Abstract: A method for writing servo patterns on a hard disk drive disk in a hard disk drive assembly. The assembly includes a disk having at least one magnetic surface in which a reference pattern has been written, determining a reference track. Also included is an actuator having a shaft engaged with the disk to provide rotational motion to the disk, an actuator arm, and a micro-actuated read/write head mounted on the actuator arm. The method includes the following steps. First, the read/write head is used to position the actuator arm at a first fixed position over the reference track. The actuator arm is maintained at the first fixed position while the read/write head is used to write a second servo pattern, determining a second track. The read/write head is used to position the actuator arm at a second fixed position over the second track. Then, the actuator arm is maintained at the second fixed position while the read/write head is used to write a third servo pattern.

Abstract: This invention comprises an architecture for voltage mode control of a voice coil motor in a hard disk drive. In contrast to conventional current mode control, coil current is not sensed or measured, which simplifies the feedback design with less hardware required in the implementation. Common design methodologies for the square root velocity profile, linear velocity profile and regulator/estimator control system designs can be migrated from the current mode architecture to the voltage mode architecture.

Abstract: A mass data storage device (10) and methods for making and using it are disclosed. The mass data storage device (10) has a read/write head (18) carried in proximity to one end of a selectively positionable arm (42), and an actuation device (20) in proximity to another end of the arm for moving the arm in response to an input signal (31). The mass data storage device (10) has a sensor, such as an accelerometer (38), or the like, carried on the arm (42) for generating a motion signal for use in position control of the arm (42). The sensor (38) is located on the arm (42) at a location at which the motion signal (39) and the actuator input signal (31) have a minimum phase difference. The signal (39) from the sensor (38) may be fed back to control the actuation device (20), and may include a filter (60) that shapes the motion signal to equalize any resonances in the arm or rejects torque effects of the arm (42).

Abstract: A method transforms any linear control system into its estimator/regulator equivalent(s) and also may select from such equivalents a particular one pursuant to additional one or more criteria. The transformation can be found from solutions to a quadratic matrix equation.

Abstract: According to one embodiment of the invention, a method of moving a device from a first position to a second position by an actuation system includes moving the device in response to providing a control signal having a first amplitude for a first time period. The method also includes, immediately after the first time period, moving the device in response to providing a control signal having a second amplitude for a second time period, the device having a nonzero velocity after the second time period. The nonzero velocity has a magnitude that allows the device to coast to, and stop at, the second position after the second time period without receiving a control signal.

Abstract: An actuator architecture allows precision control of a micro-actuator read/write head 16a, 16b by measuring the position directly with the read/write heads rather than relying on a position sensor. The position of the micro-actuator head 16a, 16b with respect to the conventional actuator assembly 12 is determined by comparing the position of the micro-actuator head 16a with the position of a second head 16b affixed to the conventional actuator 12 using disk servo patterns.