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