Droplet Observer for Pulsed Gas Metal Arc Welding

In this paper an observer for detecting droplet
detachment/no-detachment for a pulsed gas metal arc welding
(GMAW) is developed. The observer is based on simple calcu-
lations made on the measured welding apparatus voltage. Two
phenomena are used in the observer, one is the shape of the
voltage in a limited time interval and the other is detection of a
potential spike in the voltage. The observer is implemented on
a Migatronic embedded welding computer and tested on-line
on a welding. The observed droplet detachment is compared
with photos from a high speed camera showing good results.
One use of the droplet observer is to automatically adjust the
pulse current level to obtain a proper welding. This controller
is tested and able to achieve an appropriate welding current.