Robotic penstock welding

Abstract

In the hydraulic business, the steel penstock liner sections involved in construction projects are typically welded manually on site. Confronted with a scheduling conflict with a critical project, Hydro-Quebec (HQ) teamed up with LAR Machinerie (LAR) to robotize the penstock welding. HQ's SCOMPI® portable robots were put to the task. The robot's curved track provides good accessibility to the entire joint. A welding procedure was developed that allows the joint to be welded completely from the inside. To obtain satisfactory joint preparations, a unique cutting system was designed that uses a pair of oxyacetylene torches, coupled with a pair of 2D laser cameras for seam tracking. The resulting high-precision preparation allows the root pass to be performed from the inside without back gouging. This robotized technique has been employed in five different construction projects involving penstocks.