Patent ID: 6768607
Filing Date: 2004-07-27
Classification: G11B

Abstract:
A disk drive comprising:an actuator servo control system including: at least one disk having a plurality of radially-situated data tracks, an actuator structure comprising at least one transducer head for writing and/or reading data from the disk surface, a suspension, an arm structure and a voice coil motor, and providing a transducer head position error signal (PES); a servo compensator applying a servo-control algorithm to the PES to thereby produce a servo control signal; and an adaptive resonant disturbance attenuator adapted to analyze the PES for a transducer head at a data track radii, identify resonant disturbances present in the PES, select two adjacent resonant disturbances having a first and second resonant frequency, ascertain coefficients of at least a fourth-order elliptic notch filter transfer function having a first zero-notch with a frequency substantially at the first resonant disturbance frequency and a second zero-notch with a frequency substantially at the second resonant disturbance frequency, apply the ascertained coefficients to the at least fourth-order elliptic notch filter transfer function to thereby generate a tuned fourth-order digital elliptic notch filter, and apply the tuned fourth-order digital elliptic notch filter in the servo system to thereby substantially attenuate the selected adjacent resonant disturbances.