Longitudinal flight performance improvement strategy for high-altitude long-endurance flexible aircraft: mass-actuated aeroelastic control

For the high-altitude long-endurance (HALE) flexible aircraft, aeroelastic design and control have an important impact on enhancing the flight stability and control performance. In this study, a novel longitudinal flight performance improvement concept is proposed by employing mass-actuated aeroelastic control (MAAC) strategy, along with the mathematical modeling, performance analysis and control verification. Considering the couplings among longitudinal flight dynamics, structural dynamics, aerodynamic loads, and mass motion, an integrated mathematical model is firstly established for the HALE flexible aircraft with MAAC. Steady-state analyses reveal that the trimming thrust and elevator deflection can be reduced through MAAC, and the critical stable speed can also be adjusted without introducing drag penalty. Meanwhile, the control authority and variation tendencies are endowed with designable space by the variable spanwise and chordwise position of the mass. Integrating the mass-actuated aeroelastic wing, an auxiliary longitudinal control framework of the HALE flexible aircraft is finally established, which includes altitude control, wing deformation control, and stability augmentation control. With the proposed MAAC, simulation results show that lower energy consumption, smooth wing deflection control, and an extended flight envelope of the HALE flexible aircraft are achieved.