Robust controller synthesis for disturbance

Robust controller synthesis is considered for disturbances generated by an uncertain filter. The uncertainties are characterized by an integral quadratic constraint (IQC) with general frequency dependent multipliers. By exploiting the problem structure originating from the fact that the uncertainty enters the disturbance filter but not the plant, it is shown how to derive LMI-synthesis conditions for an a priori specified L2-induced gain. For a specific sinusoidal disturbance rejection problem, it is shown that specifying a bound on the rate-of-variation of an uncertain parameter can improve performance if compared to earlier results based on static scalings.