TWI Industrial Member Report Summary 211/1983
By J Doherty and S J Holder
A study has been made of alternative approaches to the adaptive control of arc welding. This initial work has been confined to the correction of variations in joint path and gap for the vertical down MIG butt welding of steel sheet. It has been demonstrated that a relatively small computer can be used for the closed loop control of a completely mechanised MIG welding system comprising a commercial power source, traverses and wire feeder, although an inbuilt calibration system is essential to maintain adequate control of the welding parameters. The signal from a monochrome video camera has been used to view the seam ahead of the arc to provide the computer with data on the variations of joint alignment and gap width. A simple computer logic system has been used to achieve the necessary real time correction of welding
head alignment and welding parameters to cater for these variations. The complete system has been demonstrated in the laboratory for the MIG welding of 1.6mm steel sheet with a ±10° variation in joint alignment angle and 0-2mm variation in joint gap.