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飞机的飞行性能与重心(CG)位置密切相关,尤其是后掠式无尾飞机的重心位置对其飞行性能影响更甚,如果重心位置发生变化,升力分布随之改变,进而影响飞机航时。针对这个问题,从气动布局和设计方法两方面,设计了一种航时对重心位置不敏感的无尾无人机(UAV)。气动布局上,提出了利用螺旋桨动力配平纵向力矩的鸥翼(GW)布局,以减小重心位置变化对升阻特性的影响;设计方法上,采用稳健性优化设计(RDO)理论,分析重心位置不确定时的航时低敏感度问题。以一架小型电动无人机为研究对象,建立了无尾无人机稳健性优化设计环境,包括总体设计、代理模型构造以及稳健性优化。分析结果表明:利用螺旋桨动力配平的鸥翼布局使重心可用范围增加了5%;静安定裕度在5%~15%变化时,该布局可以有效提高航时稳健性。采用稳健性优化得到的无人机几何参数,大幅度降低了重心位置对航时的影响,显著提升了满足约束的概率。
The flight performance of the aircraft is closely related to the position of the center of gravity (CG). In particular, the center of gravity of the swept-back tailless aircraft affects its flight performance even more. If the position of the center of gravity changes, the lift distribution changes, which affects the aircraft flight time. In response to this problem, from the aerodynamic layout and design methods, a tailless UAV (UAV) insensitive to the position of center of gravity was designed. On the aerodynamic layout, a gull wing (GW) layout using propeller power to trim the longitudinal moment is proposed to reduce the influence of the position change of the center of gravity on the lift-resistance characteristics. On the design method, the robust optimization design (RDO) Uncertainty in flight time low sensitivity problem. Taking a small electric unmanned aircraft as the research object, the robust optimization design environment of the tailless UAV is established, including the overall design, the construction of the proxy model and the optimization of robustness. The results show that the usable range of the center of gravity is increased by 5% when the propeller power leveling gull wing layout is used; and the layout stability can be effectively improved when the static stability margin is varied from 5% to 15%. The geometric parameters of UAV optimized by robustness can greatly reduce the impact of the center of gravity on the flight time and significantly improve the probability of satisfying the constraint.