Visual servoing of a robot manipulator using 3-D information from hand-held camera motion

A new method of visual servoing for a robot manipulator is proposed together with the method to obtain 3-dimensional information on the object in motion via a single hand-held camera. For this, a distance formula is derived by utilizing two different images sensed from the different positions lying in the same line of sight of the camera. An iterative focusing method is also developed to effectively handle the defocusing problem. Further, a visual feedback scheme for robot motion is proposed by employing the 3-dimensional information obtained from the camera motions. In the proposed technique, it is found that computation of the coordinate relationship between hand and eye system is not necessary. To show the validities of the proposed algorithms, the PUMA 560 robot system with a newly designed hand-held camera, a robot controller including VAL controller and a vision system have been utilized and tested in real-time for grasping an arbitrarily positioned object in a 3-dimensional work volume.