Fault detection in finite frequency domain for T-S fuzzy systems with partly unmeasurable premise variables

This paper is concerned with the problem of finite frequency fault detection (FD) for a class of T-S fuzzy systems with partly unmeasurable premise variables. To fully use the available information of the considered T-S fuzzy system, an FD observer whose premise variables consist of the measurable premise variables and the estimations of unmeasurable ones of the fuzzy model is designed. However, the membership functions of the fuzzy model and the observer to be designed are unsynchronized, such that the existing FD methods based on parallel distribute compensation (PDC) strategy may be infeasible. To overcome this difficulty, a novel non-PDC H∞/H− unknown input observer is designed to achieve the purpose of fault detection and provide less conservative results. Finally, two simulation examples are given to illustrate the validity and merits of the presented FD scheme. © 2020 Elsevier B.V.