Robust disturbance attenuation of nonlinear systems using output feedback and state-dependent scaling

Automatica ◽  
2004 ◽  
Vol 40 (9) ◽  
pp. 1621-1628 ◽  
Author(s):  
H. Ito ◽  
Z.-P. Jiang
Keyword(s):  
Nonlinear Systems ◽  
Output Feedback ◽  
Disturbance Attenuation ◽  
State Dependent ◽  
Robust Disturbance Attenuation

Disturbance Attenuating Adaptive Controllers for Parametric Strict Feedback Nonlinear Systems With Output Measurements

1999 ◽  
Vol 121 (1) ◽  
pp. 48-57 ◽  
Author(s):  
I. Egemen Tezcan ◽  
Tamer Bas¸ar
Keyword(s):  
Nonlinear Systems ◽  
Output Feedback ◽  
Robust Adaptive Control ◽  
Disturbance Attenuation ◽  
Parameter Estimates ◽  
Minimum Phase ◽  
Feedback Form ◽  
Output Measurement ◽  
Adaptive Controllers ◽  
Strict Feedback

We present a systematic procedure for designing H∞-optimal adaptive controllers for a class of single-input single-output parametric strict-feedback nonlinear systems that are in the output-feedback form. The uncertain nonlinear system is minimum phase with a known relative degree and known sign of the high-frequency gain. We use soft projection on the parameter estimates to keep them bounded in the absence of persistent excitations. The objective is to obtain disturbance attenuating output-feedback controllers which will track a smooth bounded trajectory and keep all closed-loop signals bounded in the presence of exogenous disturbances. Two recent papers (Pan and Bas¸ar, 1996a; Marino and Tomei, 1995) addressed a similar problem with full state information, using two different approaches, and obtained asymptotically tracking and disturbance-attenuating adaptive controllers. Here, we extend these results to the output measurement case for a class of minimum phase nonlinear systems where the nonlinearities depend only on the measured output. It is shown that arbitrarily small disturbance attenuation levels can be obtained at the expense of increased control effort. The backstepping methodology, cost-to-come function based H∞ -filtering and singular perturbations analysis constitute the framework of our robust adaptive control design scheme.

scholarly journals Disturbance Attenuation via Output Feedback for Uncertain Nonlinear Systems with Output and Input Depending Growth Rate

2014 ◽  
Vol 2014 ◽  
pp. 1-8 ◽  
Author(s):  
Weiyong Yu ◽  
Fangfang Zhang
Keyword(s):  
Growth Rate ◽  
Nonlinear Systems ◽  
Output Feedback ◽  
Closed Loop ◽  
Rate Function ◽  
Disturbance Attenuation ◽  
Uncertain Nonlinear Systems ◽  
Closed Loop System ◽  
Growth Rate Function ◽  
Dynamic Gain

The problem of output feedback disturbance attenuation is investigated for a class of uncertain nonlinear systems. The uncertainties of the considered systems are bounded by unmeasured states with growth rate function of output and input multiplying an unknown constant. Based on a dynamic gain observer, an adaptive output feedback controller is proposed such that the states of the closed-loop system are globally bounded, and the disturbance attenuation is achieved in theL2-gain sense. An example is provided to demonstrate the effectiveness of the proposed design scheme.

Global Robust Disturbance Attenuation for Uncertain Minimum Phase Nonlinear Systems

1997 ◽  
Vol 30 (16) ◽  
pp. 315-320
Author(s):  
Weizhou Su ◽  
Lihua Xie ◽  
Carlos E. de Souza ◽  
Zhiming Gong
Keyword(s):  
Nonlinear Systems ◽  
Disturbance Attenuation ◽  
Minimum Phase ◽  
Robust Disturbance Attenuation
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