• freeplay
• electromechanical
• algorithm
• actuator
• prognostic

This master thesis focuses on the development of a prognostic algorithm, in order to evaluate the mechanical freeplay evolution of an electromechanical actuator for aircraft control surface, through a model-based approach.
A characterisation of freeplay increase effects over the actuator system performances has been carried out with a detailed Matlab-Simulink® model of the EMA, developed in previous and parallel works. An additional freeplay model has been inserted within the mechanical section of Simulink blocks and, subsequently, the freeplay has been injected gradually through an aging factor related to the dead zones parameters.
A particular attention has been paid on the development of a normalization approach able to energise the fault’s limit cycles amplitudes at characteristics frequencies, in terms of FFT analysis results. Therefore, a comparative analysis has been made to justify the usefulness of the technique. Subsequently, appropriates prognostic models have been achieved in order to perform the health-monitoring and determine the freeplay entity in the actuator.
Finally, random simulations have been carried out to validate the algorithm and, therefore, uncertainties have also been taken into account to demonstrate its robustness, accuracy and limitations.