基于FPGA的静力加载谱生成与控制算法研究

静力加载试验谱是根据静力加载试验中的载荷表形成的加载谱形,由不同的目标值和其它参数组成;试验加载谱的生成过程指按规定时间和曲线类型运行到指定值的过程;针对当前静力加载试验中对加载谱控制的多功能要求,参照主流控制系统中上位机的操作流程,实现了一种基于FPGA的加载谱生成与控制算法,满足现有控制系统中试验加载谱的生成模式和各种命令的操作,包括连续加载谱的生成、谱的单步调节、单点控制、选择谱段控制和控制方式切换等,配合系统控制算法为自主控制器的开发奠定基础。     

100kW风力机叶片的静载荷测试试验研究

风力机叶片的全尺寸检测是对叶片质量和安全性进行评估的重要手段,而叶片的静载荷试验是分析叶片结构稳定性的重要基础。对100 k W风力机叶片进行了静载荷试验,对试验方法和试验条件进行了详细介绍。采用不测力法,分别从最大摆振、最小摆振、最大挥舞、最小挥舞4个方向施加载荷。基于测得的叶片静载荷数据,分析了叶片在载荷作用下的刚度及应变等性能,并通过失效试验对叶片的安全性能进行了评价。评价表明,叶片具有较大的安全裕量。     

风电叶片多点静力测试神经网络PID解耦控制

风电叶片多点静力加载测试中由于存在各加载点之间的交联耦合现象,其加载精度难以得到保证.为此在研究耦合机理和解耦控制的基础上,提出变步长BP神经网络PID自整定算法.建立多点静力加载控制系统耦合模型,通过仿真并与实际实验数据比较,验证该算法的有效性.结果表明该算法可有效降低各加载点之间的耦合效应,有利于提高网络的稳定性和搜索速度,同时还具有自学习功能以适应不同尺寸和参数的叶片.     

MW级风机叶片静力加载系统设计与研究

为了满足MW级风机叶片静力加载试验的要求,改变国内普遍采用的半自动加载模式,设计了一套基于CAN总线的分布式多节点液压静力加载试验台.叶片在静力加载过程中弯曲极大且不规则,采用液压绞车作为牵引力输出设备,并分析了加载过程中的变牵引特性;为了提高加载过程中的牵引力精度及跟随性能,采用“V—F”的控制模式,通过比例调速阀的...     

空间站载荷转移机构机器人的力加载控制方法

针对机器人在空间站载荷转移机构力加载过程中,由于展开完成后的载荷转移机构在力的方向上发生变形,导致机器人力控制系统难以保持稳定、加载精度不足或调节时间过长的问题,提出了自适应调整导纳控制器参数的策略．首先,根据导纳控制理论建立力与位移的关系,初步提出了基于直角坐标系的力跟随/力加载控制器;然后,根据加载实验数据,采用最小二乘法对载荷转移机构模型进行参数辨识,建立机器人特定工作空间的力与位置关系;最后,通过自适应调整导纳控制器参数使机器人动力学模型与载荷转移机构的动力学模型近似匹配,实现机器人对展开完成后的载荷转移机构末端的空间力实时加载．实验得出机器人对载荷转移机构位置跟随偏差不超过0.1 mm,加载力误差不超过1%．仿真结果表明,该机器人满足精度要求,为载荷转移机构提供了较为真实的等效空间载荷．     

耦合加载方式下复合材料叶片的预应力模态分析

针对大型风力机叶片在静止和变速运转工况下,振动模态计算分析方法和转速对频率的影响进行了研究.建立了叶片有限元模型,静力分析时采用耦合加载方式;采用分块Lanczos法分析了叶片的模态,考察了叶片固有频率对预应力效应的敏感程度及稳定性,探讨了转速对叶片频率的影响程度,分析了预应力效应产生的原因.结果表明:叶片主要以挥舞和摆阵振动形式为主;预应力效应对叶片的固有频率产生了较大影响,随转速的不断增大叶片的固有频率也随之增大,且预应力效应对叶片挥舞刚度的影响程度大于摆阵刚度的影响.     

水平单调载荷作用下的桩基桥墩滞回特性

为研究桩基桥墩-地基系统的非线性性能,根据模型与原型的物理相似关系制作1∶5比例的桩基桥墩模型. 采用力-位移混合控制加载的拟静力试验方法,通过在墩顶施加水平单调增加载荷,得到墩顶水平载荷下桩基桥墩的载荷-位移滞回曲线、骨架曲线和滞回特性. 用非线性弹簧单元模拟土体、用梁单元模拟桩和桥墩,建立模型桥墩的计算模型. 计算模型的骨架曲线与试验模型的骨架曲线吻合较好,表明采用非线性弹簧单元和梁单元分别模拟土体和桩是可行的,可以为考虑土-结构相互作用时的桥梁抗震分析提供参考依据.     

随机谱疲劳试验协调加载控制技术研究

针对随机载荷谱结构复杂、谱段载荷之间连接具有随机性的特点,介绍了某型飞机后机身-尾翼联合体结构疲劳试验中采用的三级分布式控制方式与调试加载控制策略、按照关键通道载荷变化量配置加载时间的方法,解决了随机谱疲劳试验中控制参数易变、加载时间不易确定、加载协调性不易实现等问题,提高了随机谱试验的加载速度、试验精度和加载协调性.     

基于双目视觉的直升机旋翼桨叶挥舞角测量

为实现直升机旋翼桨叶挥舞角的测量,提出了一种基于双目视觉的测量方法.首先,在直升机旋翼桨叶上均匀布置编码标记点,用已标定的双目摄像机对旋翼桨叶每隔一定角度采集标记点图像;其次,对左右摄像机图像上的标记点进行解码和匹配,得到标记点的左右图像视差,进而计算标记点三维坐标;再次,利用标记点在各个角度下的三维坐标,计算旋翼中心和转轴方向,建立旋翼坐标系;最后,在旋翼坐标系下,根据标记点静止与高速旋转时在同一角度下的三维坐标,计算挥舞角大小.利用风扇叶片进行仿真试验,结果验证了该方法具有自动化程度高和测量精度高的特点,可满足直升机旋翼桨叶挥舞角测量的要求.     

基于ANSYS APDL语言实现复杂载荷加载

针对通用有限元分析软件现有载荷形式无法进行复杂载荷加载的问题,以某船用柴油机惯性载荷连杆的静力分析为例,提出基于ANSYS APDL进行复杂载荷加载的方法. 对该连杆在复杂载荷条件下的零部件力学仿真分析表明,此方法可方便、高效地实现不同节点惯性力的计算,完成众多节点力的加载.     

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。