直流调速系统广义通用模型控制器的设计及应用

在直流调速系统中,转速、电流双闭环调速系统是应用最广的直流调速系统,设想应用Lie导数概念结合通用模型控制器对于直流调速系统的电流调节器和转速调节器进行设计,可以将被控对象的模型嵌入到控制器中,适当地选择主导极点可以获得比较好的调节品质,仿真结果验证了所设计的控制器的有效性.     

动力集中型列车调速系统仿真研究

介绍了采用电流、转速双闭环进行直流调速的方法,分别对电流和速度调节器进行了设计,描述了系统的组成及其数学模型。采用MATLAB中SIMULINK仿真软件,对动力集中型SS9(韶山9电力机车)直流调速系统进行建模仿真,仿真结果与实际数据相吻合。     

直流电机双闭环调速系统

采用工程设计方法对双闭环直流调速系统进行辅助设计,选择调节器结构,进行参数计算和近似校验.并建立起制动、抗电网电压扰动和抗负载扰动的Simulink仿真模型.分析转速和电流的仿真波形,并进行调试,使双闭环直流调速系统趋于完善、合理。     

基于模糊控制的直流双闭环调速系统仿真

将模糊控制应用于直流双闭环调速系统中的转速调节器,设计出模糊转速控制器,并与传统的双闭环调速系统进行了比较。利用MATLAB语言对这两种直流调速系统进行了仿真分析。仿真结果表明,用模糊控制方法得到的转速调节器参数比传统的工程整定方法得到的参数控制性能好,响应快,过渡过程时间短,基本无超调。     

直流双闭环调速系统及其模糊控制的仿真

给出了常规直流双闭环调速系统的仿真模型,采用Matlab对该模型进行了仿真,得出结论:常规直流双闭环调速系统具有较好的动态与静态特性,可以很好地抑制扰动量对电动机转速的影响,但该系统依赖精确数学模型,在增加解决环节的同时,系统模型趋于复杂,可能还会影响系统的可靠性。在该分析结果的基础上,提出了一种基于模糊控制+PI转速调节器的直流双闭环调速系统的设计方案,该方案中电流环仍采用常规PI调节,转速环改为模糊控制器与常规PI调节分时作用方式。仿真结果表明,引入模糊控制器的新系统响应速度高、过渡稳定、系统超调得到改善。     

基于模糊控制的双闭环直流可逆调速系统的设计

对于双闭环直流可逆调速系统,提出了一种将模糊控制与常规PI控制相结合应用在转速环调节器设计的方法。根据工程经验与专家知识所确定的模糊控制规则,进行模糊推理,实现转速环调节器参数的动态整定。应用Matlab软件构建了双闭环直流可逆调速系统的仿真模型,并对转速环分别采用模糊PI控制器和常规PI控制器的直流可逆调速系统分别进行仿真实验并对比结果。从仿真结果可以得出采用模糊控制可以对直流可逆调速系统的动态与静态特性、抗扰性能、恢复性能以及跟踪性能有比较明显的改善与提高。     

直流调速系统中常规PI 与模糊PI 控制器的比较

转速电流双闭环直流调速系统中的PI控制器直接影响其调速性能,利用MATLAB分别建立了由常规PI与模糊PI控制器组成的转速电流双闭环控制直流调速系统的仿真模型,并进行了仿真。仿真结果表明,模糊PI控制器与常规PI控制器相比具有更好的动态稳定性和跟踪性能,对外界干扰具有较强的鲁棒性。     

基于MATALB的无刷直流电机调速系统的调速特性分析

介绍了直流无刷电机的转速、电流双闭环直流调速系统的组成及数学模型,通过对该系统的动态特性和静态特性的分析得出,双闭环直流调速系统避免了在单环系统中存在的两种反馈牵制的缺陷,可以获得了良好的静、动态品质。同时,运用了Matlab软件对采用正弦脉冲宽度调制的直流无刷电机系统进行建模与仿真,观测双闭环系统稳态与动态以及有关控制参数变化的影响。最后,仿真结果证明采用正弦脉冲宽度调制技术对双闭环直流调速系统控制的有效性。     

基于单神经元PID的直流脉宽调速系统研究

针对传统直流调速系统存在因PID控制器参数固定而导致调速性能差的问题,提出了基于单神经元PID的双闭环直流脉宽调速系统的设计方法,即采用单神经元PID控制器替代传统的转速PI调节器,并用S函数编写该控制器的算法程序。Matlab仿真结果表明,基于单神经元PID的双闭环直流脉宽调速系统具有较快的响应速度和较强的抗干扰能力,调速性能得到了较好的改善。     

直流双闭环调速系统动态性能的仿真分析

本文阐述了利用数字仿真技术对现场广泛应用的可控硅直流电动机双闭环调速系统进行仿真分析,分别得出了电流调节器和速度调节器的参数与系统动态性能指标之间的关系,从而可以有效的指导实际系统的设计和调试。     

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.