Adaptive fuzzy control of hybrid active slider design with thermal and piezoelectric actuators

Abstract

Recent advance of magnetic storage technology includes active thermal fly-height control (TFC) technique that is able to reduce clearance between read/write heads and disk surface within few nanometers. However, it has been estimated that TFC technique alone cannot provide further smaller clearances necessary to achieve Tbit/in2 recording density due to the presence of bouncing vibrations and slider dynamic instabilities. In this work, a hybrid active slider technique with both thermal and piezoelectric actuators is proposed with goal placed in achieving extremely high-density recording. Nonlinear system dynamics of the thermally actuated slider is established through test-based identifications. To fully eliminate the high frequency bouncing vibrations, an adaptive fuzzy control hybrid active slider design in which piezoelectric actuation is added to the existing thermally actuated slider design is suggested and examined in this work. Along with state-of-the-art and matured manufacturing techniques of piezoelectric slider and TFC slider, it is anticipated that with the proposed method, more than Tbit/in2 recording density with sub-nanometer level clearance can be achieved.