一种四余度电液伺服阀的伺服舵机系统的Simulink仿真

通过分析舵机伺服系统的工作原理,建立了四余度伺服舵机系统工作的数学模型,分析了余度舵机的故障隔离方法和余度系统工作原理;运用Simulink对舵机在1个和3个电液伺服阀发生故障以及同一系统中的2个电液伺服阀同时发生故障的情况进行仿真;仿真结果表明,与单通道舵机相比,余度舵机可以有效地隔离故障元件,实现控制目的,具有更好的稳定性和可靠性。     

电动舵机通用测试系统设计

舵机系统是一个高精度的位置伺服系统,是导弹控制系统的重要执行机构。电动舵机系统的测试是对舵机系统质量及技术性能进行综合评价的重要环节,是舵机系统投入使用前的重要工序。为了测试应用不同通信协议的电动舵机系统性能,基于MATLAB/GUI平台,设计了一种针对异步串行通信协议都适用的测试系统。通过对人机界面的操作,主要实现对舵指令、数据长度以及校验方式等不同的帧封装,从而实现对电动舵机的测试,并接收来自电动舵机系统反馈的舵偏角信息,将舵指令和舵偏角进行综合处理,以得到舵机系统的性能。此外,还对测试系统的性能进行了评估测试。测试结果表明,测试系统能满足通用测试要求,且便于更改和携带。     

基于LabWindows/CVI的多路电动舵机自动化综合测试系统设计

舵机有三种工作状态(航向、俯仰、滚动),其性能指标直接决定着导弹功能实现。为实现舵机三种工作状态下的空载和加载性能指标测试,设计了一种基于LabWindows/CVI的多路电动舵机自动化综合测试系统。该系统应用1553B总线、PC104总线、虚拟仪器、多线程等技术,可实现同时对多路、多种测试功能模块的实时测试,测试过程中数据能够自动读取、处理、显示以及生成和存储报表。本文详细论述了电动舵机自动化测试系统的硬件、软件设计和功能组成。该系统已被应用于某型舵机的功能和性能指标的测试,人机交互界面友好,操作简单,运行稳定。     

飞行仿真系统中舵机特性建模与模型降阶

针对某型电液伺服舵机特性,首先建立了线性数学模型,在此基础上推导出了传递函数。其次针对该传递函数阶数较高,难以在仿真系统中实现的问题,通过基于Gram矩阵的均衡模型降阶法,运用matlab工具箱对该传递函数进行降阶处理,得到了降阶最小实现模型。然后对原始高阶函数和降阶后函数分别进行了仿真试验,比较测试结果发现,两者仿真曲线基本一致,符合要求。最后将最小实现模型加入飞行仿真系统进行测试,结论表明该系统性能良好,完全能够替代真实舵机进行飞行控制系统仿真试验。     

基于LabWindows/CVI的导弹舵机测控系统设计

舵机是导弹控制系统的重要执行机构,为实现对电动及气动多种型号导弹舵机性能的测试,设计开发了一种基于LabWindows/CVI虚拟仪器的测控系统。介绍了该测控系统硬件组成和软件结构流程,软件设计过程中充分利用多线程、数据库等技术,准确快速完成舵机自动化性能测试。应用结果表明:该舵机测控系统工作稳定,测试精度和自动化程度高,满足舵机试验测试精度和技术指标要求,为舵机的性能研究和维修维护提供了良好的测试环境。     

无人机舵机测试系统软件设计与应用

根据无人机系统的舵机测试需求,给出了基于虚拟仪器组成舵机测试系统的设计思想,在软件开发中对舵机各个参数的测试方法和测试流程给出了恰当设计等,用几个典型的参数测试阐明了该系统的应用.利用该系统全面测试舵机的各项性能指标,对研发新的舵机产品具有实用价值.     

弹载电液舵机的Bang—Bang＋PID双模控制研究

本文结合一弹载电液舵机系统,介绍了电液位置伺服系统的工作原理。经过推导,建立了该舵机的数学模型。在MATLAB／Simulink中搭建了舵机的仿真模型,分别对PID控制和Bang—Bang控制进行了仿真,仿真结果表明这两种控制方法无法获得满意的控制效果。为取得良好的控制效果,将PID控制和Bang－Bang控制相结合,设计TBang-Bang＋PID双模控制器,提高了系统的控制效果。     

舵机电动加载测试系统设计及数值仿真研究

舵机电动加载测试系统用来模拟铰链力矩对电动舵机进行加载。针对由于加载对象主动运动引起的多余力矩问题,影响系统稳定性和跟踪精度等性能。为提高系统设计性能,从舵机加载测试系统的硬件搭建和控制方式两个方面考虑,搭建了电动加载测试系统,并建立了系统的简化数学模型,采用BP神经网络算法控制系统的模型进行仿真与分析。仿真结果表明舵机加载测试系统的阶跃响应速度和对力矩指令的动态跟踪性能明显提高,从而为小功率的舵机电动加载测试系统的工程化提供一定的理论依据。     

基于LabVIEW的直流舵机性能测试系统

介绍了舵机性能测试系统的硬件组成、软件设计和功能测试实验。系统采用LabVIEW做为软件开发环境进行程序设计．实现了激励信号的产生、舵机输出信号的采集、回放、数据处理以及舵机性能分析等功能。测试过程分手动测试和自动测试两种，可根据不同情况进行相关性能指标的测试。实验结果表明，该系统极大地提高了测试效率和精度,降低了测试成本。     

舵机自动测试系统的设计与实现

为更灵活准确的测试舵机性能和寿命,研制了基于工控机、力矩加载器、力矩传感器、角度传感器的舵机性能和寿命自动测试系统。测试系统采用NI公司生产的便携式一体化PXI机箱和高精度多功能采集卡,在测试过程中实时监测采集舵机控制器的电压电流和舵机位置信号;采用Lab VIEW编程平台开发了相应的测试软件,设计了友好的人机交互界面,实现了舵机产品的参数测量及合格性判断。通过实验比对新旧测试系统对同一舵机产品测试数据,证明新测试系统测试精度和测试效率都更高。     

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。