基于蚁群算法的六自由度并联平台控制参数优化

由于PID控制具有高度的非线性、时变不确定性等特点,因此控制过程较为复杂。针对PID控制的关键问题——PID参数整定,设计了一套基于蚁群算法的PID参数优化系统。对六自由度并联平台控制参数优化进行了研究。蚁群算法是一种寻优简单、鲁棒性强、效率高的寻优方法。该算法可根据蚁群信息素反馈载体确定决策点。为了规划蚁群活动的行为方向,需要根据相应的信息素更新规则,对每只蚂蚁个体进行信息素的增量构建,以达到优化PID控制器三个参数的目的,进而消除系统参数不确定性对控制系统的影响。详细阐述了基于蚁群算法的六自由度并联平台的电液伺服PID控制参数优化。理论分析和实例仿真研究表明,提出的优化策略是有效、可行的。该方案不但降低了设计的难度,而且提高了控制系统设计的品质,在控制工程领域中有着十分广阔的应用前景。     

进化规划模糊算法在PID控制中的应用

针对非线性控制系统,利用进化规划模糊算法,对PID控制器规则基的参数进行离线优化,优化后的模糊控制规则可对系统实现实时控制。该控制算法无需任何先验知识和量化因子,具有很强的数据挖掘能力,且模糊规则基的寻优速度较快。通过对非线性系统进行仿真,验证了该算法的有效性,与传统固定参数PID控制方法及遗传算法整定参数PID控制方法相比,明显地提高了系统的稳定性和动态性能。     

改进蚁群神经网络及其在滞后系统中的应用

针对热连轧监控AGC系统具有多变量、强耦合、非线性、大滞后及参数时变的特点,提出了一种改进蚁群神经网络,采用动态局部信息素更新和自适应调节信息素挥发的全局信息素更新相结合的方式对蚁群算法进行了改进。并利用改进后的蚁群算法对神经网络权值和阈值进行优化,利用优化后的神经网络对PID控制器参数进行整定。改进的蚁群算法稳定性好,寻优效率高,避免了神经网络参数陷入局部极小等问题,从而实现大滞后系统的优化控制。仿真结果表明,在监控AGC系统中,在对象的滞后时间发生变化的情况下,基于改进蚁群神经网络的优化控制系统具有动态响应速度较快,对外部扰动具有良好的鲁棒性,使控制品质得到很大的提高。     

汽包水位粒子群-PID优化控制

对循环流化床锅炉汽包水位控制系统,采用串级三冲量PID控制,应用粒子群优化算法对PID控制器进行参数整定,并获得了最优参数。仿真结果表明,与传统整定方法相比,这种参数整定方案使汽包水位控制系统具有更好的控制品质,提高了系统的静动态特性。     

基于最大-最小蚂蚁系统的PID参数整定

PID参数是影响PID控制器控制效果的重要参数。本文提出一种基于最大-最小蚂蚁系统(MMAS)进行PID参数整定的新型算法MPID,并给出了MPID算法的具体实现步骤。实验仿真表明,MPID算法与基于遗传算法、基本蚁群算法的PID整定方法相比,优化效果有明显改善,说明了该算法的可行性和优越性。     

一种PID参数整定的粒子群优化算法

提出了一种PID控制器参数整定的粒子群优化算法。该方法首先通过定义一个包含系统超调量、上升时间和稳态误差指标项的适应度函数,并根据系统的实际控制要求对各指标项适当加权。之后由带收缩因子的粒子群算法对PID进行多目标寻优,从而实现PID控制器的自动参数整定。仿真结果表明,该方法优化得到PID控制器的综合性能优于常规方法得到的PID控制器。     

BP神经网络在PID控制器参数整定中的应用

研究工业控制过程,针对控制器优化问题,PID控制是迄今为止在过程控制中应用最为广泛的控制方法.但在实际应用中,对有非线性、时变性系统,无法建立精确模型.为了解决控制参数整定,达到精确控制,改善系统性能,提出一种基于BP神经网络的PID控制器参数整定方法.通过建立三层神经网络模型,在控制过程中将神经网络的隐含层单元分别作为PID的比例(P)、积分(I)、微分(D)单元,从而构造参数自学习的PID控制器,在控制过程中动态调整PID的三个控制参数,从而进行PID控制参数的在线整定.仿真结果表明,基于BP神经网络的PID控制方法在处理非线性和时变系统时,提高了实时性能,增强系统稳定性,并获得更好的控制效果.     

非线性系统的蚁群优化预测PID控制

针对非线性、时变及大惯性系统的控制问题,提出了一种基于蚁群算法的预测PID控制算法。该算法以神经网络作为预测模型,将预测控制和PID控制相结合,并用蚁群算法在线优化控制器参数,其中以常规的Ziegler-N ichols方法整定的控制器参数为基础,选取蚁群优化变量的动态搜索区间。该算法考虑了控制能量受限情况下,非线性系统的预测控制问题。计算机仿真结果表明,该非线性控制方案具有较好的鲁棒性,相对传统PID控制策略还表现出了良好的动态性能,能够满足对再热汽温对象的控制要求。     

基于改进粒子群算法的PID参数优化与仿真

提出了一种基于改进的粒子群优化（PSO）算法的PID控制器参数整定方法。该方法采用了PSO的惯性权值自适应调整机制和粒子种群的动态更新策略,用以加速优化算法的收敛和维持群体的多样性。与常规的PSO算法相比,该方法简单易行,更容易找到全局最优解,优化效率和性能明显提高。将该算法应用非最小相位、一阶滞后等系统的PID控制器参数的优化,能够使控制系统获得较好的动态特性和很强的鲁棒性。仿真实验表明了所提出算法的有效性和优越性。     

支持向量机在PID控制器参数整定中的仿真研究

PID控制是应用最为广泛的控制方法,由于系统中存在非线性和时变性,影响建立精确的模型,系统性能.为了解决控制参数整定,改善系统性能,提出一种基于支持向量机的PID控制器参数整定方法.通过将支持向量机和PID控制器相结合建立支持向量机的参数整定模型,在控制过程中将PID控制的参数作为支持向量机的输入,构造参数自适应学习的PID控制器,在控制过程中动态调整PID的三个控制参数,进行仿真的在线整定.仿真结果表明,支持向量机的PID控制方法在处理非线性和时变系统时,提高了实时性能,增强系统稳定性,并获得更好的控制效果,为通用非线性PID控制器设计提供了依据.     

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.