Development of a proof-of-concept aircraft smart control system

Hutapea et al((1)) showed that an actuation system based on shape memory alloy coils could be employed for a wing flap of an aircraft. A continued research and development of these previously demonstrated smart flight control mechanisms was performed with the goal to develop a proof-of-concept shape memory alloy (SMA) actuation system, which utilises SMA springs to control the six degrees of freedom of an aircraft. For this actuation system, the springs are heated via an electric current, causing the spring to contract as the metal's phase changes from martensite to austenitel((2-5)). The contraction allows the springs to function as linear actuators for the aircraft's control surfaces, specifically the flaps and ailerons on the wings and horizontal stabilisers and a rudder on the tail. As a significant advancement to the overall actuation system, an air burst-cooling system increases the cooling rate of the coils by means of forced convection. Computer-based finite element model analysis and experimental testing were used to define and optimise SMA spring specifications for each individual control surface design. A one-sixth scale proof-of-concept model of a Piper PA-28 Cherokee 160 aircraft was constructed to demonstrate and to verify the final actuation system design.