Robust Performance Analysis for Linear Slowly Time-Varying Perturbations

Robust performance analysis problem is considered for LTI systems subject to block-diagonal structured and bounded LTV perturbations with specified maximal variation rates. Analysis methods are developed in terms of semi-definite programming problems for the computation of upper and lower bounds for optimum robust performance levels. Upper bound computation is based on an IQC test developed using a generalized version of the so-called swapping lemma. Lower bound computation method employs a power-distribution- theorem-based result from the literature together with a generalized version of the KYP lemma and serves as a means to assess the conservatism of the computed upper bounds in the case of dynamic LTV perturbations.