Sensitivity and robustness of sampled-data control systems: a frequency domain viewpoint

Considers a frequency domain, input-output based approach to the analysis of hybrid sampled-data systems. Based on previous works, the authors expound a frequency-domain lifting technique as an alternative to the time-domain lifting framework for sampled-data systems. In some cases, the approach pursued here can provide considerably simpler, more intuitive methods than time-domain lifting techniques to the analysis of the same problems. As applications, the authors consider the induced L/sub 2/ norms of the hybrid sensitivity and complementary sensitivity operators and the stability robustness of the hybrid system to linear time-invariant perturbations. In particularly for the single-input single-output case, "closed form" expressions arise for the induced norms, which allow straightforward numerical implementation.