Tuning of a Hard Disk Drive Servo Controller Using Fixed-Structure H∞ Controller Optimization

Abstract

As the storage capacity of hard disk drives (HDDs) increases dramatically, the demand for positioning control accuracy of a read/write head of HDD is becoming more stringent. This paper presents a tuning methodology for fixed-structure controllers using the H∞ optimization. The tuning of a PID (Proportional plus Integral plus Derivative) controller for head positioning of an HDD is presented as an application example. The H∞ optimization problem of fixed-structure controllers can be locally solved by using the transformation into an H∞ synthesis problem of static output feedback control. Simulation and experimental results show the effectiveness of the proposed approach as a fine tuning method to improve controller performance without requiring profound knowledge and experiences in manual loop-shaping.