Optimisation of a Torque Controller for Electro-Mechanical Flight Surface Actuation

Kurzfassung

Electro-mechanical actuation is pursued for primary flight control of future commercial aircraft. An electro-mechanical actuator (EMA) has the interesting property, that its output torque is nearly proportional to the motor current, which offers to regulate the flight surfaces’ aerodynamic torques. Since an aircraft’s dynamics are determined by aerodynamic forces, a flight control system that regulates surface torques is thus simpler than the state-of-the-art that regulates surface positions. In addition, dynamic gust load alleviation is achieved as a by-product. This paper describes a torque controller developed for the aileron EMAs of a short to mid-range aircraft. The torque controller was tuned using multi-objective optimisation. Quality criteria related to performance and stability margin are applied. Then, the optimisation is performed for different flight points and operating cases that the torque-controlled actuation must cover. Optimisation results are showing a high control accuracy and gust load alleviation while maintaining the control loop’s stability.