An apparatus includes a microactuator controller configured to generate a microactuator control signal, a feedforward microactuator compensator configured to generate a microactuator compensation signal, and a microactuator model filter configured to filter a modified microactuator control signal. The microactuator compensation signal is configured to be injected into the microactuator control signal to generate the modified microactuator control signal. The microactuator model filter generates a filtered modified microactuator control signal and injects the filtered modified microactuator control signal into a position error signal to generate a modified position error signal.

A method and apparatus for detecting tightness of a pick-up head, and a method and apparatus for controlling the moving of the pick-up head are disclosed. The method for detecting the tightness of the pick-up head includes moving the pick-up head to an inner area of the disc reading device when then disc reading device is powered on, moving the pick-up head to an outer area of the disc reading device within a predetermined time period, moving the pick-up head from the outer area of the disc reading device to the inner area at a constant speed by a first fixed force, and recording the moving duration for moving the pick-up head from the outer area of the disc reading device to the inner area at the constant speed.

Various aspects of the present disclosure are directed toward a disc drive actuator assembly including an e-block, a bearing, and a sleeve. The bearing includes an inner race, an outer race and a plurality of balls between the inner and outer races. The inner race being coupled to a pivot shaft of a disc drive, and the bearing being configured and arranged to facilitate rotation of the e-block around the pivot shaft. The sleeve coupling the outer race of the bearing to the e-block, and includes a groove along an inner diameter of the sleeve adjacent the outer race. The groove and outer race mitigate rotational torque changes due to thermal effects upon the disc drive actuator assembly by allowing the outer race of the bearing to deform into or away from the groove and therein mitigate or prevent the generation of certain forces in bearings.

A data storage device is disclosed comprising a voice coil motor (VCM) and a secondary actuator configured to actuate a head over a disk. A control signal is applied to the secondary actuator while processing a sensor signal generated by the secondary actuator. A vibration signal is generated based on the sensor signal, wherein the vibration signal has a cut-off frequency between ten percent and ninety percent of a bandwidth of a control loop for controlling the secondary actuator.

A method includes performing a first seek operation using a first voice coil motor (VCM) control signal by utilizing a first drag component value. The method further includes determining a position error signal (PES) and a DC offset component of the PES measured during the first seek operation, and determining that the DC offset component is above a predetermined threshold. In response to determining that the DC offset component is above the predetermined threshold, the method further includes determining a second drag component value different than the first drag component value. The method further includes generating a second VCM control signal by applying the second drag component value.

A method and apparatus for detecting tightness of a pick-up head, and a method and apparatus for controlling the moving of the pick-up head are disclosed. The method for detecting the tightness of the pick-up head includes moving the pick-up head to an inner area of the disc reading device when then disc reading device is powered on, moving the pick-up head to an outer area of the disc reading device within a predetermined time period, moving the pick-up head from the outer area of the disc reading device to the inner area at a constant speed by a first fixed force, and recording the moving duration for moving the pick-up head from the outer area of the disc reading device to the inner area at the constant speed.

Various aspects of the present disclosure are directed toward a disc drive actuator assembly including an e-block, a bearing, and a sleeve. The bearing includes an inner race, an outer race and a plurality of balls between the inner and outer races. The inner race being coupled to a pivot shaft of a disc drive, and the bearing being configured and arranged to facilitate rotation of the e-block around the pivot shaft. The sleeve coupling the outer race of the bearing to the e-block, and includes a groove along an inner diameter of the sleeve adjacent the outer race. The groove and outer race mitigate rotational torque changes due to thermal effects upon the disc drive actuator assembly by allowing the outer race of the bearing to deform into or away from the groove and therein mitigate or prevent the generation of certain forces in bearings.

According to one embodiment, a magnetic disk device includes a magnetic disk and a magnetic head. The magnetic disk includes a data area on/from which data can be recorded/reproduced. The magnetic head records data on the data area and reproduces data from the data area. An outer edge of the data area includes first outer edge, second outer edge positioned on the further inner circumferential side of the magnetic disk relatively to the first outer edge, and third outer edges each connecting between the first outer edge and the second outer edge. The outer edge of the data area incudes concave parts made inwardly concave toward the inner circumferential side of the magnetic disk at not less than part thereof.