Arctech20-Mechanical weaving pipes

[shirazsu]

Dear Colleague,
with the KRC1 I want to weld two pieces of metal pipes.
During the welding process the metal pipes are rotated by manipulator with the constant speed, and the robot don't
move.
The problem is in the dimensions of the ends of pipe, namely it's not always the same (not perfectly straight line).
If I want to make a good connection I must used some pattern of the  mechanical weaving.

My question is about:
How to setting  the mechanical weaving with the trapezoidal pattern when the robot don't move in the direction of the welding, just stay in the welding position and make lateral deflection on the welding direction?   
 
any suggestion be welcome..
                                                           Thomas