<i>Soft yet secure</i> : Exploring membrane buckling for achieving a versatile grasp with a rotation-driven squeezing gripper

Nowadays, there is a growing demand for versatile robotic grippers that facilitate adaptive grasping across a range of objects, characterized by diverse attributes such as shapes, sizes, and mechanical properties. This research introduces a new soft gripper, denoted as ROSE ( RO tation-based S queezing Gripp E r), dedicated to the torsional buckling phenomenon to achieve its grasping capability. The inherent gripping pattern, formed through a single rotational actuation, enables ROSE to dynamically accommodate various objects (relatively smaller than the diameter of ROSE), even in challenging environments like an oil container, without a complicated controller. Experimental tests demonstrate that ROSE exhibits substantial gripping force, reaching up to more than 300 N in the specific setup, and a remarkable payload-to-weight ratio. Especially, ROSE can maintain mechanical integrity through long-term open-close operation cycles in a specific condition. In this paper, we also introduce non-linear simulations for the elaboration of behaviors of ROSE concerning different morphologies, encompassing geometry configurations and material properties. The findings highlight a significant correlation between morphological features and grasping performance, leading to the refinement of a dependable version of ROSE. This refined version was subsequently assessed through experimental trials in crop harvesting tasks, where ROSE demonstrated high success rates in picking both individual and clustered crops, regardless of their soft or stiff characteristics. Project’s website with videos: https://sites.google.com/view/rosesoftgripper .