Further refinement on LMI-based digital redesign: delta-operator approach

This paper sharpens the recently developed linear-matrix-inequality-based digital redesign (LMI-based DR) technique. The motivation comes from the fact that some unexpected state matching performance might be experienced as a sampling period approaches zero. To improve the state matching performance for that case, a refined LMI-based DR is proposed by using the delta operator that creates rapprochement between the differential and the shift operators. It is proved that the analog control performance is recovered by the refined DR scheme in the fast sampling limit.