Técnicas para estimação de expoentes de Lyapunov em sistemas dinâmicos nâo-lineares

Abstract

Thestability of trajectories in the phase space of a dynamical system can be characterized through Lyapunov characteristic exponents. In simple situations, these exponents correspond to the eigenvalues of the linearized equation of motion. However, for complex trajectories occurring in many nonlinear systems, specially during the occurrence of chaos, the determination and the very concept of stability and of the values of those exponents becomes more elusive, creating technical difficulties. This work makes a pedagogical review, presenting and explaining the concepts of stability, and Lyapunov exponents, discusses its application to the characterization of nonlinear dynamical systems, and proposes a study about the techniques do evaluate those exponents. To illustrate this study, we analyze some specific systems, such as Lorenz’s and Rössler, and discuss the properties that can be inferred from our study.