基于单参数迭代的TAEM在线轨迹生成方法

针对大升力体轨道再入飞行器末端能量管理（TAEM）段制导控制能力强、末端约束不惟一的问题,将TAEM段分为动压跟踪和着陆预备2个阶段,设计了不同的纵向轨迹剖面,从而将TAEM段在线轨迹生成问题转化为单参数搜索问题。第1阶段设计标称动压剖面为纵向参考轨迹,使得飞行器过程约束得到保证。第2阶段纵向剖面设计为标称高度剖面,从而使得末端点高度和倾角约束得到保证。根据末端动压误差设计修正律,迭代修正第一阶段动压剖面,从而使得最终的纵向轨迹满足所有的状态约束。在线轨迹递推采用以时间为自变量的数值积分,递推过程引入闭环制导律,通过实时修正攻角跟踪纵向剖面,修正倾侧角跟踪地面轨迹,从而保证在线生成的轨迹符合物理特性,降低闭环制导难度。在考虑初期再入末端大范围状态散布情况下,数值仿真显示了所提算法的鲁棒性。

Online trajectory design method for terminal area energy management based on single parameter iteration

In consideration of the problems of strong control ability and multi-terminal constraints in the Terminal Area Energy Management (TAEM) of lifting reentry vehicles, the TAEM phase is divided into two stages: the dynamic pressure tracking stage and the pre-landing stage. Different longitudinal trajectory profiles are designed for the two stages respectively to transform the online trajectory generation problem in the TAEM phase into a single parameter search problem. In the first stage, the longitudinal reference trajectory is the nominal dynamic pressure profile, which ensures the aircraft process constraints. In the second stage, the longitudinal trajectory is designed as the nominal height profile to guarantee the height and inclination constraints of the terminal point. The dynamic pressure profile of the first stage is modified iteratively by designing a correction law according to the dynamic pressure error at the TAEM terminal. In the process of online trajectory recurrence, the numerical integration with time as the independent variable is adopted, and the closed-loop guidance law is introduced by adjusting the angle of attack to track the dynamic pressure profile and modifying the bank angle to track the ground trajectory. Consequently, the trajectory generated online conforms to the physical properties and the difficulty of closed-loop guidance is reduced. Numerical simulation considering large range state dispersion at the end of initial reentry shows the robustness of the proposed algorithm.