H∞ and Mixed H2/H∞ Control of Dual-Actuator Hard Disk Drive via LMIs

Abstract

In this paper, H_infin and mixed H₂/H_infin controllers are designed for a hard disk drive (HDD) using linear matrix inequalities (LMIs). In the proposed algorithm, the problem of minimizing track misregistration (TMR) in the presence of unmodeled dynamics of voice-coil motor (VCM) is formulated as robust H_infin and mixed H₂/H_infin problems. Additional stack variables are introduced to characterize H₂ and H_infin performances. The simulation and comparison results demonstrate the significant performance improvement of TMR under unmodeled dynamics of VCM.