基于航路点分段的预测校正再入制导方法

A Way-point based Piecewise Predictor-corrector Re-entry Guidance Algorithm

针对可重复使用空天飞行器的再入及返场问题,通过设置航路点开展了分段预测校正再入制导方法研究。首先,在发射坐标系下建立了动力学模型,对再入过程中的约束条件进行了分析与转化;其次,给出了数值预测校正制导方法的设计逻辑,针对该算法迭代中可能产生的发散问题与饱和问题,一是引入一个调节因子来自适应地调整迭代步长,二是为迭代设置与速度相关的误差限,三是采用了设置航路点的方式对再入过程分段,缓解了气动不确定性带来的影响,完成了数值预测校正方法的改进;最后,通过对某空天飞行器的数值仿真验证了该方法的有效性,使用航路点分段策略能够进一步消除制导指令饱和,提升制导精度。

This paper focus on a way-point based piecewise numerical predictor-corrector guidance based on ASV’s re-entry problems.First of all,the dynamical model of ASV is established in the launch coordinate system and the trajectory constraints are analyzed and transformed for the re-entry phase.Then,the logic of numerical predictor-corrector guidance algorithm is proposed.Simultaneously,three strategies are applied in order to avoid the numerical divergency problem at the end of re-entry phase.Firstly,an adaptive factor is introduced to adjust the iteration step length.Secondly,the error limit for the iteration is set to be speed-dependent.Thirdly,piecewise solution is proposed to ease the random dynamic impacts.Finally,numerical simulations have been carried out to test the validity of the re-entry guidance algorithm.The results demonstrate that the re-entry guidance works well and the precision can be further improved once the piecewise strategy is introduced.