Nonlinear structurally stable control of a flexible spacecraft

The problem of counteracting nonlinear perturbations in order to maintain output regulation with internal stability of a flexible spacecraft is discussed. Asymptotic tracking of the main body and antenna rotations of a flexible spacecraft in the face of system uncertainties and disturbances is considered. The structurally stable control scheme proposed relies upon a novel extension to nonlinear systems of the internal model principle. Plant extension is investigated in three different cases, with the aim of providing an overview of the possible applications of the methodology used. A switching logic, working also in the case of large initial errors, is proposed for feedback control of spacecraft attitudes