External disturbance rejection control based on identification of transfer characteristics from the acceleration sensor for access control of hard disk drive system

In this paper, a new method for external disturbance rejection control which is based on the identification of transfer characteristics from an acceleration sensor is proposed. For hard disk drives, the external disturbance which should be reduced is growing with widespread use of movable computers and other independent machines. In order to reject the effect of the external disturbance, the authors apply the feedforward controller which is designed by a recursive least squares (RLS) algorithm and fixed trace (FT) algorithm utilizing the acceleration signal and the estimated disturbance signal. Some experimental results in which a disk drive is shaken in the vertical direction are shown to verify the effectiveness of the proposed method.