连续小推力航天器的深空探测轨道优化方法综述

SURVEY OF LOW-THRUST TRAJECTORY OPTIMIZATION METHODS FOR DEEP SPACE EXPLORATION

连续小推力作用下航天器的深空探测轨道的优化设计是一个存在大量局部最优解的全局优化问题.轨道设计流程总体上分为全局优化和局部优化.全局优化为粗略设计,通常在对航天器受连续推力作用下的轨道作近似处理的前提下大致确定探测序列和时间节点.局部优化方法可分为直接法、间接法和混合法.直接法是将连续的问题离散成一个参数优化问题.间接法是求解由变分法和极大值原理推导的满足一阶最优必要条件的两点或多点边值问题.混合法利用间接法推导的方程,再离散后优化求解.本文综述当前轨道优化设计领域最新和最常用的方法,分析各种方法的优缺点.

Low-thrust optimization and design of spacecraft trajectory for deep space exploration is a global optimization problem with large numbers of local solutions.The strategy of trajectory design consists of global optimization and local optimization as a whole.As a concept design,the goal of global optimization is to approximately determine exploration sequences and node times after simplifying spacecraft trajectory generated by low thrust.Local optimization is generally cataloged as direct methods,indirect methods,and hybrid methods.Direct methods convert the continuous optimal control problem into a parameter optimization problem through discretization.Indirect methods are involved in solving two- or multi-point boundary-value problems satisfying the first-order necessary conditions derived from the calculus of variations and the maximum principle.Hybrid methods partly utilize the conditions derived by indirect methods,and then as what direct methods do,resort to parameter optimization.This paper surveys the state of the art in low-thrust trajectory optimization,and describes the benefits and deficiencies of the newest and most popular methods.