Next generation GPS-aided space navigation systems

The next generation of low cost Global Positioning System (GPS) receivers for space navigation and attitude determination are positioned to take full advantage of the improvements made in the commercial GPS receivers used for terrestrial applications. There have been recent improvements made to the GPS receivers that include the addition of extra GPS satellite channels that can be tracked simultaneously. The older style GPS receivers were only able to handle five channels at a time. In order for proper determination of three-dimensional position, a minimum of four channels was required and the fifth channel of the receiver was reserved to perform search functions for finding the next satellite. This included searching for satellites that could be used to replace exiting satellites moving out of the Field of View (FOV). The search function also enables the GPS receiver to search for the best constellation for maximum performance accuracy. The fifth roaming channel also provided a best next-satellite selection capability in case the field of view to one of the satellites was blocked or shaded.     

Next generation functional test program development system

While superior-quality functional board test has been a goal for most high reliability electronics manufacturers, the time and effort for generating such test programs using today's tools and processes makes this difficult to achieve in a cost effective manner. This paper will introduce a revolutionary approach to functional board test program development that combines the comprehensiveness of software-based simulation with the speed and simplicity of hardware emulation. The result is a functional Test Program Set development system that can produce high fault coverage, diagnostic test programs in a fraction of the time it takes using traditional techniques, and at a lower unit cost. In this paper we will first provide a brief background on the strengths and weaknesses of current software and hardware TPS development techniques-simulation hot mock-up. Next, the new approach is described in detail and contrasted against the existing techniques. Finally, actual experience to date using a prototyped system is presented     

民用飞机全寿命周期成本及经济性设计研究

总结了民用飞机全寿命周期成本研究方法,对民机型号研制中通常采用的成本估算方法和软件工具进行了介绍。在此基础上,一方面从民机运营经济性的角度对不同市场条件下的计算分析模型进行了对比,指出发展更可靠的直接维修成本（DMC）模型的必要性;另一方面,从民机研制的角度,通过将经济性分析模块有机融入传统飞机设计流程,提出面向经济性设计的总体思路,为实现民用飞机的多学科设计提供了基础。     

新一代战斗机全机地面强度试验技术

介绍了全机地面强度试验及验证要求,分析了试验的新问题和新挑战。通过试验顶层规划,采用全新设计模式、先进的加载技术,从试验的边界条件、综合平台、动力系统、测量与控制、损伤检测与监测等方面制定了总体技术方案。研究并应用了全硬式单侧双向加载技术、试验综合平台设计技术、试验边界条件模拟技术、动力系统设计技术等多项新技术,提高了设计效率、加快了试验实施速度、提升了试验安全性和可靠性。这些新技术在新一代战斗机多架次全机静力/疲劳试验中成功应用,结果表明各试验系统安全、可靠,达到了试验要求和预期试验目标,实现了全机地面强度试验技术的跨越式进步,技术成果为后续型号试验提供了较高参考价值。     

利用做过高载试验的飞机结构进行疲劳寿命研究

某型飞机的某框下半框腹板发生严重的腐蚀损伤.为保证飞机安全,对该部位采取了补强修复.根据规范要求,需要进行全尺寸疲劳试验.但受条件限制,疲劳试验只能在做过高载试验的飞机结构上进行,为此,进行了高载对疲劳寿命的影响研究和全尺寸疲劳寿命试验等研究工作.研究结果表明,使用做过高载静力试验的飞机结构进行疲劳寿命试验是可行的.     

涡轮盘多轴低循环疲劳寿命预测及试验验证

应用单轴及多轴疲劳寿命预测的Von Mises等效应变模型和临界平面模型对某两级涡轮盘传动臂销钉孔的疲劳寿命进行预测.组装和调试了全尺寸两级涡轮盘联合试验件,在旋转试验器上完成了低循环疲劳试验,得到两级涡轮盘传动臂销钉孔试验失效寿命.预测寿命与试验寿命对比分析显示单轴和Von Mises等效应变模型预测误差较大;临界平面模型误差较小,尤其是拉伸型失效SWT(Smith-Watson-Topper)模型误差为9.26%.      

Predictive information design for the novel generation of display for the highly-augmented aircraft

We consider the task of predictive information design allowed for improvement of flying qualities in precise tracking tasks, in particular for the landing of an aircraft, the dynamics of which is characterized by the transportation time delay.     

新一代飞机任务系统概念与构架

新一代飞机是面向全球战略的空中力量组织,其任务系统是利用全球、全域和全空间能力组织,构建全球、全域和全空间警戒、到达和对抗的优势,实现面向全球的战略目标。从全球战略、战术和任务组织思想的角度,论述了新一代飞机任务系统战略需求和存在的挑战,描述了任务系统的"蝴蝶效应"及其形成过程等基本概念,构建了基于战略、战术、任务构架组织的战略云、战术云和任务云的系统框架组织,论述了相应的复杂系统、不确定性和智能化处理思路。     

基于安全寿命法的高压涡轮盘低循环疲劳寿命试验

基于英军标Defence Standard 00971对盘类零件的安全性要求,采用安全寿命法对某型发动机高压涡轮盘的低循环疲劳寿命试验进行了研究.通过有限元法对发动机工作条件下的高压涡轮盘进行了应力分析,考虑了温度场对应力分布的影响,按照Defence Standard 00971的要求确定了高压涡轮盘的关键部位及其标准循环,制定了高压涡轮盘低循环疲劳寿命试验方案,给出了基于试验结果确定高压涡轮盘安全寿命的方法.分析表明:中心孔和螺栓孔的应力系数分别为1.0和1.017,均在合理范围内;提高高压涡轮盘转速同时截短涡轮叶片的试验方法能有效模拟热应力对寿命的影响,对高压涡轮盘低循环疲劳寿命试验具有重要指导意义.      

基于试片超高周疲劳试验的叶片高周疲劳寿命估算方法

依据梁的振动理论,推导了叶尖振幅a与叶片自振频率f乘积af值,来表征叶片振动应力;基于某型航空发动机压气机叶片材料试片超高周疲劳试验结果,结合af值理论,推断该叶片高周疲劳寿命.对该叶片进行1阶弯曲高周疲劳试验,结果显示:af值为1 700,1 800,1 900mm/s时,超高周试验疲劳试片和实际叶片的疲劳寿命均在1×107,0.7×107,0.5×107周次附近,即超高周疲劳试验试片和实际叶片的疲劳寿命基本一致.     

Hybrid life support systems with integrated fuel cells and photobioreactors for a lunar base

The development of regenerative and sustainable life support systems (LSS) is a basic prerequisite to realize human long-term habitation in space. An efficient and reliable LSS is of high importance for assembling a future research base on the Moon and for further human space exploration missions beyond Low Earth Orbit. Because of longer distance to Earth and longer transfer times new requirements appear for LSS operation and functionality in comparison to the International Space Station. The minimization of resupply mass is a crucial factor to cope with this challenge. Regenerating the main media oxygen, water, and carbon as well as demonstrating a closed loop are essential milestones for an efficient and sustainable LSS. The logical step between partly regenerative physico-chemical and bioregenerative LSS is a so-called hybrid LSS characterized by the crosslinked integration of physico-chemical and simple biological system components.The Institute of Space Systems of the University of Stuttgart (IRS), the Institute of Technical Thermodynamics (ITT) of the German Aerospace Centre (DLR) and the Fraunhofer-Institute for Interfacial Engineering and Biotechnology (IGB) work together in a project on advanced LSS research and development. The IRS will investigate the integration of a photobioreactor (PBR) for algae cultivation as biological component and a reversible proton exchange membrane fuel cell (PEFC) as physico-chemical component into an LSS. Algae in the PBR absorb the carbon dioxide exhaled by the crew and produce biomass (food) and oxygen under light influence. The oxygen can be directed either into the crew cabin or into the fuel cell for generating electricity. Vice versa the electrolysis process splits water (from the PBR or the fuel cell process) into oxygen and hydrogen used as energy storage or propellant. Main task at IRS is a feasibility study on the mentioned technologies, considering the capability of media and product regeneration as well as the ability of integration of the components into a system. Synergies, mass reduction, dissimilar redundancy, and safety enhancement must be taken into account in order to specify integration problems and filtration costs. The IGB supports this study by its expertise in PBR operation, algae cultivation, and algae species selection. The ITT investigates the coupling of the PBR with three different fuel cell types: namely PEFC, SOFC (Solid Oxide Fuel Cell), and AFC (Alkaline Fuel Cell) under electrochemical performance aspects. The influence of PBR products on performance and lifetime of the different fuel cells is of high interest. The potential of potable water and electrical power supply is considered.     

飞翼布局高速风洞尾支干扰试验修正技术研究

飞翼布局飞行器模型往往具有尾部扁平的结构特点,进行高速风洞尾支测力时,尾部需要局部放大,由此带来尾部畸变和尾支杆的气动干扰,直接影响对巡航效率、焦点位置以及配平迎角的预测;另外,飞翼布局飞机为改善隐身特性,取消了平尾和垂尾,侧力和偏航力矩量级比较小,模型尾部的局部变形必然会对飞机横、航向试验数据带来不利影响。本文针对某飞翼布局模型,采用风洞试验和 CFD 数值模拟相结合的手段,通过腹支撑作为辅助支撑的“两步法”获得了尾部畸变及尾支杆的纵、横向支撑干扰影响。研究结果表明：该飞翼布局模型尾部畸变支撑纵、横向支撑干扰修正结果合理、可靠,精准度较高;所建立的试验与 CFD 相结合的研究方法可以用于类似布局的试验数据修正。同时,发展的数值计算方法与风洞试验有很好的一致性,已成功应用于某飞翼布局模型尾部支撑干扰修正,已具备工程使用价值。     

蒙皮镜像铣削支撑技术的研究现状和发展趋势

镜像铣作为一种飞机蒙皮加工的新技术,是一种高效、绿色的加工方法,具有逐步取代化铣加工的趋势,是众多工业发达国家的研究热点。支撑技术是飞机蒙皮镜像铣削系统的关键技术,关系到蒙皮的尺寸精度和表面质量,直接影响蒙皮外表面的形貌。本文在阐述飞机蒙皮零件加工工艺特点的基础上,介绍了飞机蒙皮减薄技术的发展,总结了蒙皮镜像铣削加工方法的优势及国内外研究现状。在详细分析镜像铣支撑技术的研究现状的同时,指出了当前镜像铣支撑技术存在的问题与难点,预测了镜像铣支撑技术的发展趋势,为镜像铣支撑技术的深入研究提供参考和指导。     

鸭式布局飞行器的翼体摇滚特性风洞试验

为研究鸭式布局飞行器摇滚特性,设计了一种包括鸭翼、脊型前体、边条翼、主翼和垂尾的模型,进行了自由滚转、扰动滚转、静动态测力和烟线流场显示多种技术手段相结合的风洞试验。通过自由滚转和扰动滚转试验得到了该模型翼体摇滚的时间历程,静态测力和动导数测定验证了非极限环运动形式摇滚的发生。结果表明该鸭式布局模型摇滚不仅同侧存在多个摇滚平衡点,而且在临界俯仰角,摇滚过程中可能出现从一摇滚平衡点跳动至同侧另一摇滚平衡点的突变。通过流场显示技术得到该鸭式布局模型复杂流场的基本形态分布,并对滚转角为0°时的全机涡系干扰和摇滚形成机理进行了简要分析。     

Synthesis and test issues for future aircraft inertial systemsintegration

A survey is presented of the potential benefits, possible pitfalls, and anticipated testing needs of integrating inertial guidance systems with systems dependent on the availability of the electromagnetic spectrum. Commonly referred to as integrated communications, navigation, and identification avionics (ICNIA), these systems of the future offer the combined potential for superb positioning and secure communications. The general characteristics (if current development trends continue) of the next-generation inertial navigation systems (INS) are briefly presented, followed by key modular and conceptual issues in the synthesis of this INS with systems dependent on the EM spectrum. Modular issues as considered here are those related to detailed implementation and resulting efficiency. Conceptual issues are those related to overall military strategy and resulting effectiveness. An example of modular systems integration is given, and a few preparations which can be anticipated for the field testing of integrated systems are presented, followed by concluding comments     

C919飞机全机静力试验技术

介绍了C919大型客机全机静力试验的目的及任务需求,分析了试验特点和难点。从试验飞机支持、试验加载及控制、试验测量及监控、损伤检测及状态监测等方面制定了总体技术实现方案,验证结果表明试验系统可靠,技术实现方案满足任务要求。试验中采用了多项创新技术：试验综合加载平台设计技术优化了多系统集成,加快了试验准备速度,降低了试验准备风险;约束点误差转移控制技术将约束部位误差转移至非重点考核部位,提高了关键考核区域试验精度;机身双层地板双向加载技术优化了机身加载及扣重设计,改善了局部载荷的加载精度。技术成果为后续型号试验提供了较高参考价值。     

飞机结构强度试验应急载荷限定系统

多轮多支柱起落架飞机主起落架数量较多,试验机及试验设备重量大。试验应急卸载时,试验件和设备重量、以及加载过程中试验件变形所聚集能量快速释放的不协调性易对支持点结构产生较大冲击载荷,且该载荷不可控,影响试验的考核,存在安全隐患。针对多轮多支柱起落架飞机的强度试验要求,设计一种载荷限定系统。在应急卸载或者试验停试情况下,能够为非支持点起落架输出设定载荷,保证应急瞬间所产生的所有载荷按要求分配到所有起落架上,从而防止支持点起落架超载;试验过程中,能够对非支持点起落架施加试验主动载荷。利用仿真软件验证了系统原理的可行性。依据原理设计载荷限定系统,对其结构和工作性能进行应用验证,并在某型飞机全机疲劳试验中进行应用调试,结果表明,该系统完全能够满足试验要求。     

Optimization of fixed aviation support resource station configuration for aircraft carrier based on aircraft dispatch mission scheduling

Before the dispatch of the carrier-based aircraft, a series of pre-flight preparation operations need to be completed on the flight deck. Flight deck fixed aviation support resource station configuration has an important impact on operation efficiency and sortie rate. However, the resource station configuration is determined during the aircraft carrier design phase and is rarely modified as required, which may not be suitable for some pre-flight preparation missions. In order to solve the above defects, the joint optimization of flight deck resource station configuration and aircraft carrier pre-flight preparation scheduling is studied in this paper, which is formulated as a two-tier optimization decision-making framework. An improved variable neighborhood search algorithm with four original neighborhood structures is presented. Dispatch mission experiment and algorithm performance comparison experiment are carried out in the computational experiment section. The correlation between the pre-flight preparation time (makespan) and flight deck cabin occupancy percentage is given, and advantages of the proposed algorithm in solving the mathematical model are verified.     

Assistant systems for aircraft guidance: cognitive man-machine cooperation

This paper presents the concept of cognitive assistant systems which represents an approach to ensure the highest degree possible of situation awareness of the flight crew as well as a satisfactory workload level. This concept offers the solution to counteract susceptibility to pilot errors typical of lack of attention or other cognitive limitations. It is founded on cognitive system engineering. This technology enables a cockpit design in order to systematically comply with the requirements of ‘Human-Centred Automation (HCA)’. The underlying approach behind the concept has become real with the development of the cockpit assistant system prototype family CASSY/CAMA as described in this paper. CASSY/CAMA has been extensively tested in a flight simulator and successfully field tested with the ATTAS (Advanced Technologies Testing Aircraft System) of the DLR. Some of the test results with CAMA will be presented in this paper.