Experimental Study on Modal Characteristics of Large Flexible Aircraft

Abstract

High altitude long endurance unmanned aerial vehicle (UAV) is a type of UAV that operates at an altitude of around 10000 meters and can fly for several days, relying on solar panels.Usually, this type of aircraft has the structural characteristics of high aspect ratio, large wingspan, low wing load, and high flexibility.In engineering applications, it is often necessary to measure the vibration modes of such aircraft, and the modal measurements of such aircraft are often not accurately obtained.This article conducts relevant research on the issue of inaccurate measurement in modal experiments of such aircraft. By establishing a finite element model, the reasons for the inaccurate measurement of low order frequencies in modal experiments of such aircraft are analyzed, and the magnitude of data errors in different situations is quantitatively calculated.Based on the above research, this article proposes two methods for solving modal tests of such aircraft. This method has important guiding significance for ground modal testing of large flexible structures, which is beneficial for dynamic analysis and flight control research of such aircraft.