Approximate linearization via feedback - an overview

Fostered by a growing interest in nonlinear control theory and catalyzed by the discovery in the early 1980s of the exact conditions under which a non linear plant can be linearized by static-state feedback and coordinate tran sformation, in the last decades there has been a rapid increase of interest in the search for approximate solutions to the problem of linearizing nonl inear systems by slate or output feedback. Main reason for that is the limi ted applicability of the rigorous methods, and the complexity, sensitivity and design difficulties of the exact linearizing compensators, if any. In t he present paper, the literature on the subject is reviewed and organized i n what is believed to be a new and consistent perspective. Recent works, es pecially in the area of data-based techniques, are in fact described and re lated, whenever possible, to fundamental results previously obtained by mod el-based differential geometric methods; this is expected to bring modern s ystem linearization methods closer to the needs of practicing control engin eers and to stimulate further research eventually able to fill visible gaps in this direction. (C) 2000 Elsevier Science Ltd. All rights reserved.