Position control system and method for magnetic hard disk drive systems with dual stage actuation

A method for controlling a position of a read and write head using a dual actuator assembly, the dual actuator assembly including a primary actuator operable to position a primary actuator arm and a secondary actuator attached to the primary actuator arm operable to position a secondary actuator arm upon which the head is attached, the method comprising:

• receiving an input command signal including a desired track number;
• first modifying the input command signal to create a primary actuator error signal;
• processing the primary actuator error signal to control operation of the primary actuator to position the primary actuator arm;
• independent of the first modifying, second separately modifying the input command signal to create a secondary actuator error signal;
• and
• processing the secondary actuator signal to control operation of the secondary actuator to position the secondary actuator arm.

A disk drive assembly, comprising:

• an actuator assembly comprising a head for reading and writing data to a storage media, a primary actuator for positioning a primary actuator portion and a secondary actuator for positioning a secondary actuator portion, wherein the secondary actuator portion supports the head and the secondary actuator is mounted on the primary actuator portion;
• a system processor for responding to a request corresponding to the storage media from a host by issuing an input command signal;
• and
• a position control system for receiving the input command signal and modifying the input command signal to create a primary error signal and a secondary error signal, wherein the primary and secondary error signals are not the same, and wherein the position control system includes a primary actuator controller responsive to the primary actuator signal to control operation of the primary actuator and a secondary actuator controller responsive to the secondary actuator signal to control operation of the secondary actuator, whereby control of the positioning of the primary and secondary actuator portions is performed independently.

A disk drive assembly, comprising:

• an actuator assembly comprising a head for reading and writing data to a storage media, a primary actuator for positioning a primary actuator portion and a secondary actuator for positioning a secondary actuator portion, wherein the secondary actuator portion supports the head and the secondary actuator is mounted on the primary actuator portion;
• a system processor for responding to a request corresponding to the storage media from a host by issuing an input command signal;
• and
• a position control system for receiving the input command signal and modifying the input command signal to create a primary error signal and a secondary error signal, wherein the position control system includes a primary actuator controller responsive to the primary actuator signal to control operation of the primary actuator and a secondary actuator controller responsive to the secondary actuator signal to control operation of the secondary actuator, whereby control of the positioning of the primary and secondary actuator portions is performed independently, the position control system includes a feedback system adapted for creating a position error signal (PES) for use in the modifying by using position information obtained from servo wedges in the storage disk combined with received runout information
• wherein the feedback system comprises a spatial position reconstruction circuit for producing a reconstructed error signal comprising angular position information for the primary actuator portion utilizing an operating parameter of the primary actuator and wherein the primary error signal is produced by modifying the primary input signal using the reconstructed error signal.

A method for controlling a position of a read and write head using a dual actuator assembly, the method comprising:

• first modifying an input command signal to create a primary actuator error signal;
• processing the primary actuator error signal to control operation of a primary actuator to position a primary actuator arm;
• independent of the first modifying, second separately modifying the input command signal to create a secondary actuator error signal;
• and
• processing a secondary actuator signal to control operation of a secondary actuator to position a secondary actuator arm.

A system for controlling a position of a read and write head using a dual actuator assembly, the dual actuator assembly including a primary actuator operable to position a primary actuator arm and a secondary actuator attached to the primary actuator arm operable to position a secondary actuator arm upon which the head is attached, the system comprising:

• means for receiving an input command signal including a desired track number;
• means for first modifying the input command signal to create a primary actuator error signal;
• means for processing the primary actuator error signal to control operation of the primary actuator to position the primary actuator arm;
• independent of the first modifying, second means for separately modifying the input command signal to create a secondary actuator error signal;
• and
• means for processing the secondary actuator signal to control operation of the secondary actuator to position the secondary actuator arm.