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针对传统化学火箭难以重复使用、发射成本高的问题,提出了一种水平起飞/降落的新一代可重复使用运载器飞行方案,并对其动力模式设计和上升段轨迹优化方法等关键技术进行深入研究。设计了一种涡轮冲压发动机结合火箭冲压发动机的组合动力模式,建立了发动机推力与高度、马赫数等变量间的耦合模型,根据动力形式将上升段轨迹分为两段并采用全局搜索法确定动力切换的最佳时机。根据分段结果,分别以燃料最省和终端速度最大为指标,利用hp自适应伪谱法对两段进行轨迹优化设计。该算法基于双层策略求解最优控制问题,兼备伪谱法和有限元法的优点,与打靶法、伪谱法和间接法相比,初值更易选取,收敛速度更快。
Aiming at the problem that the traditional chemical rockets are difficult to re-use and the launch cost is high, a new generation of reusable carrier flight plan of horizontal take-off and landing is proposed, and the key technologies such as dynamic mode design and ascending section trajectory optimization are further studied the study. A combined power model of turbo ramjet combined with rocket ramjet engine was designed and a coupled model of engine thrust, height, Mach number and other variables was established. According to the dynamic form, the ascending section trajectory was divided into two sections and the global Search method to determine the best timing power switch. According to the segmentation results, the optimal sections of the two sections were optimized by hp adaptive pseudospectra with the most fuel efficient and terminal speed as the maximum. The algorithm is based on the bilevel strategy to solve the optimal control problem, which combines the advantages of the pseudospectral method and the finite element method. Compared with the shooting method, the pseudospectral method and the indirect method, the initial value is easier to choose and the convergence speed is faster.