Robust adaptive estimation of nonlinear system with time-varying parameters

2014 ◽  
Vol 29 (8) ◽  
pp. 1055-1072 ◽  
Author(s):  
Jing Na ◽  
Juan Yang ◽  
Xuemei Ren ◽  
Yu Guo
Keyword(s):  
Nonlinear System ◽  
Adaptive Estimation ◽  
Time Varying ◽  
Varying Parameters ◽  
Time Varying Parameters ◽  
Robust Adaptive

Adaptive Estimation of Time-Varying Parameters in Linearly Parametrized Systems

2005 ◽  
Vol 128 (3) ◽  
pp. 691-695 ◽  
Author(s):  
Yongliang Zhu ◽  
Prabhakar R. Pagilla
Keyword(s):  
Adaptive Estimation ◽  
Parameter Estimate ◽  
Time Varying ◽  
Time Intervals ◽  
Varying Parameters ◽  
Time Varying Parameter ◽  
Time Varying Parameters ◽  
Parametrized Systems ◽  
Simulation Results ◽  
Estimation Of Time

Adaptive estimation of time-varying parameters in linearly parametrized systems is considered. The estimation time is divided into small intervals; in each interval the time-varying parameter is approximated by a time polynomial with unknown coefficients. A condition for resetting of the parameter estimate at the beginning of each interval is derived; the condition guarantees that the estimate of the time-varying parameter is continuous and also allows for the coefficients of the polynomial to be different in various time intervals. A modified version of the least-squares algorithm is provided to estimate the time-varying parameters. Stability of the proposed algorithm is shown and discussed. Simulation results on an example are given to validate the proposed method.

scholarly journals Adaptive Hybrid Function Projective Synchronization of Chaotic Systems with Time-Varying Parameters

2012 ◽  
Vol 2012 ◽  
pp. 1-18 ◽  
Author(s):  
Jinsheng Xing
Keyword(s):  
Chaotic Systems ◽  
Projective Synchronization ◽  
Time Varying ◽  
Chen System ◽  
Varying Parameters ◽  
Function Projective Synchronization ◽  
Time Varying Parameters ◽  
Hybrid Function ◽  
Robust Adaptive ◽  
Different Chaotic Systems

The adaptive hybrid function projective synchronization (AHFPS) of different chaotic systems with unknown time-varying parameters is investigated. Based on the Lyapunov stability theory and adaptive bounding technique, the robust adaptive control law and the parameters update law are derived to make the states of two different chaotic systems asymptotically synchronized. In the control strategy, the parameters need not be known throughly if the time-varying parameters are bounded by the product of a known function oftand an unknown constant. In order to avoid the switching in the control signal, a modified robust adaptive synchronization approach with the leakage-like adaptation law is also proposed to guarantee the ultimately uni-formly boundedness (UUB) of synchronization errors. The schemes are successfully applied to the hybrid function projective synchronization between the Chen system and the Lorenz system and between hyperchaotic Chen system and generalized Lorenz system. Moreover, numerical simulation results are presented to verify the effectiveness of the proposed scheme.

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