Fault estimation for nonlinear systems: an observer structure design criterion technique

This paper mainly focuses on the observers design and fault estimation for nonlinear systems with faults. The considered nonlinear system is assumed to be represented by T-S fuzzy models or from a LPV system, where the coefficient matrix of measured output is time-varying. A lower triangle matrix (LTM)-based observer structure design criterion (OSDC) for the given nonlinear system is proposed. Under the proposed LTM-based OSDC, an estimation observer with generality and relaxed constraints is designed, by which the fault occurring in the system can be well estimated online. Linear matrix inequality (LMI)-based stability conditions for the estimation error dynamics are given. Simulation examples test the proposed OSDC technique.