A unified dual-stage actuator control scheme for track seeking and following in hard disk drives

This paper presents a unified approach to track seeking and following control of a hard disk drive (HDD) dual-stage actuator (DSA) system. Based on doubly coprime factorization (DCF) method, the DSA controller and the closed loop dynamics are expressed explicitly in terms of two design parameters. This greatly simplifies the optimization of design parameters in meeting desired specifications. We then address how to use the design parameters to deal with specific problems in the DSA, i.e., control allocation for disturbance rejection and trajectory planning for track seeking. Simulated results are also presented to verify the effectiveness of the proposed DSA controller. Compared to previous works, the proposed approach can fulfill track seeking and following tasks by a single controller without switching. Moreover, the unified controller can achieve desirable performances for both tasks which are equivalent to that by two separate conventional controllers.