Flight control algorithm for small UAVs with aerodynamic asymmetry

The aerodynamic asymmetrical problem plays a critical role in the safe and stable flight of Unmanned Aerial Vehicles (UAVs). Due to technical defects of manufacture and the limit of material selections, the degree of asymmetry usually performs especially so obvious on small UAVs, out of its sensitivity to errors, that imbalanced flying has to be prevented. In this paper, we focus on the need for flight control method of a small U AV with aerodynamic asymmetry. The aerodynamic model of the UAV is built aiming at the asymmetrical system. Several control algorithms are presented in order to counteract the effects of asymmetry. An offline rudder trimming algorithm is proposed, assuming the asymmetry keeps conserved. Considering that the asymmetry is uncertain and changeful, a novel trimming algorithm by importing feedback control to the rudder control channel is put forward. Simulations show that the online trimming method works quite well in improving the safety of UAVs' steady flight. And the engineering feasibility is also considerable and discussed in this paper. The proposed method has great application value in engineering.