Add-on type loop shaping controller design for high precision track following in hard disc drives (hdds) [Brief Paper]

In this study, the authors present a systematic design method of the add-on type loop shaping scheme for high precision track following with plant modelling perturbations in HDDs. The proposed controller minimises the standard deviation of the position error signal (PES) of certain closed-loop transfer function while satisfying the robust stability condition in HDDs. Compared with the conventional H_∞ control, the proposed method yields estimated plant states, which can be used for estimator-based controller design. Also, the proposed control method can be implemented in a parallel manner by performing a partial-fraction expansion for easy implementation. The effectiveness and practicality of our work is demonstrated through various experimental results.