基于虚拟仪器平台的检测系统开发及信号处理方法的应用研究

【作者】 曾明；

【导师】 杨欣荣；

【作者基本信息】 中南大学 ， 控制理论与控制工程， 2003， 硕士

【摘要】 采用虚拟仪器技术，计算机技术与仪器技术相结合的产物，代表了仪器的最新发展方向，它把传统仪器中的某些硬件乃至整个仪器都用计算机软件替代，这样不仅可以节省硬件开支，而且缩短了研发时间，减小了设计难度。在众多的开发平台中，我们选择NI公司开发的图形化开发平台LabVIEW，这种平台的采用，使得设计者很容易构建复杂虚拟仪器测控系统。 论文探讨了虚拟仪器应用研究的新方向，即虚拟仪器开发平台的功能扩展和基于虚拟仪器技术的应用程序开发。 通用数据采集卡驱动程序开发就是针对虚拟仪器开发平台的功能扩展方面的研究。NI公司的数据采集卡系列相对比较昂贵，很多用户希望采用低价位同型的通用数据采集卡，但LabVIEW对于非NI公司产品是不支持的，所以与开发LabVIEW兼容的通用数据采集卡驱动程序是非常有必要的。在设计中我们充分利用LabVIEW平台的开发性，通过CIN调用代码接口节点、CLFN调用库函数节点及直接利用LabVIEW中In Port，Out Port控件三种方案，通过编制相应软件很好地解决通用数据采集卡驱动程序开发问题。 本论文还介绍了利用虚拟仪器技术开发的两个应用实例，油品含水量智能检测系统设计是基于虚拟仪器平台的应用系统开发方面所做的研究，研究主要涉及如何充分而合理利用虚拟仪器平台的功能控件构建一个集信号采集、存储、分析和处理为一体的测试系统，油品含水量智能检测系统设计，为在这方面的研究提供了一个很好的研究对象。我们采用射频电容法测量油品中的含水量。由于电容传感器存在交叉灵敏度问题，为了解决交叉灵敏度对测量产生的影响，我们引入了多传感器信息融合技术。油品含水量智能检测系统具有测量精度高，操作简便，抗干扰能力强等众多优点。把虚拟仪器技术和信息融合技术这两项新技术有机地结合，应用于油品含水量检测，在国内尚无先例，处于领先水平。 轧机振动在线监测系统设计是针对信号、数据处理方面开展的研究。在轧机振动监测系统设计中，使用了多种信号、数据处理方法，使基于虚拟仪器技术的检测系统具有强大信号、数据分析处理能力这一优势得以充分的体现。更多还原

【Abstract】 Traditional measurement and automation systems consist of expensive, closed instruments designed for specific tasks. In these traditional systems, the hardware defines the system. Taking advantage of Virtual Instrument Technique, substitute software for the part or the whole of hardware in traditional instruments, saving your both valuable development time and resources. There have many programming languages for developing Virtual Instrument, from which we select graphical programming language LabVIEW (Laboratory Virtual Instrument Engineering Workbench) which provides an easy means for non-programmers to quickly design and implement complex test and measurement and automation applications.Data acquisition boards are the most important component in the hardware design of measurement and automation systems. In order to cut down the expense of the whole system, many instrument users prefer to select general data acquisition boards which have the same functions in the measurement process. Therefore, It is necessary to develop the drivers for the general data acquisition boards. The LabVIEW Call Library Function Node (CLFN) and the Code Interface Node (CIN) are block diagram objects that link source code written in a conventional programming language (for example Visual C++) to LabVIEW. Using the two Nodes, we can develop the drivers for general boards. Use the icons of In port and out port to is an another way to solve this problem.Based on Virtual Instrument Technique, we designed water content in oil detector. The dielectric constant of water is much greater than that of oil, so they show different properties in the respect of radio-frequency impedance. On the other hand, the system has certain cross sensitivity about the environment which also affects measurement precision. In use of the theory of radio-frequency impedance and concerning the effect of temperature, a method of curved surface fitting is introduced. Compared with results without information-fusion processing, both the temperature stability and the measuring precision compared with results before information-fusion processing were greatly improved.Monitoring system for the vibration is focused on the research work of signal analysis. The vibration in rolling mills is a ubiquitous problem, which directly influences the quality of armor plate. Also, it is a typical parameter which can be used to analyze the state of rolling mills. Based on the theories of monitoring and diagnosing mechanical systems and combined with the new modern measurement developing workbench (LabVIEW), we designed the online monitoring system for the vibration in rolling mills and solved many problems which can not be solved or are very difficult to deal with them by using traditional ways.更多还原