Experimental Modal Analysis of a Small Unmanned Aerial Vehicle with Variable Aspect Ratio Wing

The main purpose of this paper is to present the natural frequencies and mode shapes of a small unmanned aerial vehicle (sUAV), designed and test-flown at the Florida Institute of Technology obtained via experimental modal analysis (EMA). The EMA was performed in order to understand the UAV's modal characteristics as a first step aimed towards understanding the aeroelastic characteristics of the aircraft. The Variable Aspect Ratio (VAR) unmanned aerial vehicle (UAV) studied employs a telescoping wing which, by adaptively-changing its span can evolve optimally in all flight regimes. Data acquisition and analysis were performed with ModalVIEW. The modal tests employed hammer excitation and accelerometer response measurements. In particular, the study focused on the difference between modal characteristics of two different VAR wing configurations: fully retracted vs. fully extended wing.