基于干扰观测器的高速列车RBF自适应滑模控制方法

针对高速列车动力学模型的不确定性和存在外部干扰难以实现高速列车对目标轨迹的高精度跟踪控制的问题,设计了一种基于非线性干扰观测器的RBF神经网络自适应滑模控制方法。首先,针对高速列车模型非线性系统的不确定性问题,设计自适应RBF神经网络鲁棒控制器进行跟踪控制,基于RBF神经网络的特性设计神经网络权值自适应律,对列车模型中的未知函数进行估计。其次,针对高速列车跟踪控制外部干扰问题,采用指数收敛干扰观测器进行干扰补偿,提高高速列车对目标轨迹追踪的抗干扰能力。最后,李雅普诺夫(Lyapunov)稳定性分析保证了闭环系统的渐近稳定性,以秦沈客运专线为仿真对象。结果表明,所设计的控制方法不仅解决了列车模型未知阻力部分的自适应逼近,而且在此基础上引入干扰观测器对外部非线性干扰进行补偿实现了对期望轨迹的高精度快速跟踪。     

船舶航向控制的多滑模鲁棒自适应设计

针对带有未知虚拟控制增益和常参数不确定的非匹配不确定船舶航向非线性控制问题,设计了一种新的多滑模鲁棒自适应控制算法.该算法利用神经网络来逼近系统模型的不确定性;应用逐步递推的多滑模控制算法降低了控制器的复杂性;尤其是采用Nussbaum函数处理系统中符号未知的问题,避免了可能存在的控制器奇异值问题;然后借助Lyapunov稳定性分析方法,理论分析证明了所得闭环系统全局一致最终有界,且跟踪误差收敛到零.仿真试验结果表明,该方法具有较好的控制效果.     

电液负载模拟器的自适应滑模控制方法

针对电液负载模拟器存在的系统非线性、不确定性和强干扰的控制难点,设计了自适应滑模控制方法.设计积分滑模以降低控制器对期望跟踪轨迹高阶导数的要求;设计动态滑模算法抑制抖振;采用小脑模型关节控制器(CMAC)在线学习系统不确定性以降低控制器参数设计的保守性.设计了自适应滑模控制律,给出了CMAC神经网络权值调整算法,证明了控制器的稳定性,以确保系统稳定且输出跟踪误差渐近收敛于零.仿真结果证明了控制策略的有效性.     

基于神经网络的不确定机器人自适应滑模控制

提出一种机器人轨迹跟踪的自适应神经滑模控制。该控制方案将神经网络的非线性映射能力与变结构控制理论相结合,利用RBF网络自适应学习系统不确定性的未知上界,神经网络的输出用于自适应修正控制律的切换增益。这种新型控制器能保证机械手位置和速度跟踪误差渐近收敛于零。仿真结果表明了该方案的有效性。     

基于扩张状态观测器的UCAV自适应滑模控制

针对固定翼UCAV（Unmanned Combat Aerial Vehicle）系统中存在的不确定性和外部扰动，设计了一种基于扩张状态观测器的自适应超扭曲滑模控制器用来抑制系统扰动，从而提高对于UCAV的控制性能。建立固定翼UCAV的六自由度非线性模型，针对姿态控制和速度控制分别设计扩张状态观测器对模型中难以精确测量的状态量和外部扰动进行估计，依据奇异摄动原理分别对姿态和速度设计自适应超扭曲滑模控制器，实现对UCAV的姿态和速度的跟踪控制。采用某型固定翼UCAV非线性模型对所设计的控制器进行仿真验证，并且与传统的自抗扰滑模控制方法进行了对比，仿真结果表明，基于扩张状态观测器的自适应超扭曲滑模控制器具有更小的超调量和稳态误差。     

严格反馈非线性系统的自适应神经网络输出反馈控制

基于非线性反馈函数,文章设计神经网络状态观测器,解决一类非线性系统的输出反馈控制问题.非线性反馈神经网络观测器在系统存在不确定性函数的情况下实时估计系统状态.利用所获得的状态信号,设计了自适应神经网络动态面控制器,同时保证了闭环系统的稳定性和所有信号的有界性.通过调节设计参数的取值能够达到期望的闭环跟踪性能.数值仿真表明,所设计的状态观测器不需要对原系统做状态变换,能够克服输出反馈滑模控制器带来的抖震问题.     

非完整移动机器人的神经网络鲁棒自适应控制

在非完整移动机器人轨迹跟踪问题中,针对机器人运动学与动力学模型的参数和非参数不确定性,提出了一种混合神经网络鲁棒自适应轨迹跟踪控制器,该控制器由运动学控制器和动力学控制器两部分组成;其中,采用了参数自适应的径向基神经网络对运动学模型的未知部分进行了建模,并采用权值在线调整的单层神经网络和自适应鲁棒控制项构成了动力学控制器;基于Lyapunov方法的设计过程保证了系统的稳定性和收敛性,仿真结果证明了算法的有效性。     

一类不确定非线性系统的鲁棒自适应控制

针对一类具有一般不确定性和未知参数的非线性系统,设计出一种适用于输出跟踪 的鲁棒自适应控制器.该控制器对系统的参数和状态的不确定性具有鲁棒性,能保证闭环系 统的全局稳定性,并解决了ε-跟踪问题.仿真实例表明,所设计的鲁棒自适应控制器具有良好 的跟踪性能.     

基于滑模变结构的空间机器人神经网络跟踪控制

研究了在无需模型估计值的情况下不确定空间机器人轨迹跟踪问题,提出了滑模变结构的神经网络控制方案.首先基于Lyapunov理论设计了一种径向基函数（RBF）神经网络控制器来补偿系统中的未知非线性,该神经控制器能够保证闭环系统的稳定性,而通过利用饱和函数把神经网络和滑模控制结合起来的控制器来不仅可以进一步削弱滑模控制输入的抖振,且当神经网络控制器无效时仍能保证系统鲁棒性.仿真结果证明了该控制器能在初期及强干扰情况下均能达到较好的控制效果.     

一类不确定非线性系统的输出反馈鲁棒自适应控制器的设计与分析

考虑一类具有三角形结构和参数未知的不确定性非线性系统 (1). 首先设计出一个稳定的滤波器, 从而获得状态的实时估计 ;然后依此设计出一种用于跟踪参考信号的输出反馈自适应控制器. 该控制器对系统的参数和状态的不确定性具有鲁棒性, 能保证所建立的闭环系统的全局稳定性, 并解决了ε 跟踪问题. 仿真结果表明, 所设计的自适应控制器具有良好的跟踪性能, 而且控制量在允许控制的范围之内.     

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。     

基于QTE的蒙古文显示机制研究与实现

蒙古语言是中国蒙古族使用的通用语言,由于蒙古文区别于其他文字的书写方式和其自身变形机制等特点,在很多通用的文字处理引擎中都不被支持。在嵌入式产品开发与应用领域中Linux加QTE已经成为流行方式。该文给出了一种在QTE环境上实现基于标准Unicode的蒙古文点阵显示和变形算法, 并自定义了支持蒙古文的QTE组件,扩展了QTE功能,为在Linux加QTE方式的嵌入式体系结构中处理蒙古文提供了一种解决方法。