直流无刷电机控制器设计与仿真

关于无刷电机性能优化问题。无刷直流电机工作过程中电气参数具有非线性、时变性的特性,造成实时性差,由于传统的PID控制器的参数不能在线调整,在对其进行控制时存在鲁棒性差、精度低等缺点。为解决上述问题,提出将模糊自适应PID控制器应用于无刷直流电机的控制中,根据系统的转速偏差e和偏差变化率ec,经过模糊逻辑推理,动态自适应调整PID控制器的三个参数。在分析电机模型的基础上,借助在Matlab仿真平台设计了无刷直流电机模糊自适应PID控制器的仿真模型。结果表明:较之传统的PID控制器,模糊自适应PID控制器响应速度快、鲁棒性强、无超调、精度高,达到了较好的控制效果。     

基于模糊九点控制器的自适应控制系统设计方法研究

由于传统自适应PID控制算法在线调节PID的三个参数难度较大,现将模糊九点控制器加入到自适应控制系统中,根据系统偏差e和偏差变化率ec的不同,将系统状态分为九神情况,运用模糊九点控制器进行参数自整定,调节系统在不同状态下的控制特性.该控制方法不依赖数学模型,切实有效,具有稳定型好,调节精度高等特点,是一种表达人类控制思...     

通用测试转台控制系统的设计与研究

设计并研制了一款针对弹舱测试的通用型测试转台,并针对其在测试不同负载过程中所出现的系统振荡、系统响应时间长等问题进行了深入研究。提出了一种模糊自适应PID控制方法,以误差和误差变化率ec作为输入,利用模糊规则在线对PID参数进行修正以满足不同负载下的e和ec对PID参数自整定的需求,从而消除系统振荡并提高系统响应速度。通过进行系统建模及仿真,对比不同负载下的普通PID控制与模糊自适应PID控制的控制效果。由仿真分析可知,相对于普通PID控制,模糊自适应PID控制可以及时识别到负载的变化,从而相应地调节系统的PID参数,使系统保持一定的响应速度。     

基于FUZZY-PID直流调速系统的仿真与分析

针对常规PID在直流调速系统中控制参数难以整定等问题,在对直流调速系统建模的基础上,以偏差e和偏差变化率ec作为输入,找出常规PID的三个参数与e和ec之间的模糊关系,在运行中通过检测e和ec,根据模糊推理原理来对三个参数在线修改,从而满足不同时刻的e和ec对PID参数自整定的要求,以此设计了一种基于模糊控制原理的PID控制器,并对采用FUZZY-PID控制的直流调速系统的动态过程进行仿真分析.仿真结果表明:采用FUZZY-PID控制策略的直流调速系统响应快、超调较小、鲁棒性强,较传统PID控制具有更好的动、静态特性,这说明了这种控制策略的正确性和有效性.     

基于模糊自适应整定PID的活套高度控制系统

针对板带热连轧机传统活套高度控制策略存在的问题,提出用模糊自适应整定PID的控制策略．控制器输入取活套量的偏差e和偏差变化率ec,输出取PID控制器3个参数的修正量,从而实现了PID参数的在线自整定．通过MATLAB语言,进行了传统PID控制与模糊自适应整定PID控制动态性能的仿真比较,结果表明采用模糊自适应整定PID控制可明显提高活套高度控制系统的动态性能．     

基于模糊控制器的直流无刷电动机控制

利用自整定模糊-PID控制器实现对直流无刷电动机的控制.在分析直流无刷电动机数学模型的基础上,建立一种新型的三相直流无刷电动机数学模型,并将自整定模糊-PID控制器应用于直流无刷电动机的控制系统中.系统采用双闭环调速,电流环采用电流滞环控制,转速环采用自整定模糊-PID控制器,通过不断检测速度偏差e和速度偏差变化率ec,对参数KP,KI和KD进行在线校正,控制器参数随e和ec变化而变化,以提高系统的控制效果.研究结果表明,这种基于自整定模糊-PID控制器的直流无刷电动机控制系统具有响应快、超调小、控制精度高等特点,比传统PID控制器具有更好的静、动态特性.     

PID控制器改进方法研究

分析了常规PID(比例—积分—微分)控制特点,针对其在非线性控制中存在的问题,基于参数自整定和控制器误差组合方式,分别设计了参数自整定模糊PID控制器、参数自整定RBF神经网络PID控制器和非线性自抗扰PD控制器.并进行了实验验证,实验结果表明,从参数自整定和控制器误差组合角度出发,所采用的控制策略可使非线性系统具有较好的动态特性、鲁棒性和自适应能力.     

模糊逻辑在PID参数整定中的应用

PID控制是最早发展起来的控制策略之一,由于受到参数整定方法烦杂的困扰,常规PID控制器参数往往性能欠佳,对运行工作情况的适应性差。本设计将模糊控制和PID控制结合起来,构建自适应模糊PID控制器,实现PID参数的最佳调整。该模糊自整定PID控制器既具有PID控制器高精度的优点,又具有模糊控制器快速、稳态特性。     

基于多模型模糊自适应PID的无人机纵向姿态控制研究

针对无人机典型的非线性,且气动参数随着工作环境时变的问题,文中研究了基于模糊控制规则下的多模型模糊自适应控制方法,以实现对无人机纵向姿态控制;该方法对局部采用经典PID设计的子控制器进行加权处理,从而达到多控制器集的平滑切换,在利用S函数建立的无人机六自由度模型基础上进行控制仿真,得出仿真曲线;基于无人机纵向姿态俯仰角控制仿真结果表明,设计的多模型模糊自适应PID控制器具有较好的控制性能和鲁棒性。     

模糊自适应PID控制的研究及应用仿真

传统PID控制器参数的整定是在获取对象数学模型的基础上,根据某一整定规则来确定的,难以适应复杂多变的控制系统。针对其参数整定不良、性能欠佳,对被控过程的适应性差等缺点采用模糊控制与自适应PID控制结合起来,设计了模糊自适应PID控制器。利用模糊推理方法实现对PID参数的在线自整定,进一步完善PID控制器的性能,提高系统的控制精度。仿真结果表明该模糊自适应PID控制器既具有PID控制器高精度的优点,又具有模糊控制器快速、适应性强的特点,使被控对象具有良好的动、稳态特性,有较好的工程应用前景。     

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.