An observer-based approach for input-independent global chaos synchronization of discrete-time switched systems

The work presented in this paper deals with chaos synchronization of discrete-time switched systems for communication purposes. In a chaotic masking scheme, the main problem arising lies in the fact that the state-reconstruction-error equation involves a term depending on the embedded information which may prevent the convergence. To tackle such a situation, an input-independent global synchronization (IIGS) observer-based method is proposed. It differs from the standard unknown input observers framework, which cannot be applied for the class of systems considered in this paper. It is shown that IIGS may result from both a special partial-pole placement and the notion of polyquadratic stability. Two configurations are distinguished: a subsystem configuration and an observer one. The analysis in the subsystem configuration or the design in the observer configuration is performed by solving a tractable linear-matrix inequalities setting. Two illustrative examples are given.