EXPLOITING ELLIPSOIDAL PARAMETER SET ESTIMATES IN H-INFINITY ROBUST-CONTROL DESIGN

The focus of this investigation is the exploitation of knowledge of an ellipsoidal bound on system parameters for the identification of mode ling uncertainty information vital to the H-infinity, robust control d esigner, a time to frequency domain uncertainty transformation. The ch aracterizations of parametric uncertainty as coprime factor and additi ve perturbations to a nominal plant model are addressed in worst-case analyses. A Kharitonov type analysis provides sufficient conditions fo r the use of an additive plant perturbation uncertainty characterizati on. Original optimization results for the coprime factor perturbation enable the essential task of loopshaping to be conducted in the contro l design phase. A novel scheme is introduced to interpolate magnitude samples of the perturbation bounding function and is further developed into a technique for identification of reduced-order perturbation wei ghtings, vital for practical control design. An example serves to illu strate the success of the developed techniques.