Abstract
This research shows the new design concept of an actuator in hard disk drives. The actuator which has several higher-order mechanical resonance determines the stability and mechanical noise suppression ability of the servo control system. We presented the new design concept that higher resonance are made in-phase to the first major resonance. In this concept, all the resonance with high gain are in-phase but the outphase resonance's gain are reduced. This mechanical characteristic can be achieved by the carriage arm shape design which pay its attention to 1st and 2nd arm sway mode. In the actuator based on this concept, the higher resonance can be compensated only by the compensator which is designed for the first major resonance.
