Practical L 2 Disturbance Attenuation for Nonlinear Systems

Abstract In this work, a definition of generalized L 2 -gain for nonlinear systems, where the gain IS considered asa function of the state instead of a (global) constant, is presented. This new notion seems to be adequate to characterize the gain properties of several. nonhnear systems which do not possess a uniform L 2 -gain property (i.e. the L 2 -gain depends on the operating point). Moreover, a notion of practical L 2 -gain attenuation, which extends the. standard definition and parallels (mutatae mutandis) the concepts of practical stablhty, IS also proposed.