【作者】 张军；

【导师】 杨一栋； 黄一敏；

【作者基本信息】 南京航空航天大学 ， 导航、制导与控制， 2011， 博士

【摘要】 以末端区域能量管理段(TAEM)关键技术验证为目的的可重复使用运载器(RLV)上升段的最大高度和最大马赫数分别约为30km和3。如果在上升段正常飞行，RLV到达最高点后经TAEM到达自动着陆窗口(ALI)；如果在上升段出现发动机故障停车，RLV将经应急上升段、应急返回段到达ALI。本文研究以TAEM飞行试验为背景的RLV上升段及应急返回段轨迹设计技术。RLV正常上升段称为标称上升段，其轨迹设计是受到多性能指标(因RLV而异)、多物理约束(主要指动压、过载约束)共同约束的两点边界值问题。样例RLV的性能指标主要是最大马赫数和最大高度。因发动机工作时间有限制，所以分别表征动能和势能的两指标会此消彼长。因此，标称上升段轨迹设计须在不违反物理约束的前提下平衡各指标量。本文提出的方案是从质点动力学角度先定性规划出航迹倾斜角剖面方案，然后通过轨迹推演来确定剖面参数，并获得参考轨迹各剖面。应急上升段起于故障停车而止于航迹改平，飞行中须排空剩余燃料。为使随后的应急返回段初始能量最大，应急上升段轨迹设计须在不违反物理约束的前提下使终点能量最大即能量衰减最慢。影响能量衰减快慢的因素主要是克服阻力做功量(主要取决于航迹倾斜角剖面)和燃料排空时机，二者耦合在一起。本文提出一种航迹倾斜角剖面方案可解除此耦合，并在此基础上从质点动力学分析入手研究了排空时机影响能量衰减快慢的规律，给出排空时机方案，并用于应急上升段在线参考轨迹设计。应急返回段起于应急上升段终点而止于ALI，TAEM可视为其特例。TAEM轨迹设计以能量走廊为核心概念，忽略纵向/横侧向机动之间的耦合，属于二维轨迹设计。对于非TAEM的应急返回段，可采用二维设计方法。因初始高度无法预知，轨迹设计须基于待飞距离，本文提出一种基于待飞距离的轨迹设计方法，可使轨迹迭代推演快速收敛，并用于应急返回段二维参考轨迹在线设计。在应急返回段，轨迹设计中若要实现按需使用横侧向机动，则须使用三维轨迹设计方法，必须规划考虑纵向/横侧向机动间耦合影响的横侧向参考轨迹，并基于动压参考剖面和横侧向参考轨迹迭代推演三维参考轨迹。本文基于蛇形机动式轨迹，提出一种组合使用三种轨迹模态来消除位置、航向误差的横侧向参考轨迹规划算法，可根据位置误差的大小选择不同轨迹形式规划轨迹。对于应急返回段三维轨迹迭代推演，本文提出一种在同一优化问题中跟踪动压参考剖面和横侧向参考轨迹的算法，使三维轨迹迭代推演可以快速收敛。最后，在MATLAB的Simulink模块下搭建了轨迹仿真验证环境，对上升段及应急返回段全程轨迹进行了数字仿真，验证了各飞行段参考轨迹的准确性、物理可飞性、稳定性。更多还原

【Abstract】 For a Reusable Launch Vehicle (RLV), the maximum altitude is about30kilometers and the maximum Mach number is about3for the ascent flight which aims to certify the key technologies of Terminal Area Energy Management (TAEM). If the RLV can ascend as planned, it will flight powerlessly return to Auto-landing Interface (ALI) after attending to the maximum altitude and then undergoing TAEM. If the RLV powers off because of malfunction of its engine during its ascent, it have to renturn urgently to ALI after urgent ascent and urgent return flight phase. The designing technologies of trajectories for ascent and urgent return flight have been researched in this dissertation with a background of the TAEM flight test.The normal ascent trajectory of a RLV is called the trajectory of nominal ascent flight phase. Designing of the trajectory of this phase is a Two Point Boundary Problem with multi-index and multi-restriction. The main indexes in this paper include the maximum altitude and the maximum Mach number. Its physical restrictions comprise dynamic pressure restriction and over loading restriction. During ascent flight of a RLV, the time length of its engine is limited. Meanwhile, the index variables altitude and Mach number are the symbol of potential energy and kinetic energy respectively. Therefore, the maximum altitude and the maximum Mach number limit each other. Hence, when designing the trajectory of nominal ascent flight, balance must be made between the different indexes and the restrictions must be obeyed. In this dissertation, the designing strategy is to plan the flight path profile first and to propagate the trajectory to get its profile parameters and all the other profiles of the reference trajectory.The urgent ascent flight phase originates from the power-off point and ends when the flight path angle becomes zero. In this phase, the remnant poisonous fuel must be discharged totally. The object of designing of the trajectory for this phase is to maximize the end energy of the RLV without disobeying the physical restrictions. The main factors that can affect the energy loss are overcoming dynamic resistance and discharge of the fuel. The two factors couple each other. Flight path angle profile determines how much work overcoming dynamic resistance does. A flight path angle profile has been provided in the dissertation to uncouple the coupled effect. By analysis of mass point dynamics, the law that discharge timing affects velocity of the energy loss has been researched and a plan of discharge timing was selected. An onboard trajectory designing method was provided using the above-mentioned flight path angle profile plan and the plan of discharge timing.The urgent return flight phase originates from the end of the urgent ascent flight phase and ends at ALI, and TAEM is its special case. Energy Corridor is the core concept of TAEM trajectory designing.The coupling between longitudinal and lateral maneuvers is ignored. Thus, it is a two-dimensional (2D) trajectory designing method. For the other cases of urgent return flight, the2D trajectory designing method can also been used.The difference is that the propagation step is not altitude but range-to-go. A trajectory designing method with range-to-go steps is provided in the dissertation, and it was used in onboard trajectory designing for urgent return of the RLV.In urgent return flight phase, if the lateral maneuver can been used when needed, the three-dimensional (3D) trajectory designing method must be used. That is, the coupling between longitudinal and lateral maneuvers must be considered and the lateral reference trajectory is necessary. Based on the planned reference dynamic pressure profile and lateral reference trajectory, the3D reference trajectory can be propagated. Based on the snake-styled lateral trajectory, a multi-mode lateral trajectory planning method has been put forward. For different initial position errors, different mode of trajectories can be selected to erase the heading error and the position error relative to the ALI. In addition, a three-dimensional propagation algorithm has been brought forward to follow the reference dynamic pressure profile and the lateral reference trajectory in an optimization problem.The algorithm makes it available to propagate the3D trajectory fast.Last, by the Simulink module in MATLAB, a trajectory emulation environment has been built up. The designed reference trajectories have been emulated to test the veracity, physical flyability and stability of nominal ascent, urgent ascent and urgent return.更多还原