On the extraction of dead-time controllers and estimators from delay-free parametrizations

An approach to control design for dead-time (DT) systems is proposed. The underlying idea is to treat the DT element not as a part of the generalized plant, but rather as a (causality) constraint imposed upon the controller (estimator). This enables one to use well-understood parametrizations of all delay free controllers in the DT design. In particular, DT controllers can be extracted from such delay-free parametrizations. In the paper, the extraction procedures are developed in both H² and H^∞ settings. It is shown that the proposed approach yields simple solution procedures and new transparent and intuitively appealing structures for the resulting controllers and estimators.