Infrared Sensing for Adaptive Arc Welding Infrared thermography is used to sense depth of penetration

Adaptive welding enables dy­ namic altering of the welding parameters to compensate for changing environment. Sensors providing process status informa­ tion in real time are an integral part of such an adaptive system. In this investigation, infrared thermography was used as a sen­ sor to control the position of the arc and the penetration depth of the weld. Pre­ liminary work on infrared thermography showed that variation in these parameters produces a change in the surface temper­ ature distributions of the plates being welded. Subsequently, to achieve com­ puter control of these variables, image analysis techniques have been developed to quantify the changes in the tempera­ ture distribution.