Modeling of aerodynamic disturbances for proximity flight of multirotors

This paper presents a model to predict aero-dynamic disturbances during close formation flight of two multirotors. The model is based on a propeller velocity field model and characterization of change in propeller thrust under oncoming flow. Using this model, we predict forces and torques on one mutirotor due to downwash of the other with respect to relative separation of the multirotors. We conduct proximity flight experiments using two types of quadcopters to measure forces and torques using accelerometer and rategyro. Predictions from the model and results from experiments match well for vertical separations greater than seven times the vehicle size. This verifies the range of fidelity of the model.