Robust Controller Synthesis is Convex for Systems without Control Channel Uncertainties

We consider uncertain generalized plants whose control channel is not affected by uncertainties. It is shown that these configurations emerge in various concrete problems such as robust estimator or feed-forward controller synthesis. Under the hypothesis that the uncertainties are described by suitable families of dynamic integral quadratic constraints, we reveal how one can translate robust controller synthesis to a problem of designing parametric and dynamic components in a standard plant configuration, and how it can be turned into a semi-definite program.