A Comparative Study of MEMS Microactuators for Use in a Dual-Stage Servo With an Instrumented Suspension

This paper presents the design and analysis of a dual-stage servo system with an instrumented suspension for use in hard disk drives. The dual-stage system is equipped with a microelectromechanical system microactuator (MA), either rotational or translational, as a secondary actuator. In both cases, the MA has a resonance mode at 2.2 kHz and has virtually no other modes up to 40 kHz. Two design approaches, the sensitivity decoupling design and the multiobjective optimization, are applied to the design of the servo system. With either approach, the translational dual-stage actuator achieves better tracking performance than the rotational one by about 13%, which is achieved mainly by attenuating airflow-excited suspension vibrations. This improvement is significant when the servo system´s track misregistration (TMR) budget approaches the level of 5-10 nm. The airflow-excited suspension vibrations then become a significant contribution to the TMR