Anti-Windup-Like Compensator Design for Continuous-Time Systems Affected by Unknown Nonlinearities and Input Saturation

This paper addresses the stabilization of a particular class of continuous-time systems affected by unknown sector bound nonlinearities and input saturation. An observer is designed to provide an estimate of the unknown nonlinearity. Such an estimate is used by an additional compensation loop with the purpose of mitigating the effect of the nonlinearity and enlarge the basin of attraction of the system. Stability conditions are given as a set of matrix inequalities and quadratic Lyapunov functions are exploited. An optimal compensator design algorithm based on semidefinite programming is proposed. Finally a numerical example shows the results of the proposed approach.