Robust synthesis for uncertain time-varying systems

We develop and present convex synthesis conditions for robust performance in linear time-varying systems, subject to time-varying perturbations. In particular these results are exact for sensitivity minimization in the presence of multiplicative perturbations. The methods apply to a number of additional robust performance problems, and are always both necessary and sufficient when the system plant is periodic. Otherwise the conditions provided are always sufficient, and a controller can be directly constructed when this condition holds