Optimal control design of multirate sampled-data systems

The hybrid MRSD (multirate sampled-data) system is considered which consist of a continuous time plant and a digital lifted controller. The paper focuses on an explicit solution to the multirate /spl Hscr//sub /spl infin//-optimal control problem using Nehari's theorem. The solution is based on a lifting method, where an equivalent LTI system is obtained for the given periodic multirate problem. The causality constraint on the controller structure in lifting based solutions is automatically satisfied. By solving a standard Nehari's problem, we get the optimal parameterization of a linear stabilizing controller in the worst case l/sub 2/ to l/sub 2/ sense and hence the optimal h-periodic controller for the multirate systems.