Sensing challenges for mechanical aerospace prognostic health monitoring

No Prognostic Health Monitoring (PHM) algorithm can turn poor sensor data into an accurate Remaining Useful Life (RUL) prediction, and measuring high-fidelity vibration data in noisy aerospace mechanical systems can be very challenging. Generally, for sensor selection and placement, temperature, masking vibration, electromagnetic interference, and vibration transfer path dynamics must all be considered. Additionally, although aerospace systems are built to exacting tolerances, variability between systems due to manufacturing differences, overhaul, and even variability between vibration sensors must be considered when setting up condition indicators. Many of these factors have been explored through high-frequency transfer-path testing of US Army helicopter gearboxes, resulting in a better understanding of the factors which influence the measured inputs into a PHM system and improved techniques for more reliable condition-based monitoring.