Robust Control of Dual-Stage Servo Systems in Hard Disk Drives: Methodology Development, Comparative Study, and Experimental Verification

The head-positioning accuracy of hard disk drives is being continuously improved in order to achieve higher storage density and hence larger capacity. Significant efforts have been made to improve the head-positioning performance, including disturbance detection and pre-compensation, dual-stage actuation, vibration control, adaptive, nonlinear, and robust control, etc. This book focuses on the design and analysis of robust tracking control in hard disk drives, especially for dual-stage systems with a vibration sensor. After an overview of advanced servo systems, modeling and robust control designs based on SISO and MIMO configurations are presented. Detailed analysis and comparisons are made between various designs. Experimental control results are presented for a prototype microactuator fabricated using MEMS techniques. This book can serve as a reference to robust servo design techniques for graduate students in Controls, servo engineers in the hard disk drive industry, and anyone else who may be considering designing robust, multi-objective, and multirate control in various applications.