Nonlinear Control System Design by Quantifier Elimination

Many problems in control theory can be formulated as formulae in the first-order theory of real closed fields. In this paper we investigate some of the expressive power of this theory. We consider dynamical systems described by polynomial differential equations subjected to constraints on control and system variables and show how to formulate questions in the above framework which can be answered by quantifier elimination. The problems treated in this paper regard stationarity, stability, and following of a polynomiallyparametrized curve. The software package QEPCAD has been used to solve a number of examples.