Necessary and sufficient conditions for robust performance of systems with mixed time-varying gains and structured uncertainty

Considers the problem of assessing robust performance of systems under both time varying memoryless gains and structured dynamic uncertainty. Performance is measured in terms of the l/sup /spl infin// to l/sup /spl infin// induced gain and the (constructive) conditions are given in terms of the existence of a non-empty polyhedral set. Finally, the author presents an example comparing these conditions with the necessary conditions obtained using l/sup 1/ theory.