Title :
Dynamic Modeling and Control of a Piezo-Electric Dual-Stage Tape Servo Actuator
Author :
Boettcher, Uwe ; Raeymaekers, Bart ; De Callafon, Raymond A. ; Talke, Frank E.
Author_Institution :
Center for Magn. Recording Res., Univ. of California San Diego, La Jolla, CA
fDate :
7/1/2009 12:00:00 AM
Abstract :
We present a data-based approach for modeling and controller design of a dual-stage tape servo actuator. Our method uses step response measurements and a generalized realization algorithm to identify a multivariable discrete-time model of the actuator. The data acquisition and modeling can be implemented in the servo firmware of a tape drive. We have designed a dual-stage controller, based on the model, using loop shaping techniques adopted for multivariable control problems. We applied the procedure to the prototype of a dual-stage actuator tape head to reduce the effect of lateral tape motion. The prototype consists of a conventional voice coil motor for coarse positioning and a micro-actuator for fine positioning. The micro-actuator, which is mounted on the voice coil motor, uses a piezo crystal to follow high-frequency lateral tape motion (up to the kilohertz regime), while the voice coil motor follows only low-frequency lateral tape motion. Compared to a single-stage design, the dual-stage servo design provides a 25% bandwidth improvement and a voice coil motor control signal that is much smaller in magnitude.
Keywords :
microactuators; piezoelectric actuators; servomotors; tape recorders; controller design; generalized realization algorithm; microactuator; multivariable discrete-time model; piezoelectric dual-stage tape servo actuator; servo firmware; step response measurements; tape drive; voice coil motor; Magnetic tape recording; modeling; servosystems;
Journal_Title :
Magnetics, IEEE Transactions on
DOI :
10.1109/TMAG.2009.2015050