在现代焊接生产中，随着自动化、智能化程度的不断提高，焊道跟踪技术已成为自动焊接过程中最为关键的技术之一。本文基于电弧传感器理论，结合CO2焊自身熔滴短路过渡的电流变化特性，提出了一种可实现焊道坡口边界识别及焊道轨迹跟踪的自动焊接控制控制方法。在大尺寸坡口焊的摆动焊接中，通过对电弧传感器电流信号的提取、分析，并以此作为焊道边界的的识别传感信号，可实现焊炬的自动摆动。 本文通过实验建立了CO2焊电弧传感的静态模型，得到了焊炬高度与焊接电流之间的关系因子，以焊接电流的变化反映的焊炬高度的变化作为边界识别和跟踪控制的参量，为焊炬自动控制奠定了基础。 以C8051F350单片机为主控制单元，结合本课题研究的细丝（直径不大于1.6mm）CO2焊的焊接主要以短路过渡形式为主的特点，选用霍尔电流传感器设计了跟踪控制系统中的各外围电路，选择步进电机作为跟踪系统的执行机构。 根据单片机和CO2焊接的特点，设计了主程序、初始化程序模块、焊接电流信号处理程序、跟踪调节程序模块、步进电机的驱动程序模块等。针对信号处理，在A/D转换的基础上应用Matlab软件进行低通数字信号处理器的设计。 焊接过程产生的电磁辐射，对控制系统会产生电磁干扰；另外，控制系统中还存在信号线间的相互窜扰、信号线与接地线之间的共模干扰和弱电之间的干扰等，本文通过硬件、软件相结合的方法，采取了一些抗干扰措施。

Seam welding has become one of the most important technologies in the modern weld production with developing of automation and intelligence. Based on the theory model and the study of the arc sensor, together with the droplet short-circuit transfer characteristic of CO2 gas welding, to sample and analyze with the electricity signal of swing arc sensor, put forward one kind of welding following and controlling system which can achieve identify weld way track, can be used in the swing weld which of big size and the different shape ascent weld. In this paper, through experiment to constitute a static model of the CO2 weld arc sensor, to confirm the relation between welding height and weld electric current. According to the current parameter change to distinguish the welding range and control seam tracing with established the automatic control welding system. C8051F350 be used as a main control unit to meet more efficient and economical welding process. In this case, thin welding rod (<1.6mm)be used in CO2 gas welding that behave droplet short-circuit transfer characteristics, so select Hall Viltaic Sensor and design the circuit seam tracking control system, finally select Step Motor as a implement to tracking in the course of welding. It is designed program which used in seam tracking and control according to the single-chip microcomputer and CO2 gas welding peculiarity. After A/D conversion, used Matlab to design the low-pass filter, through the excellent Digital Signal Processing to meet seam tracking precision and real time. Because of violent electromagnetic radiation which interfered the system in the course of welding production and product EMI, At the same time, there are cross-talk in signal wire, and common mode interference between signal wire and ground line. so make use of the hardware and software methods to reduce these interference. Though experiment to confirm that CO2 gas sensor has the linearity. in certain condition Depend on its identity to up built the seam tracking system has excellent dynamic character and control precision, compare with other seam tracing, it has real time and economical character.