基于Qsys的时栅信号处理系统设计与实现

为提高时栅传感器位移测量精度和测量分辨力,研究采用FPGA嵌入式锁相环倍频产生4路同频且相位差为45°的高频时钟脉冲作为测量基准,利用多路并行双边沿计数方法对时栅参考信号和时栅感应信号进行相位测量,通过相位差转换得到具有高分辨力的时栅位移信号, 采用Qsys开发平台设计Nios－II软核进行数据处理,利用傅立叶级数谐波修正技术对测量结果进行误差修正,提高时栅传感器的测量精度,在72对极磁场式时栅角位移传感器上进行精度测试,实验结果表明:经过误差修正后,该系统测量的整周误差从－57.2″~ 92.5″下降到－2.0″~2.5″,作为角位移传感器满足高端装备高精度定位需求,具有重要的工程应用价值。     

基于游标细分方法的高精度时栅测量系统设计

为了提高时栅位移传感器的测量精度,介绍了一种不通过提高时钟频率而提高时栅测量精度的方法一游标细分法.借鉴于游标卡尺对齐细分的测量方法,对时栅时钟脉冲进行二次细分,实现了高分辨率、高精度时间量的测量,避开了复杂的电子细分.为了验证该方法的有效性,搭建了一套实验平台,实践证明:采用游标细分方法后,时栅位移传感器的时钟插补脉冲在41.7 ps的高分辨率下,测量误差峰峰值为±1.4”,实现了更高精度的测量.     

基于STM32F4的时栅位移传感器信号处理系统设计

为了提高时栅位移传感器的测量精度及分辨率,提出了一种基于STM32F4的时栅位移传感器信号处理系统;系统包括硬件电路设计和软件设计;硬件电路以STM32F4内核处理器芯片和复杂可编程逻辑器件CPLD为核心,集成了信号调理、信号处理等电路模块;运用高频时钟脉冲插补时栅位移传感器感应信号和参考信号之间的相位差,通过软件设计控制信号的采集和处理,实现了相位检测;经实验验证,采用以STM32F4为核心的时栅信号处理系统后,时栅位移传感器的角度误差峰峰值达到2.4”,实现了高精度、高分辨率的时栅角位移测量.     

基于数字内插法的时栅位移传感器信号处理系统设计

为了提高时栅位移传感器的动态性以及测量精度,设计了一种基于数字内插法的时栅信号处理系统;利用粗计数法和数字内插法将时栅信号分成粗测和细测两部分分别进行测量,降低了对插补脉冲频率的要求,提高了测量精度;同时采用SOPC技术实现了系统电路的高度集成,并利用自定义指令提高了数据处理速度;实验表明,采用该系统后,时栅在40 kHz激励情况下误差为±1.2″,实现了时栅信号的高精度测量。     

纳米时栅传感器数字信号处理系统设计

针对大量程纳米级精度测量难的问题,结合时栅传感器的基本原理,提出一种基于交变电场耦合的纳米时栅传感器。利用Nutt内插法对影响时栅精度的关键因素—时间量进行精密测量,降低了系统对插补脉冲频率的要求,提高了测量分辨率。采用SOPC技术设计纳米时栅信号处理系统,保证了系统高性能实时测量。实验结果表明,该系统能稳定正常工作,在行程200mm测量范围内,纳米时栅精度可达到±300nm。     

时栅角位移传感器误差测试及补偿

在工业现场,角位移传感器校准受特殊条件的限制,很难用标准器进行密集误差采样来提高精度。针对该问题提出了一种稀疏误差采样及补偿方法。在分析时栅角位移传感器的感应信号的基础上,提出稀疏采样第1个对极内细分误差+对极点零位误差的测补方式,给出用激光干涉仪获取零位和细分误差的方法及采用稀疏采样的误差补偿模型进行补偿的具体过程。以72对极时栅角位移传感器为对象进行研究,实验结果表明:该方法充分剔除了零位误差且补偿了细分误差,在稀疏采样的条件下即可实现整周范围的有效补偿,大大提高了修正效率和测量精度,时栅传感器的精度达到2.69″。     

TDC-GP21电场式圆时栅传感器信号处理系统设计

针对时栅传感器信号处理系统需要高精度时间间隔测量的需要,设计了一种基于TDC-GP21芯片测量时间间隔的时栅信号处理系统.采用FPGA控制TDC芯片的高精度测量模式对整数部分时间脉冲进行计数,小数部分时间脉冲采用门电路延迟进行细测,使时间测量更为精确,从而提高了时栅位移传感器的分辨率;通过校准测量对测量结果进行补偿修正,减小了测量误差.实验结果表明:采用该系统后72对极的圆时栅在0°～360°测量范围内,传感器的原始测量精度达到±1″,分辨率为0.036″.     

基于SOPC的时栅位移传感器信号处理系统设计

为了提高时栅位移传感器的动态性以及测量精度,设计了一种基于SOPC技术的时栅信号处理系统,将数据的采集和处理集成在一片FPGA内,采用NiosⅡ处理,并将复杂的乘除运算加入了自定义指令,提高了时栅传感器的数据处理效率,采用傅氏级数谐波修正技术来进行误差修正,大大提高了测量精度。实验表明,采用该系统后,时栅在每分钟8转情况下误差峰峰值为2.2″。     

基于TDC-GP2的高速时栅位移传感器信号处理系统的研究

随着时栅位移传感器的产业化发展,高速测量需求的趋势日益凸显,提出了一种基于TDC-GP2的时栅位移传感器信号处理系统。该系统采用STM32F4和AD9958产生时栅位移传感器所需的高稳定、高精度励磁信号,采用高分辨率TDC-GP2数字时钟转换器来测量传感器动、定测头的感应信号相位时间差,将测量结果送入微处理器中处理,以此到达以时间测量空间的目的。经实验表明:48对极时栅传感器整周(0~360°)的误差达到±2.3″,该方案优化了电路结构,提高了时栅位移传感器的测量精度。     

基于STM32F4的时栅位移传感器信号处理系统集成化设计

设计了一种基于单片STM32F4芯片的时栅位移传感器信号处理系统,将驱动电源、信号采样以及数据处理与误差补偿集成在一片芯片中完成,采用数字频率直接合成（DDS）技术进行激励源的设计,利用输入捕获方式进行高频时钟脉冲插补来采集测量信号,由芯片集成的单周期DSP指令部件完成数据计算,并采用傅氏级数谐波修正技术来进行误差修正。实验表明：采用该系统后,72对极时栅误差峰峰值为3．29”,在保证精度的同时实现了时栅信号处理系统的集成化、小型化,降低了生产成本。     

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。     

煤矿井下安全监控分站的设计及其仿真实现

为了设计一种具有低成本、低功耗、易操作、功能强且可靠性高的煤矿井下安全分站,针对煤矿安全生产实际,文章提出了采用MCS-51系列单片机为核心、具有CAN总线通信接口的煤矿井下安全监控分站的设计方案;首先给出煤矿井下安全监控分站的整体构架设计,然后着重阐述模拟量输入信号处理系统的设计过程,最后说明单片机最小系统及其键盘、显示、报警、通信等各个组成部分的设计;为验证设计方案的可行性与有效性,使用Proteus软件对设计内容进行仿真验证,设计的煤矿井下安全监控分站具有瓦斯、温度等模拟量参数超标报警功能和电机开停、风门开闭等开关量指示功能;仿真结果表明:设计的煤矿井下安全监控分站具有一定的实际应用价值.     

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。     

基于AD9626的模拟信号采集存储卡设计

自然界的绝大部分信号都是以模拟的形式存在,因此模拟信号的采集转换存储在数字时代十分关键。文章讨论了在雷达信号处理领域基于AD9626的AD采集存储卡的设计原理、硬件结构和程序设计与芯片配置等问题,为今后相关领域的研究提供了可参考的方案。     

A human-computer interface for non-computer specialists

The COM teleconferencing system was designed to be easy to use for both beginners and people with much computer experience. A number of design choices in organizing the human-computer interface were considered very carefully. These design problems are not unique for teleconferencing applications, but will appear in many other developments of human-computer interfaces for non-computer specialists. This report discusses naming conventions, menu format, user commands, help facility and the treatment of ‘type ahead’ from the users.     

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.     

View-based model-driven architecture for enhancing maintainability of data access services

In modern service-oriented architectures, database access is done by a special type of services, the so-called data access services (DAS). Though, particularly in data-intensive applications, using and developing DAS are very common today, the link between the DAS and their implementation, e.g. a layer of data access objects (DAOs) encapsulating the database queries, still is not sufficiently elaborated, yet. As a result, as the number of DAS grows, finding the desired DAS for reuse and/or associated documentation can become an impossible task. In this paper we focus on bridging this gap between the DAS and their implementation by presenting a view-based, model-driven data access architecture (VMDA) managing models of the DAS, DAOs and database queries in a queryable manner. Our models support tailored views of different stakeholders and are scalable with all types of DAS implementations. In this paper we show that our view-based and model driven architecture approach can enhance software development productivity and maintainability by improving DAS documentation. Moreover, our VMDA opens a wide range of applications such as evaluating DAS usage for DAS performance optimization. Furthermore, we provide tool support and illustrate the applicability of our VMDA in a large-scale case study. Finally, we quantitatively prove that our approach performs with acceptable response times.     

Call for papers Special issue on Modeling and control technologies for civil,energy,and power systems

正The control of civil,energy,and power systems presents significant new challenges for modeling and control theory.The purpose of this special issue is to provide a forum for researchers and practical engineers to discuss the recent advances in modeling and control technology development for civil,energy,and power systems.Prospective authors are invited to submit their original contributions with the focus on theory or applications of modeling,control     

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正http://www.zju.edu.cn/jzus http://www.springerlink.com Aim The Journals of Zhejiang University-SCIENCE(A/B/C)are edited by the international board of distinguished Chinese and foreign scientists,and are aimed to present the latest developments and achievements in scientific research in China and overseas to the world’s scientific circles,especially to stimulate and promote academic exchange between Chinese and foreign scientists everywhere.