Electro-hydraulic servoactuators failure identification: Health features extraction through a high-fidelity physical model

Most of the commercial aircraft are equipped with Electro-Hydraulic Servo-Actuators (EHSA) for primary flight control systems. In case of failure, their standard maintenance procedures are manual, time-consuming and do not return an overall picture of the health status of the tested unit. In this framework, a research project between Politecnico di Torino and Lufthansa Technik (LHT) aims to introduce automation and advanced diagnostic methods for these components. As first contribution of this cooperation, an innovative testing procedure has been developed, which allows the extraction of a comprehensive set of Health Features (HFs) to identify the defects and failures of the unit, drastically reducing the testing time. The effectiveness of this procedure has been firstly tested using a High-Fidelity Physical Model: a modular “digital-twin” of the unit under test, which can replicate the serviceable and degraded behaviour of a real servo-actuator. Finally, the correlation between extracted HFs and degradations is assessed on simulated results by applying overall and individual evaluation metrics, based on feature-selection methods.