Abstract: A disk drive is disclosed comprising a disk, a head, and control circuitry comprising a servo control system operable to actuate the head over the disk. A plurality of disturbance signals is generated in response to a vibration. A plurality of correlations is generated in response to each disturbance signal and an error signal of the servo control system. At least one of the disturbance signals is selected in response to the correlations. A feed-forward compensation value is generated in response to the selected disturbance signal, and the feed-forward compensation value is applied to the servo control system to compensate for the vibration.

Abstract: A disk drive comprises a disk, an actuator arm and a servo controller using a position error signal to generate a controller output signal to control the actuator arm. A plant mechanically models at least a portion of the disk drive, receives a control command to which an unknown disturbance is added and generates a plant output. A disturbance observer (DOB) uses the control command and the plant output to generate a delayed and estimated version of the disturbance. The DOB comprises a Q filter having a selected center frequency. A perfect phase cancellation filter (PPCF) is configured to receive the delayed and estimated version of the disturbance, to reject selected disturbances and to align the desired attenuation frequency with the selected center frequency. The output of the PPCF is subtracted from the controller output signal to generate the control command.

Abstract: A presentation method comprises: a sender device capturing screen frames and transmitting the screen frames to a receiver device; the receiver device receiving the screen frames transmitted by the sender device and outputting the screen frames to a display device for displaying the screen frames; establishing a webpage server in the receiver device; and the receiver device storing the screen frames as web pages. Thereby, the audiences can use the browsers of mobile Internet devices to link with the webpage server and browse the web pages containing the presentation contents.

Abstract: A disk drive is disclosed comprising a disk, a head, and control circuitry comprising a servo control system operable to actuate the head over the disk. A plurality of disturbance signals is generated in response to a vibration. A plurality of correlations is generated in response to each disturbance signal and an error signal of the servo control system. At least one of the disturbance signals is selected in response to the correlations. A feed-forward compensation value is generated in response to the selected disturbance signal, and the feed-forward compensation value is applied to the servo control system to compensate for the vibration.

Abstract: A monopole slot antenna structure including a dielectric substrate, a monopole slot antenna and a feed element is provided. The monopole slot antenna is disposed on one side of the dielectric substrate and has a slot including a first slot section, a tuning slot section and a second slot section. One end of the first slot section is located at one edge of the monopole slot antenna with the other end of the first slot section being extended towards internal portions of the monopole slot antenna and being connected to the tuning slot section. One end of the second slot section is connected to the tuning slot section with the other end of the second slot section being extended away from the first slot section. The feed element is disposed correspondingly to the second slot section, and excites the monopole slot antenna to generate two operating frequency bands.

Abstract: A hexahydrophthalate based compound is adapted to use as a plasticizer that contains no phthalic acid and benzoic acid, possess physical properties superior to DEHA and DINA in transparency and adhesion and is friendly to organisms and the environment; and a process for producing the hexahydrophthalate based compound includes esterifying hexahydrophthalic anhydride, a diol, and a catalyst for decarboxylation to get hexahydrophthalic alcohol, and adding a monoacid into the hexahydrophthalic alcohol for further esterification, thereby obtaining the hexahydrophthalate based compound.

Abstract: A disk drive is disclosed operable to seek a head from a first radial location over a disk to a second radial location over the disk. A reference signal is initialized, a feed-forward control signal is initialized, and a seek is initiated. During the seek operation, a position error signal (PES) is generated and saved, wherein the PES represents a position error of the head relative to the reference signal. The PES is filtered with a compensation filter to generate a feed-back control signal. The feed-back control signal is combined with the feed-forward control signal to generate a VCM control signal. When the seek is done, the saved PES is processed using an iterative learning control (ILC) algorithm to adjust at least one of the reference signal and the feed-forward control signal.

Abstract: A hexahydrophthalate based compound is adapted to use as a plasticizer that contains no phthalic acid and benzoic acid, possess physical properties superior to DEHA and DINA in transparency and adhesion and is friendly to organisms and the environment; and a process for producing the hexahydrophthalate based compound includes esterifying hexahydrophthalic anhydride, a diol, and a catalyst for decarboxylation to get hexahydrophthalic alcohol, and adding a monoacid into the hexahydrophthalic alcohol for further esterification, thereby obtaining the hexahydrophthalate based compound.

Abstract: A disk drive is disclosed including a disk having a plurality of tracks, wherein each track comprises a plurality of servo sectors. The disk drive further comprises a head having a read element offset from a write element by a reader/writer offset. The read element is positioned over a first track and the write element is positioned over a second track. A first servo control signal is generated for servoing the head in response to the servo sectors in the first track, and first wedge repeatable runout (RRO) data is written to the second track along a substantially sinusoidal path corresponding to the reader/writer offset, wherein the first wedge RRO data are for writing data to a third track.

Abstract: A method for preparing a kind of plasticizer containing cyclohexane poly carboxylic acid ester, particularly without phthalate, and with the advantage of effective shortening of reaction time, which method comprising having cyclohexane polycarboxylic acid or its derivatives, mono-alcohol and metal catalyst of tin and titanium or inorganic acid added together at the same time into a reactor to undergo a single stage of esterification at high temperature of 200˜250° C., and a reaction mixture of cyclohexane polycarboxylic acid ester was obtained by the process which is applicably used as a plasticizer without phthalate and no hazard to the living beings and environment.

Abstract: A method is disclosed for identifying wedge time shift zones on a magnetic disk of a disk drive. The disk drive further includes a spindle motor for rotating the disk at an operating speed in response to a spindle control current generated by a spindle control system, and a head that is actuated over the disk. During operation, the control systems causes a seek of the head across the disk and measures wedge-to-wedge times between servo wedges. The control system then calculates a wedge-to-wedge time shift value using the wedge-to-wedge times and determines whether the wedge-to-wedge time shift time value exceeds a predetermined threshold. If the wedge-to-wedge time shift value exceeds the predetermined threshold, then the control system identifies a wedge time shift zone, and stores information for compensating for the identified wedge time shift zone during disk operations.

Abstract: A disk drive is disclosed having hybrid spindle speed control. The disk drive includes a disk having a plurality of servo wedges, and a spindle motor for rotating the disk at an operating speed. The spindle motor generates a back electromotive force (BEMF) voltage. In operation, the disk rotation is maintained at the operating speed during a track following operation by updating, in a wedge spindle speed control mode, the spindle control current in response to a wedge speed error. Before executing a high-speed seek, the disk drive is switched to a BEMF spindle speed control mode, and the disk rotation is maintained at the operating speed during the high speed seek by updating the spindle control current in response to a BEMF speed error signal generated based on the BEMF voltage. During a seek-settle time, the disk drive is switched back to the wedge spindle speed control mode.

Abstract: A disk drive is disclosed comprising a disk having a plurality of tracks, a head actuated over the disk, and a voice coil motor for seeking the head from a first track to a second track. A first seek time is computed corresponding to a first seek profile, and second seek time is computed which is greater than the first seek time. A second seek profile is computed in response to the first seek time, the second seek time, and a scaling factor that accounts for a back EMF voltage generated by the voice coil motor. The voice coil motor is then controlled according to the second seek profile to seek the head from the first track to the second track.

Abstract: Disclosed is a disk drive including an actuator having a coil, a head attached to the actuator, and a disk including at least a first track and a second track, and a processor for controlling operations in the disk drive including a seek operation from the first track to the second track in which the head is moved between the first track and the second track by the movement of the actuator. The processor under the control of a program generates a deceleration velocity profile for the seek operation that is determined based upon a deceleration velocity profile function that includes a back electromagnetic force (BEMF) model to take into account back electromagnetic forces (BEMFs) associated with the coil of the actuator such that the BEMFs are mathematically modeled. The head is commanded to seek to the second track utilizing the deceleration velocity profile function that includes the BEMF model.

Abstract: 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.

Abstract: 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.