Nonlinear Output Feedback Design for Linear Systems With Saturating Controls

This paper shows the existence of (nonlinear) smooth dynamic feedback stabilizers for linear time invariant systems under input constraints, assuming only that open-loop asymptotic controllability and detectability hold. 1 Introduction The study of actuator saturation in linear control design has a long history; see for instance [1], in particular Chapter 12 on dual-mode regulators, and the references given there. The search for controllers of systems subject to such saturation can be seen as a problem in nonlinear control, and that is the point of view taken here. In particular, we look at questions of stabilization, an area that has witnessed a large amount of activity during the last few years (see for instance [6] for a survey and many bibliographical references). In this paper we provide a general result on smooth stabilizability under minimal (and clearly necessary) hypotheses. The systems that we deal with have the form x = Ax + B `(u) (SYS) where A and B are n \Theta n and n ..