Sensors: Measurement of Dynamic Weld Pool Surface

这个传感器和传感器网络（NSF 05-526）研究项目的目标是开发一种创新的传感器，它可以测量高度动态的熔池表面，尽管池的镜面反射性质和明亮的等离子体的存在。该方法将利用三个相对简单的想法：（1）利用照明激光和等离子体中的传播之间的差异，在明亮的等离子体存在下清晰地成像从熔池表面反射的激光射线，从而将镜面反射表面从困难变为优势：（2）使用光学手段快速确定反射射线;（3）将传感器控制电路与图像传感器芯片分离，使传感器小型化，这对许多焊接应用至关重要。熔池是复杂焊接现象的起源，因此如果没有熔池表面数据，就无法完全理解焊接现象。所提出的传感器将提高观察、分析和理解焊接现象/过程的能力。此外，由于焊接现象如此复杂，必须使用数值模型;事实上，它们在描述焊接过程方面已经发挥了重要作用。不幸的是，熔池表面数据的不可用性使得精确的数值模型的开发变得困难。通过为模型验证提供数据，该项目将有助于开发高度可靠和值得信赖的数值模型。最后，测量熔池表面还可以提供知识库，从该知识库中开发下一代智能焊接机，以模仿和超越熟练焊工的技术，熟练焊工可以通过观察熔池表面来控制焊接熔深。就更广泛的影响而言，多学科研究和合作活动将为培训参与的博士后学者和博士生提供良好的机会，使其成为学术研究人员和教育工作者。大学生和高中生参与计划、课程开发和专门网站的建立将进一步扩大项目的影响。

The objective of this Sensors and Sensor Networks (NSF 05-526) research project is to develop an innovative sensor which can measure a highly dynamic weld pool surface despite the pool's specular nature and the presence of bright plasma. The approach will be to make use of three relatively simple ideas: (1) exploit the difference between propagation in illumination laser and plasma to clearly image laser rays mirrored from the weld pool surface in the presence of bright plasma, thus changing the specular surface from a difficulty to an advantage; (2) use optical means to rapidly determine the reflected rays; (3) separate the sensor control electronics from the image sensor chip to enable sensor miniaturization, crucial for many welding applications.The pool is where complex welding phenomena originate so welding phenomena cannot be understood completely without pool surface data. The proposed sensor will improve the capability to observe, analyze and understand welding phenomena/processes. In addition, because welding phenomena are so complex, numerical models must be used; in fact, they have already played a significant role in depicting aspects of the welding process. Unfortunately, the unavailability of weld pool surface data makes the development of accurate numerical models difficult. By providing data for model validation, this project will help develop highly reliable and trustworthy numerical models. Lastly, measuring the pool surface can also provide the knowledge base from which to develop the next generation of intelligent welding machines to emulate and surpass the art of skilled welders who can control weld penetration by observing the weld pool surface. In terms of broader impact, the multi-disciplinary research and collaborative activities will provide good opportunities for training the participating post-doctoral scholar and PhD student as academic researchers and educators. The plans for undergraduate and high school senior participation, curriculum development, and special website establishment would further the impact of the project.