Robust synthesis of feedforward compensators

The design of a feedforward compensator for robust Hscr,8 or Hscr,2 performance under structured uncertainty is considered. For linear time-invariant uncertainty, a convex method based on linear matrix inequalities (LMIs) across the frequency variable is given. For nonlinear or time-varying perturbations andHscr,8 performance, the design problem is reduced exactly to a state-space LMI, and extensions toHscr,2 performance are discussed. An example illustrates the application of these techniques to two-degree-of-freedom control design