连续推力最优轨道规避

Continuous-thrust Optimal Orbital Avoidance

应用非线性规划方法研究了连续推力时间最优和燃料最优航天器规避问题。航天器空间飞行中,为了避免与其他航天器或空间碎片相撞,需采取措施实施规避策略。由于航天器最优规避问题是典型的具路径约束的轨迹优化问题,间接法即应用极大值原理难于处理。考虑航天器推进系统为固定比冲发动机,用改进的轨道根数描述航天器动态,在给定最大推力幅值和中间过渡轨道时,将规避问题划分为转移和返回两个阶段,然后应用非线性规划方法统一考虑时间最优和燃料最优航天器最优规避问题。数值仿真结果表明,最优规避任务能够完成;在时间最优或燃料最优规避情形时,航天器均以最大推力工作,且时间最优规避时消耗燃料最少。

The nonlinear programming method is used to study the continuous-thrust minimum-time and the minimum-fuel- consumption orbital avoidance in this paper. During the spacecraft mission lifetime, a encounter with other space objects is possible and to avoid collision, some maneuver strategy is required. The optimal orbital avoidance is a typical trajectory optimization problem with path constraints, but is difficult to be solved by indirect methods. The dynamics of the spacecraft is described by the modified elements. Given the optimal parking orbit, the orbital avoidance mission is divided into transfer and roundtrip phases. Considering the minimum-time or the minimum-fuel-consumption performance, the optimal orbital avoidance problem can be formulated. Furthermore, the nonlinear programming method is applied to deal with the two phase orbital transfer problem. The simulations demonstrate that the minimum time/fuel-consumption orbital avoidance mission is well accomplished. The simulation results also show that the spacecraft flies around the earth with the maximum thrust magnitude during its whole time history both in the minimum-time and the minimum-fuel-consumption cases.