Fault estimation filter design for discrete-time Takagi-Sugeno fuzzy systems

This study is concerned with the fault estimation problem of discrete-time Takagi-Sugeno fuzzy systems with low-frequency faults. A fault estimation filter is designed to solve this problem. To make the estimation error as small as possible in the presence of high-frequency disturbances, the filter is designed to satisfy two finite-frequency H-infinity performance indices simultaneously. An algorithm is proposed to calculate the parameters of the desired filter. The obtained filter can estimate the faults in low-frequency domain effectively, e.g. stuck faults. For comparison, a full-frequency fault estimation method is also given. An example is given to illustrate advantages of the proposed finite-frequency method.