Abstract
Robotic welding is applied in many manufacturing industries due to higher welding efficiency and improvement in the working environment. In ships and bridges, however, the latter stages of the manufacturing process often involve large three-dimensional structures featuring tight spaces and poor groove precision, and the use of robotic welding is difficult. The main issues to be addressed in these cases are automation technology for groove sensing, as well as superior handling. In order to solve these issues, A compact, lightweight and high frequency oscillation arc method has been developed. Initial report on this subject confirmed the operations of an oscillation mechanism (maximum oscillation of 40 Hz) internalized in the torch and weighing less than 1 kg, and clarified the bead formation phenomenon in horizontal fillet welds. Second report discussed a new arc sensor that utilizes arc characteristics unique to this welding method so as to enable simultaneous detection of deviation of torch aiming and groove gap. In continuation, this paper here focused on development of an automatic control system with welding speed as a control parameter, based on the arc sensor. Using this newly developed automatic welding control system, stable weld quality was obtained for gap variation up to 3 mm. The method under discussion was applied together with this automatic control system for the further development of self-propelled automatic welding robot that is both compact and lightweight, and which features superior handling.
