Improvement of a multi-rotor UAV flight response simulation influenced by gust

Unmanned aerial vehicles (UAVs) are widely used, particularly in urban environments. However, existing studies on multi-rotor UAVs have rarely attempted simulations or experiments considering the significant intensity of gust induced by buildings. This study develops an improved real-time flight simulation for predicting the transient response of a multi-rotor UAV influenced by gust. The unsteady rotor aerodynamics which is appropriate to be implemented in the flight simulation is coupled with the nonlinear flight dynamics to predict the response of UAV due to gust accurately. Further, a straightforward gust estimation approach that is based on the nonlinear flight dynamics is proposed and validated to consider the influence of an unidentified gust. To validate and compare the proposed flight simulation, gust experiment that corresponds to urban operation is performed. The prediction obtained by the proposed flight simulation considering the gust profile was well correlated with the gust experiments. Moreover, using the flight simulation, the transient behavior and rotor aerodynamics are investigated under large gust intensities. It is found that appropriate rotor aerodynamics is crucial to predict the transient behavior of UAV by the effect of large gust intensities. Also, the transient behavior of UAV shows significantly different trend in response to the intensity of gust.