a data obtaining section for obtaining a plurality of position and orientation {HEAD ~ data} at {TAIL ~ a plurality} of different teaching points previously taught and included in said welding operation program 
a data obtaining section for obtaining a plurality of position and orientation { HEAD ~ data } at { TAIL ~ a plurality } of different teaching points previously taught and included in said welding operation program
OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH HEAD HEAD HEAD HEAD HEAD REL TAIL TAIL TAIL TAIL TAIL TAIL OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH