Integrated PLC-fuzzy PID Simulink implemented AVR system

Improving the transient response of power generation systems using automation control in a precise manner is the key issue. We design a fuzzy proportional integral derivative (PID) controller using Matlab and programmable logic controllers (PLCs) for a set point voltage control problem in the automatic voltage regulator (AVR) system. The controller objective is to maintain the terminal voltage all the time under any loads and operational conditions by attaining to the desired range via the regulation of the generator exciter voltage. The main voltage control system uses PLCs to implement the AVR action. The proposed fuzzy controller combines the genetic algorithm (GA), radial-basis function network (RBF-NN) identification and fuzzy logic control to determine the optimal PID controller parameters in AVR system. The RBF tuning for various operating conditions is further employed to develop the rule base of the Sugeno fuzzy system. The fuzzy PID controller (GNFPID) is further designed to transfer in PLCs (STEP 75.5) for implementing the AVR system with improved system response. An inherent interaction between two generator terminal voltage control and excitation current is revealed. The GNFPID controller configures the control signal based on interaction and there by reduces the voltage error and the oscillation in the terminal voltage control process. We achieve an excellent voltage control performance by testing the proposed fuzzy PID controller on a practical AVR system in synchronous generator for improve the transient response.     

Between the Local and the Global: History of Science in the European Periphery Meets Post‐Colonial Studies

The aim of this paper is to discuss two historiographical issues pertaining to the history of science in the European periphery. The first issue concerns the wide use of the centre‐periphery dichotomy in historical accounts discussing the diffusion and institutionalization of science across the world. The second issue concerns the use of appropriation (instead of transfer, or adaptation) as a means to overcome the diffusionist model in history of science. Recent work at the intersection of history of science with post‐colonial studies will provide the framework for reassessing these matters. As it will be shown, theoretical discussions about the history of science in post‐colonial context can help historians overcome the centre‐periphery dichotomy and turn European periphery into a privileged standpoint for showing the actual diversity of ‘European science.’ At the same time, the experience of post‐colonial studies can also help sharpen the historiographical tool of appropriation. The assumption that will be made is that by focusing on appropriation rather than on discovery and innovation (the favourite categories of much of mainstream historiography), or on transfer and adaptation (the favourite categories of the diffusionist model), historians of science can not only set aside the artificial distinctions of the diffusionist model, but also bring forward the re‐inventions, the conceptual shifts and the cultural adjustments, which are responsible for the emergence of science as a global phenomenon in the periphery. Especially concerning European periphery, the use of appropriation may bring forward the particular historical circumstances under which certain knowledge patterns gained universal epistemic authority as constitutive elements of an imagined European intellectual identity.     

利用STEP的设计意图信息交换

设计意图信息交换标准是异构CAD系统之间设计意图信息交换的基础.对ISO 10303(STEP)标准最近公布的关于基于特征的设计意图信息交换标准的内容、表达模式及实施的中间交换文件格式进行分析;对设计意图信息交换特点、交换映射模式,以及交换过程中涉及的主要关键技术进行探讨;通过基于AP203交换协议的中间物理交换文件,实现设计意图信息交换,最后给出一个基于设计意图交换标准的零件特征参数化模型数据交换实例.     

基于B/S模式的零件加工特征文件传递与存储技术研究

为使ISO14649标准在目前汽车行业中得到应用,研究产品模型数据交换标准(STEP)文件在制造过程中的传递,提出建立远程数据库的方法。首先对STEP和STEP-NC接口进行分析,然后建立基于STEP的B/S模式远程数据库的框架模型,并给出STEP文件的远程传递存储解决方案,最后以汽车发动机零件———连杆为例,对上述技术进行测试和验证。     

结构化编程在轧钢设备中的应用

简单介绍了STEP7编程的三种程序结构,重点论述了结构化编程在轧钢设备中应用的优点,以钢管矫直机程序编写为例,具体阐述了结构化编程的方法.     

基于STEP文件的图匹配方法研究

从零件的CAD模型中获取工艺设计所需的加工特征信息是CAPP的基础,也是实现CAPP与CAD集成的关键。研究旨在探讨中等复杂程度的机械零件加工特征识别方法,采取其方法从三维设计软件中得到CAD模型。对该模型输出的STEPAP203文件进行处理,获得面特征及其连接边的凹凸性,得到属性邻接图,将其进行处理得到全凹（或全凸）连接的子图,然后将子图中所有代表毛坯面的节点去掉,剩下的就是各特征对应的特征子图。再按照特征子图匹配法,将每个子图与预先定义的特征图进行匹配,就得到了所需要识别的特征。实例结果显示,该方法简便有效,大大减少了图匹配的计算量。     

面向下一代制造企业的信息系统

分析了面向下一代制造企业的信息系统 ,为了适应动态变化和异质环境的要求 ,信息系统必须具有适应性和响应性。讨论了实现信息系统需要的支持技术 ,包括基本模型、标准、通信网络和集成框架。指出网络通信、产品建模和软件互操作方面的国际标准 (Internet和www、STEP、CORBA)是建立系统的技术基础     

Technical and economic design support system in construction within the context of concurrent engineering

The authors demonstrate the usefulness of concurrent engineering techniques and at the same time highlight some of the difficulties encountered in creating knowledge bases and using electronic data interchange.     

网络控制系统在低能强流离子束装置中的应用

为了提高中国原子能科学研究院串列加速器控制的自动化水平,设计并实现了一种先进的低能强流离子束网络控制系统.该系统吸取了近年来IT领域的最新发展成果,建立了传输介质为光纤的以太网控制网络.经过实际运行表明,应用设计合理,达到了预期设计目的.     

钢铁制造业信息化集成方案与优化技术研究*

结合钢铁制造企业特点,提出了一个基于STEP标准的企业内外信息集成方案;研究了以实现整个企业及供应链集成优化为目标的高级计划排程系统;围绕原材料的充分利用问题,研究了原料的优化下料决策支持系统;给出了采用数据挖掘技术实现库存控制和故障分析的思想。