A GENERAL FRAMEWORK FOR LINEAR PERIODIC-SYSTEMS WITH APPLICATIONS TO H-INFINITY SAMPLED-DATA CONTROL

We present a framework for dealing with continuous-time periodic systems. The main tool is a lifting technique which provides a strong correspondence between continuous-time periodic systems and certain types of discrete-time time-invariant systems with infinite dimensional input and output spaces. Despite the infinite dimensionality of the input and output spaces, a lifted system has a finite-dimensional state space if the original system does. This fact permits rather constructive methods for analyzing these systems. As a demonstration of the utility of this framework, we use it to describe the continuous time (i.e., intersample) behavior of sampled-data systems, and to obtain a complete solution to the problem of parametrizing all controllers that constrain the L2-induced norm of a sampled-data system to within a certain bound.