改进多段高斯伪谱法的近空间可变翼飞行器小翼伸缩优化研究

Stretch-out and drawback optimization of the winglets of near-space morphing hypersonic aircraft based on the improved multiband Gauss pseudospectrum

针对Gauss伪谱法在处理近空间可变翼飞行器最省燃油轨迹优化与可变小翼伸缩状态的最优关系等问题时存在计算量大、计算效率低下、优化精度低等缺陷,本文提出一种改进的多段整合优化的高斯伪谱法的求解策略。考虑到本文研究对象带有可伸缩小翼的特殊性及飞行过程中声速、密度、地球引力及发动机推力变化等因素的影响,对爬升模态进行合理分段,建立多段优化模型,应用本文所提的改进方法进行了整体优化仿真试验。通过数值仿真得到整个爬升各子段的最少耗油爬升轨迹及小翼伸缩状态。仿真结果表明:改进后的优化方法在计算时长、优化精度等整体性能上得到了进一步的提升。

The Gauss pseudospectral method exhibits defects,such as large calculation amounts,low calculation efficiency,and low optimization accuracy,when dealing with problems,including finding the optimal relation between the fuel-saving trajectory optimization of the near-space variable wing aircraft and the stretch-out and drawback states of the variable winglet.In this study,an improved multistage integrated optimization method that can be referred to as the multistage Gauss pseudospectral method is proposed.The climbing modes are segmented reasonably because of the particularity of the extensible winglets and the influence of the changes in sound speed,density,gravity,and engine thrust during flight;further,a multistage optimization model is established.Finally,an overall optimization simulation experiment is conducted using the improved method proposed in this study.The climbing trajectory that consumes the minimum amount of fuel and the winglet stretch-out and drawback states with respect to the climbing segment are obtained via a numerical simulation.The simulation results denote that the improved optimization method has improved the overall performance with respect to the calculation time and optimization accuracy.