Catenary-based visual servoing for tethered robots

Tethers are used to supply power and transfer data for teleoperated robots. They are known to limit the robot's workspace and could have the effect of hampering its motion. What if we could take advantage of the tether? In this paper a new visual servoing scheme for catenary shaped deformable objects is introduced in order to control the tether parametric shape by properly moving its fixation point. In most of the visual servoing approaches the target object is rigid and distant from the controlled robot. On the contrary, in this paper, the object is deformable and attached to the robot, thus its 3D shape changes while the robot is moving. The experimental system is composed of two terrestrial mobile robots of the same motion capabilities linked with a slack rope. Simulation and real experiments validate the proposed control scheme for proper tether handling.