Stacking Jacobians Properly in Stereo Visual Servoing
Résumé
Most visual servoing applications are concerned with geometrically modeled objects. In this paper, the problem of controlling a motion by visual servoing around an unknown object with a stereovision system is addressed. The main goal is to move the end-effector around the object in order to observe several viewpoints of the object for other tasks, e.g. inspection or grasping. The present work uses the well-known image-based visual servoing approach with a point, but the importance of the relationship between the end-effector and camera frames is clarified and emphasized. This relationship is needed for properly stacking the Jaco-bians or interaction matrices of each camera. A comparison with a visual servoing approach with a direct stacking of the Jacobians is presented. The centroid of a region, obtained by color segmentation, is used to move around the observed object. Experiments are developed on a PA-10 robot connected to a real time stereovision system, with two cameras mounted on the end-effector. Experimental results demonstrate the importance of a proper definition of the stacked Jaco-bians, to avoid undesired motions in the servoing task. Particularly, when turning around an unknown object, undesired motions on roll angle of the stereovision system can be avoided.
Domaines
Automatique / RobotiqueOrigine | Fichiers produits par l'(les) auteur(s) |
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