Control apparatus for tracing a weld line in a welding apparatus and control method therefor

A control apparatus for enabling a welding torch to trace a weld line in a welding apparatus while oscillating said welding torch in opposite left and right directions crossing said weld line with an overpass comprising:

• position detection means for detecting a position of said welding torch and outputting a position detecting signal representative thereof;
• first sampling means for sampling said position detecting signal with a predetermined first period and outputting a position digital signal representative thereof;
• first storage means for sequentially storing said position digital signal;
• first reading means for reading out a series of said position digital signals and outputting a position data signal comprised of a series of said position digital signals;
• current detection means for detecting a welding current flowing between said welding torch and works to be welded responsive to changes in an arc length and a wire extension and outputting a current detecting signal representative thereof;
• second sampling means for sampling said current detecting signal with a predetermined second period and outputting a current digital signal representative thereof;
• second storage means for sequentially storing said current digital signal;
• second reading means for sequentially reading out a series of said current digital signals;
• calculation means for sequentially calculating a moving average value of said current data signal comprised of a series of said current digital signals for a predetermined smoothing time interval so as to eliminate a high frequency noise component of said current digital signal, and outputting a current data signal comprised of a series of the calculated moving average values;
• composing means for composing both said position data signal outputted from said first reading means and said current data signal outputted from said calculation means, and outputting a waveform signal representing both said position data signal and said current data signal;
• and
• control means for moving the center of said oscillation to enable said welding torch to trace said weld line responsive to said waveform signal outputted from said composing means.