基于神经网络的非线性扩张状态观测器

自抗扰控制方法是一种新型的非线性设计方法,在自抗扰控制器中主要存在着确定待定参数的问题;非线性扩张状态观测器是自抗扰控制器的核心,在研究非线性扩张观测器中的参数整定问题时,将神经网络的思想引入参数整定,提出了基于神经网络的非线性扩张状态观测器的设计方法,运用该方法可以对任意阶的非线性扩张状态观测器进行参数设计;大量仿真算例表明,设计出的观测器具有良好的鲁棒性,有一定工程应用参考价值.     

内模控制框架下时延系统扩张状态观测器参数整定

作为一种有效的控制设计方法, 自抗扰控制研究获得了广泛关注, 然而针对自抗扰控制器的参数整定方法则相对较少. 本文针对一阶惯性加延迟系统, 将线性自抗扰控制转化为内模控制结构, 导出了其中控制器、滤波器、乘性不确定性、互补灵敏度函数的对应表达式, 随后, 利用频域鲁棒稳定性判据, 分析了自抗扰控制器核心—–扩张状态观测器的参数对闭环系统稳定性的影响. 基于该分析, 总结出一阶惯性加延迟系统扩张状态观测器的两条参数整定准则. 数值仿真结果验证了该整定准则的有效性.     

基于最小拍观测器的自抗扰控制器设计与性能分析

自抗扰控制器设计中,扩张状态观测器需要较高的观测带宽,才能更快的观测出状态变量.本文采用最小拍观测器,使得其具有最快的观测速度.以2阶系统为例,得到了离散系统下,基于最小拍观测器的自抗扰控制器的等价复合控制模型,其开环补偿器等价为超前校正器.仿真结果表明,基于最小拍观测器的自抗扰控制器可以最快的观测出系统状态变量,且控制器带宽的选取一般应小于采样周期的倒数.由于不再需要设计观测器带宽,从而简化了参数设计.     

一类混沌系统的状态观测与控制

基于混沌系统运动的有界性,使得不依赖于对象模型的扩张状态观测器可用于一类混沌系统的状态观测。只要扩张状态观测器充分观测到混沌系统的状态,自抗扰控制器就可以控制混沌系统,几个混沌数值仿真表明了扩张状态观测器和自抗扰控制器可有效地用于混沌系统的观测和控制。     

基于自适应神经模糊推理系统的船舶航向自抗扰控制

在实际的船舶航向控制中,航向系统在受到外界风浪干扰时表现出的模型非线性和参数不确定性,为航向控制器的设计带来了困难。针对该问题,设计了常规的线性自抗扰控制器和两种在线学习的自抗扰控制器。利用自适应神经模糊推理系统(ANFIS)实现自抗扰控制器参数的在线调整,设计了自适应PD的自抗扰控制器和自适应扩张状态观测器(ESO)的自抗扰控制器;分别在船舶受到外界扰动和参数摄动的两种情况下进行了仿真,仿真表明自适应自抗扰控制器控制效果更好,抗扰能力更强,表现出较强的鲁棒性。     

用模型补偿自抗扰控制器进行参数辨识

自抗扰控制器中扩张状态观测器的输出提供了进行系统参数辨识的足够信息,受控对象若有已知部分,把此部分补偿给扩张状态观测器输入项,能提高扩张状态观测器的逼近精度,从而也能提高其输出值来进行参数辨识的精度。     

基于高阶控制器设计的线性自抗扰控制参数调整

将反馈控制器/扩张状态观测器闭环极点配置在同一位置是线性自抗扰控制器(linear active disturbance rejection control,LADRC)最常用的整定方法.该方法只需调整两个参数,在工程应用上极为方便.但是,由于极点配置在同一位置的限制,整定的LADRC可能达不到期望的性能.本文提出以现有控制器参数为基础的LADRC调参方法.该方法以现有控制器参数为基础,通过降阶及逼近,保证LADRC控制能接近现有控制系统的性能.仿真设计表明采用高阶控制器设计的LADRC可以取得与原有控制系统相当的控制性能.该方法不受带宽法调参的需使反馈控制器及扩张观测器极点配置在同一位置的限制,因此可以期望获得比带宽法更好的性能.同时,该方法为已经熟悉掌握其他控制器设计方法的工程控制人员提供了一种便捷的调整线性自抗扰控制参数的方案,具有较好的应用价值.     

航天器姿态自抗扰控制

为抑制航天器自身结构参数变化和内外扰动对姿态控制精度和姿态稳定度的影响, 设计了航天器姿态自抗扰控制器. 自抗扰控制器(ADRC)由跟踪微分器(TD)、扩张状态观测器(ESO)和姿态反馈控制器(AFC)3部分组成.跟踪微分器负责安排姿态指令过渡过程, 并提取其微分信号. 扩张状态观测器(ESO)充分利用姿态敏感器与速率陀螺的量测信息, 可对航天器姿态及内部和外部干扰进行观测. 姿态反馈控制器则在补偿ESO估计的干扰的同时,实现航天器的姿态控制. 与已有研究相比, 扩张状态观测器采用复合量测信息对状态估计进行校正, 性能较好. 而自抗扰控制器只采用一个环路即可实现姿态控制及干扰补偿, 结构简单. 对某航天器姿态控制系统的仿真结果表明,以上自抗扰控制器是可行的.     

二阶自抗扰控制器的参数简化

为了克服PID控制器自身具有的缺陷，在PID的基础上提出了自抗扰控制器（ADRC）。该控制器由跟踪微分器、扩张状态观测器和非线性状态误差反馈三部分组成，其控制效果优于经典PID控制器，但是参数众多、调节复杂。通过线性简化和参数整合建立简化的线性自抗扰控制器。MATLAB仿真表明，简化的线性自抗扰控制器参数调节过程大大简化，而控制性能并未受到明显影响。     

基于自适应免疫整定的机器人无标定自抗扰视觉伺服控制

研究了机器人无标定自抗扰视觉伺服控制问题. 针对系统中所用的自抗扰控制器参数选取困难问题, 提出了基于自适应免疫算法的自抗扰控制器参数整定方法. 证明了系统中所用的非线性离散二阶扩张状态观测器稳定的充要条件, 并将该条件应用在参数整定过程中. 6 自由度工业机器人的实验结果表明了该方法的可行性和有效性.     

煤矿井下安全监控分站的设计及其仿真实现

为了设计一种具有低成本、低功耗、易操作、功能强且可靠性高的煤矿井下安全分站,针对煤矿安全生产实际,文章提出了采用MCS-51系列单片机为核心、具有CAN总线通信接口的煤矿井下安全监控分站的设计方案;首先给出煤矿井下安全监控分站的整体构架设计,然后着重阐述模拟量输入信号处理系统的设计过程,最后说明单片机最小系统及其键盘、显示、报警、通信等各个组成部分的设计;为验证设计方案的可行性与有效性,使用Proteus软件对设计内容进行仿真验证,设计的煤矿井下安全监控分站具有瓦斯、温度等模拟量参数超标报警功能和电机开停、风门开闭等开关量指示功能;仿真结果表明:设计的煤矿井下安全监控分站具有一定的实际应用价值.     

View-based model-driven architecture for enhancing maintainability of data access services

In modern service-oriented architectures, database access is done by a special type of services, the so-called data access services (DAS). Though, particularly in data-intensive applications, using and developing DAS are very common today, the link between the DAS and their implementation, e.g. a layer of data access objects (DAOs) encapsulating the database queries, still is not sufficiently elaborated, yet. As a result, as the number of DAS grows, finding the desired DAS for reuse and/or associated documentation can become an impossible task. In this paper we focus on bridging this gap between the DAS and their implementation by presenting a view-based, model-driven data access architecture (VMDA) managing models of the DAS, DAOs and database queries in a queryable manner. Our models support tailored views of different stakeholders and are scalable with all types of DAS implementations. In this paper we show that our view-based and model driven architecture approach can enhance software development productivity and maintainability by improving DAS documentation. Moreover, our VMDA opens a wide range of applications such as evaluating DAS usage for DAS performance optimization. Furthermore, we provide tool support and illustrate the applicability of our VMDA in a large-scale case study. Finally, we quantitatively prove that our approach performs with acceptable response times.     

A pragmatic multi-method investigation of discrepant technological events: Coping,attributions, and ‘accidental’ learning

Discrepant technological events or situations that entail a problem, a misunderstanding or a difficulty with the Information Technology (IT) being employed, are common in the workplace, and can lead to frustration and avoidance behaviors. Little is known, however, about how individuals cope with these events. This paper examines these events by using a multi-method pragmatic approach informed by coping theory. The results of two studies – a critical incident study and an experiment – serve to build and test, respectively, a theoretical model that posits that individuals use a variety of strategies when dealing with these events: they experience negative emotions, make external attributions, and adopt engagement coping strategies directed at solving the event, eventually switching to a disengagement coping strategy when they feel they have no control over the situation. Furthermore, users’ efforts may result in ‘accidental’ learning as they try to overcome the discrepant IT events through engagement coping. The paper ends with a discussion of the results in light of existing literature, future opportunities for research, and implications for practice.     

Call for Papers The 6^th International Conference on Grid and Cooperative Computing

Recent years have seen rapid advances in various grid-related technologies, middleware, and applications. The GCC conference has become one of the largest scientific events worldwide in grid and cooperative computing. The 6th international conference on grid and cooperative computing (GCC2007) Sponsored by China Computer Federation (CCF),Institute of Computing Technology, Chinese Academy of Sciences (ICT) and Xinjiang University ,and in Cooperation with IEEE Computer Soceity ,is to be held from August 16 to 18, 2007 in Urumchi, Xinjiang, China.     

The Distributed Time-Triggered Simulation Scheme: Core Principles and Supporting Execution Engine

Distributed real-time simulation is a young technology field but its practice is under increasing demands. In recent years the author and his collaborators have been establishing a new approach called the distributed time-triggered simulation (DTS) scheme which is conceptually simple and easy to use but widely applicable. The concept was initiated in the course of developing a new-generation object-oriented real-time programming scheme called the time-triggered message-triggered object (TMO) programming scheme. Some fundamental issues inherent in distributed real-time simulation that were learned during recent experimental studies are discussed along with some approaches for resolving the issues. An execution engine developed to support both the TMOs engaged in control computation and the TMOs engaged in DTS is also discussed along with its possible extensions that will enable significantly larger-scale DTSs.     

Software-Konfigurationsmanagement in großen Softwareprojekten

Zusammenfassung Mit zunehmender Größe der Softwaresysteme verschärfen sich die für die Software-Herstellung typischen Probleme: Beherrschen großer Objektmengen, Erhalten der Systemkonsistenz, Kontrolle der ständigen Änderungseinflüsse und Gewährleisten einer langen Lebensdauer. Die Disziplin Konfigurationsmanagement bildet den methodischen Ansatz, diese Probleme besser zu beherrschen. Software-Konfigurationsmanagement faßt die Herstellung von Softwaresystemen als eine Abfolge von kontrollierten Änderungen an gesicherten Zwischen- und Endergebnissen auf. Dargestellt werden die Objekte und Funktionen des Software-Konfigurationsmanagements sowie die hierfür in großen Software-Projekten benötigten Methoden, Instanzen und Hilfsmittel.     

Information for Authors

正http://www.zju.edu.cn/jzus http://www.springerlink.com Aim The Journals of Zhejiang University-SCIENCE(A/B/C)are edited by the international board of distinguished Chinese and foreign scientists,and are aimed to present the latest developments and achievements in scientific research in China and     

Editorial:Brain-machine interface(BMI) and cyborg intelligence

正Brain-machine interfaces(BMIs)aim at building a direct communication pathway between the brain and an external device,and represent an area of research where significant progress has been made during the past decade.Based on BMIs,mind information can be read out by neural signals to control     

Information for Authors

正http://www.zju.edu.cn/jzus http://www.springerlink.com Aim The Journals of Zhejiang University-SCIENCE(A/B/C)are edited by the international board of distinguished Chinese and foreign scientists,and are aimed to present the latest developments and achievements in scientific research in China and overseas to the world’s scientific circles,especially to stimulate     

SCIENCE CHINA Information Sciences SUBJECT INDEX TO VOLUME 57(2014)

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