毕业设计 基于虚拟仪器的振动测试系统研究.doc
基于虚拟仪器的振动测试系统开发毕业设计(论文)任务书设计(论文)题目:基于虚拟仪器的振动测试系统研究姓名院系电气信息学院专业班级学号指导老师职称教研室主任一、基本任务及要求:设计一个基于LabVIEW的振动测试系统,采用适当的传感器采集到振动信号后由NIM系列数据采集卡6221将数据传至主机。通过LabVIEW可视化编程对采集到的信号进行相应处理预处理以及时域频域分析。设计的主要任务是:查阅相关资料确定总体设计方案;根据课题要求确定硬件方案、硬件设计;软件设计,学习LabVIEW可视化编程软件,对软件的具体模块编程并对信号进行处理;完成文献综述、开题报告及毕业设计说明书及设计说明书的撰写工作。二、进度安排及完成时间:3月2日3月22日:查阅相关资料,搜集课题所需资料,了解课题现状、课题研究的目的和意义,学习LabVIEW软件,完成开题报告和文献综述。3月23日4月5日:毕业实习4月6日4月15日:系统总体方案和硬件电路设计以及传感器选型;4月16日5月15日:完成各软件模块的编写及调试5月16日6月14日:整理资料,撰写毕业设计论文。6月15日6月19日:毕业论文审定、打印,答辩准备6月20日6月24日:答辩毕业设计论文目录摘要·············································································································IAbstract···········································································································II第1章绪论···································································································11.1课题研究的背景和意义·············································································11.2振动测试技术发展现状和发展趋势·····························································11.3课题主要研究内容···················································································2第2章虚拟仪器和labview···············································································42.1虚拟仪器································································································42.1.1虚拟仪器的概述·················································································42.1.2虚拟仪器的发展历史、现状和趋势·······················································52.1.3虚拟仪器的特点·················································································62.1.4虚拟仪器的分类·················································································62.2labview··································································································72.2.1labview概述······················································································72.2.2labview的应用···················································································82.2.3labview的特点···················································································8第3章振动测试分析系统··············································································103.1振动测试系统概述·················································································103.2振动测试系统的组成··············································································113.3信号测试与分析····················································································13第4章虚拟震动测试分析系统的硬件配置························································154.1传感器·································································································154.2电荷放大器···························································································164.3数据采集卡的选用·················································································16第5章虚拟震动测试分析系统的软件设计························································195.1数据采集模块·······················································································205.2信号预处理模块····················································································225.3时域分析模块·······················································································235.4频域分析模块·······················································································255.4.1FFT分析·························································································255.4.2功率谱分析·····················································································265.4.2.1自功率谱密度·············································································265.4.2.2互功率谱密度·············································································285.4.2.3相干函数···················································································285.5时频分析模块·······················································································29毕业设计论文第6章总结与展望························································································31参考文献········································································································33致谢···········································································································34基于虚拟仪器的振动测试系统研究I基于虚拟仪器的振动测试系统研究摘要:随着计算机和软件技术的发展,虚拟仪器正在逐渐成为测试领域的发展方向,采用虚拟仪器实现振动测试与分析也成为振动测试的发展趋势。为了解决工程振动问题,机械振动测试系统随着振动测试技术理论的发展和生产对测试的需求与日俱增,并有着广泛的应用领域。在工程现场的振动测试中,迫切需要低成本、高精度、高效率,同时方便灵活的测量仪器。振动测试试验系统是根据某些零部件振动测试的要求设计的,通过对被测系统施加各种波形的激励,使其产生振动,由传感器测量其振动的响应,将此信号进行调理放大,再由频谱分析仪获得系统的响应特性。为此,本课题研究开发了以PC为硬件平台、以美国国家仪器(NI)公司开发的LabVIEW软件为开发平台,配合必要的传感器、信号调理器和数据采集卡组成的振动测试分析系统。采用虚拟仪器图形化编程语言LabVIEW组建的振动测试分析系统,减少了测试过程中的硬件设备,同样实现了对振动信号的采集、处理和分析的目的,大大降低了硬件成本。关键词:虚拟仪器,振动测试,LabVIEW,数据采集,信号分析基于虚拟仪器的振动测试系统研究IITheDesignofVibrationTextSystemBasedOnVirtualInstrumentAbstract:Withthedevelopmentofcalculatorandthesoftwaretechnology,thevirtualinstrumentisbecomingthedevelopmentdirectionintextdomains,andusingvirtualinstrumenthasbeenadevelopmenttrendtorealizethetextandanalysisofvibration.Asthedevelopmentandproductionoftechnologytheoryinvibrationtext,inordertosolvetheproblemofvibration,theneedoftextinvibrationtextsystemincreasewitheachpassingday,andhasextensivefieldofapplication.Thevibrationtextinprojectspot,itisurgenttoneedmeasuringinstrumentsthatarelowcost,highdegreeofaccuracy,highefficiency,andatthesametimeconvenient.Thevibrationtextsystemisdesighedbasedondemandofsomeparts,tomakeitvibrate,allkindsofwaveformstimulationsareexertedtotextedsystem.,thenconditioningandenlargingthesignalthattransducermeasurestherespondingofvibrationinsystem,thenceforthobtaintherespondingcharacteristicsbyanalyzer.Forthis,thetaskhasstudyedanddevelopedavibrationtextsystemwhichtakePCashardwareterrace,thelabviewthattheUnitedStatesnationinstrumentcompanyopendupassoftwareterrace,coordinatewithnecessarytransducer,signalconditioninganddatacollecter.Adoptingthevibrationtextsystemwhichismadeupbyvirtualinstrumentfiguredprogramlanguagelabview,reducethehardwareequipmentduringtext,atthesametimerealizetheobjectivethatcollects,analyseandprocessvibrationsignal,decreasehardwarecost.Keywords:Virtualinstrument,Vibrationtext,Labview,Signalanalysis,Dataacquisition.基于虚拟仪器的振动测试系统研究-1-第1章绪论1.1课题研究的背景和意义要想紧跟技术的发展,就要不断更新测量设备,以满足越来越高的测量要求,同时测量手段的进步也为技术的进一步发展奠定了基础。虚拟仪器则是提高测量精度和效率的有效手段。它改变了传统的测量模式,使测量系统由松散结合的、常常不兼容的独立仪器发展成紧密结合的虚拟测量系统,把计算机技术与仪器技术完美结合起来。振动是自然界最普遍的现象之一。这类现象有的是由其本身固有的原因引起,有的是外界干扰引起。在运转的设备中,振动信号是最重要的信息来源。旋转机械的振动信号中包含着大量可反映设备运行状态的有用信息或称为信号特征。振动信号分析是旋转机械状态监测和故障诊断的重要组成部分,并在设备预测维修中发挥着重要作用。通过振动特征分析可以找出旋转机械设备70的故障源,而且可以确保机器运转的安全性,避免事故的发生,同时结合较好的维修项目管理还可以显著降低机器的运行成本。在一些情况下,振动是一种公害,它能损伤人体器官、损害健康、降低劳动效率,甚至产生“振动病或“运动病,如常见的晕车、晕船现象就是由于小于1Hz的极低频振动引起的。研究人体各器官的振动传递特性,设计能减振隔振的座椅、驾驶舱、手持工具的把手等也必须依赖于振动测试。目前市场上已有用于人体振动测量的传感器和测试仪出售。振动测试分析仪器则将振动测试与分析技术转化为生产力,它随着振动测试技术理论的发展和生产中对测试需求的与日俱增。从最初的机械式测振仪,发展到今天,各种应用物理学原理制成的传感器、FFT分析仪、结构动力学分析软件己在广泛使用。为提高测试效率,降低测试成本,适应在速度、准确度、数据分析以及现场实用性等方面日益提高的测试要求,我们需要将虚拟仪器技术引入在用车辆性能测试领域,开发基于虚拟仪器的车辆性能测试系统。1.2振动测试技术发展现状和发展趋势振动是各种设备在工作过程中经常发生的现象,振动问题是机械工程领域一个十分重要的研究课题。但工程实际中复杂的振动现象并非都能通过理论分析得出可靠结果,此时往往需要求助于实验手段,而且理论分析结果的正确性也需要通过实践来验证,这就使振动测试在振动研究中占有重要地位。在过去的三十多年中,无论国际还是国内,振动测试技术都获得了突飞猛进的发展,各种全新的分析方法如雨后春笋般大量涌现,并在科研、教学特别是工业上获得了广泛基于虚拟仪器的振动测试系统研究-2-应用。从1967年世界上第一台基于FFT的动态信号分析仪问世以来,振动信号分析技术已经经历了三次突破性的发展。虚拟仪器在我国的研究和开发有着十分现实的意义,广泛采用虚拟仪器技术有助于提高我国仪器的整体水平,节省仪器开发的人力和费用。我们有理由相信,随着软件业和测试技术的发展,虚拟仪器技术必将在更多、更广的领域得到应用和普及。随着振动测试技术理论的发展和生产中对测试需求的与日俱增,高质量的测试仪器、设备和现代化的测试方法不断出现。20世纪20年代,由于汽轮发电机组等设备的发展,机械式测振仪已不能满足要求,于是磁电式传感器应运而生,实现非电量信号向电信号转换的电测量。二次大战后出现了压电式传感器,由于它具有体积小、重量轻、频率范围、动态量程大等特点,且既可测量振动,又可用于冲击测量,直到今天仍在广泛应用。近些年随着微电子技术的发展,又出现了可在各种恶劣环境下使用的压电传感器和内装阻抗变换器、放大器、滤波器的集成电路式压电传感器,简化了测试系统,大大地拓宽了这种传感器的应用范围,提高了抗干扰能力和测量的精度。而压阻传感器的出现和使用进一步拓宽了低频率的测量范围,与此同时,还陆续发展了各种换能原理的传感器和配套仪器,如变电容传感器、光纤传感器、电涡流传感器等,pc机性能的提高引发了测试仪器领域的一场革命性变化,即产生了插卡式加软件的所谓虚拟仪器。虚拟仪器是当前计算机的主流技术与应用开发软件和高性能模块化的硬件相结合的产物,可由用户自己设计和定义,用软件在屏幕上生成仪器控制面板,进行信号分析和处理。而国内生产的针对振动测试的设备大多是模拟式和数字式仪表,功能比较单一,与国外设备相比,精度较差,可靠性低。这些仪器基本上属于硬件组成的专用信号分析与处理仪器,一般不能存储记录。这就为国内开发高性能的动态测试分析仪提出了迫切要求,同时随着PC机的广泛应用,虚拟仪器技术用于动态测试领域已成为发展趋势。1.3课题主要研究内容本文从虚拟仪器开发的角度,首先对虚拟仪器的概念和内容做简要介绍,然后对虚拟仪器的软件开发平台LabVIEW进行阐述,在分析了信号分析处理的原理后,使用图形化编程语言LabVIEW进行振动测试与分析虚拟仪器系统的软件设计。整个系统按照模块化的思想,拟采用菜单的形式搭建如下5个功能模块:(1)数据采集:实现Windows下基于6221数据采集卡的单通道数据采集、双通道数据采集和多通道数据采集,采样频率默认为1024Hz。(2)信号预处理:数字滤波器一般用在数据采样之后,对采样后的信号做信号预处理