Experimental modeling and feedback control of a piezo-based milliactuator

In magnetic disk drive actuators, requirements to record and read data at higher track densities has made mechanical resonances of the servo actuator, suspension and the head gimbal assembly a critial consideration. The application of piezo electric material in the servo actuator can be used to re ne and accomplish track following in (extremely) high track density magnetic data storage by controlling the mechanical resonance modes and serving as a so-called milli-actuator. In this paper the results on the modeling and control of a piezobased milli-actuator are presented. The modeling is done on the basis of a least squares curve tting of an estimated frequency response and taking into account uncertainties in the modeled resonance modes of the servo actuator. The design and implementation of a robust Author to whom all correspondence may be addressed, email: [email protected] Now with IBM Storage Systems Division, 5600 Cottle Rd., San Jose, CA 95193 Center for Magnetic Recording Research at UCSD