Feasible spaces in weld gun selection

An important requirement of any robot-assisted welding process is to ensure that a set of weld locations on a work assembly can be reached by the robot-weld gun assembly without colliding with the work assembly and surrounding tooling. A weld gun that maintains a valid contact at the a weld location without interference is said to be feasible at that location. An important class of problems in welding process planning and optimization reduce to the problems of verification and synthesis of feasible weld guns for a given set of weld locations. We formulate these problems using standard geometric modeling operations and show how they can be solved in a commercial CAD system. Our approach exemplifies a more general strategy for planning in reconfigurable manufacturing in terms of configuration spaces. A prototype implementation in Unigraphics NX4 with realistic industrial models demonstrates the effectiveness of the proposed approach to weld process planning.