An RGB-D Visual Application for Error Detection in Robot Grasping Tasks

The ability to grasp is a fundamental requirement for service robots in order to perform meaningful tasks in ordinary environments. However, its robustness can be compromised by the inaccuracy (or lack) of tactile and proprioceptive sensing, especially in the presence of unforeseen slippage. As a solution, vision can be instrumental in detecting grasp errors. In this paper, we present an RGB-D visual application for discerning the success or failure in robot grasping of unknown objects, when a poor proprioceptive information and/or a deformable gripper without tactile information is used. The proposed application is divided into two stages: the visual gripper detection and recognition, and the grasping assessment (i.e. checking whether a grasping error has occurred). For that, three different visual cues are combined: colour, depth and edges. This development is supported by the experimental results on the Hobbit robot which is provided with an elastically deformable gripper.