UNCERTAIN CHAOTIC SYSTEM CONTROL VIA ADAPTIVE NEURAL DESIGN

2002 ◽  
Vol 12 (05) ◽  
pp. 1097-1109 ◽  
Author(s):  
S. S. GE ◽  
C. WANG

Though chaotic behaviors are exhibited in many simple nonlinear models, physical chaotic systems are much more complex and contain many types of uncertainties. This paper presents a robust adaptive neural control scheme for a class of uncertain chaotic systems in the disturbed strict-feedback form, with both unknown nonlinearities and uncertain disturbances. To cope with the two types of uncertainties, we combine backstepping methodology with adaptive neural design and nonlinear damping techniques. A smooth singularity-free adaptive neural controller is presented, where nonlinear damping terms are used to counteract the disturbances. The differentiability problem in controlling the disturbed strict-feedback system is solved without employing norm operation, which is usually used in robust control design. The proposed controllers can be applied to a large class of uncertain chaotic systems in practical situations. Simulation studies are conducted to verify the effectiveness of the scheme.

2000 ◽  
Vol 10 (05) ◽  
pp. 1149-1156 ◽  
Author(s):  
S. S. GE ◽  
C. WANG ◽  
T. H. LEE

This paper is concerned with the control of a class of chaotic systems using adaptive backstepping, which is a systematic design approach for constructing both feedback control laws and associated Lyapunov functions. Firstly, we show that many chaotic systems as paradigms in the research of chaos can be transformed into a class of nonlinear systems in the so-called nonautonomous "strict-feedback" form. Secondly, an adaptive backstepping control scheme is extended to the nonautonomous "strict-feedback" system, and it is shown that the output of the nonautonomous system can asymptotically track the output of any known, bounded and smooth nonlinear reference model. Finally, the Duffing oscillator with key constant parameters unknown, is used as an example to illustrate the feasibility of the proposed control scheme. Simulation studies are conducted to show the effectiveness of the proposed method.


2002 ◽  
Vol 19 (9) ◽  
pp. 1257-1259 ◽  
Author(s):  
Chen Shi-Hua ◽  
Liu Jie ◽  
Feng Jian-Wen ◽  
L  Jin-Hu

2001 ◽  
Vol 11 (06) ◽  
pp. 1743-1751 ◽  
Author(s):  
C. WANG ◽  
S. S. GE

In this letter, adaptive synchronization of two uncertain chaotic systems is presented using adaptive backstepping with tuning functions. The master system is any smooth, bounded, linear-in-the-parameters nonlinear chaotic system, while the slave system is a nonlinear chaotic system in the strict-feedback form. Both master and slave systems are with key parameters unknown. Global stability and asymptotic synchronization between the outputs of master and slave systems can be achieved. The proposed approach offers a systematic design procedure for adaptive synchronization of a large class of continuous-time chaotic systems in the chaos research literature. Simulation results are presented to show the effectiveness of the approach.


2014 ◽  
Vol 2014 ◽  
pp. 1-6 ◽  
Author(s):  
Yeguo Sun ◽  
Heng Liu

This paper presents a fuzzy adaptive control method for MIMO uncertain chaotic systems in nonstrict feedback form, which is capable of guaranteeing the prescribed performance bounds. For the prescribed performance bounds, we mean that the tracking error should converge to a predefined arbitrarily small set, with convergence rate no more than a prescribed value. A novel output error transformation is introduced to transform the original constrained system into an equivalent unconstrained one, and it is proved that the stabilization of the unconstrained system is sufficient to solve the problem. Based on the error transformation technique, a fuzzy adaptive controller is designed for the unconstrained system. For updating the parameters of the fuzzy logic systems, a proportional-integral adaptation law is proposed. Finally, an illustrative example is given to demonstrate the effectiveness of the proposed results.


Author(s):  
Thanh T Tran ◽  
Oscar R Gonzalez

This article investigates a backstepping-based control method for aircraft roll dynamics. The research starts with a formulation of backstepping control law for a general class of a strict-feedback form of nonlinear dynamic systems. The backstepping control law is formulated by introducing a normal tracking error. Then, control and virtual control inputs are selected by addressing each layer of the design process with a chosen corresponding control Lyapunov function. The parameter assignment in each design layer is selected to ensure the stability of the entire system. Next, a backstepping-based control algorithm with online-gain schedule or variable gains is provided for the standard strict-feedback system. In order to validate the proposed method, application of roll dynamics of aircraft is implemented. Dynamic equations of free-to-roll aircraft model is restructured in a standard strict-feedback model for formulating the backstepping control. Then, a backstepping control–based control strategy is provided for aircraft free-to-roll dynamics. Indoor experimental and simulation studies of roll angle control for the L-59 free-to-roll aircraft model at NASA Langley Research Center are implemented to verify and validate the proposed approach.


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