APPROXIMATE I O FEEDBACK LINEARIZATION OF DISCRETE-TIME NONLINEAR-SYSTEMS VIA VIRTUAL INPUT DIRECT DESIGN/

The design of linearizing compensators via output-feedback for discret e-time non-linear plants, using I/O measurements only, is typically pe rformed in an indirect way by identifying first a non-linear model of the plant, and resorting then to a suitable model-based design techniq ue. In this paper we propose the use of a new method, based on a virtu al input direct design (VID2) approach. The main feature of such a met hod is to carry the control design into a standard non-linear mapping approximation problem, thus avoiding any preliminary plant-identificat ion phase. As compared with the existing methods, the new one requires less computational effort, while taking full advantage of the non-lin ear approximation software tools already available. In this paper, the new method is described, and some theoretical results are given, conc erning the I/O linearization of discrete-time systems via dynamic outp ut feedback. (C) 1998 Elsevier Science Ltd. All rights reserved.