航空发动机故障诊断系统设计与实现

利用LabVIEW和C语言、MATLAB混合编程,设计并实现了航空发动机故障诊断系统。利用C语言设计了数据采集仪的DLL驱动程序,LabVIEW调用DLL实现了数据采集;针对航空发动机振动信号的特点,设计了信号处理与故障特征提取模块;利用MATLAB编译了多算法优化的支持向量机COM组件,LabVIEW调用该组件实现了故障诊断;利用数据库连接工具包设计了数据库管理模块。在航空发动机转子实验台上对该系统性能的测试结果表明,该系统达到了较高的故障诊断精度,同时也验证了文中设计思想的可行性。     

基于CAN的多通道数据采集系统的设计

提出了一种基于CAN总线,应用于航空发动机动态测试的多通道数据采集系统的设计方案。完成了对各传感器输出信号及电源信号的调理、采集、分析处理及上传,并对系统进行了非线性误差标定。给出了数据采集系统各模块的设计思想及系统软件设计流程。试验结果表明,该多通道数据采集系统具有抗干扰性强、采集精度高、接口灵活等优点,满足该型航空发动机测试系统的需求。     

8通道静态应变信号调理模块研究

在航空发动机的测试中,需要测量发动机的各种性能参数,如温度、压力、转速、流量、振动等,其中压力的测试是可以通过测量发动机叶片产生的应变来完成,通常应变测试系统包括应变片、信号调理器、数据采集模块和软件处理几部分;北京长城测控公司结合近几年开发航空发动机测试系统的经验,基于VXI总线测试技术开发了信号调理模块与数据采集模块高度集成的航空发动机测试系统,同时针对测试中存在的多种物理量开发了多种信号调理模块;文章主要针对静态应变信号调理模块的使用方法及在数据采集系统中的应用进行了介绍,并对关键电路的设计方法进行了详细说明。     

航空发动机高速振动智能检测监控系统设计与实现

设计了一种航空发动机高速振动智能检测监控系统,系统采用CPCI和模块化架构实现;针对航空发动机高速振动信号的特征,设计了基于DSP的信号采集与处理模块,实现同步采集多路振动信号并进行数据处理;利用FPGA和PowerPC设计信号智能检测与数据记录模块;通过多线程DSP软件实现振动数据的智能检测和监控;试验测试和验证结果表明,系统满足飞行安全实时检测监控工程应用的需求。     

基于PC104的航空发动机频谱分析仪设计

针对航空发动机复杂振动信号难以检测和提取的问题,设计了一种基于PC104总线技术的便携式频谱分析仪。硬件部分以PC104模块为核心,通过自行设计的信号调理电路,实现了对8路振动信号和2路转速信号的采集,其中4路振动信号被ICP传感器采集,提高了采集信号的信噪比;软件部分基于LabWindows/CVI虚拟仪器开发平台设计,采用模块化的设计思想,实现了数据采集、处理、分析和存储等功能。实际应用表明,该设备运行稳定、可靠性好,能够及时、准确地反映出发动机中存在的故障。     

旋转机械状态监测与故障诊断软件数采模块开发

针对旋转机械振动信号的特点,使用Visual Basic语言开发一个基于DAQ-2213数据采集卡的振动信号采集模块;该模块运用采集卡提供的功能函数实现振动信号和转速信号的采集,在振动信号采集中,使用双缓冲区采集的办法来获得连续的数据,使用转速信号触发的外部数字触发模式实现了对振动信号数据的整周期采集,在转速测量中,使用采集卡上两个独立计数器串联的方法实现单转子低起步转速的转速测量,最小测量转速为100rpm.设计一个操作简单、内容简明友好的人机交互数采界面用来设置采集参数并显示所采集的振动信号波形和转速值,所开发的采集模块具有高精度、高采样率、多通道整周期采集的优点,达到了预期目标,具有一定的工程应用价值.     

基于VI的工程机械整机性能测试系统

该设计是为了对36路工程机械整机性能模拟(温度、压力、油耗、车速及轮边转速、发动机转速、扭矩、增压器转速、牵引力、液压流量、噪音、烟度、排放)信号进行采集和处理。该设计以动态数据采集模块PXI系列及前端调理适配设备SH系列为硬件平台,以流行的虚拟仪器(VI)软件Lab VIEW为运行平台,开发了拥有系统配置模块、参数配置模块、状态检测模块、标定系统模块、自校准模块、数据采集模块、数据处理模块七个模块组成的系统软件。最后通过应用证明了该系统的实用性、先进性、经济性和可靠性的特点。     

基于ECT技术的航空发动机尾气监测系统设计

为克服现有航空发动机尾气监测系统性能欠稳定和成本较高的问题,设计了基于电容层析成像(ECT)技术的航空发动机气路状态实时监测系统,实现了集传感器设计、数据采集及图像处理功能的一体化.系统主要包含多电极电容传感器模块、数据采集系统模块和计算机成像模块三大模块.概述了各个模块的设计思路,并详细论述了核心模块即采集系统模块的设计方法与控制流程.仿真实验表明:该系统具有性能稳定、非侵入性和实时性好等特点.     

基于CompactRIO的便携式航空发动机温度采集系统

为了满足航空发动机外场测试的便携性要求,利用NI公司的CompactRIO(CRIO)平台设计了发动机便携式温度测试系统.利用LabVIEW FPGA开发了CRIO的底层FPGA模块,实现对数据采集模块的控制与管理;利用LabVIEW RTOS开发了CRIO的底层实时操作系统,实现了对采集数据的组织、管理及与上位机通信;最后利用LabVIEW开发了上位机软件,实现测试数据的实时显示和数据存储.基于CRIO的便携式温度采集系统具有体积小、重量轻、精度高、实时性强、灵活性较高的优点,充分满足了航空发动机外场便携式测试的功能要求.     

航空发动机转子故障诊断系统设计与实现

为准确、高效地诊断航空发动机转子系统故障,采用面向对象的程序设计方法,在VC++开发环境下,设计开发了航空发动机转子故障诊断系统。系统包含四个模块:数据采集模块采用多线程处理技术,配合数据采集设备实现多通道数据同步采集;信号分析和特征提取模块利用封装的改进经验模态分解算法类CEmd进行故障信号处理并从中提取故障特征;模式识别模块基于Lib SVM和GAlib库模板建立了基于支持向量机的故障识别模型。在航空发动机转子模拟实验台上对该系统进行测试,结果表明参数设置适当时,系统对转子典型故障的诊断精度达到了98%。     

Only connect: teaching, technology and telesis

Abstract This paper describes an approach to the design of interactive multimedia materials being developed in a European Community project. The developmental process is seen as a dialogue between technologists and teachers. This dialogue is often problematic because of the differences in training, experience and culture between them. Conditions needed for fruitful dialogue are described and the generic model for learning design used in the project is explained.     

European Community policy and the market

Abstract This paper starts with some reflections on the policy considerations and priorities which are shaping European Commission (EC) research programmes. Then it attempts to position the current projects which seek to capitalise on information and communications technologies for learning in relation to these priorities and the apparent realities of the marketplace. It concludes that while there are grounds to be optimistic about the contribution EC programmes can make to the efficiency and standard of education and training, they are still too technology driven.     

一种自适应子融合集成多分类器方法

融合集成方法已经广泛应用在模式识别领域,然而一些基分类器实时性能稳定性较差,导致多分类器融合性能差,针对上述问题本文提出了一种新的基于多分类器的子融合集成分类器系统。该方法考虑在度量层融合层次之上通过对各类基多分类器进行动态选择,票数最多的类别作为融合系统中对特征向量识别的类别,构成一种新的自适应子融合集成分类器方法。实验表明,该方法比传统的分类器以及分类融合方法识别准确率明显更高,具有更好的鲁棒性。     

Avoiding semantic and temporal gaps in developing software intensive systems

Development of software intensive systems (systems) in practice involves a series of self-contained phases for the lifecycle of a system. Semantic and temporal gaps, which occur among phases and among developer disciplines within and across phases, hinder the ongoing development of a system because of the interdependencies among phases and among disciplines. Such gaps are magnified among systems that are developed at different times by different development teams, which may limit reuse of artifacts of systems development and interoperability among the systems. This article discusses such gaps and a systems development process for avoiding them.     

Designing economic np control charts: A programmed simulation approach

This paper presents control charts models and the necessary simulation software for the location of economic values of the control parameters. The simulation program is written in FORTRAN, requires only 10K of main storage, and can run on most mini and micro computers. Two models are presented - one describes the process when it is operating at full capacity and the other when the process is operating under capacity. The models allow the product quality to deteriorate to a further level before an existing out-of-control state is detected, and they can also be used in situations where no prior knowledge exists of the out-of-control causes and the resulting proportion defectives.     

The development of robot art

Going through a few examples of robot artists who are recognized worldwide, we try to analyze the deepest meaning of what is called “robot art” and the related art field definition. We also try to highlight its well-marked borders, such as kinetic sculptures, kinetic art, cyber art, and cyberpunk. A brief excursion into the importance of the context, the message, and its semiotics is also provided, case by case, together with a few hints on the history of this discipline in the light of an artistic perspective. Therefore, the aim of this article is to try to summarize the main characteristics that might classify robot art as a unique and innovative discipline, and to track down some of the principles by which a robotic artifact can or cannot be considered an art piece in terms of social, cultural, and strictly artistic interest. This work was presented in part at the 13th International Symposium on Artificial Life and Robotics, Oita, Japan, January 31–February 2, 2008     

Explanation and prediction: an architecture for default and abductive reasoning

Although there are many arguments that logic is an appropriate tool for artificial intelligence, there has been a perceived problem with the monotonicity of classical logic. This paper elaborates on the idea that reasoning should be viewed as theory formation where logic tells us the consequences of our assumptions. The two activities of predicting what is expected to be true and explaining observations are considered in a simple theory formation framework. Properties of each activity are discussed, along with a number of proposals as to what should be predicted or accepted as reasonable explanations. An architecture is proposed to combine explanation and prediction into one coherent framework. Algorithms used to implement the system as well as examples from a running implementation are given.     

Three Process Perspectives: Organizations, Teams, and People

This paper provides the author's personal views and perspectives on software process improvement. Starting with his first work on technology assessment in IBM over 20 years ago, Watts Humphrey describes the process improvement work he has been directly involved in. This includes the development of the early process assessment methods, the original design of the CMM, and the introduction of the Personal Software Process (PSP)^SM and Team Software Process (TSP){^SM}. In addition to describing the original motivation for this work, the author also reviews many of the problems he and his associates encountered and why they solved them the way they did. He also comments on the outstanding issues and likely directions for future work. Finally, this work has built on the experiences and contributions of many people. Mr. Humphrey only describes work that he was personally involved in and he names many of the key contributors. However, so many people have been involved in this work that a full list of the important participants would be impractical.     

基于复小波噪声方差显著修正的SAR图像去噪

提出了一种基于复小波域统计建模与噪声方差估计显著性修正相结合的合成孔径雷达(Synthetic Aperture Radar,SAR)图像斑点噪声滤波方法。该方法首先通过对数变换将乘性噪声模型转化为加性噪声模型,然后对变换后的图像进行双树复小波变换(Dualtree Complex Wavelet Transform,DCWT),并对复数小波系数的统计分布进行建模。在此先验分布的基础上,通过运用贝叶斯估计方法从含噪系数中恢复原始系数,达到滤除噪声的目的。实验结果表明该方法在去除噪声的同时保留了图像的细节信息,取得了很好的降噪效果。     

基于QTE的蒙古文显示机制研究与实现

蒙古语言是中国蒙古族使用的通用语言,由于蒙古文区别于其他文字的书写方式和其自身变形机制等特点,在很多通用的文字处理引擎中都不被支持。在嵌入式产品开发与应用领域中Linux加QTE已经成为流行方式。该文给出了一种在QTE环境上实现基于标准Unicode的蒙古文点阵显示和变形算法, 并自定义了支持蒙古文的QTE组件,扩展了QTE功能,为在Linux加QTE方式的嵌入式体系结构中处理蒙古文提供了一种解决方法。