A Novel Design of Short-seeking Control for Dual-actuator Hard Disk Drives

Authors:	Yang Li, University of California-Berkeley, United States Tomizuka Masayoshi, University of California-Berkeley, United States
Topic:	4.2 Mechatronic Systems
Session:	Mechatronics for Data Storage Devices I
Keywords:	dual actuator, short seeking, actuator saturation, hard disk drive (HDD)

Abstract

This paper discusses short-seek control for a dual-actuator HDD consisting of a coarse actuator(VCM) and a fine actuator(PZT). A novel design is proposed based on the dual-stage track following control and initial value adjustment(IVA). This method, 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 design also takes into consideration the saturation property of the fine actuator by using a two-stage IVA scheme: (1)only VCM loop is utilized in the first stage(beyond PZT stroke limit), and IVA is designed to yield a high speed seeking; (2)PZT loop is switched on when the head approaches the target track in the second stage(within PZT stroke limit), and IVA is used to produce a fast and smooth response. Simulation results verify the effectiveness of the proposed method.