Passive Suction Enhanced Adhesion Pads for Soft Grippers

Abstract

The suction capabilities of octopuses' arms are an evolutionary marvel in surface adhesion that have long fascinated scientists and engineers in soft robotics. In this study, we report the design and the fabrication of a pad inspired by the suckers of the octopus O. vulgaris. The pad houses several pores connected to a vacuum system on one end and covered by a soft membrane on the other end. The membrane is used as an interface between the pad and payloads. Vacuum actuation strains the membrane resulting in a secondary passive vacuum space between the pad and a payload. Material composition and geometric parameters of the pad were first optimized using finite element analysis to maximize both conformability to rough surfaces and adhesion force. The optimized pad exhibited a 73% enhancement in adhesion force compared to a traditional pad, with the ability to adhere strongly to objects with smooth, rough, or wet surfaces, even with a small initial contact area. Finally, the pad was tested in a single joint soft finger mounted on a small gripper to showcase basic gripping capabilities on a wide range of objects.