Experimental Studies on Active Shape Control of Composite Structures using SMA Actuators

In this article, the experimental modeling and active shape control of hybrid composite structures actuated by shape memory alloy (SMA) wires are presented and discussed. The thermomechanical properties of the SMA wires are experimentally measured. SMA actuators with residual strains are prepared by loading-unloading tensile tests. Hybrid composite structures are established by attaching the SMA actuators on the surface of a graphite/epoxy composite beam and plate by bolt-joint connectors. The first-order numerical model is used to model the response of the hybrid composite structures attached to the SMA actuators. The parameters of the first-order model are experimentally determined and the response is compared with experimental data. For faster and more accurate shape/deflection control of the hybrid composite structure, feedforward and proportional integral derivative (PID) feedback controllers are designed and applied to the hybrid composite structure. The PID feedback controller significantly improves the performance of the SMA actuators.