Polytopic observer for global synchronization of systems with output measurable nonlinearities

Chaos synchronization has been tackled by considering the problem as a special case of an observer design. The considered dynamical systems to be synchronized have measurable nonlinearities. Their dynamical matrix is described in a polytopic way. By using the notion of polyquadratic stability, the problem of the observer synthesis is turned into the resolution of a set of Linear Matrix Inequalities (LMI) which are less conservative compared to the case of an usual quadratic Lyapunov approach. This enables to enlarge the class of systems for which synchronization can take place. The resulting matrix gain of the observer is computed by interpolating vertices gains resulting from the solution of the LMI's.