基于无传感器控制技术的永磁同步电机驱动系统转矩控制

传统方法在进行永磁同步电机驱动控制时,存在电机驱动转矩脉动大,频率不恒定的问题.为此,本文引入无传感器控制技术,对电机驱动系统转矩进行控制.仿真实验表明,本文方法能够大幅降低驱动系统转矩脉动,保证了开关频率恒定,实用性强.     

基于余弦反比气隙磁场的交流永磁同步电机

通过永磁电机径向结构分析与设计获得余弦反比气隙磁场,改进交流永磁同步电机低速大转矩性能,提高交流永磁电机永磁电机性能。对于电机气隙机械结构机理设计给出量化讨论。本设计已经提出发明专利请求书。     

基于负载角限制的永磁同步电机模型预测控制

针对永磁同步电机电磁转矩与负载角之间强耦合及非线性的关系,并就传统直接转矩控制容易失步的问题,该文提出了一种负载角限制的策略。基于直接转矩控制基本原理对电机失步原因进行研究,重点分析负载角与转矩之间的关系,提出了对负载角限制避免电机失步的控制思想。详细介绍了基于永磁同步电机的模型预测数学模型,考虑到消除系统预测误差加入了控制延时补偿。最后通过评价函数有效地限制了电机转矩和磁链脉动,直接限制负载角确保了电机的稳态运行。通过仿真分析可看出该文提出的方案有效可行,在保持快速响应的情况下,降低了转矩和电流脉动,避免了电机失步的风险。     

基于自适应粒子群优化算法的永磁同步电机参数辨识

永磁同步电机广泛应用于工业驱动系统中,开展永磁同步电机参数在线辨识对实现电机高性能控制和可靠状态监测具有重要意义.针对永磁同步电机动态数学模型具有非线性、多参数、强耦合等特点,从电气系统和机械系统两方面建立了永磁同步电机数学模型,针对参数辨识问题的特点,提出了一个惯性因子的自适应公式,在此基础上,建立了以粒子群算法为框架的自适应粒子群优化算法,对永磁同步电机定子电阻Rs和负载转矩TLd进行了在线辨识,并基于实验平台验证了辨识结果.研究结果表明:自适应粒子群优化算法通过不超过20次迭代就可以发现最优参数,模型参数的估计值和测量值匹配良好,该算法可在其他类型电机的参数辨识中推广应用.     

电动汽车中永磁同步电机转速的控制

为了更好地实现对以永磁同步电机为驱动电机的电动汽车车速的控制,设计了一套基于滑模控制的永磁同步电机控制系统,并且在此基础上加入最大转矩电流比控制,对滑模控制和最大电流转矩比控制的数学模型进行了分析.仿真分析表明,加入最大转矩电流比的滑模控制系统不会受到外界变化影响,永磁同步电机能够稳定运行.同时系统响应更快,抗干扰能力大大提高,鲁棒性更强.     

永磁同步双转子/双定子电机控制策略

针对混合动力电动汽车的永磁同步双转子/双定子电机的驱动控制,依据该型电机的特点,对内部电机的运行过程进行研究,通过分析提出一种控制策略.该策略以内部电机发电工作为分界点,结合负载所需求的转矩和转速,使内外电机配合工作,从而使发动机工作在给定的转矩和转速下,不随负载的变化而变化.该研究为将永磁同步双转子/双定子电机运用到混合动力电动汽车的驱动中提供了参考.     

带神经网络观测器的永磁同步电机极点配置自校正前馈控制

由递归神经网络构成综合负载转矩观测器,从而把综合负载转矩视为可测干扰,并利用极点配置自校正前馈控制策略实现了永磁同步电机的速度控制,解决了永磁同步电机系统中参数变化和负载扰动等不确定性问题.仿真结果表明该方法具有较强的鲁棒性.     

基于负载转矩反馈的永磁同步电机动态面控制

针对永磁同步电机在运行过程中因负载变化,使控制系统性能下降的的问题,提出一种负载转矩反馈的永磁同步电机动态面控制策略.建立了永磁同步电机的数学模型,定义一种新型的状态变量方程,并设计了一种新型动态面滑模控制器,使用一种指数收敛的干扰观测器得到负载转矩反馈量,实现了永磁同步电机的高精度控制.仿真结果表明,新型控制策略可以有效地提高控制系统的控制性能,与线性自抗扰控制策略相比,负载变化时转速波动更小,恢复时间更短.     

采用双自由度PI速度控制器的PMSM矢量控制仿真研究

分析了永磁同步电机的数学模型.采用励磁电流id=0的转子磁场定向矢量控制方法,在Matlab/Simykuink环境下构建了永磁同步电机(PMSM)矢量控制仿真模型.针对常规PI控制无法满足当电机转速和负载转矩发生阶跃变化时,电机动态响应曲线中转速超调量小和转速恢复施加短的要求,提出了一种双自由度PI速度控制方法.仿真...     

具有死区补偿的自抗扰控制下PMSM转矩脉动抑制方法

空间矢量脉宽调制死区效应对永磁同步电机(PMSM) 的调速控制系统及转矩脉动有一定影响, 为了削弱其不利作用, 在永磁同步电机矢量控制基础上, 提出一种新型的具有死区补偿的自抗扰PMSM控制方案, 针对传统自抗扰控制策略下电机转矩脉动较大的缺陷, 在原有的自抗扰控制策略中加入死区补偿. 仿真及实验结果表明, 具有死区补偿的自抗扰PMSM驱动系统, 谐波含量明显减少, 速度驱动系统更加平稳, 有效抑制了转矩脉动.

     

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     

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.     

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。