###### Abstract  
This paper comprehensively reviews effective control applications using shape memory alloy (SMA) actuators. Among many applications, this paper focuses on the vibration and stiffness control of flexible structures and shape control in the aerospace engineering field. In the vibration control of flexible structures, three different methods are introduced and discussed, including their merits and demerits. In addition, several control strategies, such as neuro-fuzzy controller, are investigated in terms of the implementation associated with the microchip. In the control process, the inherent hysteretic behavior of SMA is also reviewed as a feedforward loop or actuating force compensator. At the second part, applications on the morphing wing in the field of aerospace engineering are reviewed, and salient characteristics are discussed. In this review, the morphing wing, which is closely related to aircraft stability, is mainly investigated considering control logics and geometrical parameters. For easily understanding morphing control using SMA, a table which summarizes the main contribution of each research is presented. It is expected, since this review article provides numerous approaches for vibration and morphing control conducted over the last decade, it will be very helpful to the same research community to create novel ideas to achieve more advanced and effective results in vibration and morphing control using SMA actuators. shape memory alloy; actuator; vibration control; flexible structure +
Footnote †: journal: Applied Sciences  
by external heat, but it has the advantage of being small in volume, biocompatible, and having high actuation force. In addition, it has the advantage that it can be manufactured in various forms such as wire, spring, and strap. Taking advantage of these points, SMA is being studied for application in various engineering fields. Various review papers on SMA have been reported in the material-level point of view and modeling/simulation point of view, and, among them, some papers on the actuator application point of view are also reported. [PERSON] et al. presented a review on the progress and development in optimization of an SMA linear actuator with different design methods, techniques, and approaches [4]. [PERSON] et al. reviewed rotary actuators triggered by SMA and discussed the characteristics and possibilities of SMA actuators for engineering applications [5]. [PERSON] et al. provided a review of research works related to SMA actuators for bi-directional rotational motion [6]. To obtain shape changing, investigations on design methods for the origami robot applications were conducted. [PERSON] et al. reported a review article on various aspects of high-speed actuation of SMA wires in the high driving force regime. [7]. [PERSON] et al. summarized the development and application of Fe-SMA technology in civil engineering, covering various aspects such as structural retrofitting and seismic damping. [8]. [PERSON] et al. reviewed SMA actuators in robotic applications over the last decade focusing on the control aspects of the actuator [9]. [PERSON] et al. reported in a review paper for SMA actuators for morphing wing application, and they focused on the design strategies of actuators [10]. As described above, although various review papers about SMA actuators have been published, a review article focusing only on the vibration and morphing motion control of structural systems using SMA actuators is considerably rare. Consequently, the main contribution of this review paper is to focus on the application of SMA actuators to the field of structural control systems, including both vibration and stiffness control of flexible structures and shape control in aerospace engineering. An in-depth review of papers published over the last decade was conducted to investigate the system characteristics and control results of research in the related fields.