应用直接配置非线性规划法求解最优气动辅助轨道转移

首先研究了一种求解轨迹最优化问题的直接方法,即直接配置非线性规划方法(DCNLP),该方法使用分段的多项式来代表系统中的状态变量和控制变量,并通过配置来满足系统微分方程,最终将最优控制问题转化成非线性规划问题。然后将该技术应用到异面气动辅助转移问题中,通过采用大气外轨道预调整方案,增加了大气入口速度,针对大气内飞行的动力学方程,建立极小时间性能指标,将最省燃料指标转化为相应的最佳入口、出口条件。最后针对形成的最优控制问题,应用DCNLP方法进行求解,成功地得到了大气飞行最优轨迹。

Direct Collocation with Nonlinear Programming for Solution of Optimal Aeroassisted Orbital Transfer

A direct method for solution of trajectory optimization problem is introduced firstly,which is termed direct collocation with nonlinear programming.In this method,piecewise polynomials are used to represent state variables and control variables,and are collocated to satisfy the differential equations.The control optimization problem is so converted into a nonlinear programming problem which will be solved numerically.This method being used in nonplanar aeroassisted orbital transfer problem,the atmospheric entry velocity is enlarged.The orbital preliminary adjusting out of atmosphere is also presented.The minimum flight time for the atmospheric portion of the trajectory is used as a index for the performance while the minimum fuel consumption index is converted into corresponding entry point conditions and exit point conditions.Finally,DCNLP is applied to solve this control optimization problem and the optimal trajectory for atmosphere flight is so obtained.