Spectral Signatures of Pneumatic Actuator Failures: Closed-Loop Approach

This paper presents a new approach for fault detection and prognosis, using the principle of reduced interference on a probing signal in a closed-loop control system. The method is based on multisinusoidal signals, filter banks, and spectral analysis. A case study is presented to show that it is possible to design and introduce a disturbance into an aircraft pneumatic control loop to measure the degradation of the system components due to different factors including aging. The presented results are based on a validated nonlinear model of an aircraft pneumatic system, and the results indicate that the proposed method can be used to detect and isolate systems failures, estimate the time-to-failure information, and design health management systems.