精确动力学模型中的行星引力辅助轨道设计

Trajectory Design of Gravity Assist in the High-fidelity Dynamic Model

轨道设计分为初步设计和精确模型迭代两步,初步设计基于等效脉冲模型,用圆锥曲线拼接法确定时间窗口和引力辅助产生的速度脉冲。精确模型中引力辅助看作是一个连续的过程,将简化模型得到的引力辅助双曲线轨道化为行星心目标B平面参数,以地心逃逸速度作为设计变量,通过微分修正的方法进行求解。通过算例对比分析了简化模型和精确模型设计结果之间的关系,结果表明,引力辅助脉冲等效模型精度较好。

The precision orbit design using planet gravity assist in the high-fidelity model was studied. Orbit design was divided into two steps, preliminary design and iteration in the high-fidelity model. Preliminary design was based on the simplified model. Conic patched method was used to determine the launch window and the impulse induced by gravity assist. Taking the gravity assist as a continuous process in the high-fidelity model, the swing-by hyperbola was transformed into B-plane parameters. The earth-centered departure impulse was taken as design variable and the problem was solved by differential correction. Orbit design for Flora rendezvous in main asteroid belt after Mars gravity assist was presented and the relation of the results between the two models above was compared and analyzed in the illustrative example analysis. The result indicates that the orbit in the high-fidelity model which is based on the simplified model can be reached after few iterations.