Robust control of a shape memory alloy wire actuated flap

In this paper, shape memory alloy (SMA) wire actuators are used to control the flap movement of a model airplane wing. Conventionally, the flap of an aircraft wing is driven by electric motors or hydraulic actuators. The use of SMA actuators has the advantage of significant weight reduction. Two SMA actuators are used: one to move the flap up and the other to move the flap down. A sliding mode based nonlinear robust controller is designed and implemented on a real-time data acquisition and control platform to control the position of the flap. Feedback control experiments of both position regulation and tracking control are conducted. To demonstrate the controller's robustness to uncertainties and disturbances, experiments are conducted with additional mass on the flap, changing thermodynamic conditions and time varying aerodynamic loads. Experiments in all cases show that the actual position of the flap closely follows the desired command during experiments. In conclusion, this paper shows the feasibility of using SMA wire actuators for aircraft flap control.