A novel design of short-seeking control for hard disk drives

This paper discusses short seeking control for a hard disk drive with voice coil motor (VCM). A novel design method is proposed based on the track following control and initial value adjustment (IVA). Initial value adjustment, which adjusts the initial values of the track-following controllers for short seeking, makes the use of the feedforward controller and reference trajectory unnecessary. The proposed design also takes into consideration the compromise between speed and overshoot in short seeking when seeking distance becomes longer by using a two-stage IVA scheme: (1) In the first stage (when the read/write head is far away from the target track), the integral action of the track following controller is inactivated and IVA is designed to yield a high-speed seeking; (2) In the second stage (when the head approaches the target track), the integral action is switched on, and IVA is designed to produce a fast and smooth response without overshoot. A design example verifies the effectiveness of the proposed method.