航天飞机三维最优再入轨道及气动加热过程

本文应用现代控制理论研究了航天飞行器三维最优再入轨道和与轨道参数密切相关的气动加热过程。文中选择飞行器迎角和倾斜角作为控制变量,以飞行器气动加热率和飞行过载沿轨道积分最小作为优化性能指标,按极大原理导出最优再入轨道有约束控制的非线性两点边值问题。采用了数值优化方法——共轭梯度法求解有升力飞行器的最优再入轨道及其热过程。文中以允许误差法讨论了权系数和罚函数的选取方法;对不同速度范围研究了不同的加热模型;按热平衡方程与优化轨道同步迭代的方法求得了算例数值结果。算例的数值结果与文献13]的量值是一致的。

Three-Dimensional Optimal Reentry Trajectory and Aerodynamic Heating History of the Space Shuttle

In this paper, the optimization problem of reentry trajectory and aerodynamic heating history of the space shuttle has been discussed using the modern control theory by selecting the attack angle and the bank angle as control variables. The optimal reentry trajectory and aerodynamic heating history of the vehicle are simulated numerically . According to Pontryagin's Maximum Principle, selecting the total aerodynamic heat transferred to unit area of the nose stagnation point and the integration of the overload as the performance index, the nonlinear two-point-boundary-value problem of the optimal reentry trajectory is derived. The numerical computation algorithm-the conjugate gradient method is used in order to improve the iterated convergence. The method based on tolerable error is proposed which is implemented to choose the weighting factors in the performance index and the penalty factors for processing the constraints of terminals, state variables and control variables required.The results obtained in this paper agree with the reference 13].