提高机载电子产品的可靠性——某告警系统的故障分析

介绍电子产品设计时元器件选用对系统可靠性的影响。结合实际案例,总结并强调在电子产品设计时的元器件选用应从质量等级入手,充分进行降额设计和热设计。阐明合理选用元器件是实现电子产品系统设计高可靠性水平的基础。     

The 1553 Advanced Communication Engine (1553-ACE)

The next-generation 1553 terminals will address the concerns of reducing the size, power, and cost and adding features required to off-load the system designer. The 1553-ACE series programmable terminal and the BUS-61580 ACE terminal are described. The various features incorporated especially the programmable options which make this series terminal so flexible are discussed. The ACE series has an advanced set of registers, internal 4 K words of shared RAM, dual encoder/decoders, and three-state buffers for address and data I/Os in one monolithic. It has selective I/O features, such as buffered DMA, or a shared RAM interface, with or without zero wait states to support a variety of microprocessors. Additional programmable features incorporated are RT circular data stacks programmed by individual subaddress, internal RAM command illegalization, and advanced bus controller and bus monitor options for bus snooping or for selective monitoring. The electrical, mechanical, and special competitive features of the 1553 ACE-series are highlighted. The military screening and mechanical specifications and other product options are covered     

现代飞机交流电源系统的不中断供电技术

现代飞机上安装了大量的微处理机、计算机。由于电源之间正常转换而出现的电源短暂中断现象会对微处理机、计算机的工作产生干扰。研制不中断供电的电源系统已是刻不容缓的任务。本文讨论了电源正常转换时电源中断现象及原因。以现代大型飞机上的电源系统不中断供电技术为例,阐述消除电源中断的技术方案以及汇流条保护控制组件(BPCU),发电机控制组件(GCU)内有关不中断电源转换的逻辑。     

Digital avionics-an international perspective

It is maintained that the dynamism of electronics technology, especially in displays, microprocessors and software, makes for exciting promises and problems in avionics. International barriers are disappearing, and the trends towards downsizing, new alliances, and consolidation should ultimately lead to a stronger avionics industry worldwide     

航空装备的完整性

 简述完整性概念在航空装备上的应用情况,提出了航空装备完整性概念,并简介了航空装备的完整性原理,     

Mobile military communications beyond 2000-systems engineeringneeded

The performance of mobile military communications could be improved if the next generation equipment would be designed from the systems approach, not limited to any existing solutions. The capabilities of software and microprocessors should be utilized to enhance the primary functionality of the devices and a comprehensive study of antennas, wave propagation and mechanical aspects should be included     

Microprocessor-Controlled Communications in an Advanced Instrument Landing System

The application of 4-bit microprocessors to the communication of the control and status signals found in an advanced aircraft instrument landing system is presented. The advantages as well as some of the peculiarities of such an approach are described. Among the benefits, one must include the possibility of a very convenient and understandable human interface.     

智能结构模糊振动控制的在环仿真

提出了采用压电材料作为传感器和驱动器,基于模糊逻辑的柔性结构主动振动控制方法,并在嵌入式微处理器上实现模糊控制策略.柔性智能梁结构为例,以单片机为控制器,采用数值方法在计算机上模拟柔性结构模型,利用计算机与单片机的串行通讯技术实现了梁结构振动控制的硬件在环仿真,并编制出良好的人机界面和硬件接口程序.仿真结果表明本文提出的模糊控制方法能够很好的实现对智能梁结构的振动抑制.     

Changing safety-critical software

Changing software to implement new features, correct problems, update functions, or replace obsolete hardware components (e.g., microprocessors) is a way of life in today's industry. A systematic software change process is essential for the maintenance and reuse of safety-critical software. This paper presents activities to consider when changing software in safety-critical systems. The focus is on the aviation industry; however, the concepts are also applicable to other safety-critical domains, such as medical or nuclear     

飞机电子测试车实施原位检测的分析

近几年来,航空工程机务工作转移到以可靠性为中心的维修思想上,似科学维修代替传统的经验维修,使机务维护工作出现了新局面。用电子测试车实施机载电子设备原位检测是维护手段改革的重要成果,现将使用情况作一介绍。 一、使用飞机电子测试车的可靠 长期以来,飞机电子设备定检工作采用离位的方法,即依飞行时间将电子设备从飞     

Replacement strategy for aging avionics computers

With decreasing defense dollars available to purchase new military aircraft, the inventory of existing aircraft will have to last many more years than originally anticipated. As the avionics computers on these aging aircraft get older, they become more expensive to maintain due to parts obsolescence. In addition, expanding missions and changing requirements lead to growth in the embedded software which, in turn, requires additional processing and memory capacity. Both factors, parts obsolescence and new processing capacity, result in the need to replace the old computer hardware with newer, more capable microprocessor technology. New microprocessors, however, are not compatible with the older computer instruction set architectures. This generally requires the embedded software in these computers to be rewritten. A significant savings-estimated in the billions of dollars-could be achieved in these upgrades if the new computers could execute the old embedded code along with any new code to be added. This paper describes a commercial-off-the-shelf (COTS)-based form, fit, function, and interface (F³I) replacement strategy for legacy avionics computers that can reuse existing avionics code “as is” while providing a flexible framework for incremental upgrades and managed change. It is based on a real-time embedded software technology that executes legacy binary code on the latest generation COTS microprocessors. This technology promises performance improvements of 5-10 times that of the legacy avionics computer that it replaces. It also promises a 4× decrease in cost and schedule over rewriting the code and provides a “known good” starting point for incremental upgrades of the embedded flight software. Code revalidation cost and risk are minimized since the structure of the embedded code is not changed, allowing the replacement computer to be retested at the “blackbox” level using existing qualification tests     

嵌入式微处理器NCS多任务管理单元MTU的研究

确立了多任务管理单元 MTU的设计方案,探讨了多任务管理的定义、数据结构,给出了微处理器多任务切换算法,提出了多任务管理单元 MTU细胞群结构。细胞群结构由细胞组成,每个细胞可进行一种测试并输出测试的布尔值给微程序控制器来控制微程序的转移。多任务管理单元 MTU的 RTL级 VHDL描述经 EDA工具 MENTOR GRAPHICS的综合与仿真验证了多任务管理单元 RTL级 VHDL描述的正确性与有效性。     

Extended Area Range Instrumentation System Utilizing DME Links

Updated and expanded range instrumentation installations require a system capable of actually tracking and controlling large numbers of vehicles over expanded areas. A range instrumentation system is discussed based on distance measurement equipment (DME) coupled with high performance data links which satisfies these requirements. Previously developed DME systems utilized a single frequency data link, required a low sample rate, and accomodated only a few vehicles. The DME range instrumentation system described will handle a large number of test vehicles and accomodate high data rates without performance degradation. This is accomplished by incorporating surface acoustic wave (SAW) devices and microprocessors with previous developed technology. A system performance analysis for various configurations of the range instrumentations system design is also presented.     

Sensor validation using hardware-based on-line learning neuralnetworks

The objective of this document Is to show the capabilities of parallel hardware-based on-line learning neural networks (NNs). This specific application is related to an on-line estimation problem for sensor validation purposes. Neural-network-based microprocessors are starting to be commercially available. However, most of them feature a learning performed with the classic back-propagation algorithm (BPA). To overcome this lack of flexibility a customized motherboard with transputers was implemented for this investigation, The extended BPA (EBPA), a modified and more effective BPA, was used for the on-line learning, These parallel hardware-based neural architectures were used to implement a sensor failure detection, identification, and accommodation scheme in the model of a night control system assumed to be without physical redundancy in the sensory capabilities. The results of this study demonstrate the potential for these neural schemes for implementation in actual flight control systems of modern high performance aircraft, taking advantage of the characteristics of the extended back-propagation along with the parallel computation capabilities of NN customized hardware     

Recent developments of electric vehicles and their propulsionsystems

Major recent electric vehicle (EV) programs in North America, Europe, and Japan are reviewed. The developments discussed include electric vehicles for fleet operation and electric passenger cars for urban transit. All major auto makers have had their own concept electric vehicle programs, targeted at commercial production in the late 1990s. It Is noted that, with different objectives for various electric vehicles, considerations such as cost, reliability, efficiency, maintenance, durability, weight, size, and noise level should be compromised for the propulsion system design. Consequently, DC motor drives, induction motor drives, and permanent magnet brushless DC motor drives will continually be used for EV propulsion systems in the future, with DC drives being gradually replaced by AC drives. The rapid advances in power semiconductor devices and microprocessors have made it possible to build reliable and cost-effective AC drive systems     

An Adaptive Model Following Control of Industrial Manipulators

Using the adaptive model following control (AMFC) technique, a control system is developed to obtain high performance of an industrial manipulator that has wide variations in its payload and spatial configuration. The main advantage of this technique over other methods is simplicity in computation, which provides the capability of real-time control calculation with today's microprocessors. Moreover, it guarantees automatically the stability of the overall system without requiring any additional stability analysis. In order to demonstrate the capability of this technique, we have conducted a computer simulation for the Unimation PUMA 600 series manipulator. The simulation results agree well with the expected high performance of the control system: (1) computational requirements are much less than other existing ones, and (2) it provides the capability of adapting to large variations in payload and spatial configuration. Also presented is a comparison of the amount of its required computation with that of other methods.     

Europe needs a space policy

Space - or, more precisely, space technologies which enable us to enter and make use of space for a wide range of purposes - concerns us all for many reasons.     

某型机外形数模修形设计

在某型机外形数模修形设计过程中,探讨如何确定修形原则,即针对存在各种问题的曲面形态,如何确定不同的修形方法,使整个飞机外型数模达到光顺性、结构可实施性、曲面连续性要求。     

Electronic technologies that enables aerospace

This section highlights early electronics milestones that have made significant contributions to aerospace and defense. Today everyone thinks digital, whereas more than 50% of electronic advances since society founding 50 years ago were in the analog or continuous domain. It is too easy to forget that before the 1970s and 1980s analog systems had been the norm. Digital electronics emerged late in WWII, when the US Army contracted with the University of Pennsylvania to compute extensive artillery firing tables. The Cold War substantially accelerated advances in solid state electronics which led to the microelectronics that are so ubiquitous today. Defense and then aerospace programs were symbiotic with electronics in the development and mass production of transistors, integrated circuits, microelectronics, microprocessors, magnetic and then solid state memory. Small, reliable, low power and high performance electronics were the key to aerospace progress. The government backed virtually all these developments out of necessity. The power of computers has increased by over a million since 1972 and is still climbing. The initial enabling technology for advances in military electronics was the almost forgotten vacuum tube. The existence of electrons was first recognized as the “Edison Effect” in 1883. The seminal event in electronics was the audion invented by Lee De Forrest in 1906. The audion appeared just three years after the first Wright brother's flight and four years before the Army purchased their first Wright airplane. Up until the World War I (WWI) radio amateurs were the electronics pioneers, but the war created new demand for radio communications. Electronics expanded from communications into radar, navigation and control systems in World War II (WWII). Both wars brought about dramatic improvements in electronics, which resulted in a surplus of equipment and trained personnel to fuel postwar advances     

Optimization method for sensor planning

This article looks at the development of algorithm-based tools with a view to meeting future operational needs for intelligence. More precisely, it concerns the management of sensors and proposes a new heuristic capable of optimizing (globally speaking and subject to constraints) the planning of sensors to meet the intelligence needs expressed by the High Command.