Interval observer-based fault detection in finite frequency domain for discrete-time fuzzy systems

This paper presents a new method for detecting faults in discrete-time fuzzy systems. First, the piecewise interval observers are constructed based on the output-space partition technique. Second, l1 performance is introduced to attenuate the persistent bounded disturbances and H− performance in finite frequency domain is employed to improve fault sensitivity of the residual intervals. Then, the observer gains can be determined by solving the disturbance attenuation, fault sensitivity and non-negativity conditions, simultaneously. Different from the classical fault detection methods with residual evaluation functions and threshold generators, the proposed interval observers are able to generate the natural thresholds. Finally, the developed technique is demonstrated in a simulation example.