CR approach of nonlinear trim and flight load analysis of very flexible solar powered UAV

A very flexible solar powered UAV under aerodynamic load undergoes large deformation; thus it is impossible to obtain its precise nonlinear trimming and flight load characteristics with the structural models that have rigid or linear assumptions. Therefore, combining the co-rotational theory with the aerodynamic strip theory, we develop an analysis algorithm which can deal with the geometrically nonlinear trimming and flight load characteristics of the very flexible solar-powered UAV. Taking a UAV with the layout similar to Helios for example, we explore the nonlinear trimming and flight load characteristics of the UAV under different payloads. The exploration results, given in Fig. 5 through 12, and their analysis show preliminarily that: when applying the linear structural model to a large payload region, the trimming error of the UAV reaches 50% and the forecast error of its wingtip displacement reaches 25%. Our analysis algorithm can forecast the reasonable results on the very flexible solar-powered UAV and satisfy the precision requirements for the very flexible solar-powered UAV design in engineering.