基于气动辅助变轨的变气动外形飞行器概念研究--二层优化与求解方法

一个飞行器的气动外形,在给定的气体流动状态下将决定其气动特性,而这些气动特性又和变轨的优化解密切相关,这是考虑了热载荷、峰值过载和飞行的机动性等限制.因此构成一个二层优化问题;气动外形优选(上层问题)和变轨优化(下层问题).通过定义一个最优值函数,可以把二层优化问题转换成单层的数学规划,通常这是非凸的和非线性的问题,且难于求解,然而基于智能优化的现代优化方法,将为这类复杂问题提供可解的途径.最后,给出一个变气动外形飞行器的变轨优化的框图和求解步骤.

New Concept of Variable Aerodynamic Shape Spacecraft Based on Aeroassisted Orbital Transfer--Bilevel Programming Problem and Solving Method

The aerodynamic performance of a spacecraft is depended on its aerodynamic configuration under a given flow regime. And the optimal control solution for orbital transfer strategy is closely concerned with the aerodynamic perfermance, considering the constrants of heat load, peak acceleration and the maneurver in flight, etc. So there is a bilevel programming problem (BLPP) to describe the relationship between the aerodynamic configuration ( upper level problem) of a spacecraft and its optimal orbit transfer (lower level problem). By the definition of a optimal value function, the BLPP can be transformed to a level programming problem which is usually nonconvex and nonlinear and is difficult to solve. However the modern optimization algorithm based on artificial intelligence, may provide effective algorithm to solve this complex problems. Finally the logic flow and the solving steps for the optimality to the orbital transfer of a variable aerodynamic shape spacecraft are suggested.