Vision Based Control for Space Applications

This paper presents the work performed in the context of the VIMANCO ESA project. It has the o bjective of improving the autonomy, safety and robustness of robotics system using vision. The approach we propose is based on an up -to -date recognition and 3D tracking method that allows to determine if a known obje ct is visible on only one image, to comp ute its pose and to track it in real time along the image sequence acquired by the camera, even in the presence of varying lighting conditions, partial occlusions, and aspects changes. The robustness of the proposed method has been achieved by combining an efficient low level image processing step, statistical techniques to take into account potential outliers, and a formulation of the registration step as a closed loop minimization scheme. This approach is valid if only one camera observes the object, but can also be applied to a multi-cameras system. Finally, this approach provides all the necessary data for the manipulation of non cooperative objects using the general formalism of visual servoing, which is a closed loop control scheme on visual data expre ssed either in the image, or in 3D, or even in both spaces simultaneously. This formalism can be applied whatever the vision sensor configuration (one or several cameras) with respect to the robot arms (eye - in -hand or eye -to -hand systems). The global appro ach has been integrated and validated in the Eurobot testbed located at ESTEC. 2. Background, Objectives and Overall Approach