Modelling and control of a redundant electromechanical actuator for stability augmentation systems of helicopters

There is an ongoing transition towards power-by-wire (PBW) electromechanical actuators (EMAs) in the aerospace field, since they offer significant advantages over traditionally employed hydraulic actuators. However, this transition is hindered by safety issues due to the probability of jamming of the required mechanical transmission systems, as it often consists in a single-point-of-failure with possibly catastrophic consequences. This thesis investigates a possible architecture for a redundant electromechanical actuator for helicopters, to be employed by the Automatic Flight Control System (AFCS) for yaw control purposes. The mechanical and electrical redundancies of the actuator give it the capability to remain operational after most single failures, averting losses of functionalities with possibly catastrophic repercussions. This thesis focuses on the physical modelling of the conceived architecture, and on the design and testing of a dedicated control system, carried out within the Simulink environment.