Nonconservative adaptive robust control and structure selection for SISO plant under coprime factor perturbations

Abstract

Abstract A robust indirect adaptive controller for SISO plant under coprime factor perturbations and bounded external disturbance is presented. The structure of the plant (orders and time delay) are assumed to be from a finite known family of possible structures. It is assumed also that a linear controller stabilizing the nominal part of the plant is given for known nominal parameters. Closed loop estimation of model structure, model parameters, and the nouns of perturbations and additive disturbance is based on overall criterion taken as the worst case steady-state absolute value of the output. It is proved that the adaptive controller achieves robust performance arbitrarily near to that in the case of completely known plant.