小型无人机纵向姿态模糊自适应PID控制与仿真

针对某小型实验无人机智能自主飞行的要求,提出了一种无人机纵向姿态的模糊控制方法,设计了模糊自适应PID控制器,可有效实现该无人机的纵向姿态控制和纵向航迹跟踪.仿真结果表明,所设计的模糊自适应PID控制器较传统的PID控制器具有更好的控制性能,其响应快、超调小、精度高,而且鲁棒性和自适应能力也较强,可满足自主飞行的要求.     

基于改进跟踪微分器与前馈的模糊自适应PID控制

经典PID控制器在工程领域应用广泛,但其快速性和超调量之间不能很好地实现协调控制,且误差信号在经典意义上不可微,导致微分难以被有效利用。基于此,在典型跟踪微分器研究的基础上,采用一种具有良好的动态响应和滤波功能的改进非线性跟踪微分器对输入信号进行快速、无超调跟踪。并结合前馈控制和模糊自适应PID控制提升系统的稳定性和快速性,设计了一种基于改进跟踪微分器与前馈的模糊自适应PID控制器。以移相全桥变换器为控制对象,用经典PID与其进行对比分析。仿真与实验波形分析发现,所提控制器的鲁棒性更高,同时可将调节时间缩短至40%,响应速度也更快。     

基于灰色预测模糊PID算法的空调房间温度控制

针对中央空调系统房间温度控制系统的大惯性、纯滞后和时变性特点,设计了将等维新息灰色预测控制与模糊自整定PID相结合的新型控制器,建立中央空调房间温度控制系统的数学模型,介绍灰色预测模糊PID控制器结构,并对该控制方案进行了数字仿真。仿真结果表明,该控制器比PID控制器、模糊PID控制器有更多优越性,调节迅速,超调小,有更好的动、静态性能,具有一定的可行性。     

胎面生产线辅线速度链模糊自适应PID控制

针对常规PID控制在胎面挤出联动生产线辅线速度链整定中,参数整定不尽人意的问题,设计出一种基于模糊控制理论的自适应PID控制器。通过建立模糊控制规则和进行模糊推理来确定PID的参数,实现对辅线速度的调节。利用Matlab的模糊逻辑控制工具箱对算法进行仿真,仿真结果表明,该控制器与常规PID控制器相比,具有调节时间短、超调量小、跟踪调节性能好、鲁棒性等优点。实践证明,这种模糊自适应PID控制器比常规的PID控制器具有更好的控制特性。     

新型模糊PID控制及在HVAC系统的应用

为了推广模糊控制器在非线性系统中的应用,提出一种利用PID控制器的参数优化和调节模糊控制器的新型设计方法.通过模糊控制器的结构分析建立与PID控制之间的精确解析关系之后提出基于PID控制增益因子的模糊控制器设计算法,然后利用改进的变论域思想进一步优化模糊控制器设计参数.将其应用于暖通空调(HVAC)系统的节能控制中并与常规PID控制器相比较,仿真和实验结果表明这种模糊控制器具有超调量小、跟踪迅速、鲁棒性强等优越的控制性能.     

基于模糊神经网络PID控制器的EEC数字化设计

为实现航空发动机模拟式电子控制器(EEC)的数字化设计,以其低压压气机导流叶片调节通道为主要研究对象,提出一种模糊神经网络PID控制器,将模糊控制、神经网络、PID控制相结合,利用模糊控制专家经验优势和神经网络的自学习、自适应能力,优化PID控制参数,实现控制性能提升。仿真结果显示,基于模糊神经网络的PID控制器控制性能有较大提高,具有比常规神经网络PID控制器更小的超调量和更好的抗干扰性;适用于定常系统和非定常系统,具有更好的自适应性与鲁棒性;可应用于航空发动机模拟式电子控制器(EEC)的数字化设计。     

磁悬浮轴承系统的模糊控制仿真

以磁悬浮轴承系统的组成及工作原理为基础,应用模糊控制方法在MATLAB中建立了模糊控制模型,并运用SIMULINK软件建立了磁悬浮系统的仿真模型,仿真结果表明,该模糊控制器模型控制响应时间短,鲁棒性好,超调量小。     

基于自适应的大气相干长度测量仪控制系统设计

通过跟踪移动信标来测量大气湍流参数时,高精度的伺服控制技术是影响其测量精度的主要因素之一;在常规PID 控制的基础上,从自适应的角度出发,设计了一种适用于相干长度测量仪的且参数可自整定的控制器;当系统受扰动作用或系统运行状态变化时,在对系统不断辨识的基础上,依据性能指标,配置期望极点,实时调整控制器的参数值,实现系统的自适应,改善系统的鲁棒性;仿真及实验结果表明,采用自适应PID控制,在常值干扰下,系统的超调量减少26%,调节时间缩短1.28 s;跟踪20 mrad/s的目标时,系统的脱靶量峰峰值减小41.78%,稳态误差减小29.3%。相较于常规PID控制器,自适应PID控制器可减小超调量,缩短调节时间,优化跟踪性能,控制效果更好。     

基于模糊PID控制的太阳能电池板跟踪系统

由于太阳能电池板跟踪系统具有非线性的特点,使得利用简单模糊控制和传统PID控制精度不高,因此,文中提出利用模糊PID控制器实现对跟踪系统的控制,并设计了模糊PID控制器。通过SIMULINK对系统进行仿真,其结果表明：该控制方法调节精度较高、动态响应快、超调较小。     

基于RBF神经网络自适应PID四旋翼飞行器控制北大核心CSCD

四旋翼飞行器具有高非线性、强耦合、欠驱动等特点,飞行控制器设计困难。首先根据牛顿欧拉方程建立系统动力学模型;然后根据系统动力学模型推导出控制器设计模型,根据系统模型设计出串级控制策略以实现对系统姿态控制和位置控制的解耦;最后针对四旋翼飞行器的控制难点提出了基于RBF的多变量神经网络自适应PID控制方法。该方法具有神经网络自学习、自适应的能力,同时具有一定的非线性控制作用。仿真结果表明,该方法相对于常规PID控制方法具有更短的调节时间、更少的超调量、更好的抗扰动能力,同时,在模型参数变化的情况下该控制器比常规PID控制器的鲁棒性更强。     

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.