PID控制器设计与仿真研究

研究优化PID控制器性能问题,在过程控制中,系统存在纯滞后性、时变性、非线性的复杂系统,传统模糊控制和PID控制方法解决上述问题效果不佳,导致超调量大和调节时间长。为了解决控制系统中超调量大和调节时间长等难题,在Smith预估器和传统PID控制的基础上,结合模糊PID控制的优点,提出一种模糊PID-Smith的智能控制方法。方法通过对模型的纯滞后进行补偿,来减小纯滞后系统的超调量,从而增强系统的稳定性。通过对火电机组主汽温控制系统进行仿真,结果表明,方法降低了超调量,减少了调节时间,极大地改善了控制性能,提高了控制系统的自适应性和鲁棒性。     

模糊Smith在温控系统中的仿真研究

研究电厂锅炉温度优化控制问题,由于温度的稳定性受到多种因素的影响,所以温度控制系统是一个具有时滞性、非线性和时变性的复杂系统,传统PID控制和模糊控制难以建立精确的数学模型,控制系统的超调时间长,超调大.为了解决控制系统的超调时间长,超调大等问题,为了优化温控制系统,在传统PID控制和Smith预估计器的基础上,结合模糊控制系统良好非线性优点,提出模糊Smith的温控制系统.方法通过Smith预估器对模型的时滞性进行补偿,使时滞系统的超调减小,系统的稳定性增强.通过建立温控制系统数学模型并进行仿真实验,结果表明模糊Smith的控制方法降低了超调量,缩短了超调时间,有效提高了温控制系统的鲁棒性和抗干扰性.     

舰用恒压供水装置模糊PID控制器设计及仿真

舰用恒压供水装置可根据用水量自动变频及平滑加减泵,从而实现恒压供水.由于系统具有非线性、时滞性和时变性,建模和控制具有一定难度.传统的PID控制算法在应用中易引起响应速度慢、水泵在工作模式切换临界点附近反复启停等问题,控制效果较差.为解决上述问题,提出利用最小二乘系统辨识法,建立了某型舰用恒压供水装置系统模型,设计了模糊自整定PID控制器,并进行了仿真分析.仿真结果表明,上述设计的舰用恒压供水装置模糊自整定PID控制器控制效果较单纯PID控制具有适应性强、响应速度快、超调量小等优点.     

模糊PID 技术在焚烧系统中的研究与应用

复杂控制系统由于其非线性、滞后和参数时变性的特点,传统的PID控制技术难以获得满意的控制效果。以焚烧这一典型复杂控制系统为例,结合模糊控制理论,提出模糊PID控制技术,并利用MATLAB进行仿真。结果表明,模糊PID具有超调量小、稳定性好和适应性强等特点,达到预期的控制效果。     

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。     

基于智能PID的废水处理pH值控制系统的设计

针对废水处理中pH值对象的非线性、时变性以及不确定性等特点,设计的废水处理pH值控制系统采用的一种基于粒子群优化算法的智能PID控制方法,以STM32单片机作为处理器核心实现。介绍了控制对象的特性、智能控制算法、系统的工作原理、控制器设计实现方案,并给出了实验结果。结果表明：该控制系统弥补了常规pH控制的不足,获得了更好的控制效果,同时系统结构设计合理、成本低、实用性强,很好的满足了污水处理pH值自动化控制的要求。     

开关模糊神经PID控制的无刷直流电机仿真

无刷直流电机是一种时变性的、非线性的以及强耦合性的系统.对于控制精度要求高的场合,传统的PID控制难以满足对无刷直流电机控制的性能要求.模糊PID控制器虽然具有一定的自适应性,但是模糊规则主要靠经验制定具有一定局限性.为解决上述问题,研究了基于双闭环的开关模糊神经PID控制的无刷直流电机,该方法综合了模糊、神经网络和PID的优点,具有适应能力强,控制精度高,专家知识利用较好等.仿真结果表明模糊神经PID控制相对于模糊PID具有转速响应快、超调量小、抗干扰能力强等优点.     

废水中和过程的RBF神经网络预测控制

废水中和过程有较强的非线性、时变性和滞后特性,对于过程模型的辨识与控制较为困难,采用常规的线性化模型或传统PID控制方法存在模型过于复杂,算法难以在线实施,控制精度不能保证等问题,很难取得满意的控制效果、针对该问题,应用酸碱中和的强酸当量模型,提出了一种基于敏感度(Sensitivity Analysis,SA)和动态粒子群优化算法(Dynamic Particle Swarm Optimization,DPSO)相结合的RBF神经网络模型辨识方法,通过调整网络结构和辨识出系统的滞后时间来提高模型辨识效率和预测精度,将RBF神经网络辨识器与神经网络控制器相结合构成电厂废水处理pH中和过程的预测控制系统。经过仿真研究和试验验证,与电厂实际应用的PID控制方法相比较,该方法能有效地对pH值进行控制,并实现较小的控制误差和节约药剂的效果。     

基于模糊Smith方法的温控系统仿真研究

在过程控制中,经常会碰到纯滞后、时变、非线性的复杂系统,传统的模糊控制和PID控制方法解决上述问题效果不佳。为了解决控制系统中超调量大和调节时间长等问题,针对热疗温度控制对象的纯滞后特性,在Smith预估器和传统PID控制的基础上,结合模糊PID控制与模糊自适应Smith预估控制,提出模糊Smith智能控制方法。方法通过对模型的纯滞后进行补偿,来减小纯滞后系统的超调和增强系统的稳定性。通过建立热疗数学模型并进行仿真研究,结果表明无论在参数不变还是参数改变的情况下,方法在超调量和凋节时间等方面都有很大提高,极大地改善了控制性能,提高了温度控制系统的鲁棒性和抗干扰性。     

基于改进PID的恒温控制软件设计与实现

恒温控制环境中,存在随机性很强的温度跳变.为将温度控制在一定值,需要PID控制过程做出快速反应.但是针对非线性、滞后性和时变性的控制系统,PID需要大幅改变参数才能保证在跳变环境下的恒温控制,导致控制过程中的响应时间和超调量效果较差.提出基于改进PID的恒温控制软件设计方法,利用免疫控制的原理,将传统的PID控制方法与免疫控制原理相结合,对免疫参数η和K进行合理调整,在不同的免疫响应阶段,通过T细胞的促进和抑制作用,使得响应时间和超调量之间的矛盾得到极大的改善.通过冷库恒温控制系统的仿真实验表明,改进PID恒温控制软件在工况发生较大改变时仍然具有优良的控制效果.     

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.