摘要:
A disk drive is disclosed comprising a disk having a plurality of tracks, an actuator arm, a head connected to a distal end of the actuator arm, and a voice coil motor (VCM) for rotating the actuator arm about a pivot to actuate the head over the disk. A driving current is applied to the VCM to control the motion of the actuator arm. A back EMF voltage generated by the VCM is detected, and a velocity of the VCM is estimated in response to the back EMF voltage. The estimated VCM velocity is compared to a target velocity in a velocity profile, wherein the velocity profile comprises at least an acceleration component and a coast component. The driving current is adjusted in response to the comparison so that the velocity of the VCM substantially follows the velocity profile.
摘要:
A disk drive is disclosed including a disk, a head coupled to a distal end of an actuator arm, and a voice coil motor (VCM) operable to rotate the actuator arm about a pivot to actuate the head radially over the disk, wherein the VCM comprises a coil. Control circuitry within the disk drive measures a load resistance of the coil prior to executing a load operation, wherein the load operation moves the actuator arm off a ramp to load the head onto the disk. The load resistance of the coil is then converted into an initial coil temperature estimate.
摘要:
A disk drive is disclosed comprising a spindle motor having a plurality of windings including at least a first winding, a second winding, and a third winding. During a spin-up operation, a voltage is applied to the first winding and a first rise time is measured for current flowing through the first winding to reach a predetermined threshold. A voltage is applied to the second winding and a second rise time is measured for current flowing through the second winding to reach a predetermined threshold. A voltage is applied to the third winding and a third rise time is measured for current flowing through the third winding to reach a predetermined threshold. A difference is computed in response to the first rise time, the second rise time, and the third rise time, and an angular position of the spindle motor is estimated by computing an arctangent in response to the difference.
摘要:
A disk drive is disclosed employing either back electromotive force (BEMF) spindle speed control mode or wedge spindle speed control mode. A BEMF detector monitors the BEMF voltage generated by the windings of the spindle motor to generate a BEMF speed error. The BEMF spindle speed control mode is used to spin up the disk to an operating speed, and the wedge spindle speed control to maintain the disk at the operating speed. While in the wedge spindle speed control mode, a BEMF detection window is disabled to reduce acoustic noise.
摘要:
A disk drive is disclosed comprising a head actuated over a disk, and control circuitry including a vibration sensor. A position error signal (PES) is generated representing a radial location of the head over the disk, and the head is servoed radially over the disk in response to the PES. A first vibration signal is generated in response to the vibration sensor, and a second vibration signal in response to the PES. The first vibration signal is combined with the second vibration signal to generate a third vibration signal, and a vibration event is detected in response to the third vibration signal.
摘要:
A disk drive is disclosed employing either back electromotive force (BEMF) spindle speed control or wedge spindle speed control. The BEMF spindle speed control is used to calibrate a reference time period representing an accumulation of a predetermined number of wedge-to-wedge times. During wedge spindle speed control, a wedge time period representing an accumulation of a predetermined number of wedge-to-wedge times is measured, and a wedge speed error is computed as the difference between the reference time period and the wedge time period.
摘要:
A disk drive is disclosed comprising a disk having a plurality of tracks, a head, and a voice coil motor (VCM) and a microactuator for actuating the head over the disk in response to a feed-forward compensation value. A sinusoidal disturbance is applied to the microactuator, and the resulting feed-forward compensation value is processed to characterize the microactuator.
摘要:
A disk drive is disclosed comprising a head actuated over a disk, the disk comprising a plurality of servo tracks defined by a plurality of servo sectors. An estimated radial location of the head is generated in response to an actuator control signal. A Gray coded track ID is detected from reading a servo sector, and decoded into a detected track ID. A burst position error signal (PES) is generated from reading servo bursts in the servo sector, wherein the burst PES represents a detected fractional servo track offset of the head. When the detected track ID is corrupt, a corrected track ID is generated using the estimated radial location and the burst PES, and the actuator control signal is adjusted in response to the corrected track ID and the burst PES.
摘要:
A disk drive is disclosed comprising a first disk surface, a first head coupled to a distal end of an actuator arm, and a voice coil motor (VCM) and a first microactuator operable to actuate the first head over the first disk surface. A servo loop for servoing the head in response to the servo sectors is disabled, and after disabling the servo loop, the first microactuator is excited with a control signal at a test frequency in order to accentuate a crack in the first microactuator. After exciting the first microactuator, the servo loop is enabled, and after enabling the servo loop, the first microactuator is evaluated to detect the crack in the first microactuator.