Near-contact grasping strategies from awkward poses: When simply closing your fingers is not enough

Abstract

Grasping a simple object from the side is easy - unless the object is almost as big as the hand or space constraints require positioning the robot hand awkwardly with respect to the object. We show that humans - when faced with this challenge - adopt coordinated finger movements which enable them to successfully grasp objects even from these awkward poses. We also show that it is relatively straight forward to implement these strategies autonomously. Our human-studies approach asks participants to perform grasping task by either “puppetteering” a robotic manipulator that is identical (geometrically and kinematically) to a popular underactuated robotic manipulator (the Barrett hand), or using sliders to control the original Barrett hand. Unlike previous studies, this enables us to directly capture and compare human manipulation strategies with robotic ones. Our observation is that, while humans employ underactuation, how they use it is fundamentally different (and more effective) than that found in existing hardware.