Design of periodic output feedback and fast output sampling based controllers for systems with slow and fast modes

Abstract

It is well known that the straight forward application of controller design methods to two‐time‐scale systems is susceptible to numerical ill‐conditioning and stiffness problems. However, it has been demonstrated in this paper that the presence of time‐scales can be exploited for achieving better computational efficiency in case of the design of controllers based on periodic output feedback and fast output sampling principles. In particular, an approach for design of periodic output feedback and fast output sampling controllers for a two‐time‐scale system by decomposition into a slow and a fast subsystem problems, has been presented. These smaller order problems are then separately solved and the results thus obtained for the slow and fast subsystems are combined to obtain the solution of the original design problems. The procedure has been illustrated with the help of a very simplified nuclear reactor model.