A nonlinear control scheme for fast settling in hard disk drives

Abstract

Conventional integral compensation to deal with unknown bias usually leads to long settling process in hard disk drives. This paper proposes a nonlinear proportional integral derivative control scheme to shorten the settling time by reducing the overshoot caused by the integrator, without degradation of other performance specifications. Experiment results show that it is robust against different bias sizes and step sizes. Furthermore, the single-track seek time can scale down well with the track pitch.