一种小推力轨迹优化的改进方法

针对小推力轨迹优化这一难点和热点问题,提出了一种在直接法的基础上进一步提高优化结果的改进方法。分析了直接法在离散后存在求解维度较高的不足,借鉴了间接法推导出的最优解必要条件,提出了推力仅取最大值或零的取值改进方法。通过多次优化计算,根据产生速度增量需要的能量来确定推力和追击时间的取值范围,缩减了直接法的求解维度。最后进行了数值仿真,改进方法计算得到的优化指标高于直接法结果,表明该改进方法优于直接法。

Improvement of Low-Thrust Trajectory Optimization

It is a challenging and popular issue to optimize low thrust trajectory.A rigid method on modification of the direct-shoot method is given to improve the result.The multidimensional insufficiency of the direct-shoot method after making the thrust discrete is investigated.And the condition for the optimum solution is picked from the indirect-methods idea.The thrust is fixed to take the magnitude of the max or zero.The magnitude of the force and the time of flight are determined by several times of optimization calculations according to the energy needed to make a certain velocity increase and thus the variables dimensions are reduced.Numerical simulation shows that this method gets a better result than the direct-shoot method.The results demonstrate that the modified method is effective and is valid for low-thrust trajectory optimization.