探月返回飞行器小过载跳跃式再入制导算法研究

摘要:

针对探月返回跳跃式再入飞行器再入峰值过载大的问题,本文通过将再入轨迹划分为等倾侧角飞行段、等高飞行段、终端再入段,设计了一种基于分段制导的小过载再入方案。首先,获取了基于分段飞行的再入走廊,考虑再入走廊约束及待飞航程,迭代获得等高飞行段终止条件,并进一步迭代得到等倾侧角飞行段的倾侧角幅值。其次,利用反馈线性化的方法实现对等高飞行段参考轨迹的跟踪,并引入航迹倾角反馈加速算法收敛。最后,等高飞行结束后,通过预测校正制导实现对剩余航程的导引,并通过引入反馈修正项调整倾侧角指令,使得再入制导段结束时飞行器高度达到期望高度。仿真表明,该算法能够降低峰值过载,对于不同再入航程具有良好的适应性,具有制导精度高、高度控制能力好、鲁棒性强的特点。

Abstract:

Aiming at the problem of excessive peak overload of lunar probe skip reentry vehicle, a piecewise small overload reentry guidance scheme was designed in this paper by dividing the reentry trajectory into equal bank angle flight, equal-height flight and terminal entry flight segment. Firstly, the reentry corridor based on segment flight was obtained, considering the constrains of the reentry corridor and the flight range to be cover, the terminal condition of the equal-height flight segment was confirmed; Furthermore, the amplitude of the bank angle of the equal bank angle flight segment was got by iteration. Secondly, the feedback linearization was applied to tacking the reference trajectory of the equal-height flight segment, and the flight path angle was introduced to accelerate of convergence. Finally, the last segment was guide by predictive correction guidance. By augmenting feedback correction and adjusting the bank angle command, the height of the Crew reached the desired height at the end of the reentry process. Simulation results demonstrate that the algorithm can reduce the peak overload significantly, and has good adaptability to difference ranges. It has the characteristics of high guidance accuracy, powerful height control ability and strong robustness.