Constrained output feedbacks for singularly perturbed imperfectly known nonlinear systems

Global attractors are investigated for a class of imperfectly known, singularly perturbed, nonlinear systems subject to control constraints. The uncertain systems are modelled as nonlinear perturbations to a known nonlinear idealized system. The model is represented by two time-scale systems involving a scalar singular perturbation parameter, which reduces to a system of lower order when the singular perturbation parameter is set to zero. A class of constrained static output feedback controllers is developed which guarantees global attractivity of a compact set, containing the state origin, for all values of the singular perturbation parameter less than some threshold value.