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Paper details
Number 3 - September 2013
Volume 23 - 2013
Robust nonlinear observer design for actuator fault detection in diesel engines
Boulaid Boulkroune, Issam Djemili, Abdel Aitouche, Vincent Cocquempot
Abstract
This paper is concerned with actuator fault detection in nonlinear systems in the presence of disturbances. A nonlinear
unknown input observer is designed and the output estimation error is used as a residual for fault detection. To deal with the
problem of high Lipschitz constants, a modified mean-value theorem is used to express the nonlinear error dynamics as a
convex combination of known matrices with time-varying coefficients. Moreover, the disturbance attenuation is performed
using a modified H∞ criterion. A sufficient condition for the existence of an unknown input observer is obtained using a linear matrix inequality formula, and the observer gains are obtained by solving the corresponding set of inequalities. The advantages of the proposed method are that no a priori assumption on the unknown input is required and that it can be applied to a large class of nonlinear systems. Performances of the proposed approach are shown through the application to a diesel engine model.
Keywords
diesel engine, fault diagnosis, nonlinear unknown input observers, LMI