基于单片机通信网络的集散式电机同步控制系统设计

一种基于单片机通信网络的集散式电机同步控制系统.详细论述了构成控制系统的单片机环型通信网络、同步控制器、集中控制器的设计及工作原理.     

基于自由通信协议的多电机的同步控制

提出了利用自由通信协议,以PLC作为主站,通过RS-485总线与多台变频器串行通信构成的变频同步控制系统。介绍了系统的硬件构成,根据PLC与变频器之间的通信原理和通信协议,对于速度的设定,采用了定时中断发送数据的方式,实现了线速度的同步;而对于电机的启动和停止,则可采用广播方式或单独发送方式;最后给出了系统的软件流程图。实践表明,该同步控制系统与传统同步控制系统相比具有速度控制灵活、准确和可靠性高等优点。     

基于CAN总线的智能馈线终端的研究

介绍一种基于CAN总线和交流同步采样技术的新型智能馈线终端。重点探讨了该馈线终端的工作原理,系统构成及软件设计思路。     

伪随机码频域相关器同步方案

本文讨论了利用频域相关器输出信号中的频率信息,通过由单片机构成的智能化电路进行快速同步的设计原理。给出了一个具体实例的设计方法和软件框图。     

基于PLC和矢量变频器的涂层机同步传动控制系统的实现

基于PLC和矢量变频器,设计涂层机同步传动控制系统,提出系统的构成和工作原理,给出由PLC、矢量变频器、同步控制器、力矩控制器、交流电动机和张力检测器等装置构成的闭环控制系统,实现涂层机不同传动单元的同步运行.其中的设计方法可用于其它需要同步运行的纺织设备.实际应用表明,这种交流调速系统具有与直流调速系统相同的动、静态控制性能,还具有运行可靠和维护简单的特点.     

基于ISP技术的正交信号激励模块设计

本文利用ISP技术产生了四路同步正交信号，在ISP器件内部实现了脉冲调制，节省了硬件资源，简化了电路设计。本文给出了电路的硬件构成以及逻辑结构和原理。     

矿井提升机行程-速度全数字监控器的研制

介绍了矿井提升机行程 -速度全数字监控器的构成、功能及工作原理 ,指出了以行程为变量的速度给定方式的重要性 ,并讨论了井筒同步校正开关设置的意义及监控器的抗干扰措施。     

基于UC1637的同步发电机励磁控制器设计

详细介绍了UC1637的特点及其工作原理,并给出了其应用于同步发电机励磁控制器的应用电路.实践证明,用该设计方法构成的PWM控制电路结构简单、性能可靠,具有良好的系统运行效果.     

基于远程监控的PLC-多变频器同步调速系统

利用LG=K120S系列PLC与LG-IG5系列变频器共同组成PLC-多变频器同步控制系统,详细说明了利用RS485通信网络、MODBUS通信协议构成同步控制系统的系统组成、工作原理与控制算法等,并利用计算机通过公用电话网对系统进行监控,已在实践中得到应用。     

基于FPGA的多路同步实时数据采集系统

结合数据采集系统在电力系统中的应用,设计了一种基于FPGA的多路同步实时数据采集系统,该系统将多个功能模块集成到一片FPGA中,构成片上可编程系统,使用一片FPGA完成对A/D转换和双口RAM等模块的控制;给出了系统的硬件原理框图,并结合系统的设计方案对其中的主要功能模块进行了阐述;以此构成的多路同步实时数据采集系统具有性能稳定、实时性强、集成度高、扩展性灵活等特点。     

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