针对结合行星借力和小推力技术的行星际转移轨道设计问题,提出一种基于形状逼近策略的初始设计方法。采用改进的逆六次多项式策略计算小推力弧段,通过引入B平面参数和推进器开关点时间系数实现行星借力和推滑混合轨道的拼接,将初始设计问题转化为求解混合整数非线性规划问题。为降低规划模型求解难度,通过参数变换对模型进行简化处理,并采用具有全局大范围搜索能力的改进微分进化算法求解最优设计参数。数值结果表明:相比正弦指数曲线设计方法,本文方法可以有效对交会型转移轨道进行设计,并且可以提供更少燃料消耗的探测机会。
A method for designing interplanetary low-thrust trajectory with planetary swing-bys is proposed based on shape-based theory.In this method,the modified inverse polynomial is used to approximately calculate low-thrust arcs.The B-plane parameters and switching time parameters are introduced to achieve the patch of planetary swing-bys and thrust-coast hybrid trajectories.The preliminary design problem can be transformed into solving a mixed-integer nonlinear programming problem(MINLP).In order to obtain optimal design parameters,the design model is simplified by parameter transformation,and a modified differential evolution algorithm is used to solve the MINLP.Numerical simulations demonstrate that,compared with the exponential sinusoid method,the proposed approach can be used to design transfer trajectories for rendezvous missions,and also to realize exploration opportunities with less fuel.