组合动力飞行器吸气段轨迹设计方法研究

水平起降组合动力可重复使用运载器是未来航天运输系统的重要发展方向。针对采用空气预冷涡轮火箭发动机的组合动力飞行器在吸气爬升段受多约束条件限制、动力与质量特性变化大的特点，提出了一种基于动压高度剖面的轨迹设计方法。通过推导基于高度的质点运动学方程，得到轨迹参数解算流程，并结合动压、迎角与法向过载的约束边界以及任务窗口确定动压高度剖面形状，从而得到满足要求的吸气段标称轨迹。在此基础上，设计了标称轨迹高度跟踪制导律。仿真结果表明，标称轨迹在吸气段多种不确定性偏差的影响下满足多约束要求，具有较强的鲁棒性。

Air-breathing stage trajectory design method research for combined power vehicle

The future direction of space transportation systems involves the development of a reusable carrier capable of horizontal takeoff and landing. Aiming at the characteristics of multiple constraints and large variation in dynamic and mass characteristics of the combined power vehicle using pre-cooling air turbo rocket (PATR) during the air-breathing stage, a trajectory design method based on dynamic pressure-altitude profile is proposed. The particle kinematics equations based on altitude are derived, the trajectory parameter solving process is obtained. The shape of dynamic pressure-altitude profile is determined by integrating constraints from dynamic pressure, angle of attack, and normal overload, as well as mission windows, resulting in the attainment of the required air-breathing nominal trajectory. On this basis, an altitude-tracking guidance law is designed. The simulation results show that the nominal trajectory meets the requirements of multiple constraints under the influence of various uncertainty deviations during the air-breathing stage, which has strong robustness.