Robust stability under mixed time-varying, time-invariant and parametric uncertainty

Robustness analysis is considered for systems with structured involving combination of linear time-varying, linear time-invariant and parametric perturbations. A necessary and sufficient condition for robust stability in terms of the structured singular value mu is obtained, based on a finite augmentation of the original problem. The augmentation corresponds to considering the system at a fixed number of frequencies. Sufficient conditions based on scaled small gain are also considered and characterized. Copyright (C) 1996 Elsevier Science Ltd.