Fault Detection Observer Design in Low Frequency Domain

This paper studies the H_/H_infin fault detection problem in the low frequency domain with the aid of the recently developed generalized Kalman-Yakubovic-Popov (KYP) lemma, which gives an accurate characterization of the H_ index in the low frequency domain. The low frequency H_ index and another important performance index H_infin norm are used to measure the low frequency fault and disturbance effects respectively, and an LMI-based method of designing fault detection observers is presented. An example of the VTOL aircraft is studied to illustrate the effectiveness of the proposed method.