Robust track-following control of hard disk drives using improved integral sliding mode combined with phase lead peak filter

An integral-type sliding mode control (SMC) scheme with application to track-following control in hard disk drives (HDDs) is investigated in this paper. With the proposed technique, the dynamics of the sliding mode is analytically obtained without any reaching phase by using the integral sliding surface. To reconstruct estimates of the system states for use in a full information SMC law, an asymptotic observer is also employed and the fulfillment of sliding condition, including the case when estimated states are used, is also verified. In addition, the proposed control scheme integrated with a phase lead peak filter (PLPF) is also investigated for better rejection of disturbance of narrow-band type at mid-frequency ranges. Simulation studies on the design of a track-following controller in HDDs are conducted to illustrate its feasibility and effectiveness. The simulation results also demonstrate that the proposed scheme provides better performance than the conventional sliding mode and proportional-integral-derivative control methods. Copyright (C) 2007 John Wiley & Sons, Ltd.