Exploratory Hand: Leveraging Safe Contact to Facilitate Manipulation in Cluttered Spaces

Abstract

We present a new gripper and exploration approach that uses a finger with very low reflected inertia for probing and then grasping objects. The finger employs a transparent transmission, resulting in a light touch when contact occurs. The finger elements are stiff and mounted on precise Cartesian axes for accurate proprioceptive sensing. Experiments show that the finger can safely move faster into contacts than industrial parallel jaw grippers or even most force-controlled grippers with backdrivable transmissions. This property allows rapid proprioceptive probing of objects. Contact information is leveraged to execute grasping actions with a contact-first strategy and to reduce environment state uncertainty. We evaluate a particle filtering algorithm that inputs contact information from either proprioception, or a combination of tactile sensing and proprioception, to estimate object location. Both methods can estimate location within 2 mm; combined tactile sensing and proprioception requires fewer observations.