Servo control of a dual-stage actuator for a high performance disk drive part 2: Controller design and implementation

In this paper we describe the controller design and implementation for a dual stage servo actuation system for a high performance disk drive. The system utilizes a standard Voice Coil Motor (VCM) combined with a piezo-electric microactuator in a dual stage drive. The VCM provides low-speed motion with a very large stroke enabling coarse positioning and rejection of large amplitude low-frequency disturbances. The microactuator provides very high-speed motion but with limited stroke, enabling fine positioning and rejection of high frequency disturbances. The overall dual-stage system provides a high bandwidth actuation system, capable of very fine positioning despite disturbances with a wide variety of spectral content. In part 1 we focus on the drive and it's analysis, modeling, and simulation. The controller design and implementation is discussed in part 2 (this paper), together with closed-loop in-drive results.