基于模糊切换增益调节的燃气流量滑模控制

将模糊控制方法与滑模控制方法相结合,针对燃气流量调节伺服系统设计一种基于模糊切换增益调节的滑模控制器,固冲发动机流量调节伺服控制系统的不确定部分通过滑模控制器来补偿,从而可实现固冲发动机流量调节伺服系统的鲁棒控制。使用matlab对固冲发动机流量调节伺服系统进行建模仿真并与单纯使用滑模控制方法进行比较,仿真结果表明基于模糊切换增益调节的固冲发动机模糊滑模控制系统具有较好的给定适应性和抗干扰性,采用该控制方案能有效的抑制系统随机干扰对控制系统的不利影响,控制效果优于纯滑模控制方法,消弱了控制信号的抖振,为提高固冲发动机流量调节控制系统的动态性能奠定基础。     

力反馈电液伺服阀优化

研究力反馈电液伺服阀的初步设计问题,伺服阀的各个参数往往不是最佳的.针对动态性能(包括超调、调节时间、峰值时间及频宽)进行优化.为了优化系统性能,建立了力反馈式电液伺眼阀线性及非线性模型,根据喷嘴流量最优及非线性有约束多变量的优化函数对其静态结构参数进行优化,在保证了伺服阀的最优流量和综合控制性能的前提下,提高了伺服阀的频宽.对非性模型进行仿真计算,结果验证了改进方法优化系统的品质特性,为设计提供了可靠的参考.     

瓦斯发电系统建模与仿真

针对燃气瓦斯发电系统中的动力传递过程进行建模研究,研究了燃气发动机的工作原理以及影响发动机输出的核心参数,推导了发动机输出与节气门、空燃比等参数的关联模型,并在Simulink下搭建了空气流量控制、燃烧控制以及燃料控制部分的仿真模型,应用Stateflow工具箱实现了不同空气、压力、速度以及节气门角度参数条件下,发动机对应的输出变化.实验结果与发动机的出厂MAP参数对比表明,仿真模型能够正确模拟发动机的工作特性;依托该模型,可以实现常见故障的模拟仿真,为后续故障诊断的研究奠定基础.     

加热炉炉温智能控制系统的一种设计方案

针对步进式加热妒炉温控制系统中存在时变、非线性等特征,设计了燃气、空气回路流量设定值调节系统,并在该系统中了采用RBF神经网络整定PID控制器参数;针对炉温控制系统中参数耦合和系统模型不确定的问题,分别在燃气和助燃空气回路中设计了一种基于最小二乘支持向量机(LS-SVM)的逆控制解耦系统,并对燃气和空气回路流量设定值进行动态跟踪.仿真结果表明:该步进式加热炉炉温智能控制系统具有鲁棒性好、抗干扰能力强、超调小,动态跟踪品质好和稳态精度高等特点.     

固冲动力导弹纵向通道控制弹机一体化设计

以固体冲压发动机为动力的导弹武器,其弹道规划中应充分考虑发动机工作的经济性以及进气道的安全性,根据实时飞行状态调节燃气流量实现燃料最优控制,同时限制补燃室压强以满足进气道裕度要求。本文,提出了一种基于速度控制策略设计的导弹纵向通道弹机一体化控制系统,建立发动机及导弹控制线性化数学模型,设计控制律并进行数学仿真,仿真结果表明本文设计的纵向控制系统可实现导弹能量管理需求,并对进气道进行保护,满足固冲发动机的使用要求。     

固冲发动机补燃室压强控制技术研究

以固体冲压发动机为动力的导弹,其纵向通道控制系统设计中需要考虑固冲发动机的可控性、控制的经济性以及发动机的安全性,需要对固冲发动机开展充分的试验验证,通过补燃室压强控制试验验证发动机性能,为导弹总体控制创造条件;文章提出了一种基于补燃室压强闭环的控制策略,可以在固冲发动机地面直连试验中有效验证固冲发动机控制性能;建立了固冲发动机燃气发生器、补燃室数学模型,设计控制律并进行数学仿真;仿真结果表明,文章设计的补燃室压强闭环控制系统可实现补燃室压强控制,充分反应了固冲发动机控制性能,可根据研究结果开展导弹纵向通道控制系统设计,实现导弹总体对固冲发动机能量管理及进气道保护等方面的需求。     

进气道调节系统数字式控制器的控制策略分析

飞机进气道调节系统使用数字式控制器与进气道斜板位置传感器,形成斜板控制指令,改变进气道斜板开度,使进气道和发动机流量匹配。基于进气道调节系统的工作原理及系统结构,利用Simulink建立仿真模型,分析进气道调节系统数字式控制器的控制策略,提出基于线性叠加原理的调节电压输出控制策略,并通过进气道斜板的阶跃响应,验证采用此控制策略的数字式控制器的超调量和响应时间可以满足进气道调节系统的动态特性需求。     

基于Matlab的内模法航空发动机PID控制仿真

针对某型涡喷发动机,基于内模原理(IMC)设计了自整定PID控制器;研究在发动机处于不同转速状态时的变参数PID控制,实现对发动机加速过程的分段控制;在建立发动机模型时将大偏差过程分取了若干段,对每一小段分别用相应的小偏离动态过程的数学模型表示;由这若干个小偏差动态模型组合成描述全工作范围动、静态特性的发动机模型;利用MATLAB/Simulink对加速过程进行了仿真,仿真结果表明该控制系统具有良好的控制效果,各种加速过程和小偏离动态响应的超调量与调节时间都令人满意.     

双侧切向进气固冲发动机二次燃烧仿真

研究发动机性能优化问题,燃烧是关键技术.为提高同冲发动机二次燃烧效率,提出了一种新型切向进气方式,采用Realizablek-ε湍流模型及单步涡团耗散燃烧模型,对双侧切向进气式固冲发动机补燃室内三维反应流场进行了数值仿真,研究了切向进气对同冲发动机二次燃烧的影响.当空气射流以切向进入补燃室时,气流产生旋转,燃料与空气的...     

金属/水冲压发动机进水道工作特性

研究优化冲压发动机性能,针对水下航行器动特性改善问题,为了深入对金属/水冲压发动机进水道工作特性动态规律变化进行了解,提出建立水力特性三维数值模型.运用模型对一种运用于超空泡航行器的水冲压发动机复杂进水道内流场行了数值仿真研究.分析航行器航行速度和深度的增大,进水道流量系数增大,总压恢复系数减小;航行器攻角增大,流量系数减小,总压恢复系数减小.仿真证明超空泡航行器速度、深度及航行器攻角对金属/水冲压发动机给水效率和压力损失的影响机理.可为进一步研究水冲压发动机特性提供了参考.     

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。     

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.     

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     

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.     

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.     

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.