Track seeking control for hard disk drives using the approaching index switching algorithm

This paper deals with the servo system design for hard disk drives using the approaching index switching algorithm introduced in [1]. The index represents a closed loop measure of the closeness of the system output to the reference set value. A switching algorithm is designed to switch between two different control sets according to the value of the index. The first control set is supposed to be suitable to drive the system output fast enough towards the required set value while the other control set should have enough damping to reach the final destination without overshoot. The simulation results using a mathematical model of a voice-coil-motor VCM actuator of a hard disk drive show that this approach is very effective. Giving rise to faster rise time, minimal overshoot, and a limited control signal compared to a conventional PID controller.