Improved Aerodynamic Analysis for Multirotor-Type UAS Flight Simulation Using Dynamic Inflow and Rigid Blade Flapping

Abstract

Recently, studies on the control and aerodynamics of multirotor unmanned aircraft system (UAS) have been performed. However, some studies depend on methods that require significant computing time or are not applicable in the time-transient domain. Thus, this study focuses on constructing an aerodynamic analysis that is suitable for UAS flight simulation. First, unsteady dynamic inflow and blade element theory (BET) are combined in a feedback loop form. Additionally, rigid blade flapping, which is not considered for UAS analysis, is adopted. A parametric study is conducted under various forward conditions and the results of the proposed aerodynamic analysis are compared and verified with experimental results obtained in previous studies. The results indicate that the flight performance of a multirotor UAS is significantly affected when rigid blade flapping is considered. Specifically, while the drag shows discrepancy greater than 30% when the rigid blade flapping is not considered, it will decrease to a range smaller than 10% when the relevant term is considered. This matches well with the experimental results. As a result, the aerodynamic analysis presented in this study can be applied to flight simulations and nonlinear control algorithms for unsteady flight conditions.