Seagate Technology Incorporated

Jeffrey Don Andress

Ryan Todd Lyle

Kenneth Lee Pottebaum

Christopher R Fulkerson

David Charles Waugh

Philip Ray Woods

Jon P Baker

James W Dulaney

Phillip R Ridenour

Charles Randall Berry

A method for placing a predetermined number of notch filters in a disc drive servo control system to attenuate noise frequencies, in order of decreasing resonance magnitudes, is disclosed. The method involves calculating an open loop response for a response spectrum of the drive, calculating a notch filter for any noise frequency that exceeds a threshold, mathematically applying the notch filter into the servo control system, recalculating the open loop response and applying another filter for a noise frequency that exceeds the threshold and repeating until no noise frequencies exceed the gain threshold; selecting another frequency range and repeating the same process until a predetermined number of notch filters has been placed in the servo control system.

Rangeless servo notch optimization

Method and apparatus for compensating for a decrease in the torque constant of an actuator motor in a data storage device. An actuator supports the head adjacent a data recording surface on which a plurality of tracks are defined. A servo circuit outputs current to the actuator motor to carry out a seek to move the head from an initial track to a destination track in accordance with a velocity profile having a nominal deceleration trajectory along which the head is decelerated to reach the destination track. The servo circuit operates to adjust an initial value of gain to a second value in response to a selected parameter, and scales the nominal deceleration trajectory to a derated deceleration trajectory in relation to the second value of the gain. The derated deceleration trajectory is preferably selected in relation to the difference between the second value of gain and a predetermined threshold.

Motor torque constant variation compensation

Method and apparatus for performing a seek operation to move a data transducing head from an initial track to a destination track on a rotatable recording surface. A servo control circuit operates to sweep the head across the recording surface. Servo data from an intermediary track are transduced to obtain a detected angular position value for the head with respect to the recording surface. When the detected angular position value differs from a predicted angular position value for the head, the servo control circuit initiates an index qualification routine at the conclusion of the seek. The qualification routine involves transducing the servo data from the destination track to verify the accuracy of the predicted angular position value. In this way, the effects of spurious (false) index signals obtained from the servo data transduced during the seek operation are minimized, and unnecessary reinitializations of the servo control circuit are avoided.

Adaptive index reference position qualification

An improved attachment of an actuator E-block of an actuator apparatus to a cartridge bearing assembly for a hard disc drive, the actuator apparatus having an E-block with a central bore having a pair of cartridge bearing alignment edges and a relief area, the cartridge bearing alignment edges disposed within the central bore to engage the cartridge bearing assembly. Mounting members extend through the wall of the E-block into the central bore to apply a frictional load there against and a compressive load against the cartridge bearing assembly sufficient to maintain contact between the cartridge bearing alignment edges of the E-block and the cartridge bearing assembly.

Actuator assembly attachment in a disc drive

Apparatus for reducing mechanical resonances in a disc drive printed circuit board to reduce acoustic emissions and improve mechanical shock sensing and reporting. A constrain layer comprising a thin layer of rigid, stiffening material is disposed adjacent to the exterior surface of the base portion of a base deck of the disc drive. A vibro-acoustic isolator comprising a thin layer of dampening material, is disposed adjacent the constrain layer and the printed circuit board, the vibro-acoustic isolator and the constrain layer are secured to the base portion of the base deck using conventional fasteners. The vibro-acoustic isolator serves to isolate the printed circuit board from the constrain layer and at the same time dampen mechanical resonances established in the printed circuit board, in conjunction with the stiffening provided by the constrain layer. The constrain layer and vibro-acoustic isolator thus reduce acoustic emissions generated by resonances established in the printed circuit board, as well as reducing the potential for false triggering of a shock sensor mounted to the printed circuit board and used to detect shock events encountered by the disc drive.

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Edmond, OK, United States of America

Jeffrey Don Andress