A Smith-type Predictor for Non-minimum Phase Infinite-dimensional Plants and its Dual Structure

This paper investigates a general structure of internally stabilizing and suboptimal H^infin controllers for a class of infinite-dimensional systems. This is done by extending Smith predictors by regarding inner functions as a generalization of delays. In both cases of controllers, it is shown that any non-minimum phase factor can be compensated by a feedback structure incorporating a Smith-type predictor. As its dual result, it is also shown that the plant unstable modes lead to a specific feedforward structure in the resulting controllers