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 International Conference on Complex Systems (ICCS2007)

Chaotic control of a two-link rigid manipulator with hierarchical structure

Mahtab Nazari
Biomedical Engineering Department, Amirkabir University of T

Amir Homayoon Jafari
Biomedical Engineering Department, Amirkabir University of Technology

Seyyed Mohammad Reza Hashemi Golpayegani
Biomedical Engineering Department, Amirkabir University of Technology

     Full text: Not available
     Last modified: May 31, 2007

A new approach to control a chaotic system as a complex system is presented in this article. We supposed a system of hierarchical structure with three levels: plant, chaos controller and supervisor. The plant is a two-link rigid robot that was made chaotic with appropriate input. Parameters of the input are regulated by supervisor depending on some chaos theory’s criteria such as Lyapunov Exponent and bifurcation diagram. To control the plant, we used two different methods: nonfeedback and hierarchical chaos control. The first can be done by changing input according to those mentioned chaos criteria. One of the disadvantages of this method is the limitation of generalizing for other systems. In the second method, control of the plant is to be done in two steps: finding unstable periodic orbits (UPOs) and using OGY method with supervisor to stabilize a desirable orbit. We used Poincare map to find the UPOs. The supervisor selects the middle and main UPOs as the goals for OGY controller. Therefore, OGY is guided to control plant in the chaotic attractor in order to reach and stabilize target UPO. Moreover, this technique is able to enhance the speed of control in contrast to OGY which is one of the most important problems of OGY method. In addition, the above mentioned method can be generalized to a wide class of systems.

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