Browsing by Subject "Dynamics."

Now showing 1 - 3 of 3

Open Access
Application of dither and observer based state feedback in the control of chaotic systems
(1996) Ersoy, Umut
In the first part of this thesis, the application of dither for controlling chaotic systems is presented. Dither is a high frequency periodic signal that has been excunined in the literature before, for changing nonlinear systems effectively. The presented technique is based on a conjecture proposed by Genesio and Tesi and is mainly cipplicable to systems in Lur’e form. In the second part, the application of state feedback is presented. Unknown states of the system are constructed by using nonlinear full-state observers. The control strategy is mainly based on the mentioned conjecture and also on bifurcation diagriuns.
Open Access
Nonlinear observer design with application to the synchronization of chaotic systems
(1996) Solak, Ercan
Observers cire used to estimate the states of dynamiccil systems whenever are not available through direct measurements. Although the design of linear observers is a well-developed branch of control theory, its counterpart for nonlinear systems is a relatively new field. In this thesis, an observer construction methodology is proposed lor a chiss of nonlinear systems satisfying certain conditions. Then, the problem of synchronizing chaotic systems, which has found recent appliccitions in the area of secure message transmission, is addressed from the observer design point of view. In the design, we exploited one of the essential properties of the chaotic systems that the trajectories remain in a bounded region of the state space. It is also shown that, for certciin well-known chaotic systems, the system structure enables one to nse linecir observer schemes in order to have global synchronization.
Open Access
Structural analysis of pole assignment and stabilization in dynamic systems
(1989) Şefik, Ayla
Motivated by the need for qualitative investigation of general system properties such as controllability, obser\^bility, existence of fixed modes, etc. as the complement of the quantitative approach in analysis, especially of large-scale systems, the problems of pole assignability and stabilizability are considered from the structural point of view. The study is based on the definition of a generic property as a property that holds for almost all values of the nonzero system parameters. Structured matrices and digraphs are used for system description. Both problems are first formulated in an algebraic setting and then translated to a structural framework by means of several graph-theoretic results which give sufficient conditions for solvability, in terms of the existence of particular cycle families in the digraph. Following a similar approach, a graphical investigation of structural observability is presented. Lastly, genericity of several results are reconsidered in the light of these graphical characterizations.