基于声表面波传感技术煤矿瓦斯浓度监测系统研究

发布时间：2018-09-03 08:06

【摘要】：我国作为能源消耗大国,对于煤炭等矿产资源的需求巨大。煤矿安全是煤炭生产中的一项重要工作,而煤矿瓦斯事故则是煤矿安全事故中的重中之重,煤矿瓦斯事故给人民的生命安全以及财产安全带来了巨大的威胁。随着煤矿井下安全监测技术不断发展,以及智慧化矿山建设的迫切要求,研究新型可靠的煤矿瓦斯监测系统对于提高煤矿瓦斯安全监测技术具有重要意义。声表面波瓦斯传感器具有体积小,灵敏度高,成本低,抗干扰能力强等众多的优势,适应未来煤矿安全监测技术发展要求,有望在煤矿瓦斯检测中发挥巨大作用。本论文针对中心频率为300M的延迟线型声表面波瓦斯传感器监测系统进行研究,主要内容由两大部分构成,分别是硬件部分与软件部分。硬件部分研究方面,通过对声表面波气体传感器检测原理和检测方法的分析,选择了双通道延迟线型结构的混频检测法设计整个瓦斯浓度监测系统。硬件电路的前端部分包括高频振荡电路和混频及其差频信号处理电路。其中,高频振荡电路用于产生和声表面波传感器中心频率相关的300M高频振荡信号。高频振荡电路采用正反馈式振荡电路结构,放大器选用INA-02186集成射频放大器提供振荡电路的增益、损耗。LC移相器调节振荡信号相位差使电路处于稳定振荡状态。混频及其差频信号处理电路,对通过敏感薄膜材料的本振信号和未通过敏感薄膜材料的参考信号进行下混频、低通、放大、整形处理为易于检测的方波信号。混频电路采用集成式设计结构,选用AD831集成芯片为混频器,对外围引脚电路设置使AD831工作于低功耗下混频状态。巴特沃斯5阶低通滤波器用于去除信号振荡无用信号成分。采用2SC3355大功率三极管的放大电路对经过滤波处理的信号进行电压放大。最后,以74HC14为核心元件的整形电路将放大后的振荡信号整形为易于频率信息检测的方波信号。硬件电路的后端部分包括MCU最小系统和声光预警、LCD显示、SD卡存储、USB下载、通信电路等外围电路。MCU对经过前端电路处理的方波信号进行频率信息的提取并转化为浓度信息。声光报警电路、LCD显示电路、SD卡存储电路、USB下载电路等外围电路负责对浓度信息进行相应的声光报警、显示、存储等操作。软件部分研究方面,利用VB软件作为上位机的设计环境,整个上位机分为:账户管理、用户操作、数据操作三部分。上位机与下位机的通信通过调用VB中的Mscomm通信控件完成。利用ADO控件与ACESS数据库建立的联系,使上位机具有存储下位机的传输浓度信息的功能,并在部件中调用DataGrid控件,在上位机中建立了浓度信息查询表。此外,针对实际运用情况,利用RS-485通信以及RS-485主从多机通信方式以实现传感器浓度信息远距离传输,以及多个节点传感器与主机通信的目标。最终,既实现具有声光报警系统监测功能的瓦斯浓度监测系统终端,又对该传感系统进行简化,实现了作为简单瓦斯浓度监测传感节点的设计。本项研究对于声表面波煤矿瓦斯浓度监测系统的实际制备,以及其在煤矿井下的实际应用具有一定的意义。
[Abstract]:Coal mine safety is an important work in coal production, and coal mine gas accident is the most important one in coal mine safety accidents. Coal mine gas accident has brought great threat to people's life and property safety. With the continuous development of monitoring technology and the urgent requirement of intelligent mine construction, it is of great significance to study a new and reliable coal mine gas monitoring system for improving coal mine gas safety monitoring technology. Full monitoring technology development requirements, is expected to play a huge role in coal mine gas detection. This paper focuses on the center frequency of 300 M delay line SAW gas sensor monitoring system, the main content is composed of two parts, hardware and software. Hardware part of the research, through the SAW gas Based on the analysis of the detection principle and method of the volume sensor, the gas concentration monitoring system is designed by the mixing detection method with double-channel delay line structure. The front-end part of the hardware circuit includes the high-frequency oscillation circuit, the mixing and its differential signal processing circuit. The high-frequency oscillation circuit is used to generate the center of the SAW sensor. Frequency-dependent 300M high-frequency oscillation signal. The high-frequency oscillation circuit uses a positive feedback oscillation circuit structure. The amplifier uses an INA-02186 integrated RF amplifier to provide the gain and loss of the oscillation circuit. The LC phase shifter adjusts the phase difference of the oscillation signal to keep the circuit in a stable state of oscillation. The mixing and its differential signal processing circuit are sensitive to passing. The local oscillator signal of the thin film material and the reference signal of the non-sensitive thin film material are mixed down, low-pass, amplified, and shaping into square wave signal which is easy to detect. The mixing circuit adopts integrated design structure, selects AD831 integrated chip as mixer, and sets the peripheral pin circuit to make the AD831 work in low-power mixing state. The 5th-order low-pass filter is used to remove the useless signal components of signal oscillation. The 2SC3355 high-power transistor amplifier is used to amplify the filtered signal. Finally, the 74HC14-based shaping circuit shapes the amplified oscillation signal into a square-wave signal which is easy to detect the frequency information. The back-end part includes MCU minimal system and acoustooptic warning, LCD display, SD card storage, USB download, communication circuit and other peripheral circuits. MCU extracts the frequency information of square wave signal processed by front-end circuit and converts it into concentration information. In the aspect of software research, using VB software as the design environment of the upper computer, the whole upper computer is divided into three parts: account management, user operation and data operation. The connection established by SS database makes the upper computer have the function of storing the concentration information transmitted by the lower computer, and calls the DataGrid control in the component, establishes the concentration information inquiry table in the upper computer. In addition, in view of the actual application situation, RS-485 communication and RS-485 master-slave communication are used to realize the remote sensing concentration information. Finally, the gas concentration monitoring system terminal with the function of acoustooptic alarm system monitoring is realized, and the sensor system is simplified to realize the design of a simple gas concentration monitoring sensor node. The actual preparation of the system and its practical application in underground coal mines have certain significance.
【学位授予单位】：西安科技大学
【学位级别】：硕士
【学位授予年份】：2017
【分类号】：TD712.5

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