ETD

• Electro-Mechanical Actuator
• EMA Dynamic Modeling
• Flight Control Systems
• Luenberger Observer
• Observer-Based Control

The transition toward more-electric aircraft architectures is promoting the adoption of Electro-Mechanical Actuators (EMAs) for both primary and secondary flight-control movables. In this context, this thesis investigates the development of an observer-based control strategy for a dual-redundant active/standby electro-mechanical actuation system for leading-edge movables characterized by compliant mechanical transmission, designed to compensate for undesired structural interactions.  The EMA closed-loop control system, based on a three-loop cascaded architecture, is initially designed using a reduced-order Linear Time-Invariant (LTI) rigid-body model of the system, to define a baseline behaviour in terms of setpoint-tracking and disturbance-rejection dynamics. A high-fidelity model, entirely implemented in the MATLAB/Simulink environment and including the main system nonlinearities (load-dependent sliding friction, digital signal processing, sensor noise), is then developed to characterize the actuation dynamics under typical operating conditions in both the time and frequency domains. Subsequently, a reduced-order Luenberger Observer (LO), based on a LTI model capable of reproducing the lowest resonant frequency of the system, is designed to reconstruct the position of the leading-edge movable from EMA sensor measurements. The LO, adopted to limit the computational burden and enable the real-time execution, is finally integrated into the EMA control architecture by using the estimated states related to the movable motion to correct the setpoint signal, thereby mitigating the effects of structural compliance on the system response in the low-frequency range. Simulation results highlight that the strategy can significantly improve performances, but its effectiveness is strongly influenced by the magnitude of friction forces. If the system operates under severe friction conditions (e.g., due to wear), low-frequency limit-cycle oscillations are generated by the control scheme. Future work will address this issue, with the objective of including friction states in the observer as well as to extend the applicability of the strategy to the high-frequency range.