Soft-bubble grippers for robust and perceptive manipulation

Naveen Kuppuswamy, Alex Alspach, Avinash Uttamchandani, Sam Creasey, Takuya Ikeda, Russ Tedrake

Abstract: Manipulation in cluttered environments like homes requires stable grasps, precise placement and robustness against external contact. Towards addressing these challenges, we present the Soft-bubble gripper system that combines highly compliant gripping surfaces with dense-geometry visuotactile sensing and facilitates multiple kinds of tactile perception. We first present several mechanical design advances on the Soft-bubble sensors including a fabrication technique to deposit custom patterns to the internal surface of the sensor membrane that enables tracking of shear-induced displacement of the grasped object. The depth maps output by the internal imaging sensor are used in an in-hand proximity pose estimation framework - the method better captures distances to corners or edges on the object geometry. We also extend our previous work on tactile classification and integrate the system within a robust manipulation pipeline for cluttered home environments. The capabilities of the proposed system are demonstrated through robust execution of multiple real-world manipulation tasks.