基于FPGA的步进电机均匀细分驱动器的实现

在对步进电机细分驱动原理进行分析研究的基础上,提出一种基于FPGA控制的步进电机细分驱动器.利用FPGA中的嵌入式EAB构成LPM-ROM,存放步进电机各相细分电流所需的PWM控制波形数据表,并通过FPGA设计的数字比较器,同时产生多路PWM电流波形,实现对步进电机转角进行均匀细分控制.     

基于FPGA的步进电机细分驱动器的设计

在研究步进电机细分驱动原理的基础上,提出了一种采用丌,GA芯片实现步进电机恒转矩细分驱动的方法.利用FPGA芯片中的嵌入式阵列块(EAB)构成LPM_ROM来存储步进电机各相细分电流的数据,并把斩波控制电路集成到FPGA内部,从而提高了系统的集成度和稳定性.微控制器只需提供细分数等参数,就能精确控制步进电机的运行,所以该设计特别适用于某些实时控制场合.     

基于VHDL步进电机控制器研制

本设计在对步进电机细分驱动原理进行分析研究的基础上,提出一种基于FPGA控制的步进电机细分驱动器。在该设计中利用硬件描述语言（VHDL）对步进电机控制器的各功能模块进行行为描述。在MAX＋plusⅡ下进行编译仿真,完成对步进电机控制器的设计。     

基于VHDL步进电机控制器研制

本设计在对步进电机细分驱动原理进行分析研究的基础上,提出一种基于FPGA控制的步进电机细分驱动器。在该设计中利用硬件描述语言(VHDL)对步进电机控制器的各功能模块进行行为描述。在MAX+plusII下进行编译仿真,完成对步进电机控制器的设计。     

基于FPGA的太阳能自动跟踪控制系统

根据太阳能电池板的工作原理,设计了基于FPGA的双轴跟踪法太阳能自动跟踪控制系统。自动跟踪控制系统采用FPGA技术,给出了FPGA内核算法及基于FPGA内核算法的步进电机速度和方向控制方法。为提高步进电机的控制精度和解决空载启动频率,采用了细分驱动的方法,介绍了细分驱动的方法的原理和具体实现。采用本文设计的控制系统可以大大提高太阳能发电系统的效率。     

步进电机宽调速多细分控制系统研究

针对步进电机的低速振荡和高速电流畸变现象,研究了步进电机驱动方式,提出了细分驱动和上下桥同时斩波的方法,设计了步进电机驱动系统。系统基于CPLD,结合了D/A转换器和单相全桥变换电路,主要分为控制电路、功率驱动电路、保护电路等,实现了宽调速多细分控制。最后,分别测试了整步和细分时步进电机的低速牵出转矩特性,以及不同斩波方式下的高速电流波形,通过实验结果的对比,验证了分析结果。     

基于FPGA小型化数传中继天线驱动控制设计

为满足航天器小型化设计需求,采用单片反熔丝FPGA作为中继天线驱动控制主控芯片。为达到天线指向机构的高精度要求,采用双通道旋转变压器配合AD2S80解码获得位置数据。为提高机构速度稳定度,采用步进电机256细分正弦斩波驱动方式。实现集通信、位置电流采集、故障报错机制及步进电机驱动功能于一体,单机重量从5～6 kg降到2.5 kg,指向精度提高到0.005 5。实验结果表明基于单片FPGA的数传中继天线驱动控制能有效提高单机集成度和运动过程平稳度,对于卫星综合性能的提高具有重要意义与应用价值。     

基于反熔丝FPGA的太阳帆板高可靠驱动控制系统设计

针对宇航用某太阳翼帆板驱动控制系统的高可靠、小型化应用要求,采用基于反熔丝FPGA芯片实现2台太阳帆板机构的驱动控制,集通信、电机驱动、变频启停控制、自主故障检测与工作模式切换等功能于一体,实现了双轴太阳翼帆板的驱动控制,机构运行平稳,且在旋变故障工况下可自主切换至步数控制模式,可靠性高。     

空间遥感相机的指向控制系统设计

设计了一个基于FPGA的指向控制系统,可控制遥感相机镜头快速跟踪角度指令.指向控制系统实现了角度位置控制、转向速度控制和平稳调速等功能.本系统采用步进电机作为角运动执行机构;使用FPGA生成电机控制驱动信号,从而简化了电机控制系统构成,降低了系统成本.指向控制系统因模块化设计可灵活应用于多种场合.     

基于PIC16F876的步进电机细分驱动电路设计

介绍了由PIC16F876控制的步进电机细分驱动电路的设计,该电路主要包括单片机控制电路、斩波电路、功率驱动电路及温度报警与限流电路等。给出了细分驱动电路的设计原理及其实现的方法,提出细分按照线性加正弦规律的方法输出阶梯电压,经脉宽调制(PWM)输出各相驱动信号,实现细分驱动信号波形。应用于天文望远镜的90BF003步进电机驱动,性能良好。     

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。     

How do children do mathematics with LOGO?

Abstract  This paper considers some results of a study designed to investigate the kinds of mathematical activity undertaken by children (aged between 8 and 11) as they learned to program in LOGO. A model of learning modes is proposed, which attempts to describe the ways in which children used and acquired understanding of the programming/mathematical concepts involved. The remainder of the paper is concerned with discussing the validity and limitations of the model, and its implications for further research and curriculum development.