H_∞混合灵敏度方法在大包线飞控系统中的应用

针对现代飞机飞行包线的不断扩展,当前飞控系统设计中一个非常重要的问题就是要实现全包线飞行控制功能。为了获得大包线飞行范围模型参数变化系统良好的操纵品质,在给定飞行包线内选取标称设计点,应用基于H_∞混合灵敏度方法,设计大包线范围内的俯仰角运动的H_∞鲁棒控制器,并选取验证点对设计出的控制器进行验证。仿真结果表明,所设计出来的飞行控制系统在大包线范围内具有良好的鲁棒稳定性,还具有很好的鲁棒性能。     

航空发动机四输入四输出H∞控制与仿真

随着对航空发动机性能要求的不断提高,发动机控制系统逐渐发展成为多变量控制系统.为提高静态稳定性和动态品质性能,根据发动机的工作原理确定发动机的四输入四输出变量,并建立航空发动机四变量小偏差状态变量模型,将H∞混合灵敏度设计方法应用于航空发动机多变量控制中,通过加权阵的选取获得了满足性能指标要求的航空发动机H∞鲁棒控制器进行仿真,仿真结果表明,控制系统不仅在标称设计点满足各项性能指标要求,且在整个飞行包线内具有鲁棒稳定性和鲁棒性能.     

自抗扰实现飞翼布局无人机全包线飞行控制

本文以大展弦比飞翼布局无人机为研究对象,基于线性自抗扰控制(linear active disturbance rejection control,LADRC)理论设计了包含内环姿态控制和外环轨迹控制的全包线飞行控制器.在姿态控制中,提出一种抗时滞LADRC控制方法,可以有效解决控制延迟和执行机构动态特性引起的LADRC响应振荡;在轨迹控制中,考虑飞翼布局无人机的气动特性,分别设计了高度、航向、侧向偏离等常用飞行模态的跟踪控制器.仿真结果表明,在气动参数存在不确定性及强风干扰的全包线环境中连续飞行时,所设计的控制器具有较好的控制性能和较强的鲁棒特性.与常规全包线控制方案相比,本文设计的全包线飞行控制器待整定参数较少,参数整定过程相对简单,为进一步的工程应用提供了参考.     

模糊自整定PID的航空发动机转速控制研究

航空发动机具有强非线性和强时变性的特点,使用定参数PID方法的转速控制系统的性能在全飞行包线内难以保证.针对上述问题,提出设计模糊自整定PID控制器,利用输入误差及变化率建立一组PID参数在线调整规则,运用模糊推理方法实时进行参数自整定.结合某型航空发动机核心机非线性实时模型,进行转速串级控制硬件在回路仿真.结果表明,提出的模糊自整定PID控制方法实现了控制器参数在线调整,参数切换扰动小,满足全包线内转速控制的指标要求.     

航空发动机二自由度鲁棒控制器设计与验证

为了克服传统单自由度控制算法无法兼顾系统的性能和鲁棒性要求的缺陷,将二自由度和H∞控制相结合,引入二自由度H∞回路成形控制方法对某型涡扇发动机进行控制器设计;同时为了保证被控对象的输出在稳态下能较好地跟踪参考模型的输出,引入一个常数矩阵对控制回路进行了变形;为更充分对控制器性能进行验证,在设计的航空发动机数控系统实时仿真平台上进行了仿真,证实了所设计的鲁棒控制器在航空发动机控制上具有良好的性能。     

具有未知干扰的无人机鲁棒滑模飞行控制

研究无人机飞行稳定性控制问题,由于无人机飞行控制系统存在时变外部干扰,飞行过程中升阴比变化激烈,控制稳定性难度较大。利用滑模控制良好的鲁棒能力提出一种神经网络的鲁棒飞行控制方法。因神经网络有良好非线性逼近能力,可对无人机飞行系统中的不确定进行在线逼近,并将神经网络权值误差引入到权值的自适应律中用以改善系统的动态性能。利用神经网络的组合,设计无人机鲁棒滑模飞行控制器。控制器分为两部分,一部分是等效控制器,另一部分是滑模控制器,能有效减小系统的跟踪误差。最后将所设计的鲁棒滑模控制对无人机飞行姿态控制进行仿真。仿真结果表明,新方法能提高无人机的鲁棒飞行控制能力且能实现无人机姿态的精确跟踪和稳定性控制。     

飞行器模型簇描述及鲁棒控制器设计

通过分析飞行器运动方程，给出了分段线性化模型簇描述．为了得到一定飞行区域的鲁棒控制器，选取负实极点并采用对角占优势的方法对状态反馈矩阵进行设计．同时，提出了全飞行区域(飞行包线内)的多个子系统划分及鲁棒镇定控制的设计方法．为了抑制飞行器的建模误差，采用了输入补偿方法．与常规鲁棒控制设计方法相比较，该方法可以降低飞行控制器设计的复杂度．飞行控制器设计结果表明，该方法对不确定系统的分析和设计是有效的。     

基于LMI的高超鲁棒控制及仿真

研究了高超声速飞行器鲁棒飞行控制器设计以及飞行控制系统的仿真验证问题,通过选择适当的加权函数矩阵,确定广义受控对象.线性矩阵不等式(LMI)技术是控制领域中研究问题的有效工具,控制器的分析与综合等问题可转化为LMI问题的求解,采用基于线性矩阵不等式的H∞控制器设计方法,设计了鲁棒控制器.仿真结果表明所设计的飞行控制系统具有鲁棒性,能有效地抗飞行过程中存在各种各样的干扰及摄动,很好地满足了飞行控制系统性能指标.     

数据链指挥下的战斗机H∞飞行控制器设计

基于神经网络对数据链指挥下的战斗机提出了鲁棒飞行控制器设计方案. 为了克服由于数据链的引入对战斗机飞行控制所带来的不利影响, 设计了基于 RBF 神经网络的鲁棒飞行控制器. 通过对神经网络参数在线调整, 使飞行控制系统能跟踪期望指令, 并满足给定的性能指标. 最后将所设计的飞行控制系统用于数据链指挥下的战斗机飞行控制, 仿真结果表明所设计的飞行控制系统是有效的.     

基于LFT的鲁棒飞行控制系统设计与仿真研究

针对飞机在大飞行包线飞行时,模型的参数会受高度和马赫数等发生变化.通常设计基于变化参数的飞机模型,模型阶次较高,导致设计的鲁棒控制系统阶次很高,难于工程实现.因此,设计具有低阶的鲁棒控制系统具有霞要的意义.提出了一种利用线性分式变换(LFT)建立参数不确定性模型和μ综合相结合设计低阶的鲁棒飞行控制系统的方法.通过飞机在不同状态下,选取m个状态点处的数据,进行最小二乘曲线拟合,利用莫顿方法建立参数不确定性飞机的LFT模型.用μ综合的方法对所建立的横侧向的LFT模型进行鲁棒飞行控制系统设计和仿真研究.仿真结果表明,该方法对大飞行包线的低阶的鲁棒飞行控制系统设计是有效和可行的.     

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.     

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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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