Active aerodynamic enhancement control for hybrid quadrotors with moving wings

This article focuses on the aerodynamic enhancement control of a hybrid quadrotor with two moving wings (HQWMW), —a configuration that integrates a pair of rotatable wings onto the airframe of a conventional quadrotor, which provides additional aerodynamic forces during flight to enhance its aerodynamic performance. A unified mathematical model for the HQWMW based on motor and wing dynamics is established. This model avoids the risk of unstable control processes caused by flight mode switching in conventional Vertical Takeoff and Landing (VTOL) vehicles, and thereby significantly reduces the complexity of controller design. A cascade controller with moving wings (MWs) dynamic feedforward compensation is designed to mitigate the aerodynamic effects of the MWs for the HQWMW, and to improve the robustness of control system. Additionally, a control allocation strategy based on active angle-of-attack (AOA) adjustment is proposed to improve MWs dynamic efficiency, thereby extending endurance of the HQWMW. The effectiveness and aerodynamic enhancement performance of the proposed methods are verified through comparative flight experiments involving three configurations: HQWMW with the proposed methods, HQWMW with different fixed AOA configurations, and HQWMW with MWs removed (a conventional quadrotor). Experimental results indicate that the HQWMW with different fixed AOA configurations can improve the endurance of the conventional quadrotor; furthermore, the HQWMW with the proposed methods achieves the highest flight efficiency. At a mission flight velocity of 15 m/s, the maximum reductions in high velocity flight thrust and electrical power are 48.27% and 54.73%, respectively.