Aerodynamics-Driven Morphing Control and Flight Test for Compound Flexible Multibody Aircraft

The compound multibody aircraft, created through flexible wingtip docking of multiple unit aircraft, not only capitalizes on high aerodynamic efficiency, but also holds the potential for in-flight reconfiguration. This study addresses the challenges of controlling the inherently unstable morphing process through aerodynamic surfaces, eliminating the need for additional driving mechanisms and offering advantages in structural simplicity. In-flight controllable morphing was achieved, significantly elevating the mission flexibility and environmental adaptability of the Compound Flexible Multibody Aircraft. A multibody dynamics model with 10 degrees of freedom is developed, and a modified control allocation strategy is proposed to enhance morphing control capability. The control structure placing the configuration controller and the overall attitude controller in parallel is developed to simultaneously guarantee the morphing and trajectory control task. Finally, a successful morphing flight test is implied, in which the configuration commands are determined according to the attainable configuration envelope. This paper presents a control method for compound flexible multibody aircraft that accommodates varying numbers of connections and provides solutions for the stable flight and aerodynamic morphing of such aircraft, expanding their usage and offering insights for the control of more general flexible aircraft.