基于LabWindows/CVI的电能质量分析仪

针对传统电能质量分析系统存在存储容量小、显示功能单调等缺点,设计了以高性能数据采集卡PCL-818H与工业控制计算机为核心的硬件系统。该系统对实时信号进行采集与分析,并利用虚拟仪器LabW indows/CVI的强大测试分析功能,完成了基波和谐波的幅值与相位、电压偏差、有功和无功畸变率等参数计算,且具有数据存盘的软件功能。通过反复验证,该分析仪具有精度较高、直观易读、工作可靠和性价比高等特点。     

轴承变载荷压力实验系统设计

针对现有轴承实验台的加载力不可按照任意载荷谱调节的缺陷,提出了PLC与虚拟仪器共同控制的方案.下位机采用PLC进行简单可靠控制,上位机采用虚拟仪器进行复杂的加载控制.详细阐述了控制方案及与PLC传输协议协调的实现方法.在允许的载荷输入范围内,该方案通过实验台加载力的可调输入,进行设定载荷谱试验,使试验时间有效缩短.试验结果表明,该方案灵活,且成本低,满足了产品测试需求.     

Product structure (BOM)-based product similarity measures using orthogonal procrustes approach

In geometry, two configurations are called similar if they can be brought to a complete match by rigid motions and dilations. In the simplest case, product designs X and Y have the same dimensionality and same number of points which can be brought into a one to one correspondence by substantive considerations. Under orthogonal transformations, product design Y can only be rotated and reflected in order to approximate product design X. As for the “as close as possible” or “relatively close” criterion, a reasonable definition would be to measure the distances between corresponding points, square these values, and add them to obtain the sum-of-squares criterion L. In this paper, a product structure (BOM)-based product similarity measures using orthogonal procrustes approach is proposed. A structural product is first transformed into bill of materials (BOM), the structural similarity measurement between a product query and target product is calculated and evaluated using orthogonal procrustes approach. The results show that the proposed product structure similarity measure method can help companies find desired product information based on BOM feature.     

基于虚拟仪器文氏桥混沌电路的建模与仿真

为缩短混沌电路的研究周期,提出了一种利用虚拟仪器实现混沌电路的方法。采用改进型欧拉算法对文氏桥混沌电路的状态方程进行近似处理,建立了相应的离散模型。在虚拟仪器(Labview)环境下进行数值仿真,可观察到在电路参数变化时电路动力学行为的演变过程,并通过构建采集系统,实现了文氏桥混沌电路离散模型的混沌信号输出。仿真结果与已有研究结果完全一致,有效地体现了"软件既是仪器"的概念。     

嵌入式XPE系统镜像的定制和优化技术研究

为了将WindowsXPEmbedded(XPE)应用在非手持和能耗不敏感的嵌入式应用中,要求能够对嵌入式操作系统实现快速安装,并进行系统优化提高性能。针对这类应用,利用Windows Embedded Studio定制了系统镜像,进而实现系统的快速移植安装,优化了系统镜像的启动画面、多用户的自动登录及其自动切换过程、系统的服务项目以及用户Shell。通过上述步骤,系统一方面能够为用户提供基于Browser/Server(B/S)架构的嵌入式网络应用,另一方面能够为用户提供与其本地语言相匹配的本地桌面应用。     

基于LabWindows/CVI和RTX的高速凸轮测试系统设计

为了研究凸轮机构在高速运转时出现的动力学问题,以LabWindows/CVI虚拟仪器开发工具和RTX实时系统为平台,设计了一个高速凸轮测试系统.该系统以工控机和数据采集卡为主要硬件,使用RTX实时系统采集数据,采样周期达到0.1 ms,利用LabWindows/CVI开发的虚拟仪器对数据进行分析处理、显示及存储.通过对...     

基于Matlab的低频频率特性测试虚拟仪器设计

介绍了直接利用Matlab的数据采集工具箱、图形用户接口和方便的计算能力完成控制系统低频频率响应特性测试虚拟仪器的一种设计方法.首先简要介绍了相关法频率响应特性测试的原理,接着论述了该虚拟仪器系统的硬软件结构,随后详细讨论了利用Matlab进行相关法频率特性测试软件设计的关键问题及其解决方法,最后给出了所设计虚拟仪器的...     

一种基于虚拟仪器技术的双锁相放大器的设计

锁相放大器是微弱信号检测的最有效手段,针对现有模拟锁相放大器和数字锁相放大器存在的问题,利用虚拟仪器技术和锁相放大器的基本原理,基于NI公司的LabVIEW软件及DAQ板卡对数字锁相放大器进行设计.设计中采用双锁相技术,通过在紫外辐射测试中的测试结果表明此锁相放大器具有更好的性能,可以精确地提取被噪声湮没的信号,可获得...     

Responsive consistency restoration in interactive product configuration by content-addressable memory

With the context of individualized product design in mass customization, the practice of product configuration is transformed from traditional unidirectional process into bidirectional design interactions. In this interactive configuration manner, maintaining the consistency of configuration assignments, often referred to as consistency restoration, is one of the primary issues which should be addressed. The task of consistency restoration faces two great challenges: the uncertainty and individualized flexibility of customer requirements. The uncertainty turns problem dynamic and deteriorates the computational complexity of existing consistency restoration methods. The individualized flexibility turns the task of consistency restoration ill-structured. Consequently, these two characteristics increase the response time in interactive configuration and make companies face the challenge of ‘customization-responsiveness squeeze’. To leverage this problem, this paper proposes a responsive approach to facilitate the task of consistency restoration. A methodology based on content-addressable memory (CAM) is established, which compiles a CSP-based consistency restoration into a memory recalling process and automatically corrects the incompleteness and inconsistency within the memory. Specific orientation mechanism based on customer preference is proposed to introduce customer flexibility into CAM model. The resulting oriented-CAM method is demonstrated by a case study and the performance and responsiveness are analyzed.     

基于TMS320F2812与LabVIEW的串口通信

介绍利用TMS320F2812数字信号处理器（DSP）的串行通信模块实现与外设间串行通信的原理,结合实际应用给出异步串行通信的程序设计。针对电力传动控制系统数字变量不易观察的问题,将DSP运算得到的数据通过RS232串口送至PC。采用LabVIEW开发上位机软件,无须额外增加硬件,实现了数据的采集、显示、处理和存储。该系统还可以对数据进行FFr变换、谐波分析等特定的分析和处理。给出利用DSP产生的4路波形数据在LabVIEW下的实验波形。