基于小型PLC的温度模糊控制系统

由开关量输入输出模块、A/D和D/A等基本单元组成的小型PLC具有体积小、成本低和可靠性高的优势.如果能通过软件编程使小型PLC具有模糊控制功能,并应用于不易建模或模型参数不确定的过程控制系统,将使系统具有较高的可靠性和性能价格比.本文提出了一种在小型PLC上构造模糊控制器的方法,并以温度控制为背景,介绍了模糊控制器的设计以及系统实现的原理.     

单片机在电阻测量中的应用

一、前言在电阻测量中采用Intel公司的MCS-51单片机为中央控制器,较采用一般的微处理器具有下列优点: (1)使仪表设计简单、结构紧凑、性能/价格比高。 (2)因CPU、I/O、RAM、EPROM等集成在一块芯片上,所以体积小,抗干扰性能好。 (3)便于调试、生产和改型设计。二、工作原理被测电阻经过欧姆-电压转换电路,转换成所需要的模拟电压,并将其放大到A/D转换器的规范值,由A/D转换器转换成数字量,再送入单片机。由单片微机根据需要进行一系列处理(如非线性校正;四则运算;计算最大值和最     

离散多时滞系统的D稳定鲁棒容错控制

针对离散多时滞系统,设计了一种D稳定鲁棒容错控制器。首先以传感器失效为例,推导出了使系统D稳定的充分条件。然后依次推广到执行器失效以及系统参数不确定的情况。所设计的鲁棒容错控制器既能保持系统的稳定性,又能使系统满足一定的性能要求,且工程上易于实现。最后通过仿真示例验证了文中方法的正确性,并对仿真结果进行了分析。     

不完全微分PID控制的FPGA的研究

介绍了一种不完全微分的PID控制器在FPGA上实现的方法.首先对不完全微分PID控制的原理和设计中使用的算法进行分析,然后,用MATLAB针对特定的被控对象模型进行仿真实验,获得了比较理想的系统输出.最后,利用VHDL语言设计不完全微分PID控制器、A/D和D/A等各个模块,并对各个模块进行设计中的优化处理.实验表明,该设计方案可行的,而且本文的设计既有很快的运行速度,又改善了传统PID控制器的控制性能.     

4(1/2)位A/D转换器ICL7135与Z80-PIO的连接

<正> ICL 7135是双积分型精密4(1/2)位A/D 转换单片集成电路,它的转换数字范围为-19999～+20000,亦即其分辨能力为1/40000,很适合于用作对取样速度要求不高而转换精度要求较高的数字测量仪表中的A/D 转换器,尤其适合于带微处理器的数字仪表。ICL7135的引脚图如图1所示,是输出时序如图     

一种高效能的机器人模糊控制方案

本文提出一种高效能的模糊控制方案,来提高机器人当存在摩擦力和负载等不确定因素 时以及动力学参数变化时的系统响应特性.该控制方案是由一个模糊逻辑(FL)控制器(主 控制器)和一个传统的微分(D)控制器(辅助控制器)所构成.FL控制器用来提高系统的瞬 态特性和稳态精度,D控制器用来保证系统的稳定性.在这一控制方案基础上,获得理想控 制特性的主要思想是研究和调整语言变量的隶属度函数.模拟结果表明了这一控制方案的 有效性和鲁棒性.此外,这一控制方案具有结构简单且易于实现的优点.     

模糊数学及其应用(十)关于模糊控制的理论研究

由于模糊控制不需要被控过程的数学模型,因此这一控制方法引起了越来越多的注意。但是在模糊控制中往往是从操作者的实际经验出发来进行设计,缺乏分析控制器性能(如稳定性、最优化等)的适当工具,这在一定程度上限制了它的应用。     

基于鲁棒伺服思想的尾坐式飞行器悬停姿态控制

针对一款小型飞翼布局的尾坐式垂直起降飞行器,通过考虑舵面失效、风场干扰、气动参数不确定以及转动惯量不确定等因素的影响,进行悬停阶段的姿态控制研究.根据悬停状态点线性化的运动学和动力学模型,设计鲁棒伺服线性二次型调节器(RSLQR)控制器来保证标称系统良好的响应及鲁棒性.同时,考虑到较大不确定及扰动下RSLQR控制器性能下降的不足,希望飞行器能够尽量在平衡点附近较大的范围内工作,为此设计$L_1$自适应控制器进行补偿,以使系统性能得到恢复.考虑到控制器的时延裕度对系统稳定性有着重要影响,讨论控制器参数与系统时延裕度的关系.通过仿真验证不同不确定影响下系统良好的性能,并提出一种基于扩张状态观测器(ESO)的补偿方法,以使设计的控制系统在飞控硬件性能较为有限时,依然能够保证良好响应.最后,通过飞行测试对所提算法的有效性和可行性进行验证.     

基于FPGA的万能试验机控制器的研制

对现场可编程门列（FPGA）在万能试验机控制器中的应用方面作了一些探索，主要包括A/D，D/A，串口通信，光电编码器等信号的处理，以经来满足万能试验机控制器各方面性能。     

应用VHDL语言设计A/D和LED显示控制器

0　引言在工业测量和控制中 ,A/D器件和LED显示是不可缺少的。LED显示器的驱动多采用通用的TTL或CMOS集成电路 ,如 82 79,MAX72 19等。传统的A/D转换器件的控制多采用单片机来完成 ,但在一些特殊应用场合 ,例如高速、强电磁干扰等恶劣条件下 ,单片机的速度和可靠性往往满足不了系统的要求。VHDL语言作为IEEE的标准 ,是一种功能强大、通用的硬件描述语言 ,得到各种EDA工具的支持。本文将介绍利用VHDL语言采用自顶向下的方法在一片ALTERA的CPLD(EPM7160SLC84 - 10 )上设计实现一种高速A/D和LED显示控制器。1　系统功能…     

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.     

Call for Papers The 6^th International Conference on Grid and Cooperative Computing

Recent years have seen rapid advances in various grid-related technologies, middleware, and applications. The GCC conference has become one of the largest scientific events worldwide in grid and cooperative computing. The 6th international conference on grid and cooperative computing (GCC2007) Sponsored by China Computer Federation (CCF),Institute of Computing Technology, Chinese Academy of Sciences (ICT) and Xinjiang University ,and in Cooperation with IEEE Computer Soceity ,is to be held from August 16 to 18, 2007 in Urumchi, Xinjiang, China.     

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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