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。     

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.     

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.     

A pragmatic multi-method investigation of discrepant technological events: Coping,attributions, and ‘accidental’ learning

Discrepant technological events or situations that entail a problem, a misunderstanding or a difficulty with the Information Technology (IT) being employed, are common in the workplace, and can lead to frustration and avoidance behaviors. Little is known, however, about how individuals cope with these events. This paper examines these events by using a multi-method pragmatic approach informed by coping theory. The results of two studies – a critical incident study and an experiment – serve to build and test, respectively, a theoretical model that posits that individuals use a variety of strategies when dealing with these events: they experience negative emotions, make external attributions, and adopt engagement coping strategies directed at solving the event, eventually switching to a disengagement coping strategy when they feel they have no control over the situation. Furthermore, users’ efforts may result in ‘accidental’ learning as they try to overcome the discrepant IT events through engagement coping. The paper ends with a discussion of the results in light of existing literature, future opportunities for research, and implications for practice.     

The Distributed Time-Triggered Simulation Scheme: Core Principles and Supporting Execution Engine

Distributed real-time simulation is a young technology field but its practice is under increasing demands. In recent years the author and his collaborators have been establishing a new approach called the distributed time-triggered simulation (DTS) scheme which is conceptually simple and easy to use but widely applicable. The concept was initiated in the course of developing a new-generation object-oriented real-time programming scheme called the time-triggered message-triggered object (TMO) programming scheme. Some fundamental issues inherent in distributed real-time simulation that were learned during recent experimental studies are discussed along with some approaches for resolving the issues. An execution engine developed to support both the TMOs engaged in control computation and the TMOs engaged in DTS is also discussed along with its possible extensions that will enable significantly larger-scale DTSs.     

Software-Konfigurationsmanagement in großen Softwareprojekten

Zusammenfassung Mit zunehmender Größe der Softwaresysteme verschärfen sich die für die Software-Herstellung typischen Probleme: Beherrschen großer Objektmengen, Erhalten der Systemkonsistenz, Kontrolle der ständigen Änderungseinflüsse und Gewährleisten einer langen Lebensdauer. Die Disziplin Konfigurationsmanagement bildet den methodischen Ansatz, diese Probleme besser zu beherrschen. Software-Konfigurationsmanagement faßt die Herstellung von Softwaresystemen als eine Abfolge von kontrollierten Änderungen an gesicherten Zwischen- und Endergebnissen auf. Dargestellt werden die Objekte und Funktionen des Software-Konfigurationsmanagements sowie die hierfür in großen Software-Projekten benötigten Methoden, Instanzen und Hilfsmittel.     

Information for Authors

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     

Editorial:Brain-machine interface(BMI) and cyborg intelligence

正Brain-machine interfaces(BMIs)aim at building a direct communication pathway between the brain and an external device,and represent an area of research where significant progress has been made during the past decade.Based on BMIs,mind information can be read out by neural signals to control     

Information for Authors

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     

SCIENCE CHINA Information Sciences SUBJECT INDEX TO VOLUME 57(2014)

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Information for Authors

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