Optimal robot placement with consideration of redundancy problem for wrist-partitioned 6R articulated robots

Rapid set-up of robotic system is critical for realising the high-mix low-volume applications. This paper presents an efficient method to determine the optimal robot base placement for executing required end-effector trajectories while dealing with redundancy problem for wrist-partitioned 6 R articulated robots. The main feature of the method includes the integration of two multi-objectives optimization loops that involve parameterized inverse kinematics of the robot to find the proper robot configurations. Firstly, an optimization scheme is introduced in consideration of all the robot and operational constraints including reachability, singularity avoidance, and collision avoidance. Then, a redundancy resolution scheme is proposed based on a modified particle swarm optimization (MPSO) for the considered target point. Consequently, the optimal robot base placement is obtained via another optimization loop which includes all robot trajectories for the application. The method was applied in a complex robotic welding application. For a set of desired welding torch trajectories on the workpiece, the optimal robot base placement is computed within a few minutes.