Non-uniform small-gain theorems for systems with unstable invariant sets

— We consider the problem of small-gain analysis of asymptotic behavior in interconnected nonlinear dynamic systems. Mathematical models of these systems are allowed to be uncertain and time-varying. In contrast to standard smallgain theorems that require global asymptotic stability of each interacting component in the absence of inputs, we consider interconnections of systems that can be critically stable and have infinite input-output L∞ gains. For this class of systems we derive small-gain conditions specifying state boundedness of the interconnection. The estimates of the domain in which the system’s state remains are also provided. Conditions that follow from the main results of our paper are non-uniform in space. That is they hold generally only for a set of initial conditions in the system’s state space. We show that under some mild continuity restrictions this set has a non-zero volume, hence such bounded yet potentially globally unstable motions are realizable with a ...

• Type: Conference
• Year: 2008
• Where: CDC
• Authors: Ivan Tyukin, Erik Steur, Henk Nijmeijer, Cees van Leeuwen
• Keywords: CDC 2008, Conditions Specifying State, Control Systems, Global Asymptotic Stability, Nonlinear Dynamic Systems