The aerodynamic design of multi-element high-lift systems for transport airplanes

High-lift systems have a major influence on the sizing, economics, and safety of most transport airplane configurations. The combination of complexity in flow physics, geometry, and system support and actuation has historically led to a lengthy and experiment intensive development process. However, during the recent past engineering design has changed significantly as a result of rapid developments in computational hardware and software. In aerodynamic design, computational methods are slowly superseding empirical methods and design engineers are spending more and more time applying computational tools instead of conducting physical experiments to design and analyze aircraft including their high-lift systems. The purpose of this paper is to review recent developments in aerodynamic design and analysis methods for multi-element high-lift systems on transport airplanes. Attention is also paid to the associated mechanical and cost problems since a multi-element high-lift system must be as simple and economical as possible while meeting the required aerodynamic performance levels.     

Technology roll lessons learned on embedded avionics platforms

Open system architectures based on commercial off-the-shelf (COTS) building block components offer the ability to leverage the latest technology into fielded products while minimizing the impact to the operational flight software, typically the most costly component of an avionics development or upgrade. Our team has developed a layered hardware and software approach based on industry standard hardware and software interfaces to abstract the application (operational) software developers from the underlying technology rolls to the hardware and operating system software that naturally occur as part of the commercial marketplace, A technology roll is defined as the replacement of a current product with a subsequent generation of a product from the same product family. In this article, we describe the components and the layered architecture of our open system architecture approach. We discuss specific system, hardware, and software technology insertions that incorporate the latest available technology and how these changes have been abstracted from the application software. The article concludes by discussing lessons Learned from the use of these common components and corresponding technology rolls across various platforms     

Processing requirements for multisensor low-cost brilliantmunitions

A generic mission for an autonomous brilliant munition is presented and used to identify the functions that embedded signal processors must perform. Based on these functions and other operational factors such as weather, countermeasures, larger search areas, reduced false alarm rates, and increased munition maneuverability, the processing loads in bits/second messages/second, operations/second, and instructions/second are derived. An evaluation of general implementation issues such as the requirements for data fusion, distributed and parallel processing architectures, reliable software, and low-cost hardware is presented     

Sustainment of legacy automatic test systems: lessons learned on TPS transportability

Sustainment of legacy automatic test systems (ATS) saves cost through the re-use of software and hardware. The ATS consists of the automatic test equipment (ATE), the test program sets (TPSs), and associated software. The associated software includes the architecture the TPSs run on, known as the control software or test station test executive. In some cases, to sustain the legacy ATS, it is more practical to develop a replacement ATE with the latest instrumentation, often in the form of commercial off-the-shelf (COTS) hardware and software. The existing TPSs, including their hardware and test programs, then need to be transported, or translated, to the new test station. In order to understand how to sustain a legacy ATS by translating TPSs, one must realize the full architecture of the legacy ATS to be replaced. It must be understood that TPS transportability does not only include translating the original TPS from an existing language (such as ATLAS) to a new language (such as "C") to run on a new test station, but includes transporting the run-time environment created by the legacy ATS. This paper examines the similarities and differences of legacy ATE and modern COTS ATE architectures, how the ATS testing philosophy impacts the ease of TPS transportability from legacy ATE to modern-day platforms, and what SEI has done to address the issues that arise out of TPS transportability.     

Checkout: A Changing Technology

On-board/in-flight checkout of future aerospace systems will necessitate a fundamental departure from today's design and checkout activities. The interrelationship of checkout, incorporated into prime vehicular functions, man as a subsystem, and standardization Of hardware/software must be considered as a functional and integral entity if the efforts of today's long-range planning are to become tomorrow's reality. This paper will describe future systems checkout, maintenance and support considerations, and actions and tentative measures necessary for implementation. The realization of the implementation of these concepts into functional elements will depend, accurately and economically, upon the degree of government perceptiveness and the extent of industrial support.     

Formal verification and legacy redesign

Sustaining weapons system hardware and software represents a significant and ever-increasing portion of total system cost. Hardware components are becoming obsolete much sooner while weapons system lifetimes are increasing, We must identify more cost-effective solutions to engineering and reengineering these subsystems. Verifying and validating weapons systems are two of the most costly parts of either engineering process. Traditionally, hardware validation and verification is done by simulation and testing, In the past few years, math- and logic-based formal methods tools have begun to scale up to and be applied successfully to real-world problems. Incorporating formal verification methods into engineering and reengineering processes will cost-effectively and significantly improve the level of trust and the quality of our weapons systems. Formal methods are especially well suited for redesigning current weapon systems which have become unsupportable due to component obsolescence because they help minimize the astronomical costs of rigorously reverifying the reengineered components. We believe that formal methods are an important tool for effective engineering of future weapon systems     

Data mining technology for failure prognostic of avionics

Adverse environmental conditions have combined cumulative effects leading to performance degradation and failures of avionics. Classical reliability addresses statistically-generic devices and is less suitable for the situations when failures are not traced to manufacturing but rather to unique operational conditions of particular hardware units. An approach aimed at the accurate assessment of the probability of failure of any avionics unit utilizing the known history-of-abuse from environmental and operational factors is presented herein. The suggested prognostic model utilizes information downloaded from dedicated monitoring systems of flight-critical hardware and stored in a database. Such a database can be established from the laboratory testing of hardware and supplemented with real operational data. This approach results in a novel knowledge discovery from data technology that can be efficiently used in a wide area of applications and provide a quantitative basis for the modern maintenance concept known as service-when-needed. An illustrative numerical example is provided     

航天飞控软件操作概图开发

航天飞控软件是具有高可靠性要求的软件系统,对其进行可靠性测试是航天飞控任务的基本要求。操作概图是进行软件可靠性测试的基础。由于开发大型软件系统的操作概图比较复杂,使其成为了制约开展软件可靠性测试的主要困难之一。本文以地面航天飞控软件为例,介绍了实时飞控软件操作概图的开发步骤和方法。首先是确定软件系统的操作模式,并确定每个操作模式所运行的相关软件;然后给出了识别每个软件的操作发起者和操作方法;最后对不同类型的操作给出了确定其发生概率的方法。     

Methodology for cost-effective software fault tolerance formission-critical systems

A computing capabilities continue to advance, there will be a concurrent rise in the number of both hardware and software faults. These will be caused by the greater volume of more complex software, by the increased number of untested software states, and by more incidents of hardware/software interaction faults as a result of increased hardware speed and density. The traditional software implemented fault tolerance: approaches have been successfully utilized in life-critical systems, such as digital flight controls, where their additional costs can be easily justified. Examples include N-Version Programming and Recovery Block approaches. However, there is still a need for dependable computing for mission-critical applications as well. Often, these traditional techniques are avoided for mission-critical systems due to the difficulty in justifying their extra up-front development cost. We provide an alternative for the high “sunk cost” of traditional software fault tolerance techniques. The methodology, called data fusion integrity processes (DFIPs), is a simple, yet effective technique for mission-critical systems. In addition, the approach establishes a framework from which other costlier, more extensive traditional techniques can be added. We present details of the DFIP methodology and a DFIP framework for Ada programs. We also briefly discuss development of a DFIP code generation system which exploits Java that will enable users to quickly build a DFIP framework in Ada, and select reusable DFIP component methods     

测控中心计算机系统的自主可控技术研究

测控中心计算机系统是测控中心的核心枢纽,通过自主可控技术加强其安全性,摆脱对国外软硬件的依赖,是当务之急。在分析测控中心计算机系统特点的基础上,对测控中心计算机系统自主可控技术的研究与实践进行了总结,列举了实践中遇到的基础部件国产化程度不高、开源软件问题多、自主可控产品商品化程度不高等问题。针对自主可控技术不甚成熟的情况,提出了国产软硬件产品的技术摸底、详尽测试、加强基础软件的版本管理和控制等发展建议,以推动自主可控技术在测控中心领域的应用和发展。     

Minimizing human-machine interface failures in high risk systems

Technology now permits the building of very complex man-machine systems with centralized controls, with the result that many processes can be run by relatively few individual workers. Studies of failures within these complex systems indicate that they are usually the consequence of a series of highly complex coincidences. There is an institutional neglect or misunderstanding of the implications of low-probability, high-consequence events for the design of complex man-machine systems. We must stop designing systems in which we virtually guarantee that operator errors will occur with catastrophic consequences. The greatest payback in reducing high risk system accidents is to reduce catastrophes induced or exacerbated by human error. This paper discusses some task breakdowns between the human element and software/hardware. These task allocations allow the complex man-machine system to be designed more robustly and prevent human error so as to reduce possible catastrophic consequences     

试验信息系统兼容性测试策略

结合试验信息系统的特点,以测试发射试验信息系统与安全管理系统的兼容性测试为例,提出了对试验信息系统进行兼容性测试的主要策略,包括业务软件与新增支撑软件在同一运行环境下的运行稳定性、安装/卸载兼容性测试;新增支撑系统或设备在运行期间对交换机网络流量影响的测试;新增系统或软件对CPU（中央处理器）、内存、端口等的占用情况测试等。通过对应用该测试策略的测试结果进行分析,发现了系统兼容性方面的问题。这些策略也可为其他类似系统的兼容性测试提供参考。     

基于航天测控的实时仿真系统设计

航天器发射试验具有高风险性,而承担航天器测控的测控系统规模庞大、关系复杂,其测控设备、软件的正确性关系到试验成败。仿真技术的广泛应用,使设备、软件的正确性在发射任务前就可以得到充分验证,从而提高发射试验的安全性。以航天器试验任务为背景设计的实时仿真系统,在航天测量船上得到了成功应用,取得了良好的效果。     

计算飞行力学的产生和发展

综述了计算飞行力学的产生背景、问题表述、理论框架和飞行力学的计算系统,以及计算飞行力学在未来飞行器研制和应用研究中的重要意义。     

Real time recovery of fault tolerant processing elements

A critical problem in the design of ultra-reliable fault tolerant systems is that of how to bring a redundant member back on-line, after a transient fault, without degrading critical real-time functions. Recovery from transients is imperative to maintain necessary system reliability in the face of transient errors which have been estimated to occur at a rate of 5 to 100 times that of permanent failures. Excessive delays associated with recovery become a problem when as much as 1 Mbytes of RAM in the faulty processor must be made congruent with the processing majority while maintaining full functionality of critical, real-time control algorithms. This paper describes a hardware assisted recovery technique which uses memory “tags” to determine which memory segments need to be restored such that recovery can be performed incrementally without affecting real-time operational tasks. Also presented is performance data associated with this technique's application to a Draper Laboratory quad-redundant processor responsible for vehicle control of a manned undersea vehicle     

运输类飞机高升力构型数值模拟研究

高升力装置对大多数运输机的大小、吨位、经济性及安全性都有重要的影响。由于复杂的流动机理、几何外形、支撑机构及驱动系统之间的矛盾关系,导致高升力系统的设计周期很长并且很大程度上依赖于试验[1]。然而,随着计算机软件和硬件的迅速发展,近几年的工程设计中N-S方程应用日趋广泛。在空气动力学设计领域,计算机辅助设计手段已经逐步替代了过去的经验设计手段,并且国内飞机设计单位的科研人员也开始花费越来越多的时间应用流体仿真软件来达到设计目标,而不是像过去那样完全依赖试验结果去设计和分析飞机气动力特性,高升力装置设计也是如此。本文着重对著名的MSES软件和CFX软件在高升力装置模拟中的工程应用进行探索,并和风洞试验结果进行比较,初步研究了高升力装置数值模拟在飞机设计工程应用中存在的一些问题。     

高级语言在数字飞行控制系统中的应用

为跟踪90年代由高级语言开发飞控实时软件的总趋势,本文综述了高级语言在飞控中应用前景;归纳了编译器效率指标、编译器与目标计算机、软件生产率等问题。还简要地以C语言开发某直升机数字飞行控制系统为例,对高级语言开发实时飞控软件作了初步探讨,叙述了方法步骤,仿真验证手段及其结论。     

Aerial Mapping Planetary Bodies

Photographic mapping missions over planetary bodies present a number of interesting hardware, operational, data retrieval, and data analysis techniques. Broadly speaking, such a mapping mission can be conducted with present level state-of-the-art equipment. The space-craft and photographic equipment must perform over long periods of time unattended in the hostile space environment. Operations must support the mission and retrieve the photographic data. Maximum data are limited by photographic capacity, operations capacity, and analysis capacity. Data analysis techniques are under development and computer maps have been developed for RANGER analysis; these techniques can be especially suited to analysis of the video (analog or digital) signal transmitted back to Earth.     

基于虚拟仪器的航空电气控制盒测试系统设计与实现

介绍了一种基于虚拟仪器的航空电气控制盒测试系统的设计和实现,该系统是一种针对各类飞机电气控制盒的开放式的综合测试系统。对系统中主要硬件的设计和上层测试软件的设计思想做了相关讨论,同时阐述了整个测试系统的实现功能和方法。利用该综合测试系统,可以开发出各类飞机电气控制盒的测试系统,克服了以往测试设备只能测试一个产品的缺点,提高了测试准确度和效率。