Electrical and Electronic Engineering - Research Publications

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On the use of switched linear controllers for stabilizability of implicit recursive equations

Nesic, D (IEEE, 1998-01-01)

Stabilizability of implicit recursive equations is investigated. These equations arise naturally in the context of output dead-beat control for systems described by NARMAX models. Due to non-uniqueness of the solutions of these equations a special kind of a constrained stabilizability problem is considered. We take a hybrid switching control approach in testing the existence of a locally stabilizing controller. A method for the design of a stabilizing switching controller is also presented.
Analysis of minimum phase properties for non-affine nonlinear systems

Nesic, D ; Skafidas, E ; Mareels, IMY ; Evans, RJ (IEEE, 1997-01-01)

A system can be termed non-minimum phase according to some definitions available in the literature and yet the same system may exhibit stable zero output constrained dynamics. We show that for non-affine nonlinear systems there may not exist a continuous control law which would keep the output identically equal to zero and for which the zero output constrained dynamics are stable, whereas a discontinuous controller which achieves this exists. We give conditions for existence and present a method for design of discontinuous switching controllers which yield stable zero dynamics. In this sense, the results of this paper enlarge the class of non-affine nonlinear systems that can be termed minimum-phase.