基于自适应干扰抑制技术的红外瓦斯检测系统的研究

发布时间：2018-01-31 20:25

本文关键词： 红外光谱吸收甲烷检测自适应滤波器 LS-FTF　出处：《吉林大学》2015年硕士论文　论文类型：学位论文

【摘要】：本论文的研究课题来自于国家自然科学基金项目“深部采动下红外瓦斯传感特性变化模式及自适应检测机制研究（61307124）”。甲烷是一种易燃易爆的气体，每年的瓦斯爆炸事故时有发生，这给人们的生命和财产安全带来巨大的危害，因此实时监测甲烷气体具有十分重要的意义。用于甲烷气体检测的方法有多种，比如催化燃烧法、气敏半导体法、光干涉法、红外吸收法等。由于红外光谱吸收技术的诸多优势：选择性好、寿命长、稳定性好、精度高、测量范围宽等，采用该技术研制瓦斯检测仪是预防瓦斯爆炸的主要措施。然而，在矿下恶劣环境中，对瓦斯检测可形成干扰的噪声较多，比如温度、压力、风速的骤变，大型机械运作形成的无规则噪声声压，电路随机噪声，背景光随机干扰等，更为严重的是，我们无法预知这些噪声的统计特性，因此我们无法采用传统滤波方法滤出上述噪声。为此，，在瓦斯检测中，本文引入了自适应现代滤波器，这种方法依靠对检测中所出现噪声的统计特性的估计，实时调整滤波器的参数，从而可较好的抑制噪声的影响。这对提高煤矿恶劣环境下改善瓦斯检测仪的性能具有重要的意义。本论文的主要研究内容包括：首先，基于自适应干扰抑制原理，采用MATLAB软件编写了LS-FTF和LMS自适应算法的实现程序,并进行了软件仿真,之后对仿真结果进行了分析，证明了自适应算法对噪声具有很好地抑制作用；紧接着选取了合适的光源和探测器，并设计了光路和气室结构，最终完成了整个光路结构的搭建；其次，基于差分式吸收的原理设计了硬件整体框图，对硬件的每一部分根据系统需要进行设计后进行焊接和调试,之后对硬件整体进行调试，完成了差分式甲烷检测系统的搭建，并针对该甲烷检测系统做了系统标定和稳定性的气体实验；之后借助于数据采集卡和LabVIEW软件搭建了自适应甲烷检测平台，取代了常规的借助微处理器完成对信号的软件处理的方法，最后进行了相关性测试实验和自适应检测平台功能验证实验，验证了该平台的功能。本论文的创新点： 1.在瓦斯检测中，引入了自适应现代滤波器，该方法依靠对检测中所出现噪声的统计特性的估计，实时调整滤波器的参数，从而可较好的抑制噪声的影响。 2.采用LabVIEW平台和PCI数据采集卡，构建了自适应甲烷气体的检测平台，验证了该平台的功能，为进一步工程应用打下了基础，具有很好的应用价值。
[Abstract]:The research topic of this paper comes from the project of National Natural Science Foundation of China, "Research on the change mode of infrared gas sensing characteristics and the adaptive detection mechanism under deep mining" (61307124). Methane is a flammable and explosive gas. Every year, gas explosion accidents occur from time to time, which brings great harm to people's life and property safety. Therefore, it is very important to monitor methane gas in real time. There are many methods for methane gas detection, such as catalytic combustion method, gas sensitive semiconductor method and optical interference method. Infrared absorption method. Due to many advantages of infrared absorption technology: good selectivity, long life, good stability, high accuracy, wide measurement range. Using this technology to develop gas detector is the main measure to prevent gas explosion. However, in the bad environment under the mine, there are many noises which can interfere with the gas detection, such as the sudden change of temperature, pressure and wind speed. The irregular noise sound pressure, circuit random noise, background light random interference and so on are formed in the operation of large machinery. What is more, we can not predict the statistical characteristics of these noises. Therefore, we can not use the traditional filtering method to filter out the above noise. For this reason, this paper introduces an adaptive modern filter in gas detection, which relies on the estimation of the statistical characteristics of the noise in the detection. The parameters of the filter can be adjusted in real time so as to restrain the influence of noise, which is of great significance to improve the performance of the gas detector in the harsh environment of coal mine. The main contents of this thesis are as follows: firstly, based on the principle of adaptive interference suppression, LS-FTF and LMS adaptive algorithms are programmed by MATLAB software. The software simulation is carried out, and the simulation results are analyzed. It is proved that the adaptive algorithm has a good effect on noise suppression. Then the suitable light source and detector are selected, and the light path and the gas chamber structure are designed, and the whole light path structure is finally completed. Secondly, based on the principle of differential absorption, the hardware block diagram is designed, each part of the hardware is designed and debugged according to the need of the system, and then the whole hardware is debugged. The differential methane detection system has been built, and the system calibration and stability gas experiments have been done for the methane detection system. After that, an adaptive methane detection platform is built with the aid of data acquisition card and LabVIEW software, which replaces the conventional method of using microprocessor to complete the processing of signal software. Finally, the correlation test experiment and the function verification experiment of the adaptive detection platform are carried out to verify the function of the platform. The innovations of this thesis are as follows: 1. An adaptive modern filter is introduced in gas detection. The method adjusts the parameters of the filter in real time by estimating the statistical characteristics of the noise in the detection. Thus, the effect of noise can be better suppressed. 2. Using LabVIEW platform and PCI data acquisition card, an adaptive methane gas detection platform is constructed, which verifies the function of the platform and lays a foundation for further engineering application. It has good application value.
【学位授予单位】：吉林大学
【学位级别】：硕士
【学位授予年份】：2015
【分类号】：TD712.5

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