A novel approach to repetitive control via sampled-data H∞ filters

A new paradigm of digital signal processing has recently been proposed in view of sampled-data control theory. This filter, called sampled-data H^infin filter, approximates a linear phase characteristic in continuous-time domain, that is, a pure delay. By this property, we propose a new repetitive controller including the sampled-data H^infin optimal filter. Moreover, to achieve the stability, we introduce the Internal Model Control (IMC). Our method solves the problem of stability, implementability, and inter sample ripples in digital repetitive control. A numerical example shows the effectiveness of our method.