Visual coordination task for human-robot collaboration

In the framework of Human-Robot Collaboration, a robot and a human operator may need to move in close coordination within the same workspace. A contactless coordinated motion can be achieved using vision, mounting a camera either on the robot end-effector or on the human. We consider here one instance of such a visual coordination task, with the robot end-effector that should maintain a prescribed position with respect to a moving RGB-D camera while pointing at it. For the 3D localization of the moving camera, we compare three different techniques and introduce some improvements to the best solution found for our application. For the motion tracking problem, we introduce a relaxed version of the pointing part of the task. This allows to take advantage of the redundancy of the robot, distributing the control effort over the available degrees of freedom. The effectiveness of the proposed approach is shown by V-REP simulations and experiments with the 7-dof KUKA LWR manipulator.