Impact of mission requirements and constraints on conceptual launch vehicle design

The objective of this paper is to analyse the impact of mission requirements and constraints on both the optimum vehicle design and the effects on flight path selection for two types of reusable two-stage-to-orbit launch vehicles. The first vehicle type considered provides horizontal take-off and landing capabilities and is intended to be propelled by an airbreathing propulsion system during stage 1 flight. The second vehicle type assumes a vertical launch and is accelerated by a rocket propulsion system during the booster stage ascent flight. The analysis employs a design tool for simultaneous system and mission optimization. It consists of a CAD-based preliminary vehicle design tool, aerodynamic and aerothermodynamic calculation software, flight simulation programs, and a two-level decomposition optimization algorithm enabling simultaneous system and flight optimization. The results to be presented show that the cruise flight requirement for an European launched mission of the airbreathing vehicle results in a loss of 60 % payload mass as compared to a mere accelerated ascent for a near equatorial mission into the same target orbit assuming constant take-off mass. The strong dependencies of mission requirements on both the optimal vehicle design and the ascent performance are determined for the rocket-powered vehicle type by varying the inclination and altitude of the target orbit.     

飞翼式UCAV低空段动静稳定性研究

采用飞翼式气动布局的UCAV能够很好地满足现代作战的要求。这种非常规布局的飞机, 由于它缺少尾翼, 对于飞机的动静稳定性分析来说是一个挑战。对于无垂尾飞机, 其稳定性的主要努力方向应该在低空段。本文在低空段, 对于飞机的纵向和侧向运动上采用解藕的分析方法获得飞机的运动方程; 接着根据风洞试验的数据, 在MATLAB中建立仿真模型获得飞机的仿真曲线, 通过对仿真曲线的分析, 验证了飞机的纵向和侧向的不稳定性。最后, 通过与已经成功应用于实战的B-2隐形飞机的对比, 分析了在应用控制增稳的控制技术后, 飞翼式布局的UCAV的实用性。     

The canberra high altitude mission platform

This presents the capabilities of two English Electric Aviation Canberra aircraft owned by High Altitude Mapping Missions, Inc. These aircraft are available for high altitude commercial, government, and scientific missions. The basic specifications of the Canberra are provided and compared to other high-performance jet aircraft falling into the same category. This describes the high altitude flight characteristics and mission capabilities of the Canberras. The aircraft are configured to conduct up to eight-hour flight operations with up to six hours at 50,000 feet altitude. Shorter missions can be conducted at higher altitudes. Potential missions include: IFSAR, magnetic field mapping, gravity field mapping, imaging (SAR, IR, & hyper-spectral), LIDAR, communications relay, dropsonde deployment, hybrid rocket launching, severe storm monitoring, and disaster monitoring. Canberra high altitude operations have minimal weather impact on missions, are free from flight constraints imposed by air traffic control, can do large area coverage, and long mission times.     

AI techniques in uninhabited aerial vehicle flight

This describes the development of an application of artificial intelligence (AI) for unmanned aerial vehicle (UAV) control. The project was part of the requirements for a class in AI at NOVA Southeastern University and a beginning project at NASA Wallops Flight Facility for a resilient, robust, and intelligent UAV flight control system. A method is outlined which allows a base level application for applying an artificial intelligence method, fuzzy logic, to aspects of control logic for UAV flight. One element of UAV flight, automated altitude hold, has been implemented and preliminary results displayed.     

基于高度控制的拖靶定高飞行分析

超低空飞行的航空拖靶需要高精度的高度控制,而作为试验和训练的消耗性装备,其低成本设计要求使得航空拖靶不能采用常规飞行器的高度控制方法。针对以拖曳力为飞行动力的航空拖靶,研究其基于非姿态控制的定高飞行的运动特性。定高飞行航空拖靶采用高稳定性的气动布局,并基于准直接力控制的升降舵面进行高度调整操纵。通过建立拖靶的纵向运动数学模型,设计非姿态控制定高飞行控制方法,详细分析拖靶气动特性,并进行定高飞行控制的仿真计算。计算结果给出拖靶的高度控制能力及飞行状态,结果表明拖靶具有一定的高度调整能力,可以实现定高飞行。     

单机多目标攻击模态综合飞/火控制系统设计及仿真

多目标攻击是现代空战中的主要形式和发展趋势。本文主要介绍了多目标攻击火控系统的总体方案、基本组成及工作过程，将空战能力、空战态势指数法及动态的层次分析法应用于火控系统攻击逻辑决策中，给出了一种多目标超视距攻击火控系统的设计方案，其中在空战态势指数法中还考虑了高度因素。同时，对飞行／火力协调控制器进行了设计，并在六自由度飞机模型上进行了多目标攻击过程的数字仿真，仿真结果表明本文的设计方案是可行的。     

多电式环控系统电动机功率选定及其经济性分析

提出多电式环控系统参数匹配计算模型,获得不同飞行工况下电动机功率的选定值,分析其影响因素以及系统的经济性.结果表明:对于一定的供气压力,飞行高度越高,电动机功率越大,而同一高度马赫数越大,电动机功率越小;对于给定的飞行工况,供气压力越高,电动机功率越大;对于相同的供气压力与飞行工况,多电式环控系统的性能代偿损失比传统环控系统要小,飞行时间越长,系统的经济性越好.      

Radar-assisted collision avoidance/guidance strategy for planarflight

We propose a radar-assisted collision avoidance/guidance strategy (RACAGS) for flight vehicles on low altitude missions. The task of obstacle avoidance and guidance are integrated in a single collision avoidance/guidance strategy. The avionic aids and computational requirements are modest as the strategy mainly depends on range-map and inertial system information. The strategy is first implemented in a planar scenario and then extended to three-dimensional and nominal trajectory following flight scenarios. Several simulation studies are presented for illustration     

基于标准特征多项式的横侧向飞控系统设计

采用基于标准特征多项式的飞控系统设计方法设计了某型飞机横侧向通道倾斜姿态保持和航向保持控制律,并进行了仿真研究。控制律的设计过程和仿真结果表明,该方法可以确切地给出系统的过渡过程时间和超调量,避免了任意选择初始参数值的盲目性和经验性,大大简化了飞控系统设计的工作量。     

基于单轴光电探测系统的MUAV目标捕获与盘旋跟踪系统

研究了基于侧向单轴光电探测系统的微小型无人飞行器(MUAV)捕获、跟踪地面目标的飞行控制方法,提出一种探测器单轴消除视场y向失谐角,MUAV航向控制消除视场x向失谐角的控制方案。采用常规的飞行动力学纵向和侧向运动方程及小干扰线性化方法,并分别对MUAV定高寻航迹段、目标搜索捕获段及盘旋跟踪段进行了MATLAB仿真。分析了侧向突风以及飞机俯仰角变化对视场中x向失谐角的耦合影响,并提出了解决方案。仿真结果验证了所提方案的有效性,其能够满足MUAV持续盘旋跟踪地面目标的飞行任务。     

Autonomous gliding entry guidance with geographic constraints

This paper presents a novel three-dimensional autonomous entry guidance for relatively high lift-to-drag ratio vehicles satisfying geographic constraints and other path constraints. The guidance is composed of onboard trajectory planning and robust trajectory tracking. For trajectory planning, a longitudinal sub-planner is introduced to generate a feasible drag-versus-energy profile by using the interpolation between upper boundary and lower boundary of entry corridor to get the desired trajectory length. The associated magnitude of the bank angle can be specified by drag profile, while the sign of bank angle is determined by lateral sub-planner. Two-reverse mode is utilized to satisfy waypoint constraints and dynamic heading error corridor is utilized to satisfy no-fly zone constraints. The longitudinal and lateral sub-planners are iteratively employed until all of the path constraints are satisfied. For trajectory tracking, a novel tracking law based on the active disturbance rejection control is introduced. Finally, adaptability tests and Monte Carlo simulations of the entry guidance approach are performed. Results show that the proposed entry guidance approach can adapt to different entry missions and is able to make the vehicle reach the prescribed target point precisely in spite of geographic constraints.     

超音通流风扇推进系统内流若干特征

探讨了一种非常规结构的推进系统-超音通流风扇推进系统的总体性能的特征。得到:(1)其必为变涵道比循环系统, 由可变几何内、外涵通道提供对涵道比的主动控制;(2)一般的变涵道比循环推进系统超音速飞行时可获较常规系统更高的风扇增压比或风扇功率;(3)该推进系统高空单位流量推力与高度无关。简介了有关算例以说明诸点。      

航天器快捷交会技术分析

快捷交会对航天乘员与飞行任务都是非常有利的。快捷交会的基本原理是减少调相段飞行圈数;为此,需设计可完成一系列交会程序的较短的飞行时间,并获得与飞行时间相匹配的较小的初相角。快捷交会的关键技术包括提高入轨精度,增强追踪飞行器的自主计算与轨道控制能力,扩大地面站覆盖范围,以及对目标飞行器轨道的精准调整。     

Electric space propulsion systems

Active development of electric thrustors began 10 years ago. Today, several kinds of thrustors have achieved efficiencies above 90 % and lifetimes of several thousand hours. The following article derives the basic theory of electric thrust production at constant exhaust velocity, and at variable exhaust velocity programmed for optimum vehicle performance. Electrothermal or arcjet; electrostatic or ion; and electrodynamic or plasma thrustors are described. At the present time, ion thrustors of the electron bombardment and of the surface ionization types are the most promising systems. Electric power in space may be generated by solar cells or nuclear-electric generators. It is expected that the incore thermionic converter will eventually be the preferred system. A variety of missions with electric propulsion systems appear feasible and highly desirable, among them orbital station keeping, attitude control, planetary probes, solar and out-of-the-ecliptic probes, deep-space probes, and manned Mars and Venus exploration. For each mission, a careful systems-design study must be made, which will provide the optimum selection of thrustor type, thrust level, exhaust velocity, thrust program, power source, trajectory, and flight plan.     

无人机自动控制仿真系统研究与实现

航迹控制回路是无人机自动控制飞行中的重要环节,它涉及无人机的姿态、航向和飞行状态等重要参数的变化。根据飞行控制的基本控制律实现了无人机在复杂航迹条件下的安全飞行控制,模拟出无人机在自动控制下的航迹、盘旋和着陆等的飞行任务。采用面向对象方法设计了基于堆栈的通用化的航线管理类。并分析了无人机在手动操作切换到自动控制方式时寻找航迹点飞行中可能出现的问题,提出了相应的解决方案。     

船载多目标模拟器的构建与应用

船载统一S频段（USB）测控系统是我国航天测控网的重要组成部分,承担着一箭单星或一箭多星的海上测控任务。从航天测量船执行多目标测控任务的特点出发,分析了测量船船载飞行目标模拟器的现状以及对多目标模拟器的需求。提出了在船载USB联试应答机的基础上,通过改造应答机的部分模块,构成多目标模拟器的方法,并成功地在某次实战任务中得到了应用。     

Spiral descent of an unmanned aerial vehicle

An intensive unsteady spiral descent of an unmanned aerial vehicle with an approach to target (object) at the design altitude and specified minimal flight speed is considered. The decisive equations describing the motion of the FV center-of-mass are solved by time intervals. The influence of controlling parameters on the spiral radius, the maneuver speed and time is studied.     

高空长航时无人机任务设备/飞行综合控制技术

首先对无人机和任务设备的发展作了简要介绍，并介绍了高空长航时无人侦察机的国内外发展现状，着重对高空长航时无人侦察机任务设备／飞行综合控制中综合控制、运动补偿、组合导航、三维定位和目标识别等关键技术进行了分析，说明了目前对高空长航时无人机的任务设备／飞行综合控制进行研究的必要性和可行性。     

某机高度稳定系统的高空振荡及气路延时的补偿

揭示了空速管路延时是造成某机高度稳定系统高空振荡的根本原因,研讨了飞行包线内运动粘性系统及与其关联的气路延时的变化规律,给出相位超前校正网络的参数特征以及用该网络补偿气路延时的工程设计方法。试飞证明,该法成功地解决了该机高度稳定系统高空振荡的关键技术问题。     

吸气式激光推进飞行器发动机特性分析

介绍了吸气式脉冲激光爆轰推进的环聚焦构形飞行器概念,建立了进气道流动模型;利用Chapman-Jouguet爆轰理论和Sedov自相似律,建立了冲量发生与推力传递模型,给出了冲量耦合系数及等效比冲与飞行参数、激光脉冲参数之间关系的解析表达式。计算了发动机冲量耦合系数及等效比冲随飞行高度、马赫数、入射激光强度和脉宽等因素变化的曲线,结果可为相关构形飞行器的弹道与激光器工作模式设计提供参考。