【作者】 张梦珠；

【导师】 戈振扬；

【作者基本信息】 昆明理工大学 ， 农业电气化与自动化， 2011， 硕士

【摘要】 本研究属于微量含水率的研究范畴,本课题是国家中小企业技术创新基金项目《云南鲜花精油、色素分离纯化技术集成》(08C26215302346)研究的内容之一。粉料含水率测量是粉料生产、加工、储藏等工作的一个重要环节。目前在我国广泛应用的粉料含水率测量方法基本上是微波干燥法和烘箱烘干法,这类方法存在时耗长、体积大、显示不直观的缺点,而国外粉料含水率测量仪表不仅价格昂贵、维修困难、而且需要核辐射防护、难以推广。因此,研究设计性能稳定、环境适应性强、成本低、测量精确、使用方便的粉料含水率测量系统亟不可待。本文着手进行了以下两方面的研究内容：(1)研究基于电容式湿度传感器测量超干粉料含水率的测量系统及数据处理和分析的方法；(2)比较采用湿度传感器和烘箱烘干法测量超干粉料含水率的关系。论文系统地研究分析了目前粉料含水率测量方法的现状,对各类方法的优缺点进行了比较；研究设计了一种快速测量超干粉料含水率的测量系统：采用12位DAQP-12数据采集卡和低湿度传感器HM1250LF为核心设计的超干粉料含水率测量系统,它具有快速性、高精确度、携带方便、功耗低等优点。DAQP-12数据采集卡中的PCMCIA接口将接收到的信号传输予计算机进行计算与分析,尤其有利于在野外测量,而HM1520LF是一种适合于低湿度测量系统的传感器(量程为：0-20%RH,工作温度范围为：-40℃-60℃),十分适合超干粉料含水率(1%-8%)测量。论文完成了测量系统的硬件选型与构建,包括低湿度传感器HM1520LF模块、数据采集卡DAQP-12模块、人机对话功能模块和电源模块等。论文软件设计部分采用了积木式的编程方法,基于LabVIEW设计了系统主程序、电压和湿度间的转换子程序、数据库配置对话框子程序等；基于Matlab7.0设计了一阶差分法和中值法及惯性滤波模型的数据处理程序。论文利用基于虚拟仪器的超干粉料含水率测量系统分别对7种粉料样品的低含水率进行了测量和分析。每个样品的测量值是从该样品中单点采集的20-40个原始数据序列,该原始数据序列曲线经过对奇异值的剔除之后,再采用惯性滤波模型进行滤波处理,所得到的平均值作为该样品的测量值,并比较与分析测量值与标准值之间的相对误差。结果显示,测量值与标准值之间的最大误差为2.21%,误差均值为0.79%,均不超过5%(测量样品数为5时置信区间为95%),表明测量系统具有可行性。论文创新点：首次研究超干粉料含水率测量方法及系统；融合了虚拟仪器技术和DAQP-12数据采集卡的PCMCIA串行接口技术；系统可以实现数据采集和数据处理、存储协同进行；系统可以实现定时采集和事件驱动采集两种采集方式；在PC机中实现对数据的管理,采用Access应用软件实现数据的储存,方便数据的读取与回放；采用改进的一阶差分法剔除替代奇异值,获得新的预测值,使得预处理的结果得以进一步的优化。结论：以七种超干粉料含水率的测量结果可知,湿度传感器可作为测量超干粉料“真实的水分含量”的有力工具；数据预处理和数据二次处理均对粉料含水率的结果的修正起到了一定的正作用,进一步保证了测量数据的可靠性和稳定性。更多还原

【Abstract】 The study belongs to the research fields of micro-moisture, it is one part of research contents of technology innovation fund project of small and medium enterprises in China "Yunnan flower essential oil, pigment separation and purification technology integration" (08C26215302346). The moisture content of powder material is an important circle for the agency of production, processing and storing. By now the extensively used powder material moisture measurement methods in China basically are the microwave drying method and oven-drying method. But they have the disadvantages, such as long time consuming, too large, and the show of screen not intuitive and so on. In the abroad, the measuring instrument of powder material is not only too expensive, but also it is hard to maintenance, needing to protect nuclear radiation and it is not easy to promotion. Therefore, it is all-important for us to design a steady performance, higher adjustability, lower cost, more exact measurement and easy operating measurement system on moisture measurement of powder material.The objectives of this work are:(1) to research the measuring system for determining moisture content of ultra-dry powder material by capacitance humidity sensor and relative signal and data analysis; (2) to compare moisture content of ultra-dry powder material between humidity sensor and oven-drying.The methods of measurement moisture content of powder material were summarized in this paper at the present. After systematically comparing and analyzing the advantage & disadvantage of the ultra-dry powder materials moisture measurement apparatus in detail, the paper put forward a new testing system of ultra-dry powder material, the system made up by the core of lower sensor 12 bit DAQP-12 data acquisition card and HM1520LF humidity sensor. The system has the merit of speediness, higher presision, easy to carrying and lower cost. The interface PCMCIA of DAQP-12 data acquisition card transmitted the received datas to the computer computational analysis, which is especially propitious to test in the powder material moisture measurement system of field work. HM1520LF (range:0～20%, temperature scope:-40℃～60℃) is suitable to apply to the lower humidity measurement system, and adapt to the ultra-dry powder material (1%～8%) moisture measurement.In this paper, we had completed the selection and construction about the hardware modules of the sensor measurement system. It included HM1520LF lower humidity sensor module, data acquisition card DAQP-12module, human-computer interaction module and power source module and so on.The paper completes the modularization design of the software. The software system can be divided into the following module:The main system program, the conversion sub-program of volt and humidity, and the database configuration dialogue sub-program, which were written based on LabVIWE. The data processing program of excluding alternative singularity with first order defference method and median method and inertia filtering model were written based on Matlab7.0.The paper mades use of the moisture measurement system of ultra-dry powder materials based on virtual instrument mentioned system, and selected seven ultra-dry powder materials to be tested in the experiment respectively. The measured value for one specimen was a raw data sequence of 20～40 raw data sequence collected on single-point from each sample respectively. Then we averaged of the datas after the curve of the raw data sequence, after filtering using excluding alternative singular, was processed by inertia filtering model. Comparing and analyzing the relative error between measurement value and true value accordingly. The result shows that the maximal relative error of moisture content between humidity sensor method and oven-drying method is 2.21% and the average error is 0.79%, both less than 5% (confidence interval 95% for 5 samples). It is showed that the precision of measurement system is acceptable.Innovative points of this paper:it is the first time to study the moisture measurement method and system of ultra-dry powder; it integrated the virtual instrument technology and PCMCIA serial interface technology of DAQP-12 data acquisition card; the system can achieve two kinds of collection methods including timing acquisition and event-driven acquisition; implemented data management by PC and using Access application software to store data for data read and playbacked; adopting the modified first order difference method to replace and alternative the singular value, and acquire the new forecast, so the results can be further pre-oprimal.It is concluded that the humidity sensor may be a powerful tool for determining "the true moisture content" of ultra-dry powder material, as demonstrated for the seven selected powder. Furthermore, the data preprocessing and data secondary processing both play a certain positive role in making the amendments the result of moisture content of powder material, thus it further ensure the reliability and stability of measurement value.更多还原