【作者】 陈斌；

【导师】 毛志伟；

【作者基本信息】 南昌大学 ， 机械工程， 2017， 硕士

【摘要】 随着自动化焊接行业发展,精确的焊缝跟踪技术尤为重要,焊缝跟踪的基本条件是焊缝偏差信息提取,而这一切工作均以旋转电弧传感焊理论模型为基础。对目前已有的旋转电弧焊理论模型加以改进,提高焊缝偏差提取精度大势所趋。首先分析焊接熔滴内部各作用力影响,建立旋转电弧熔滴生长数学模型,得以计算任意时刻焊接熔滴半径,有益于获取焊丝干伸长参数;再扫描收弧阶段焊缝形状拟合为焊接熔池形状,建立基于实际熔敷形状旋转电弧传感器数学模型;为验证理论模型的正确性并最终得到焊缝偏差,在理论模型基础上采用最小二乘方法,分别以上半周期电流和整周期电流拟合直线斜率提取焊缝偏差,对比结果表明以整周期焊接电流拟合直线提取焊缝偏差结果更为稳定,获得焊缝偏差提取数学模型,为偏差提取提供了理论依据。因实验室采用的低飞溅焊接电源自动短路抑制功能,针对试验焊接电流信号,研究各种经典滤波方法在空域与时域范围内对旋转电弧焊接电流信号滤波处理效果,提出一种以限幅滤波、中值滤波、最大值滤波和均值滤波相结合的组合滤波方法良好的消除了原始信号中的噪音并保留了较好的信号波形。对于焊接过程中的焊接电弧滞后现象,论文提出一种以焊接电流波形最低点为焊接电流周期起始点的信号起始点检测方法提取焊缝偏差,将提取到的偏差再一次削波处理,结果更加精确,试验证明该偏差提取方法能够良好的用于直线角焊偏差提取,误差在±0.5mm内。更多还原

【Abstract】 With the development of automatic welding industry,accurate seam tracking technology is particularly important,the basic conditions of seam tracking is to extract the seam deviation information,and all of these works are based on the theoretical model of rotating arc welding.This is the general trend of improving the extraction accuracy of weld deviation by improving the existing theoretical models of rotating arc welding.Firstly,the influence of the internal force in the welding droplet is analyzed for the establishment of rotating arc droplet growth mathematical model to calculate the droplet radius and get the parameters of wire extension.Then,Fitting welding pool shape by Scanning the weld shape at arc suppression stage to establish the mathematical model of rotating arc sensor based on the actual weld shape.In order to verify the correctness of the theoretical model and finally get the weld deviation,respectively using least squares method fitting line with half cycle and complete alternation current based on this model,extracting weld deviation according to the fitting straight line slope.The comparison results show that the results of the whole cycle welding current fitting line are more stable.Finally the mathematical model of weld deviation extraction is obtained,which provides a theoretical basis for deviation extraction.Because of automatic short circuit suppression function of the low spatter welding power supply.according to the current signal of trial weld,researching the effect of various classical filtering methods on the processing of rotating arc welding current signal in the space and time domain,filtering,maximum filtering,median filter and verage filter are brought together to a combined filtering method clipping which is proposed to eliminate the noise in the original signal and keep better signal waveform.In this paper,because of the welding arc hysteresis,a method of starting point detection based on the lowest point of welding current waveform as the starting point of welding current is proposed to attain weld deviation.The result of weld deviation is more accurate after a Clipping processing,and the experiment results show that this method can be used to extract the deviation of fillet welding,and the error is about 0.5mm.更多还原