基于灰色预测PID控制及LabVIEW的直流电机调速系统设计

针对目前伺服系统中速度环及电流环均采用模拟实现的不足,提出了一种基于灰色预测PID速度控制的直流电机数字调速系统,并利用LabVIEW完成调速测试平台。首先给出了数字双闭环调速系统的总体结构,并叙述了直流电机驱动电路原理;然后在灰色预测理论形成新误差序列的基础上导出了校正PID参数表达式;接着,对输出预测进行滤波处理,以消除预测值偏高的不足;在此基础上,给出了LabVIEW及硬件组成的调速测试平台实现方案;最后进行了测试实验,并对实验结果进行了分析。结果表明,采用灰色预测PID控制的调速效果有了较大提高。     

液压舵机伺服系统灰色预测模糊PID控制

研究灰色预测模糊PID控制在液压舵机伺服系统中的应用问题。由于液压舵机伺服系统具有典型非线性和不确定性,传统的PID控制很难满足控制要求。为解决这一问题,提出了灰色预测模糊PID控制方法。在SimuIink中搭建液压舵机伺服系统的模型并进行仿真,灰色预测模糊PID控制无超调,调节时间为0．008s,消除干扰使系统再次达到稳定的时间为0．045s。结果表明：灰色预测模糊PID控制与传统PID控制、模糊PID控制相比,能有效加快系统的控制速度,缩短调节时间,提高控制精度,具有较强的抗干扰能力。     

基于灰色预测PID的风光互补发电机控制研究

为了能够提高风光互补发电机控制的效果,深入地研究了灰色预测PID在风光互补发电机控制中的应用.构造了风光互补发电机的数学模型;剖析了灰色预测的基本原理.针对风光互补发电机控制的实际情况,将灰色预测PID技术引入到风光互补发电机的控制中,提出了风光互补发电机灰色预测PID控制系统,并且提出了相应的算法流程;分别利用灰色预测PID控制技术、模糊PID控制技术和传统PID控制技术对风光互补发电机进行控制仿真研究,仿真结果表明灰色预测PID技术可以获得较好的控制效果.     

基于灰色预测的自适应内模PID双重控制器设计

针对一类非线性系统,提出一种基于灰色预测的自适应内模PID双重控制方法.把由系统的输入输出数据得到的灰色预测模型作为系统的内部模型,并在基本的内模控制结构上增加PID控制器,加快了跟踪误差收敛速度, 内模控制的性能明显改善.仿真结果表明,该控制方法简单而有效, 内模PID双重控制较单一内模控制具有更好的系统性能.     

基于灰色预测PID球磨机负荷控制

为改善球磨机的负荷PID控制系统,提出了基于灰色预测PID控制的球磨机负荷控制方案。方案融合了灰色预测、常规PID控制这两者的设计思想;并将灰色预测在线应用,用其预测结果代替被控对象测量值进行控制运算。仿真结果表明,与传统的反馈方法相比,使用灰色预测PID控制器可得到更为优良的动态性能,具有鲁棒性好、跟踪快速等优点。     

气动位置伺服系统的非对称模糊PID控制

对于有杆气缸的非对称物理及摩擦力特性,提出了采用非对称模糊策略的模糊PID控制算法,较好地解决了有杆气缸由于左右两腔物理结构和摩擦力特性的不对称而造成运动过程中压力变化复杂的问题,改善了系统的动态响应性能.实验证明,采用非对称模糊策略的模糊PID控制可以明显地提高气动位置伺服系统的动态响应性能,系统具有较小的超调量和过渡过程时间,并获得了满意的重复稳态精度.     

灰色预测模糊自适应PID控制的城轨列车智能驾驶系统研究

为提高城轨列车驾驶系统的智能化程度,将灰色预测控制与模糊自适应PID控制技术相结合,应用到城轨列车驾驶系统中。在对城轨列车驾驶系统进行需求分析的基础上,针对其对各种性能指标的要求,提出了基于灰色预测模糊自适应PID控制的城轨列车智能驾驶系统的设计方案。将灰色预测控制与模糊自适应控制应用到经典PID控制中,设计出了系统的智能控制器,有效满足了城轨列车在运行时对跟踪误差、准点率、停车误差、舒适度和节能性等多个性能指标的要求。仿真结果表明:采用灰色预测模糊自适应PID算法的控制系统具有良好的控制精度且系统的智能化程度得到了相应的提升。     

机器人关节用高精度交流伺服系统研究与实现

机器人关节驱动要求满足响应速度快﹑运行稳定及精度高等性能指标,其关键是通过转矩控制及位置调节器设计来满足要求;首先针对非理想反电势的永磁交流伺服机,对转矩构成进行了推导,分析了转矩和反电动势、占空比的关系,提出了一种基于离线反电势测量实现了抑制转矩脉动的控制方法;其次,位置伺服采用了模糊自适应PID控制器实现位置的快速跟踪控制,采用此法能够克服单纯使用PID控制存在的超调和振荡,使系统输出超调明显减小,定位精度得到提高。在实验系统中,采用以英飞凌公司的XC167CI控制系统和功率MOSFET逆变器组成的伺服系统,实现了速度阶跃响应时间<20ms,速度稳定精度±2%,转矩精度±1%。整个过程速度响应迅速又运动平稳,位置能也迅速跟踪给定信号,且位置响应无超调;证明所提出的方法对于提高系统的性能是有效的,最后将其成功应用于自行研制的高压输电线巡检机器人控制系统中,获得了满意的效果。     

一种基于灰色系统理论的控制系统参数辨识算法的仿真研究

灰色预测补偿是一种对灰色系统进行白化的算法,该算法需要的信息少、计算量小。它可以克服常规PID控制存在超调的缺点。根据灰色PID控制算法,对系统不确定部分建立灰色模型,进行灰色预测补偿。通过仿真研究,该算法具有较强的鲁棒性,可以提高控制质量,减小控制系统的误差。     

多变量系统的PID 控制器设计

针对多输入多输出系统,提出一种基于微粒群算法的灰色系统预测PID 控制算法．该方案将多 输入多输出系统转化成若干个多输入单输出子系统,使用多变量一阶灰色模型GM(1;N) 预测出每个子系统的 输出,实现了多输入多输出系统的对角解耦．然后用微粒群算法优化PID 控制器的参数,用优化后的PID 控 制器对每个子系统进行控制．对两个典型的多变量控制过程进行了仿真,结果表明,这种控制方法超调量较 小,鲁棒性强,响应速度快,抗干扰能力强.     

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.