspension assembly. The initial model introduced is the APMRC 2002, and now we improve that model. The milliactuator is added flexure structure for femto slider and applied optimal design process. The objective function is to maximize frequencies of 2nd torsional mode and sway mode with stable compliance of the disk flutter. The improved suspension with milliactuator is analyzed about shock characteristics for mobile application.