Vibration-based Rotorcraft Gearbox Monitoring Under Varying Operating Conditions

Modern rotorcrafts rely on Health and Usage Monitoring Systems (HUMS) to enhance their availability, reliability and safety. The complexity of the transmission system of new helicopter designs such as the Airbus Racer provides additional challenges for HUMS. The work presented here demonstrates a vibration-based monitoring approach for the lateral gearboxes of the racer. This approach relies on the statistical analysis of different condition indicators (CIs) extracted from vibration signals under different operating regimes to define a baseline for these CIs during normal operation. This permits the normalization of CIs from newly acquired signals with respect to the expected baseline value, facilitating the detection of anomalies in the signal characteristics for a variety of operating regimes. The monitoring capabilities of the proposed approach are tested using experimental data where the vibration response to different mechanical malfunctions was artificially seeded in to the acquired signals.