On LaSalle´s invariance principle and its application to robust synchronization of general vector Lie/spl acute/nard equations

A functional version of LaSalle´s invariance principle is derived, i.e., rather than the usual pointwise Lyapunov-like functions it uses specially constructed functionals along system trajectories. This modification enables the principle to handle even nonautonomous systems to which the classical LaSalle´s principle is not directly applicable. The new theoretical results are then used to study robust synchronization of general Lie/spl acute/nard type of systems. The developed technique is finally applied to chaotic oscillators synchronization. Numerical simulation is included to demonstrate the effectiveness of the proposed methodology.