Seagate Technology Incorporated

Tien Q Le

Khosrow Mohajerani

Joseph M Sampietro

Anoush M Fard

LeRoy A Volz

Jeffrey G Barina

Muhammad A Hawwa

Daniel R Vigil

Duc T Phan

A system for positioning a transducing head in a disc drive device over a selected track of a rotatable disc includes an actuator arm which is rotatable about an axis, a head suspension mechanism connected to the actuator arm, and a slider carrying a transducing head and supported by the head suspension mechanism. A low resolution motor moves the actuator arm about the axis to effect coarse movement of the head between tracks of the disc. A piezoelectric element is embedded in the actuator arm to distort the arm to effect fine positioning of the head. Control circuitry distributes electrical signals to the low resolution motor and the piezoelectric element to selectively control movement thereof. The piezoelectric element is embedded in the actuator arm by removing a predetermined amount of material from the actuator arm and bonding the piezoelectric element in the resulting space in the actuator arm.

Method of making an actuator arm integrated piezoelectric microactuator

Actuator arm integrated piezoelectric microactuator

Methods and apparatus for controlling a plant are described. The control methods are adaptive and compensate for changes in plant component characteristics and plant environment, and are applicable to systems having a bias force. The methods are described in relation to a sampled-data control system for a computer disc drive servo actuator apparatus but the control methods are independent of plant type. Methods for extending a linear measurement range of a position sensor, for generating a plant gain constant, for measuring plant phase, for measuring plant resonance frequencies and compensating for the effects of plant resonance, and for switching between different modes depending on characteristics of the applied control value are described. These methods may be used separately or in combination to achieve the desired control.

Method and apparatus for adaptive control

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Camarillo, CA, United States of America

Tien Q Le