FAULT ESTIMATION FOR NONLINEAR DESCRIPTOR SYSTEMS WITH LIPSCHITZ CONSTRAINTS VIA LMI APPROACH

By using the linear matrix inequality (LMI), for a nonlinear descriptor system with Lipschitz constraint, a state-space observer is designed to simultaneously estimate the descriptor system states, the fault signals and the finite times derivatives of the faults. For a nonlinear descriptor system with bounded input disturbances, a robust state-space observer is proposed to simultaneously estimate the descriptor system states, the faults, the finite times derivatives of the faults, and attenuate the input disturbances. The considered fault can be unbounded (provided that the qth derivative of the fault is zero piecewise or norm bounded), the present fault estimation approach can thus handle a large class of fault signals. A numerical example is included to illustrate the present design approach.