Robust Interval Type-2 Fuzzy Observer for Fault Detection of Networked Control Systems Subject to Immeasurable Premise Variables

In this paper, a novel observer design has been suggested for fault detection of networked control systems under random measurement delays. A randomly varying communication delay structure has been assumed in data transmission between the physical system and the observer. In order to increase the applicability of the proposed Takagi - Sugeno fuzzy observer, it has been contemplated to be under immeasurable premise variables. In addition, time-varying parameter uncertainties are added to the system, which contribute to the system uncertainties. Theoretical materials related to the system and the observer design with a predetermined H∞ index are provided resulting in less conservative constraints in the proof of asymptotical mean-square stability of the closed-loop system. Simulation results, which have been applied to a real-world system of tunnel diode circuit, have shown how the proposed observer would benefit from the use of interval type-2 fuzzy sets in dealing with uncertainties of the system