火星六自由度大气进入制导方法对比分析

Analysis and Comparison of Mars Atmospheric Entry Guidance Methods in 6-DOF Model

针对传统的参考轨迹跟踪制导方法精度不高、鲁棒性不佳的问题,文章将一种数值预测校正制导方法应用到火星大气进入制导中。为了充分验证制导方法的性能,首先推导建立了完整的极坐标系下六自由度动力学模型。在标准无偏差进入状态下,考虑质心三自由度运动情况,对两种不同的制导方法设计得出的倾侧角进行了分析,结果显示了预测制导方法能根据不同任务情况自主规划控制律的灵活性。考虑不确定性参数的影响,兼顾落点精度和开伞条件约束,通过蒙特卡洛打靶的六自由度仿真,对两种进入制导方法的精度和稳定性进行了验证和分析。研究表明,相比于传统的参考轨迹制导方法,数值预测校正方法在制导稳定性、着陆精度和开伞性能上均有明显提升。

To solve the problem that traditional reference path tracking guidance is lack of accuracy and robustness,a numerical predictive-corrective guidance(NPC)is applied in Mars atmospheric entry guidance.In order to fully evaluate the guidance performance,the spherical motion equations of six-degree-of-freedom(6-DOF)are established for Mars low-lifting entry vehicle.In nominal states,bank angle profiles are designed with the two guidance methods,and analysis shows that NPC guidance is flexible for control law planning.Considering the influence of parameter uncertainties,6-DOF Monte-Carlo numerical simulations are demonstrated to analyze the accuracy and stability of the two guidance methods.Results show the robustness,landing accuracy and parachute opening performance of NPC guidance are identically promoted compared to the traditional guidance method.