【作者】 董晨；

【导师】 杨明；

【作者基本信息】 哈尔滨工业大学 ， 控制科学与工程， 2010， 硕士

【摘要】 与传统的天地往返运输系统相比,新一代可重复使用飞行器具有更高的可靠性、更低的发射成本以及更少的发射准备时间,能够实现快速、可靠、经济的进入空间的目标,因此受到世界各国的普遍关注。由于再入过程中的飞行环境异常复杂,保证飞行安全并满足任务要求的制导精度对再入制导提出了严峻的挑战。因此,需要对可重复使用飞行器的再入制导方法进行深入的研究。本文对可重复使用飞行器的再入制导方法进行了较为深入的研究:首先,在建立可重复使用飞行器再入模型的基础上,本文对可重复使用飞行器质心运动进行分析,提出再入制导问题,明确飞行器再入过程中的各种约束,并根据再入飞行各阶段的不同目的对轨迹进行分段。然后,将再入制导问题分为纵向再入轨迹规划问题、纵向轨迹跟踪问题和侧向再入制导问题,给出纵向再入走廊的计算算法,并说明影响其形状的各因素。在纵向再入轨迹规划中,引入两个轨迹过渡条件,提出一种同时设计连续的参考攻角剖面与参考倾侧角剖面的规划方法,保证各段纵向参考轨迹满足约束并光滑衔接。由于纵向参考轨迹规划过程中采用近似条件造成航程损失,在线性化质心运动方程的基础上,利用LQR方法设计纵向轨迹跟踪律,通过修正并平滑参考攻角剖面与参考倾侧角剖面,使得可重复使用飞行器满足再入任务对航程的要求。在侧向制导中,本文采用一种具有较好通用性的侧向再入制导方法为RLV设计侧向再入制导律。最后,在多种具有代表性的再入任务假定以及空气动力系数、大气密度存在偏差或扰动的情况下,通过数值仿真对本文研究的再入制导方法进行验证并给出分析和结论。数值仿真结果表明,本文研究的再入制导方法具有较好的适应性和一定的鲁棒性。该方法具有较好的应用前景。更多还原

【Abstract】 Compared with the conventional space transportation systems, the next generation Reusable Launch Vehicles (RLVs) possess higher reliability, lower launch cost, and less turnaround time. They have the ability to achieve rapid, reliable and affordable access to space and receive considerable attentions. To ensure flight safety and guidance precision, entry guidance encounters the huge challenges resulted form the extremely complex environment in entry phase. Thus, entry guidance method for RLVs needs to be researched comprehensively.The entry guidance method for RLV is investigated in this dissertation: First, mass-point dynamics of RLV is established and analysed. Entry guidance problem is proposed and the constraints are determined. The trajectory are divided into several parts according to the different objectives of entry guidance.Then, entry guidance problem is decomposed into three subproblems: longitudinal trajectory planning, longitudinal trajectory tracking and lateral guidance. The algorithm for longitudinal entry corridor computation is introduced, and the factors influenced the longitudinal entry corridor are listed. In longitudinal trajectory planning subproblem, two trajectory transition criterions are introduced, and a new method focused on planning both the angle of attack profile and the bank angle profile is proposed for constraints observance and trajectory smoothness. And in view of the range deficiency resulted from the approximations introduced in longitudinal trajectory planning, a trajectory tracking law is designed via LQR theory to follow the longitudinal reference trajectory and modify angle of attack profile and bank angle profile. In lateral guidance subproblem, a lateral guidance method with good compatibility is introduced and applied to the design of lateral guidance law for RLV.Finally, the above guidance method is demonstrated by numerical simulation under several typical entry scenarios, deflections and disturbances are taken into account.Analyses and conclusions are given at the end of this dissertation. The results of numerical simulation indicate that the entry guidance method researched in this dissertation provides robustness to some uncertainties and has adaptability to various entry missions. It has good potential for further applications.更多还原