Development of closed‐loop control of robotic welding processes

Purpose – The purpose of this research is to develop closed‐loop control of robotic welding processes. Design/methodology/approach – The approach being developed is the creation of three‐dimensional models of the weld pool using stereo imagining. These models will be used in a model‐based feedback control system. Fusion of more than one sensor type in the controller is used. Findings – Three‐dimensional images can be produced from stereo images of GMAW‐p weld pools. This requires coordinating the image capture with the arc pulse to allow observation of the pool. Research limitations/implications – This is a work in progress. The imaging is not being done in real time at this point in time. Future work will address this issue. Also, how the image information is to be used to make corrections within the controller is future work. Practical implications – Closing the loop on GMAW welding will allow robotic automation of welding to proceed to a much broader degree of application. Originality/value – This paper demonstrates that stereo imaging of out‐of‐position GMAW‐p weld pools is possible and the useful information can be obtained from these images. It also provides insights into the analysis required within the model‐based controller if one is to close the loop on the process specifically with regard to weld pool stability.