Discrete-time LQG/LTR dual-stage controller design in magnetic disk drives

This paper presents a new dual feedback loop controller design of a dual-stage actuator for hard disk drives. For precise and accurate displacement, coupled dynamic model is considered from the Newton-Euler formulation. A gain factor is introduced so that the level of microactuator's contribution and the high frequency characteristics of the system can be controlled. 2.28 kHz servo bandwidth is achieved. The 6 percent settling time is 250 /spl mu/s and 3/spl sigma/ value is 0.017 /spl mu/m from the experimental result.