Optimal finite-precision digital controller realizations based on an improved closed-loop stability measure

Download

Postscript Download (259Kb)

Description/Abstract

This paper investigates the stability issue of the discrete-time control system, where a digital controller, implemented with finite word length (FWL), is used. A new tractable stability measure is derived, which is much less conservative than some existing measures in estimating the closed-loop stability robustness of an FWL implemented controller. An optimisation procedure is developed based on this improved measure to find the optimal realization for a general controller structure that includes output-feedback and observer-based controllers. Numerical examples are used to verify the theoretical analysis and to illustrate the design procedure.