System identification based anti-torque flap design

The ducted-fan UAVs have potential for missions in urban environments, but there are still some problems in attitude control. In this paper, a dynamic model of the propeller-engine and anti-torque flap was established based on experiments and simulations, and the flap sizes were also calculated as the propeller-torque was equal to the flap-torque. Inaccuracy of the engine simulation and the high complexity of the wind tunnel test can be avoided by using this approach. Flight test results show that the ducted-fan vehicle could hover steadily along the vertical axis with the chosen flap inside.