飞机装配迎来机器人时代

机动、灵巧的自动化设备为飞机柔性装配提供了另一种选择.它舍弃了整体精度而追求局部精度,并充分利用了飞机部件自身特点,而且质量轻,更经济,可以分配到作业现场或依附到飞机部件上,不需要大的安装场地;而且设备的造价变得低廉许多.     

Prospects for electric vehicles

The state-of-the-art of electric vehicles (EVs) is discussed with examples of prototype vehicles-Electric G-Van, Chrysler TEVan, Eaton DSEP, and Ford/GE ETX-II. The acceleration, top speed, and range of these electric vehicles are delineated to demonstrate their performance capabilities, which are comparable with conventional internal combustion engine (ICE) vehicles. The prospects for the commercialization of the Electric G-van and the TEVan and the improvements expected from the AC drive systems of the DSEP and ETX-II vehicles are discussed. The impacts of progress made in the development of a fuel cell/battery hybrid bus and advanced EVs on the competitiveness of EVs with ICE vehicles, and their potential for reduction of air pollution and utility load management are postulated     

Robotic Systems for Aircraft Servicing/Maintenance

This paper explores concepts which apply emerging ground support technology (GST) to the rapid turnaround of tactical aircraft. This technology has the potential to reduce manpower requirements for ground servicing, increase sortie generation rates and expose fewer ground personnel to the lethal agents anticipated during biochemical warfare. The near term approach examines automated systems for refueling and rearming tactical aircraft assuming the returning aircraft suffer no disabling malfunctions or battle damage. In the far term, it is proposed that additional maintenance and servicing functions be performed by GST systems. Consideration is given to linking diagnostic computers on tactical aircraft with future robotic systems for direct repair and maintenance. It is concluded that GST systems, including robotics, provide the opportunity for revolutionary changes in aircraft servicing and maintenance and provide a viable option for generating sorties during and immediately following biochemical attack.     

GPS based IPS for ERP vehicles

GPS is an innovative technique for an electronic road pricing (ERP) system. By using GPS technology, ERP systems will be extremely efficient and cost-effective. This paper describes the next generation of ERP in Singapore and proposes a GPS based multisensor positioning system for ERP vehicles. Multisensor fusion algorithms are presented for the integration system. The integrated positioning system (IPS) developed in this paper makes it possible to realize GPS based ERP with a simple composition and low cost     

New battery types for space vehicles

Engineers from all over the world came to discuss their new developments at the 36^th Intersociety Energy Conversion Engineering Conference (IECEC), held in Savannah, Georgia, USA, July 30 through August 2, 2001. Twenty battery presentations covered topics ranging from powering instruments in oil-well boreholes to supplying energy to instruments on the surface of Mars. Important developments in aerospace batteries are summarized in this article     

Perspective on ultracapacitors for electric vehicles

Recent advances in performance of chemical double layer capacitors (DLC) with aqueous and non-aqueous electrolytes have made it possible to seriously consider them for commercialization. Non-aqueous (organic) carbon based laboratory monopolar devices have recently met key U.S. Department of Energy (DoE) mid-term specifications (> 5 WNkg, >500 W/kg and >100,000 life cycles) for load-leveling electric vehicles batteries. All DLC technologies currently under development by DoE are discussed. Each technology has distinct advantages and none are clear winners at this time. A study has been completed by the General Electric Company on the interface electronics needed to best utilize the energy of capacitors for load-leveling batteries. System costs are presented based on this study, several battery technologies, and capacitor projections     

机器人磨抛氧化锆涂层工艺研究

使用搭建的机器人自动磨抛平台系统,针对氧化锆热障涂层磨抛工艺开展了研究,旨在通过机器人磨抛加工对涂层厚度及表面粗糙度进行合理控制,提高涂层表面质量。基于Preston理论建立了氧化锆涂层材料的去除模型;通过单因素试验研究了主要磨抛参数对材料去除深度的影响规律,基于正交试验确立了氧化锆涂层材料磨抛最优工艺参数组合和工艺步骤,对航空发动机喉道密封片氧化锆涂层进行了磨抛加工。试验结果表明,在一定范围内,材料去除深度随着磨抛压力及磨抛盘转速的增大而增大,随着进给速度的增大而减小;磨抛压力对材料去除深度的影响较大,磨抛倾角对去除深度的影响较小。机器人磨抛系统采用力控方式实现了定量均匀去除,涂层厚度和表面质量一致性良好,加工效率显著提高,同时也验证了本机器人自动磨抛系统的实用性和优越性。     

Bipolar nickel-metal hydride battery for hybrid vehicles

Hybrid electric vehicles are receiving increased interest as an approach to decrease vehicle pollution, dependence, and consumption of liquid petroleum and meet forthcoming Government vehicle emission standards. A number of schemes are under consideration (heat engine battery, fuel cell battery, peaking battery, inner-city battery, etc.). The success of any of the approaches will be dependent on battery capabilities, i.e., power, density, life, and cost. The nickel-metal hydride system appears to be the most promising of the candidate battery chemistries. Preliminary designs and analysis have been prepared and are presented for various configurations. Initial performance characterization tests are presented. It is concluded that a bipolar package arrangement for the Ni-MH chemistry appears most suited for the hybrid vehicle application considered     

众多临近空间飞行器的最优轨迹规划

针对众多临近空间飞行器在复杂飞行环境的最优轨迹规划问题,采用改进的动态规划法和基于共轭梯度法的多点边值组合算法求解了多目标优化问题,得到了全部飞行器的最优飞行轨迹.仿真结果表明,该算法能够在考虑多种环境条件约束和飞行器自身条件约束的情况下,快速规划出众多飞行器的最优飞行轨迹,具有一定的学术价值和工程应用价值.     

Electromechanical flight actuators for advanced flight vehicles

The aircraft flight quantities and success of the mission depend to a great extent upon the actuator performance, and flight actuators must be designed to achieve the specified criteria. Electromechanical flight actuators driven by electric motors have begun to displace hydraulic technology in advanced flight vehicles. In aerospace application, permanent-magnet stepper motors are perfectly suited due to their efficiency and reliability, low volume-, weight-, and size-to-torque ratios, high power and torque densities, low cost and maintenance, simplicity and ruggedness, etc. Conventional open-loop stepper motor servos do not ensure the required accuracy and dynamic performance. An innovative method in motion control of advanced electromechanical flight actuators is developed, and nonlinear controllers are designed. The specified tracking accuracy, desired stability margins, microstepping capabilities, and disturbance attenuation are ensured by the robust nonlinear controllers synthesized. Analytical, numerical, and experimental results are documented to study the performance of flight actuators directly driven by stepper motors and to demonstrate the efficiency of control algorithms     

一种机器人砂带磨削的路径规划方法(英文)

机器人砂带磨削系统具有弹性接触和宽行加工两个显著优点,被广泛应用在具有复杂工件的终加工领域,提高表面质量和加工效率。有关在曲率约束下的磨削路径规划研究较为少见。由于工件与接触轮之间存在复杂的弹性接触,因此,机器人磨削路径可以利用接触运动学的一般方法来求解。机器人砂带磨削过程且需要满足一般的砂带磨削工艺要求,其中最重要的是保证接触轮与工件的局部几何特征贴合。在曲率较小的局部,相邻刀位点的弧长加大,以保证加工效率。相反地,在曲率较大的局部,相邻刀位点的弧长较小,以保证加工精度。利用一系列平面与目标曲面相截,得到相应的截平面的轮廓曲线。对于任意一条轮廓线,优化相邻刀位点之间的弧长,在曲率较大的局部增加一个中间刀位点。本文提出了一种包含弧长优化和主曲率匹配的磨削路径生产方法,通过离线仿真验证了有效性,并利用该方法提高了曲面的磨削质量。该路径规划方法为生成光顺且精确的机器人曲面磨削路径提供了理论依据。     

Cooperative task scheduling for networked uninhabited air vehicles

In the work presented here, we study a cooperative control problem for a network of uninhabited air vehicles (UAVs) where it is assumed that after deployment a set of tasks is given to a group of UAVs and the UAVs must cooperate to decide which UAV should process each task. The cooperation must occur during real-time operation due to a need to repeatedly process each task, in spite of imperfect communications (e.g., messages with random but bounded delays), and the possibility that tasks pop-up. We show how to view this as a cooperative scheduling problem, and how to derive bounds on mission-level performance metrics. Simulations are used to compare the approach with a noncooperative strategy and to provide design guidelines for the cooperative scheduler.     

生物质-燃料电池/燃气轮机集成原理及技术分析

生物质气化-燃料电池/燃气轮机(biomass gasification fuel cell/gas turbine,BGFC/GT)发电系统在生物质能利用方面具有独特优势,近年来受到研究人员的重视.在对BGFC/GT发电系统基本原理及特点介绍的基础上,对其中2个重要研究内容,即部件技术手段、系统热力集成的研究现状进行了综述分析,指出发电系统的性能与组成系统的部件的技术手段密切相关,应针对所用生物质的特点及对产品气的要求对生物质处理技术进行选取;系统内部能量的有效利用是进行系统热力集成、提高热力学完善性的关键.目前BGFC/GT发电系统集成研究工作较少,应加强对系统内部可用能充分利用的研究,通过引入热力学系统分析方法提高系统内能量的有效利用,改善能量转化效率.     

面向等离子熔射制模的机器人轨迹生成系统的实现

构建了面向等离子熔射制模的机器人轨迹生成系统。该系统能由CAD实体模型直接生成机器人所带喷枪的运行轨迹 ,并能精确地控制喷枪的运行轨迹、角度、速度以及喷枪与原型之间的距离     

高超声速飞行器气动布局和轨道优化研究(英文)

提出了高超声速飞行器参数化模型,并在此基础上通过快速、高效的工程方法开展了初步的气动力计算。以类HTV-2布局为对象,开展了以升阻比和容积率为设计目标的气动布局优化研究;以类X-37布局为对象,开展了以航程和驻点总加热量为设计目标的弹道优化设计。采用加权求和的方法求解多目标优化问题。研究表明,通过优化可获得设计目标权重取不同值时的优化结果,各优化结果具有明显的不同,具体将哪一个优化结果作为最终的选择,主要依赖于设计者的需求。     

Night vision devices for ground environment

The PM N-V/RSTA is procuring the Driver's Vision Enhancer (DVE) thermal imaging system for use in combat and tactical wheeled vehicles. The DVE uses uncooled forward looking infrared technology compared to the I² technology currently in the field. During the development of the DVE several issues were raised regarding how specific aspects of system design were related to driver performance. As a result, DCS Corporation developed a data collection effort to provide the DVE project leader with needed performance data that could act as a foundation for making program decisions     

面向高超声速飞行器的宽速域翼型优化设计

宽速域气动设计是水平起降高超声速飞行器研制的瓶颈问题之一.水平起降高超声速飞行器在飞行过程中需要经历亚、跨、超和高超声速多个速域,而适应不同速域的最佳气动外形相互矛盾,使得实现良好的宽速域气动设计面临极大挑战.首先,针对高超声速飞行器宽速域翼型气动设计问题,发展了基于代理模型的高效全局气动优化设计方法,并设计出一种相对厚度为4％、有一定弯度、下表面具有双"S"形特征的宽速域翼型.将新翼型与常规四边形和双弧形翼型进行了气动特性对比,并进行了流动机理分析,结果表明新翼型的宽速域综合气动特性显著优于常规翼型,从而证明发展兼顾亚、跨、超和高超声速气动性能的宽速域翼型是可行的.其次,开展了宽速域翼型的多目标优化设计,通过分析Pareto解集中翼型的宽速域气动性能随几何外形变化的演化规律,进一步解释了有一定弯度、下表面呈双"S"形的薄翼型能够协调亚、跨、超声速与高超声速气动性能的原理.最后,采用平面外形为梯形的机翼,进行了三维机翼构型下的宽速域翼型多目标优化设计.三维优化设计结果与二维结果具有相似的几何特征和压力分布,说明这种通过下表面双"S"形小弯度薄翼型来兼顾亚、跨、超和高超声速气动性能的宽速域流动机理同样适用于三维情况,也证实了翼型设计对于宽速域高超声速飞行器仍然具有重要意义.     

微型扑翼的推进特性实验研究

为了研究微型扑翼的推力和推进效率特性,研制了基于虚拟仪器（VI）的微型扑翼风洞实验系统。该系统以西北工业大学现有微型风洞为基础,采用了高精度六分量天平、角度传感器、新型机翼扑动机构、可编程电源、工控机等设备,利用基于虚拟仪器（VI）的LabView软件对上述设备进行集中控制与数据处理。利用上述实验系统研究了风速、扑动频率、展弦比、根稍比及机翼扑动幅度对微型扑翼推力和推进效率的影响,总结出了微型扑翼推力及推进效率的基本规律,为微型扑翼飞行器机翼设计及飞行控制方式提供了参考。     

面向控制的高超声速飞行器推进系统代理建模

针对高超声速飞行器推进系统机理模型结构复杂、计算效率低、难以直接应用于控制器设计的问题,建立了面向控制的高超声速飞行器推进系统代理模型。首先,通过对机理模型进行分析,确定了代理模型的基本形式;然后,基于拟合优度的敏感度分析方法,将代理模型简化为最简形式;最后,采用自适应状态变量替换方法,对代理模型进行面向控制的简化。计算结果表明,自适应状态变量替换法可实现面向控制的模型简化;面向控制的代理模型能够达到较好的拟合效果。     

飞行器航迹规划中的规划区域建模方法

针对网格法用于规划区域建模的不足,提出了一种新的规划区域建模方法-多航迹区链接图法.该方法在对规划区域进行建模的过程中充分考虑飞行器的特性、飞行环境和使用特点,结合规划区域中障碍物的属性、形状和分布情况构造出航迹点的候选区域,从而得到规划空间的多路径区连接图的建模描述,基于这种建模描述使用优化算法来规划飞行器的较优或可行航迹.仿真结果表明,该算法有效的利用了背景知识,计算快,耗时少,搜索效率高,对于有效地解决战场环境下飞行器的航迹规划有工程实用价值.