Robust state estimation and unknown inputs reconstruction for a class of nonlinear systems: Multiobjective approach

We consider a novel method to design H∞ observers for a class of uncertain nonlinear systems subject to unknown inputs. First, the main system dynamics are rewritten as an augmented system with state vector including both the state vector of the main system and the unknown inputs. Then, we design a...

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Bibliographic Details
Published in:Automatica (Oxford) Vol. 64; pp. 1 - 7
Main Authors: Delshad, Saleh S., Johansson, Andreas, Darouach, Mohamed, Gustafsson, Thomas
Format: Journal Article
Language:English
Published: Elsevier Ltd 01.02.2016
Elsevier
Subjects:
[formula omitted] observer design
Automatic
Control Engineering
Engineering Sciences
H∞ observer design
Multiobjective optimization
Nonlinear systems
Reglerteknik
Unknown inputs reconstruction
Unknown inputs reconstruction
H∞ observer design
Nonlinear systems
Multiobjective optimization
H_inf observer design
ISSN:0005-1098, 1873-2836, 1873-2836
Online Access:Get full text
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Summary:We consider a novel method to design H∞ observers for a class of uncertain nonlinear systems subject to unknown inputs. First, the main system dynamics are rewritten as an augmented system with state vector including both the state vector of the main system and the unknown inputs. Then, we design a H∞ reduced-order observer to estimate both state variables and unknown inputs simultaneously. Based on a Lyapunov functional, we derive a sufficient condition for existence of the designed observer which requires solving a nonlinear matrix inequality. To facilitate the observer design, the achieved condition is formulated in terms of a set of linear matrix inequalities (LMI). By extending the proposed method to a multiobjective optimization problem, the maximum bound of the uncertainty and the minimum value of the disturbance attenuation level are found. Finally, the proposed observer is illustrated with an example.
ISSN:0005-1098
1873-2836
1873-2836
DOI:10.1016/j.automatica.2015.10.051