Fault diagnosis of nonlinear systems using reduced-order observers and algebraic observers

Two different nonlinear observers are employed in the fault diagnosis problem of nonlinear systems. A diagnosis criteria based on the differential transcendence degree of a field extension is employed. Two systems with two types of faults (multiplicative and additive) are analyzed. Faults are estimated with each observer. Some numerical results are shown to illustrate this methodology and finally, some concluding remarks are given