Observer-Based Fault Estimation for Discrete-Time Nonlinear Systems and Its Application: A Weighted Switching Approach

This paper deals with the problem of observer-based fault estimation (FE) for discrete-time nonlinear systems via a weighted switching approach. A pair of variable weights is introduced in an efficient but straight-forward way, and thus, the space spanned by the prescribed normalized fuzzy weighting function can be divided into a set of non-overlapping subspaces. A new fuzzy switching FE observer is proposed by designing exclusive FE observer gain matrices for each non-overlapping subspaces, and thus, less conservative off-line designed conditions for the proposed fuzzy switching FE observer are obtained than the previous results by adequately taking advantage of the characteristic information of each non-overlapping subspaces. More importantly, the process of on-line deciding the current subspace's index at each sampled point is very straightway and some previous time-consuming online operation is avoided, i.e., it can be said that the on-line computational burden also is alleviated in this paper. Finally, the proposed theoretical result is applied to a tunnel diode circuit and the advantages over existing literature are validated by means of objective comparisons.