LINEAR-SYSTEMS WITH INPUT NONLINEARITIES - GLOBAL STABILIZATION BY SCHEDULING A FAMILY OF H-INFINITY-TYPE CONTROLLERS

A new global stabilization algorithm is presented for linear systems t hat have (A, B) stabilizable, the eigenvalues of A in the closed left- half plane, but where the controls pass through nonlinearities of a ge neral type. This algorithm is based on a semi-global stabilization sol ution for the same class of systems. The global solution is constructe d by dynamically scheduling the adjustable parameter of the semi-globa l solution according to the size of the state. The semi-global solutio n is a family of linear control laws generated by a family of H-infini ty-type algebraic Riccati equations. We show that the closed-loop stat e feedback system has the property that additive disturbances which co nverge exponentially to zero cannot produce unbounded states. This fac t is used to show that, under a linear detectability assumption, the s tate feedback results are recovered when the solution is implemented v ia a standard linear-based observer.