模拟式大气仪动态响应数字仿真

本文采用通用数字计算机对模拟式大气仪动态响应进行数字仿真,比用模拟计算机进行仿真要简单、方便,而且精度也较高。从仿真的计算结果可以尽快了解系统动态响应范围,能及时确定系统中各环节设计参数是否合理,以便进行修改设计。     

Integrated flight control systems: a new paradigm for an old art

The automatic flight control computer was a revolutionary development in the early days of flight, even in its primitive electromechanical form. It evolved into an electronic computing device, starting as an analog computer and maturing into software run on a digital, general-purpose microprocessor. The current accepted industry standard is to use a dedicated microprocessor in its own enclosure for this function that is essentially firewalled from the rest of the systems on the aircraft. This paper will explore the opportunity to integrate the flight control function into an integrated processing platform, which is a robustly partitioned platform that supports multiple functions of dissimilar design assurance levels. This approach provides all of the benefits of an integrated system, while still maintaining the separation provided by a stand-alone unit. The paper will consider both the advantages and disadvantages of this approach. The discussion will describe each of the alternatives in general and then focus specifically on autopilot and flight control functions that have potential for integration. The end goal of the paper is to impress on the reader an understanding of the different alternatives available for autopilot, flight control, and avionics modernization in general. This includes the development of a selection matrix that will assist the reader in making decisions on how best to implement these functions according to criticality and the volatility of their future requirements     

Impact of aerospace on computers

Electronics and computers have long been associated with aviation, defense and aerospace. Many aerospace advances would have been impossible without digital computers, and digital computers would not have progressed as rapidly without aerospace. In some sense you may thank aerospace for the computer on your desk and Internet in your life. DoD and NASA programs drove computer technology for the first 25 years, but in the 80s the primary thrust transitioned to the commercial sector. Aerospace computation requirements have driven the development of many electronic components such as transistors, ICs and memory technology. Advances in memory technology progressed from delay lines to electrostatic tubes to magnetic cores and now solid-state memory. As the need for number crunching grew, computers transitioned from batch processing, time-sharing, real-time computing, networking to the ubiquitous PC and Internet. How far is it from your hand-held PDA to the nano computer?     

基于单片机的数字化舵系统设计

针对现有的某型模拟电动舵系统,利用先进的微处理器控制技术进行数字化改造,在控制算法方面和舵系统的快速性方面进行了理论上的研究,并进行了数字化舵系统原理样机的研制和实践上的调试。针对设计的数字化舵系统的线性/变结构复合控制器,介绍了数字化舵系统的工作原理和硬件电路设计,采用PL/M-96语言进行数字控制器编程,最后给出了实验结果和仿真结果的对比图,说明了设计的控制器的有效性。     

Digitally Controlled Receiver

Digital computers have evolved to an active role as components in communication systems, performing such functions as data processing, executive and adaptive control, management of waveform, and antenna characteristic selection. At one time, the interface between communication equipment and data processing was clear. At present, however, the computer is capable of accomplishing, by using digital techniques, so many classically analog functions that there is basically no interface. The discussion considers the extent to which this trend toward full utilization of digital techniques can and should be extended.     

一种支持双余度CAN总线接口的A/D采集单元设计

模拟量输入通道是无人机飞行控制系统自动检测计算机的关键部件之一.设计了某自动检测计算机内部一种基于余度CAN总线的A/D采集单元.根据总体技术指标要求,从器件选型到系统软硬件设计采用了先进性与实用性兼顾的设计思想.实际测试结果表明该接口单元工作稳定,性能良好,满足检测无人机飞行控制系统各性能指标的要求.     

Digital synthetic aperture radar processing via optical computers

A method for performing digital phase history processing of synthetic aperture radar (SAR) data using optical computers is proposed. The method has nothing in common with the old analog optical SAR processing methods (which used lenses), but is rather a totally digital (numerical) technique for computing the individual complex pixel values based on matrix-vector multiplications. The method can be expected to greatly increase the potential processing speed and coverage possibilities of high-resolution digital SAR systems     

涡扇发动机防喘控制系统的动态数学模型和数字仿真

本文以某涡扇发动机防喘控制系统为对象,建立了该系统的动态数学模型,并通过数字计算机进行仿真。判明了系统中主要结构参数和两个典型非线性对动态性能的影响。提出了改善系统品质的途径。     

Digital Flight Control Research Using Microprocessor Technology

The Flight Research Laboratory at Princeton University is engaged in an experimental program to investigate a variety of approaches to digital control by actual flight test. Experimentation is being conducted with Princeton's 6-DOF variableresponse research aircraft (VRA), which is equipped for direct side-force control, direct-lift control, feedback of all motion variables, and multiple-pilot command modes. VRA avionics have been augmented by a microprocessor digital flight control system (Micro-DFCS), which uses off-the-shelf computer components capable of operating in parallel or in series with the existing variable-response system. The digital control laws operate in conjunction either with the "bare airframe" dynamics of the VRA or with the dynamics of a simulated aircraft, provided by the existing variable-response system. The initial flight control computer program CAS-1 provides three longitudinal control options: direct (unaugmented) command, pitch rate command, and normal acceleration command. The latter two options are "Type 0" systems designed by linear-quadratic control theory. Future Micro-DFCS software will provide a variety of increasingly complex control options, including "Type 1," logic, gain scheduling, coupled 3-axis control, and "CCV" command modes.     

基于DSP的UAV飞控计算机设计与半物理仿真

飞行控制计算机(FCC)作为飞行控制系统的核心，担负着多种任务。随着系统功能的日益增多，飞行包线的不断扩大，模拟式FCC已经越来越不能满足系统要求。针对目前FCC向数字式、智能化方向发展，本文利用高速DSP芯片，结合复杂可编程器件(CPLD)，设计出一种集高可靠性、高集成度、高精度于一体的新型FCC，最后在此基础上外加了数据采集卡组成闭环半物理系统，并进行了仿真。仿真结果表明，本文这一全新尝试完全可行，且应用前景将非常广泛。     

An Ultrahigh Speed CAMAC Interface for a Large Flight Simulator System

The real-time simulation subsystem (RTSS) at the NASA Langley Research Center in Hampton, VA, consists of several CDC CYBER computers and over 20 flight simulation sites. This simulation network is used by the Langley Center to advance the state of aeronautics and to improve air safety. The current simulator interface system at NASA-Langley was installed in 1968 and uses centrally located analog and discrete conversion equipment. Of the alternatives studied by NASA for a replacement RTSS, only the network and input/output (I/O) system conforming to the international computer automated measurement and control (CAMAC) standards meets their requirements. The CAMAC serial highway provides a distributed I/O system with an extremely high data throughput approaching 24 000 000 information bits/per second. Fiber-optic links transmit the data over paths to 1 km. For multisite simulations, a computer-controlled electronic switch configures site highways in any combination. The CAMAC system uses analog-to-digital converters (ADCs), digital-to-analog converters (DACs), and synchro converters with 16 bits of resolution to give the needed system performance. The time to acquire data from 80 16-bit ADCs and 960 discrete inputs and transfer them to the CYBER central memory is less than 320 ?s. Similarly, the time from CYBER central memory to the setting of 256 16-bit DACs and 960 discrete outputs is less than 650 ?s.     

A study of flight-critical computer system recovery from spaceradiation-induced error

It is well known that space radiation, containing energetic particles such as protons and ions, can cause anomalies in digital avionics onboard satellites, spacecraft, and aerial vehicles flying at high altitude. Semiconductor devices embedded in these applications become more sensitive to space radiation as the features shrink in size. One of the adverse effects of space radiation on avionics is a transient error known as single event upset (SEU). Given that it is caused by bit-flips in computer memory, SEU does not result in a damaged device. However, the SEU induced data error propagates through the run-time operational flight program, causing erroneous outputs from a flight-critical computer system. This study was motivated by a need for a cost-effective solution to keep flight-critical computers functioning after SEU occurs. The result of the study presents an approach to recover flight-critical computer systems from SEU induced error by using an identity observer array. The identity observers replicate the state data of the controller in distinct data partitions. The faulty controller can be recovered by replacing data image of the faulty data partition with that of the healthy data partition. The methodology of applying such an approach from the fault tolerant control perspective is presented. The approach is currently being tested via computer simulation     

空空导弹成像制导系统动态仿真技术研究

提出了一种用于空空导弹制导系统动态仿真测试的数字成像导引回路设计与实现方法。通过设计合理的数字模拟接口并将真实的红外成像导引头用数学模型替代,可以实现数字导引头与导弹飞控舱实物的有效连接,完成灵活的制导系统数字/实物多重组合动态仿真。在保证必要的红外目标辐射特性和运动特性建模精度基础上,采用这种方法可以满足导弹制导算法的研制和调试需要。该方法目前已在某型红外数字化空空导弹的制导系统算法研制中获得应用,取得良好的应用效果。     

频域加权最优隐模型跟踪法及其在飞控系统设计中的应用

 把频率加权二次型法与隐模型跟踪理论综合起来,在系统设计时,考虑系统的稳定性、动态特性和鲁棒性要求,以期达到满意的综合指标。利用所述方法,设计了飞控系统的控制律。通过数字仿真及实时混合仿真表明,与通常最优二次型方法所设计的控制律比较,用本文所述方法设计的控制律,不仅有满意的稳定性和动态特性,而且还改善了鲁棒性。     

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     

全包线飞行控制系统设计方法研究

介绍了当前全包线飞行控制系统设计的几种主要方法，分析了这些方法存在的问题，研究了线性变参数系统（LPV）的自增益调度控制器设计，说明了其中两种重要的设计方法LFT（线性分式变换）法和Lyapunov函数法，应用Lyapunov函数法设计了大包线范围飞机的集镇爷角速度自增益高度控制系统，进行了变参数仿真，仿真结果说明了方法的有效性。     

The Whirlwind computer project

The authors describe how they led the development of the Whirlwind I (WWI) digital computer and its evolution into the SAGE (Semi-Automatic Ground Environment) air-defense system for North America. The project from 1945 through 1956, beginning at a time when no general-purpose, high-speed, electronic computer existed, was from the start dedicated to performance and reliability suitable for real-time control. After several shifts in objectives, Whirlwind became an experimental system for demonstrating that a digital computer could analyze the flow of radar data and generate control orders for fighter-plane interceptions of bombers. The resulting successor computers, the AN/FSQ-7, were installed in a network across the United States and Canada in the late 1950s. The SAGE System control centers were in operation about 25 years and demonstrated a 99.8% up-time reliability. In the Whirlwind Project, vacuum tube life was raised from 500 hours to 500000 hours, marginal checking allowed the automatic detection of aging and drifting of electronic components before they reached the point of failure, random-access magnetic-core storage was invented and developed to become the industry standard computer memory for more than two decades, synchronous parallel logic was used, computer-driven cathode-ray tube displays were used for the first time, light guns were used to permit an operator to identify displayed images to the computer for action, and multiple displays were time-shared between different operators     

飞机等效系统的在线辨识及其微机实现

引言 等效系统法是国外提出的评价带有复杂控制系统的飞机飞行品质的一种较有效的方法。它的基本思想是寻找一个带有等效时间延迟的低阶系统,使该系统具有或近似保留给定增稳飞机的高阶系统输出响应的主导特性,然后将低阶系统参数与规范要求相比     

某型发动机的单片机控制系统

某型发动机转速调节器是气动液压式的开闭式混合调节系统, 其结构复杂、重量大。为了研制新的控制系统, 采用16位单片机8098, 它是专门为具有16位微控制器的速度和具有8位外部总线而设计的。具有质量高、功能全且易于调整特点, 最适用于步进电机的控制。系统仿真和半物理模拟试验表明, 数字控制系统的时间响应, 在相同干扰情况下, 优于气动液压式控制系统。