Tailless UAV design optimization under center of gravity location uncertainty

There is a strict connection between aircraft performance and center of gravity (CG) location. This is especially true for a swept tailless aircraft. The shape of lift distribution deviates much from ellipse due to the presence of CG fluctuations. Then it leads to the endurance deterioration. Hence, the tailless unmanned aerial vehicle (UAV) whose endurance is insensitive to CG location is designed. In the current paper, two scenarios namely aerodynamic configuration and design method are presented. In configuration, the gull wing (GW) involving propeller thrust to trim the pitching moment is proposed in order to reduce the effect of CG location variation on lift to drag ratio. While in terms of method, the robust design optimization (RDO) theory is applied to solving the problem of insensitive endurance under CG location uncertainty. A small electric-powered UAV is taken as a case study. The RDO environment is established including UAV conceptual design, surrogate model construction as well as robust optimization. The analytical results show that the proposed GW configuration increases CG admissible region by 5% and the endurance is insensitive when static margin varies between 5% and 15%. The optimal parameters based on RDO largely improve the endurance robustness of tailless UAV. The constraints of UAV design requirements are satisfied with much higher probabilities.