Seagate Technology Incorporated

Paul Alexander Galloway

Mark A Gaertner

Jason Dale Gregg

Mark Lowell Elliott

Kyle Kenneth Eddy

Jianxu Ma

Zip Cotter

Mohammad A Miah

Bruce J Routh

ToaYou Tan

LeokHwa Chua

Daniel C Kuhl

A seek operation is performed by identifying a seek length of the seek operation and selecting a representation of a deceleration position-velocity profile based on the seek length. Successive demand velocity values are selected during the seek operation by identifying a distance-to-go and a distance-traveled of the seek length, calculating a representation of an acceleration demand velocity based on the identified distance-traveled and a representation of an acceleration position-velocity profile, identifying a representation of a deceleration demand velocity based on the identified distance-to-go and the selected representation of a deceleration position-velocity profile, and selecting the representation of either the acceleration demand velocity or the deceleration demand velocity. The representation of acceleration demand velocity is preferably performed by using a first scaling factors based on the seek length to adjust the identified distance-traveled, and using a second scaling factor based on the seek length to adjust a representation of a demand velocity of a normalized position-velocity profile.

Matching peak velocities of acceleration and deceleration seek profiles in a disc drive

An attenuating filter for the servo control processor of a disc drive data storage device. The filter is constructed by determining the peak resonance in the structure frequency response above a preselected magnitude and computing a digital notch filter to attenuate that peak resonance. The notch filter domain is then summed with the structure frequency response to derive a modified structure frequency response. The modified structure frequency response is substituted for the unfiltered structure frequency response and again the peak resonance in the modified structure frequency response above a preselected magnitude is determined and a notch filter is computed as necessary. This process of summing the structure frequency response with the latest computed notch filter domain to derive a modified structure frequency response continues until the peak resonance of the latest modified structure frequency response is less than the preselected magnitude.

Frequency attenuating filter apparatus and method for a data storage device

An apparatus and method of identifying defective servo sectors in a data storage device detects servo sectors having an associated position error signal (PES) value that exceeds a predetermined PES threshold value, as well as servo sectors that have a related transducer velocity signal that exceeds a predetermined velocity threshold value.

Servo flaw detection using PES and velocity thresholds

An information handling system, such as a disc drive, includes a base, a disc stack rotatably attached to the base, and an actuator assembly movably attached to the base. Attached to one end of the actuator assembly is one or more transducers. Attached to the other end of the actuator is a voice coil which forms a portion of a voice coil motor. Magnets attached to the base form the other portion of the voice coil motor. A current driver for the voice coil delivers an amount of current to the voice coil to move the actuator assembly. A force constant is a multiplier applied to the amplifier so that the output current to the voice coil produces a velocity output replicating the designed velocity output. The force constant is determined during the acceleration phase of the movement of the actuator and transducer. A velocity error signal is produced by comparing the actual velocity of the actuator and transducer to the demand velocity. The error signal can be based on one point in time or over a period of time. The selected time is during a linear mode of the current driver.

Voice coil motor force constant calibration method and apparatus

A method of controlling an actuator in a disc drive to move a data head to implement an access in accordance with the invention includes determining a first rotational position corresponding to a rotational position of the data head when the access will start and determining a second rotational position corresponding to a rotational position of the data head at a destination of the access. Subsequently, an access time required to move the data head from the first rotational position on a current or initial track to the second rotational position on a destination track using a fastest of multiple seek profiles is determined. A slower or slowest of the multiple seek profiles which can be used to move the data head from the first track to the second track within the access time is determined. Subsequently, the actuator is controlled using the determined slower or slowest of the multiple seek profiles to implement the access. In addition, a disc drive is provided.

Disc drive method and apparatus for dynamically adjusting seek operations

A servo system positions a transducer over a disc surface in a disc drive system. Disc surfaces in the drive each have a plurality of spaced servo samples recorded thereon. The servo samples on at least two of the disc surfaces are recorded in skewed relation to one another. A plurality of transducers are provided and one transducer is associated with each one of the plurality of disc surfaces. An actuator arm assembly is coupled to the transducers to move the transducers relative to the disc surfaces. A servo control system is coupled to the actuator arm assembly to control position of the actuator arm assembly. The servo control system includes a reader configured to read servo samples from at least two disc surfaces such that at least two servo samples are read within one servo time period.

Disc drive servo system with dual head sampling

A method for determining servo loop gain of a servo loop in a disc drive includes performing a plurality of seek operations, each seek operation moving a head in a disc drive across a plurality of tracks on the disc. Afterwards, the head is settled over a radial position on a track and a signal is injected into the servo loop at the first frequency. At least two values generated by portions of the servo loop are measured to determine a servo loop gain.

Method and apparatus for determination of disc drive structural response during typical operations

A servo control system for a voice coil motor including a servo controller using position feedback to provide an acceleration current to the voice coil motor and voice coil brake providing a deceleration current based upon velocity feedback from the voice coil motor. In one embodiment, the velocity of the voice coil motor is derived from current feedback. A method for braking an actuator driven by a voice coil motor including the steps or receiving and processing current feedback from the voice coil motor and supplying a deceleration current to the voice coil motor derived from the current feedback from the voice coil motor.

Servo control system and method for a data storage device with improved braking

A method of filtering the actuator driving energy in a disc drive is provided in which the configuration of a digital notch filter is adapted according to which data head is selected. In one embodiment of the invention, digital notch filter constants corresponding to the resonance frequencies of each individual data head are stored in memory. When a particular data head is selected for reading or writing, the digital notch filter constants corresponding to the selected head are retrieved from memory and provided to a digital notch filter, which filters the driving energy according to the retrieved digital notch filter constants. In addition, a disc drive which implements said method of filtering the actuator driving energy is provided.

Growing community of inventors

Prior Lake, MN, United States of America

Paul Alexander Galloway