Fault Detection for Nonlinear Systems With Multitone Sinusoidal Input

As sinusoidal inputs are common in engineering systems, it is therefore important to develop fault detection methods for these systems in order to improve their reliability. In this paper, a fault detection method for nonlinear systems with multitone sinusoidal input is developed. By assuming the output of the system has the almost periodicity property, the proposed method is derived based on the periodogram for fault detection using the asymptotic local approach, which is effective to detect both incipient and abrupt faults. It is shown that the fault detection problem using the proposed method is reduced to a chi
²
-test for a given confidence level. Simulation example involving a nonlinear system is used to illustrate the implementation and the performance of the proposed method.