Enhanced Particle Filter framework for improved prognosis of electro-mechanical flight controls actuators

Abstract

The technology of flight control actuators is at the forefront of the “more electric aircraft” research trend since its beginning, due to the several advantages that the introduction of Electro Mechanical Actuators (EMAs) would provide over the traditional hydraulic/mechanical solution for both primary and secondary flight control surfaces. However when compared to hydraulic actuators, technological barriers still persist for a wide adoption of EMAs especially when considering their sensitivity to certain single point of failures that can lead to mechanical jams, resulting in a reluctance to adopt EMAs for flight safety critical applications as solutions are heavy and costly (redundancy, fail safe behavior, etc.), thus creating difficulties for adoption and certification and impacts on costs. The development of an effective and reliable PHM system for EMAs could help mitigating the risk of a sudden critical failure by properly recognizing and tracking the ongoing
fault and anticipating its evolution, and will offer a possible way contributing to the acceptance of EMAs as primary flight control actuators in commercial aircraft. The paper firstly presents an enhanced Particle Filter framework for improved prognosis, discussing its benefits and its implementation inside a general PHM framework developed for EMAs. Then, three significant examples of its application are provided relevant to an electrical and a mechanical fault of the EMA: degradation of the electric motor and backlash increase in the mechanical transmission due to the growing wear of its components. The positive results obtained from the application of the enhanced Particle Filtering framework to these faults provide good confidence on the possibility of extending it to other EMAs faults and to successfully implement this technique to EMAs for flight control actuators.