Application of Modal Testing and Analysis Techniques on a sUAV

Abstract

This paper’s focus is on experimental structural analysis using contemporary testing techniques for a small unmanned aerial vehicle (sUAV). Testing was performed to find the bending and torsional modes of the wings and tail utilizing multiple methods. Data acquisition and analysis were performed using ModalVIEW, a structural analysis program supported by LabVIEW. The aircraft was excited with random excitation using a single mechanical shaker. These techniques were applied in a case study on the BTE Super Hauler airframe, a small UAS operated by the Unmanned Aircraft Systems Engineering (UASE) Laboratory at the University of North Dakota. The aircraft is primarily used for flight testing of multiple payloads, including an antenna system designed for use in sense and avoid applications. This application requires the addition of wing pods to the current airframe to avoid electro-magnetic interference from the engine of the UAS. Therefore, the effects of the two wing pods on the structural dynamic behavior of the UAS, as well as flutter analysis, were performed on the aircraft and the results are presented and compared. In addition, a statistical method of critical sensor placement for accurate modal information with limited accelerometers is discussed.