Fault estimation filter design for discrete‐time Takagi–Sugeno fuzzy systems

Abstract

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 ∞ 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.