基于多经验参数约束的等离子弧焊熔池边缘检测

对等离子弧焊接熔池图像边缘提取算法进行了研究.拍摄了等离子弧焊接正面熔池,发现强烈的正面电弧弧光被熔池液态金属表面反射后在图像中形成大面积的灰度饱和区,弧光区域边界的灰度梯度远大于真实熔池边缘的灰度梯度,导致常规的图像处理算法不能准确地将熔池边界提取出来.针对这一问题,提出多经验参数约束的边缘检测算法,使用前n幅已处理熔池图像边缘信息和弧光最小外接曲线等多种经验参数作为引导信息对图像边缘进行约束,剔除伪边界,检测出真实的熔池边缘信息.将所提取的边缘信息与试验测量结果进行比较,表明所提出的算法能够有效快速地检测出熔池边缘.     

Detection of keyhole entrance and exit in plasma arc welding

Sensing of keyhole shape and size is important for controlling of plasma arc welding process. In this study, a synchronous vision system is developed by using two CCD cameras to observe the keyhole entrance and exit simultaneously. Experiments are conducted on stainless steel workpiece, Whole keyhole exit image and part of keyhole entrance image are captured synchronously under different welding conditions. Image processing and calibration algorithms are proposed. The boundary and front point of the keyhole entrance and exit are extracted respectively. The effects of welding current and welding speed on ,front point of keyhole entrance and exit are analyzed. Compared to the front point of the keyhole entrance, the position of the front point of the keyhole exit is better to reflect the variation of the welding parameters.     

铝/钢异种金属MIG电弧熔-钎焊接界面应力演变数值分析

基于搭接结构造成的电弧热源非对称分布和过热熔滴热焓的热作用特征,建立非对称型四椭圆面热源和均匀体热源的组合热源,并基于热-弹-塑性有限元理论,数值分析1 mm厚5052铝合金和2 mm厚镀锌钢搭接接头MIG电弧熔-钎焊接应力应变场演变,讨论残余应力分布特征.计算结果表明,随着到焊缝中心的距离增加,镀锌钢母材近钎焊缝区域...