Combining arm and hand metrics for sensible grasp selection.

In this paper we propose an approach to robot grasp prioritization based on a combined arm-and-hand metric. Most traditional approaches evaluate grasps based on hand-centric metrics such as force-closure, finger spread, contact surface area and similar measures. While these are certainly important factors to predict the robustness of a grasp, they do not carry information on the feasibility of the reaching action needed to execute the grasp. Based on our observations of physical pick-up experiments, we suggest that the execution success of a pick-up task is partially dependant on the easiness of the reaching movement. We present our metric, which combines 2 measures involving arm-kinematics and an existing hand heuristic metric. Results of simulated as well as physical experiments in our robot, Crichton, are presented.