基于窄间隙焊接电容传感器及跟踪方法的研究

发布时间：2018-05-13 15:28

本文选题：窄间隙焊缝跟踪 + 圆柱型相邻电容传感器　；参考：《湘潭大学》2017年硕士论文

【摘要】：随着传感器技术在工业生产中的发展,电容传感器因其具有结构紧凑,灵敏精密,非接触测量及环境适应力强等优点,在两相流测量,物品介质重建分析与高精度测量等方面应用普及。本文首先分析窄间隙焊缝跟踪系统及电容传感器的技术背景;根据窄间隙焊接和边缘电场传感器技术的特点,建立了一类用于窄间隙焊缝跟踪的圆柱型相邻电容传感器,设计了该圆柱形相邻电容传感器的基本结构。同时阐述了该圆柱形相邻电容传感器在窄间隙焊接过程中的测量原理,并对其在窄间隙焊缝检测的能力进行可行性分析。运用电磁场基本理论及Possion方程,建立了简化后的窄间隙焊缝跟踪的圆柱型电容传感数学模型。建立了安装于焊枪喷嘴的电容传感器有限元模型,分析了电容传感器在窄间隙焊缝中电场分布的特点。通过仿真几组不同极板结构下的窄间隙焊缝跟踪传感器,研究了电场分布形貌,并计算了每组传感器的测量灵敏性和穿透性;通过观察传感器在窄间隙焊缝内横向、纵向偏移时电容的变化趋势,优化了电容电极及屏蔽层结构。在该模型下,将电容-距离曲线进行非线性映射,推导了电容值与窄间隙焊缝位置关系的方程式。从仿真结果上看,圆柱型相邻电容传感器用于窄间隙焊缝跟踪系统完全可行。针对目前电容传感器测量自电容低、杂散和寄生电容过大等弊端,提出了一种测量电容值大小的放大电路及滤波电路。并采用了AD7745双通道12位的电容-数字信号转换器(CDC)采集信号,通过单片机运算提取出焊缝偏移信号,经过上位机软件与PC端控制,采集测量了两组电容值。搭建了用于测量电容的几组实验平台。文章最后对比了仿真数据与试验结果。分析试验采集的频谱信号,并通过软件滤波处理后与ANSYS分析结果相比,其变化的趋势基本相同。排除了温度及焊接飞溅等外界干扰杂波,将滤波后的信号通过非线性映射以及数学运算后提取出焊枪所在的空间位置信息,并通过焊缝曲面重建,得出的图像结果与窄间隙焊缝基本一致。通过试验最终证明了圆柱型相邻电容传感器可完美匹配窄间隙焊缝跟踪系统。
[Abstract]:With the development of sensor technology in industrial production, capacitive sensors are measured in two-phase flow because of their advantages of compact structure, sensitive precision, non-contact measurement and strong environmental adaptability. The application of material reconstruction analysis and high-precision measurement is very popular. Based on the characteristics of narrow gap welding and edge electric field sensor, a kind of cylindrical adjacent capacitance sensor for narrow gap weld tracking is established. The basic structure of the cylindrical adjacent capacitance sensor is designed. At the same time, the measuring principle of the cylindrical adjacent capacitance sensor in the process of narrow gap welding is described, and the feasibility analysis of its ability to detect the narrow gap welding seam is carried out. Based on the basic theory of electromagnetic field and Possion equation, a simplified mathematical model of cylindrical capacitance sensor for narrow gap seam tracking is established. The finite element model of capacitive sensor installed in welding torch nozzle is established, and the characteristics of electric field distribution in narrow gap weld are analyzed. By simulating several groups of narrow gap welding seam tracking sensors with different polar plate structures, the distribution of electric field was studied, and the measurement sensitivity and penetration of each group of sensors were calculated, and the transversal of the sensor in the narrow gap weld was observed. The structure of capacitance electrode and shielding layer is optimized by the change trend of capacitance during longitudinal deviation. In this model, the capacitance-distance curve is nonlinear mapped, and the equation of the relationship between the capacitance value and the position of the narrow gap weld is derived. The simulation results show that the cylindrical adjacent capacitance sensor is feasible for narrow gap seam tracking system. Aiming at the disadvantages of low self-capacitance, stray and parasitic capacitance of capacitive sensors, an amplifier circuit and a filter circuit are proposed to measure the capacitance value. The AD7745 dual-channel 12-bit capacitance-digital signal converter is used to collect the signal, and the welding seam offset signal is extracted by the single-chip computer. Two sets of capacitance values are collected and measured by the software of the upper computer and the control of the PC. Several experimental platforms are built for measuring capacitance. Finally, the simulation data and experimental results are compared. The spectrum signal collected from the experiment is analyzed, and compared with the result of ANSYS analysis, the change trend of the signal is basically the same. The filtered signal is extracted by nonlinear mapping and mathematical operation, and the position information of welding torch is extracted, and the weld surface is reconstructed. The result of the image is basically consistent with that of narrow gap weld. Finally, it is proved that the cylindrical adjacent capacitive sensor can perfectly match the narrow gap seam tracking system.
【学位授予单位】：湘潭大学
【学位级别】：硕士
【学位授予年份】：2017
【分类号】：TP212;TG409

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