大型工件中小圆弧机器人联动焊接方法研究

Research on the method of small arc robot linkage welding in large workpiece

建立弧形焊缝的联动模型,并推导弧形焊缝与机械手臂空间相对位移关系。基于该联动模型,通过动态仿真实验,着重研究焊丝熔敷速度与焊枪移动速度以及设备极限速度之间的关系。在此基础上,进一步研究焊接机器人送丝速度对焊枪移动速度以及圆弧半径的影响规律,建立转向架构架小尺寸圆弧联动模型。基于弧形焊缝的联动模型,建立焊丝熔敷速度与焊接速度按相同比例同时降低的“同比降速法”,可有效保证焊丝熔敷速度与焊接速度变化后焊缝填充量的一致,焊缝打底层焊接速度最大降比为11%;建立相邻圆弧合并后增大其半径的“轮廓模糊法”,最大降低外部轴移动速度10%;建立支撑机器人轴的大型外部轴摆放至直指弧线中间位置的“大臂取中法”,优化弧形焊缝联动焊接模型中的数据,将九轴联动焊接降至七轴联动焊接,使得焊接机器人各轴联动焊接时的稳定性达到最佳。

The linkage model of the arc weld is established,and the relative displacement relationship between the arc weld and the robot arm space is derived.Based on the linkage model,the relationship between wire deposition speed and torch movement speed and equipment limit speed is studied through dynamic simulation experiments.On this basis,the influence law of welding robot wire feeding speed on welding gun moving speed and arc radius is further studied,and the small-scale arc linkage model of steering frame is established.Based on the linkage model of arc welding seam,the method of"year-on-year reduction"is established,which can effectively ensure the consistency of welding wire deposition speed and filling quantity of weld seam after the change of welding speed.The maximum reduction ratio of welding speed of bottom layer of weld seam is 11%.The radius of weld seam is increased after the merging of adjacent arcs.The contour blurring method can reduce the moving speed of the external axle by 10%.The method of taking the center arm of the large external axle supporting the robot axle to the middle position of the straight-fingered arc line is established to optimize the data in the model of arc seam linkage welding,and reduce the nine-axis linkage welding to seven-axis linkage welding,so that the axes of the welding robot can be connected.The stability of dynamic welding is the best.