The Research Of Methods For Uncertain Chaos Synchronization

Chaos is a quasi-stochastic phenomenon which appearing in deterministic nonlinear system. Chaotic system has the prominent characteristic which is extremely sensitive dependence on initial conditions. Chaos synchronization has become one of the important topics in the research of chaos due to its potential applications in secure communication, information technology, life sciences, and so on.Synchronization of two-order multi-scroll chaotic systems with hysteresis nonlinear function and four-order hyperchaotic system based on backstepping are discussed. According to the advantage of backstepping that only one controller needed and sliding-mode control is robust and simple realization, a backstepping sliding-mode control method is proposed to realize synchronization and parameters identification of uncertain multi-scroll chaotic system. And for the non-strict feedback chaotic system, active backstepping synchronization is proposed.To discuss a class of chaotic systems with unknown parameters when both of the states and the output of the systems are perturbed, an adaptive integral observer scheme for chaos synchronization is proposed. The disturbances are eliminated and parameters are identified using adaptive integral observer. Based on Lyapunov stability theory, we gain the sufficient criterion of gain matrix which can synchronize the drive system and the response system globally, and then transform this criterion into Linear Matrix Inequality (LMI) using Schur complements.To a class of chaotic systems when the output of the system is perturbed and the nonlinear portion of the system is unknown, an integral observer with a compensator based on orthogonal neural networks is proposed. The designed method achieves chaos synchronization using integral observer theory and the nonlinear approximation ability of the orthogonal neural networks based on the linear portion of chaotic system can be known.Coexistence of complete-synchronization and anti-synchronization (hybrid synchronization) and generalized projective synchronization (GPS) where the same structure and different structure contained are researched based on adaptive. For a general class of uncertain chaotic system, hybrid synchronization and parameter identification are achieved based on adaptive control theory. GPS and parameters identification between two same or different uncertain chaotic systems with bounded time-varying unknown parameters, robust adaptive control is proposed.