Abstract
Increasing the productivity by reducing waiting times for collision avoidance between adjacent robots has been an important issue in multi-robot welding systems. Minimization of welding job completion time by path optimization is one of the methods for the purpose. Optimization of directions and positions of workpieces when arranging them on the working stage is more effective method. In case of rectangular workpiece, the algorithm for optimizing directions by tabu search and positions by nonlinear programming has been developed in this research. Its effectiveness is shown by numerical simulations with practical workpieces.