基于μ分析的高超声速飞行器再入轨迹评估

Evaluation of re-entry trajectory of hypersonic vehicles based on μ-analysis

为解决高超声速飞行器再入过程中存在的不确定性问题,将μ分析理论应用到标称再入轨迹的评估中。采用线性稳定储备准则,在密度、升力系数和阻力系数存在不确定性时,对标称轨迹在制导律下的制导稳定性进行了分析;根据所获得的最坏参数组合,采用系统的开环尼克尔斯曲线验证了μ分析的结果;分析了系统所能容纳的最大不确定性参数,并研究了系统对不同不确定性参数的敏感性。结果表明:在密度、升力系数和阻力系数不确定性中,阻力系数对该标称轨迹的鲁棒稳定性影响最为明显。

The μ-analysis theory was applied to the evaluation of the nominal re-entry trajectory to solve the uncertainties in the course of re-entry of hypersonic vehicles. Based on the linear stability reserve criteria,the guidance stability of the nominal trajectory and guidance law was analyzed when the density,lift coefficient and drag coefficient are uncertainty. According to the worst-case combination of parameters,the Nichols curve of the open-loop system was used to verify the conclusion of μ-analysis results.The maximum uncertainty parameters which the system could accommodate were analyzed,and the sensitivity of the system to different uncertain parameters was studied. The results indicate that the drag coefficient has the most obvious effect on the robust stability of the nominal trajectory in the uncertainties of the density,lift coefficient and drag coefficient.