基于焊枪姿态与熔池局部流态测量的焊工行为研究
发布时间：2018-08-06 21:31
【摘要】：近年来,随着深海资源开发中管道的全位置焊接、核工业设备中密闭空间内构件的焊接以及空间站真空、失重条件下等极限环境中焊接的加速发展,一方面这些极限环境中对焊接质量要求高,另一方面在极限环境焊接过程中危险系数极高,焊工难以在现场手工操作。而就目前而言对于人工智能、焊接环境的识别、问题规划的研究不够透彻,还不能使机器人在陌生环境中脱离焊工而自主进行焊接作业。因此急切需要新一代智能化控制焊接机器人代替焊工在危险环境中进行焊接操作。在焊接过程中熔池液态金属表面承载着众多能够反映焊接质量、焊缝成形的特征参数信息,如熔透状态,熔宽比等。要想焊接机器人像优秀的焊工一样对熔池进行稳定控制,我们需要解析焊接过程中的焊工行为,使焊工行为移植于焊接机器人。因此测量熔池表面特征参数对于研究熔池表面物理信息动态变化行为,提高焊接质量,对智能化焊接机器人发展具有十分重要的理论意义和工程应用前景。本文利用GTAW熔池表面与金属母材对光的反射方式不同这一原理,采用激光视觉法,从以下几方面对熔池动态变化过程中的焊工行为进行了研究:(1)根据激光视觉法测量原理,设计了焊枪、激光器、成像屏以及焊枪姿态传感器夹具,建立了激光视觉与焊枪姿态传感试验系统,搭建了用于测量熔池表面特征参数信息的实验平台,实现了对熔池表面动态变化特征参数信息的测量。(2)通过采集到的GTAW熔池自由表面反射的激光条纹图像,采用所设计的算法对成像屏上激光条纹亮度进行了求解,通过对比分析焊接速度、焊接电流、电弧弧长、焊枪姿态调整下的熔池表面反射激光条纹在成像屏上聚集程度的变化规律发现,焊接规范单一调节时,焊接过程中熔池稳定性差,焊缝成形也比较差,反射激光条纹亮度变化大。对比于焊工对焊枪姿态的调整,焊枪姿态调整容易使熔池达到稳定状态,而且焊缝成形好,焊接过程中成像屏上激光条纹亮度变化小。实验结果表明获得良好焊缝成形更需要较高的焊接技能和更丰富的焊接经验。(3)为了说明焊接过程中随着焊缝熔透状态的变化,投射于熔池表面的激光条纹经熔池表面反射后在成像屏上聚集状态的不同,对焊接电流和电弧弧长变化对熔透的作用进行了仿真计算,仿真计算结果表明,所建立的数学模形能够反映焊接电流和电弧弧长对熔透状态的作用过程,而且随着熔透程度越来越大,熔池表面塌陷,这时熔池表面不再是一个半球面,激光条纹反射过程条纹在凹陷的熔池表面多次反射而使成像屏上的条纹聚集,而且仿真计算结果表明了焊接电流对熔透状态的作用更加显著。(4)通过GTAW工艺试验,采用所设计的算法计算了熔池表面反射激光条纹的曲率半径,研究了在焊工焊接过程中熔池表面动态变化以及熔池液态金属局部流态变化。结果表明,在熔池中心,激光条纹曲率半径变化率最大,远离熔池中心,激光条纹曲率半径变化率越来越小。从激光条纹曲率半径变化率趋势可以说明在焊接过程中,熔池中心位置处表面变形大,流动速率大。而且从曲率半径变化率这一特征参数可以反映熔池在XOZ面上的局部流态,靠近熔池中心,其流速较大,沿中心向边缘流速逐渐减小。这一研究将为进一步测量熔池液态金属流态提供一种新的途径,从而将为机器人焊接过程的智能化控制提供一种新方法。
[Abstract]:In recent years, with the full position welding of pipelines in the development of deep sea resources, the welding of the components in the closed space in the nuclear industrial equipment, the vacuum of the space station and the heavy condition in the extreme environment, the welding quality is high in these extreme environment, on the other hand, the dangerous coefficient is very high in the process of extreme environment welding. At present, the welder is difficult to manually operate in the field. But at present, the research on the identification of artificial intelligence, welding environment and the problem planning are not thorough enough, and the robot can not make the welding work independently in the strange environment. Therefore, a new generation of intelligent control welding robot is urgently needed to replace the welder in the dangerous environment. In the process of welding, the liquid metal surface of the molten pool is loaded with a number of characteristic parameters, such as penetration status, melting width ratio, etc., which can reflect welding quality and weld formation, such as penetration and width ratio. Therefore, it is very important for the development of the intelligent welding robot to measure the surface characteristic parameters of the molten pool and to improve the quality of the welding surface and improve the welding quality. In this paper, the reflection mode of the light is different from the surface of the GTAW pool and the metal material. One principle, using laser vision method, the welder behavior in the process of dynamic change of molten pool is studied from the following aspects: (1) according to the principle of laser vision measurement, the welding gun, laser, imaging screen and welding gun attitude sensor fixture are designed, and the attitude sensing test system of laser vision and welding gun is set up, and used to measure the molten pool. The experimental platform of the surface characteristic parameter information realizes the measurement of the characteristic parameter information of the dynamic change of the molten pool surface. (2) the laser stripe luminance on the imaging screen is solved by the designed algorithm, and the welding speed, welding current and arc are compared and analyzed by the designed algorithm. (2) the laser stripe image reflected from the free surface of the molten pool is collected. When the arc length is long, the changing rule of the laser stripe reflected on the surface of the weld pool on the surface of the welding tank under the attitude adjustment of the welding gun shows that when the welding code is single, the stability of the weld pool is poor, the weld formation is poor and the brightness of the reflected laser stripe varies greatly. The adjustment of the welding gun attitude and the adjustment of the welding gun attitude are easy to be made. The weld pool is stable, and the weld is formed well. The brightness of the laser stripe on the screen is small in the process of welding. The experimental results show that the good weld formation needs higher welding skills and more abundant welding experience. (3) in order to explain the laser strip projected on the surface of the weld pool with the change of the weld penetration state during the welding process. The effect of welding current and arc length change on the penetration of the welding current and arc length is simulated. The simulation results show that the mathematical model can reflect the process of welding current and arc length to the penetration state, and as the penetration degree is increasing, the melting is more and more melting. The surface of the pool is collapsing, and the surface of the pool is no longer a hemispherical surface, and the stripe of the laser stripe reflects on the surface of the sink on the surface of the sink to gather the stripes on the imaging screen. And the simulation results show that the effect of the welding current on the penetration state is more significant. (4) through the GTAW process test, the designed algorithm is used. The curvature radius of the laser stripe is reflected on the surface of the molten pool. The dynamic changes of the molten pool surface and the change of the liquid metal flow in the weld pool are studied. The results show that the curvature radius of the laser stripe is the largest in the center of the molten pool, and the curvature radius of the laser stripe is getting smaller and smaller. The change rate trend of curvature radius can indicate that during the welding process, the surface deformation and flow rate of the center of the weld pool are large and the flow rate is large. And the characteristic parameters of the curvature radius change rate can reflect the local flow on the XOZ surface, which is close to the center of the molten pool, and the flow velocity decreases gradually along the center to the edge. One-step measurement of liquid metal flow in molten pool provides a new way for intelligent control of robot welding process.
【学位授予单位】：兰州理工大学
【学位级别】：硕士
【学位授予年份】：2017
【分类号】：TG44
[Abstract]:In recent years, with the full position welding of pipelines in the development of deep sea resources, the welding of the components in the closed space in the nuclear industrial equipment, the vacuum of the space station and the heavy condition in the extreme environment, the welding quality is high in these extreme environment, on the other hand, the dangerous coefficient is very high in the process of extreme environment welding. At present, the welder is difficult to manually operate in the field. But at present, the research on the identification of artificial intelligence, welding environment and the problem planning are not thorough enough, and the robot can not make the welding work independently in the strange environment. Therefore, a new generation of intelligent control welding robot is urgently needed to replace the welder in the dangerous environment. In the process of welding, the liquid metal surface of the molten pool is loaded with a number of characteristic parameters, such as penetration status, melting width ratio, etc., which can reflect welding quality and weld formation, such as penetration and width ratio. Therefore, it is very important for the development of the intelligent welding robot to measure the surface characteristic parameters of the molten pool and to improve the quality of the welding surface and improve the welding quality. In this paper, the reflection mode of the light is different from the surface of the GTAW pool and the metal material. One principle, using laser vision method, the welder behavior in the process of dynamic change of molten pool is studied from the following aspects: (1) according to the principle of laser vision measurement, the welding gun, laser, imaging screen and welding gun attitude sensor fixture are designed, and the attitude sensing test system of laser vision and welding gun is set up, and used to measure the molten pool. The experimental platform of the surface characteristic parameter information realizes the measurement of the characteristic parameter information of the dynamic change of the molten pool surface. (2) the laser stripe luminance on the imaging screen is solved by the designed algorithm, and the welding speed, welding current and arc are compared and analyzed by the designed algorithm. (2) the laser stripe image reflected from the free surface of the molten pool is collected. When the arc length is long, the changing rule of the laser stripe reflected on the surface of the weld pool on the surface of the welding tank under the attitude adjustment of the welding gun shows that when the welding code is single, the stability of the weld pool is poor, the weld formation is poor and the brightness of the reflected laser stripe varies greatly. The adjustment of the welding gun attitude and the adjustment of the welding gun attitude are easy to be made. The weld pool is stable, and the weld is formed well. The brightness of the laser stripe on the screen is small in the process of welding. The experimental results show that the good weld formation needs higher welding skills and more abundant welding experience. (3) in order to explain the laser strip projected on the surface of the weld pool with the change of the weld penetration state during the welding process. The effect of welding current and arc length change on the penetration of the welding current and arc length is simulated. The simulation results show that the mathematical model can reflect the process of welding current and arc length to the penetration state, and as the penetration degree is increasing, the melting is more and more melting. The surface of the pool is collapsing, and the surface of the pool is no longer a hemispherical surface, and the stripe of the laser stripe reflects on the surface of the sink on the surface of the sink to gather the stripes on the imaging screen. And the simulation results show that the effect of the welding current on the penetration state is more significant. (4) through the GTAW process test, the designed algorithm is used. The curvature radius of the laser stripe is reflected on the surface of the molten pool. The dynamic changes of the molten pool surface and the change of the liquid metal flow in the weld pool are studied. The results show that the curvature radius of the laser stripe is the largest in the center of the molten pool, and the curvature radius of the laser stripe is getting smaller and smaller. The change rate trend of curvature radius can indicate that during the welding process, the surface deformation and flow rate of the center of the weld pool are large and the flow rate is large. And the characteristic parameters of the curvature radius change rate can reflect the local flow on the XOZ surface, which is close to the center of the molten pool, and the flow velocity decreases gradually along the center to the edge. One-step measurement of liquid metal flow in molten pool provides a new way for intelligent control of robot welding process.
【学位授予单位】：兰州理工大学
【学位级别】：硕士
【学位授予年份】：2017
【分类号】：TG44
【参考文献】
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