H_∞ Control Design for Systems With Periodic Irregular Sampling Using Optimal H₂ Reference Controllers

This paper presents a novel robust H_∞ control design for linear systems with periodic irregular sampling and regular actuation rates. A three-step design algorithm is developed to design a controller that achieves high robustness in terms of disk margin, and high performance in terms of root mean square (RMS) of 3σ-value of performance signal. The proposed method is exploited to design a track-following controller for a hard disk drive (HDD) with 30% sampling time irregularity. The simulation study presented in this paper shows the effectiveness of the proposed control design for high-order systems with large periods.