Fault Identification in Nonlinear Systems Based on Sliding Mode Observers with Weakened Existence Conditions

摘要

This paper considers the problem of fault identification in systems described by nonlinear dynamic equations with disturbances. Sliding mode observers are used for the solution. The proposed approach is based on constructing a reduced (lower-dimensional) model of the original system with selective sensitivity to defects and disturbances. This model is introduced mainly to weaken the existence conditions for sliding mode observers compared to the known works, particularly the minimum phase, detectability, and matching conditions. The weakening effect is achieved since the reduced model may not have the original system's properties hindering the construction of sliding mode observers. This theory is illustrated by an example.