Validation of optical instrumentation for EMA sensing

The shift towards an extender electrical power feed of subsystems’ commercial aircraft has brought with it the need to use new types of actuation systems for primary and secondary flight controls. In this scenario, electromechanical actuators are the most viable choice for this type of aeronautical application. Associated with this new technological introduction there is the interest of investigating innovative methods to monitor the operation state and assess the health of these EMA systems during normal operations. Nowadays, the evaluation of a system's state start from the results provided by a simulation model. The preliminary part of this thesis deals with this topic of simulation where a validation process between the behaviour of a model respect to a real system is carried out. Being the EMA system the object of study, the entire validation process was conducted with an experimental bench used as a reference; this bench is built specifically to reproduce the structure and operation of an electromechanical actuator. The main part of the thesis is focus on the study of new sensor type, based on the use of optical fibres. In particular, the capabilities of sensors called Fibre Bragg Grating (FBG) were examined. The thermal and mechanical characteristics of these sensors were analysed in two separate phases. With appropriate experimental tests based on the use of a climatic chamber, the response dynamics in measuring temperature changes were initially analysed. Subsequently, the capability of these sensors in measuring a load applied to a mechanical component was studied. For this last evaluation, the experimental bench mentioned in the preliminary phase was used to evaluate the behaviour of these new sensors integrated on an EMA system. In this last part of the study, the problem of distinguishing the mechanical characteristic from the thermal characteristic on the data returned by the sensor was discussed. In fact, the two contributions are always present at the same time and the influence of the two was not immediately clear in the data analysis due to various experimental uncertainty in tests conditions.