A Fault Diagnosability Evaluation Method for A Class of Affine Nonlinear Systems Considering Sensor Faults

In the present study of fault diagnosability of nonlinear systems, the fault diagnosability of sensor fault is not considered. The paper considered the sensor fault and the fault diagnosability evaluation method for a class of affine nonlinear systems is proposed by using the theory of differential geometry. The diagnosability of faults is regarded as an inherent property of the system and does not change with the change of diagnostic methods. Based on the controllability and observability decomposition theorems, the controllability distribution and observability distribution of faults are defined, and then the detectability and isolability criteria between process faults and sensor faults are given based on the containment relationship between each distribution. The analysis results show that the proposed method is suitable for the system which exists sensor faults.