Optimal sliding mode dual-stage actuator control for magnetic disk drives

This paper presents a discrete-time design of a dual-stage actuator (DSA) control system with sliding mode for hard disk drives. A state estimator based discrete-time boundary layer sliding mode control scheme is developed for disk drive dual-stage servo systems. In the DSA control design, an optimal sliding hyperplane is designed, that minimizes the destructive interference between the voice coil motor and microactuator and thereby produces desired time and frequency responses. The resulting DSA control system is used for track-seek in the microactuator range, settle, and track-follow. An application example demonstrates the utility of the proposed discrete-time sliding mode DSA control scheme.