Regular Papers

International Journal of Control, Automation and Systems 2016; 14(2): 569-578

Published online April 15, 2016

https://doi.org/10.1007/s12555-014-0455-z

© The International Journal of Control, Automation, and Systems

Robust Delay Dependent Fault Estimation for a Class of Interconnected Nonlinear Time Delay Systems

M. Kazerooni, A. Khayatian, A. A. Safavi

Shiraz University

Abstract

This paper focuses on the problem of fault estimation for a class of interconnected nonlinear systems with time varying delays. In contrast to the common assumption imposed on the problem in most literature, here, there is no need for the delay rate to be less than one. Both actuator and component faults are considered within the general fault model invoked as multiplicative faults in this study. Robust adaptive observers are used to detect and estimate simultaneously the states and the parameter faults in each subsystem. The designed observers ensure a prescribed H∞ performance level for the fault estimation error, irrespective of the uncertainties which are assumed here to be the unknown interconnections between the subsystems. With the aid of H∞ performance index, the common assumption regarding the observer matching condition is no longer required. Sufficient conditions for asymptotic stability of the observers are derived via a matrix inequality approach with the aid of Lyapunov Krasovskii function. Finally, a simulation example is presented to show the validity and feasibility of the proposed method.

Keywords Fault estimation, interconnected nonlinear systems, Lyapunov- Krasovskii approach, time delay.

Article

Regular Papers

International Journal of Control, Automation and Systems 2016; 14(2): 569-578

Published online April 1, 2016 https://doi.org/10.1007/s12555-014-0455-z

Copyright © The International Journal of Control, Automation, and Systems.

Robust Delay Dependent Fault Estimation for a Class of Interconnected Nonlinear Time Delay Systems

M. Kazerooni, A. Khayatian, A. A. Safavi

Shiraz University

Abstract

This paper focuses on the problem of fault estimation for a class of interconnected nonlinear systems with time varying delays. In contrast to the common assumption imposed on the problem in most literature, here, there is no need for the delay rate to be less than one. Both actuator and component faults are considered within the general fault model invoked as multiplicative faults in this study. Robust adaptive observers are used to detect and estimate simultaneously the states and the parameter faults in each subsystem. The designed observers ensure a prescribed H∞ performance level for the fault estimation error, irrespective of the uncertainties which are assumed here to be the unknown interconnections between the subsystems. With the aid of H∞ performance index, the common assumption regarding the observer matching condition is no longer required. Sufficient conditions for asymptotic stability of the observers are derived via a matrix inequality approach with the aid of Lyapunov Krasovskii function. Finally, a simulation example is presented to show the validity and feasibility of the proposed method.

Keywords: Fault estimation, interconnected nonlinear systems, Lyapunov- Krasovskii approach, time delay.

IJCAS
May 2024

Vol. 22, No. 5, pp. 1461~1759

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