Identification of contact bouncing vibrations using TFC active slider and adaptive fuzzy control for advanced active slider design

The recent advance of magnetic storage technology includes the active thermal fly-height control (TFC) technique that is able to reduce the clearance between read/write heads and disk surface to be of few nanometers. However, it has been estimated that TFC technique alone cannot provide the even smaller clearances necessary to achieve Tbit/in² recording densities due to the presence of bouncing vibrations and instability. In this work we investigate hybrid active slider technique with both thermal and piezoelectric actuators to achieve extremely high-density recording. The nonlinear system dynamics of thermal actuated slider is established by test-based identification. We propose an adaptive fuzzy control hybrid active slider design in which piezoelectric actuation is added to the existing thermal actuated slider design, so as to fully eliminate the high frequency bouncing vibrations. It can yield more than Tbit/in² recording density with sub-nanometer level clearance, while using the state-of-the-art and matured manufacturing techniques for active piezoelectric slider and TFC slider.