基于数字互相关算法的微欧电阻测量技术研究

发布时间：2018-05-09 12:12

本文选题：微小电阻 + 信噪比　；参考：《南昌航空大学》2017年硕士论文

【摘要】：随着中国经济的快速发展,交通运输、工业生产以及基础设施建设等越来越多地使用到金属材料制作的装备。工作在复杂酸性环境中的金属材料容易受到腐蚀而受损,并带来安全隐患。为了能够避免安全事故,对这些设备的金属材料进行腐蚀情况实时监测是很有必要的。监控金属材料腐蚀情况方法有很多,通过观察电阻的变化反映金属被腐蚀情况是材料学科的重要方法之一。而当前传统的微小电阻测量仪由于一般不具备网络化功能而不太适合长期监测基础设施内金属材料的腐蚀情况。因此,研究一种精度高,稳定度好且能够快速准确测量微小电阻测量的网络化仪器具有重要的意义。本课题分析了微小电阻测量特点以及测量方法现状,提出了采用低频率恒流源的方法,通过数字互相关算法提取淹没在噪声中的有用信号的一套完整的系统方案并研制了微电阻测量系统。本文详细论述了研究微小电阻测量系统的设计和整体开发过程,主要分为微电阻的测量理论与算法分析、测量系统硬件的设计、系统的软件设计、系统的调试校准和结果误差分析。首先阐述微电阻的测量理论包括微电阻测量的噪声、干扰来源以及测量信道的信噪比分析。针对微电阻的测量信噪比非常小的噪声特性分析了目前常用的微小电阻的测量方法,结合本课题的设计要求与嵌入式系统设计的特点选用低频率交流恒流测量法。详细分析了低频率恒流交流测量法的测量方案和测量过程,运用数字互相关算法模型去除有用信号中的噪声和干扰,并通过MATLAB仿真实验分析。系统硬件设计,包括硬件系统的整体设计、ARM微处理器最小系统及外围电路的设计、高精度D/A交流信号产生电路的设计、压控恒流源电路的设计、16位高精度A/D采集电路的设计和差分放大电路的设计、显示电路的设计、通信电路的设计以及电源电路的设计。系统的软件设计,主要要包括软件系统的整体设计、软件的主程序设计,负责各个任务的调度与协调各任务通信、产生10Hz交流信号的D/A转换程序设计、A/D转换采集程序的设计和算法程序的设计、触摸屏与显示程序的设计、档位匹配程序的设计、通信程序的设计和软件可靠性程序的设计。系统的调试包括硬件调试、软件调试和整体系统联合调试,详细阐述了软硬件调试过程和调试方法。提出了测试系统测量线性度,测量出其校准因子的方式的校准方法。最后,通过反复试验验证了硬件和软件的正确性。实验表明本系统在各个量程档位区间内具有良好的线性度;各个量程档都给出了实验测量结果及误差分析,最小量程档测量值数量级稳定在微欧位,能实现微欧级电阻的测量。表明数字互相关算法在本课题微小电阻测量去除噪声和干扰提高系统信噪比具有显著效果,能够精准测量微欧级电阻。所设计的微小电阻测量系统达到了预期目标,为材料学科电阻法监测金属腐蚀情况准确的测量分析奠定了基础。
[Abstract]:With the rapid development of China's economy, transportation, industrial production and infrastructure construction have been used more and more to the equipment made of metal materials. Metal materials working in complex acid environment are vulnerable to corrosion and bring safety hazards. In order to avoid safety accidents, the metal materials of these equipment are entered. There are many methods to monitor the corrosion of the metal. There are many methods to monitor the corrosion of metal materials. It is one of the most important methods to reflect the corrosion of metal by observing the change of resistance. The traditional micro resistance measuring instrument is not suitable for the long-term monitoring infrastructure because it does not have network function. Therefore, it is of great significance to study a network instrument with high accuracy, good stability and fast and accurate measurement of micro resistance. This topic analyses the characteristics of micro resistance measurement and the status of measurement methods, and puts forward a method of using low frequency constant current source, and proposes a digital cross correlation algorithm. In this paper, the design of the micro resistance measurement system and the whole development process are discussed in detail, which are mainly divided into the measurement theory and algorithm analysis of the micro resistance, the design of the hard parts of the measurement system, the software design of the system and the debugging of the system. The measurement theory of micro resistance, including the noise of the micro resistance measurement, the source of the interference and the signal to noise ratio analysis of the measurement channel, is first expounded. The measurement method of the current micro resistance is analyzed for the very small noise characteristics of the micro resistance measurement, and the design requirements of this subject are combined with the embedded system. The characteristics of the system are low frequency AC constant current measurement. The measurement and measurement process of low frequency constant current AC measurement method are analyzed in detail. The noise and interference in useful signals are removed by using digital cross correlation algorithm model and analyzed by MATLAB simulation experiment. The hardware design of the system, including the overall design of the hardware system, and the ARM micro The design of the minimum system and peripheral circuit of the processor, the design of high precision D/A AC signal generating circuit, the design of the voltage control constant current source circuit, the design of 16 bit high-precision A/D acquisition circuit, the design of the differential amplifier circuit, the design of the display circuit, the design of the communication circuit and the design of the electric source circuit. The software design of the system is mainly to package It includes the overall design of the software system, the main program design of the software, the dispatch and coordination of each task communication, the D/A conversion program design of the 10Hz communication signal, the design of the A/D conversion acquisition program and the design of the algorithm program, the design of the touch screen and the display program, the design of the file position matching program, the design of the communication program and the soft. The debugging of the system includes hardware debugging, software debugging and integrated debugging of the whole system. The debugging process and the debugging method of the hardware and software are elaborated in detail. The calibration method for measuring the linearity of the test system and measuring the calibration factor is put forward. Finally, the correctness of the hardware and software is verified by repeated tests. The experiment shows that the system has good linearity in the range of each range, and the measurement results and error analysis are given by each range gear. The magnitude of the minimum range profile is stable in the micro European position, and the micro European resistance can be measured. It shows that the digital cross correlation algorithm is used to remove the noise and the noise in the small resistance measurement of this subject. It has remarkable effect to improve the signal to noise ratio of the system, and it can accurately measure the micro European resistance. The designed micro resistance measurement system has achieved the expected goal, which lays a foundation for the accurate measurement and analysis of metal corrosion monitoring in the material subject resistance method.

【学位授予单位】：南昌航空大学
【学位级别】：硕士
【学位授予年份】：2017
【分类号】：TM934.1

【参考文献】