Design and Experiments of an Enveloping Soft Gripper by Torsional Buckling for Food Handling

Soft grippers have garnered significant attention in the food and agricultural sectors. These grippers can achieve highly compliant and damage-free object grasping through material deformation, adapting to shape changes. Among various types, envelope-type soft grippers stand out for their excellent size and shape conformability. They are capable of effectively wrapping objects, expanding the contact area, reducing the pressure per unit area on the objects, and thereby minimizing potential damage. In this study, we introduce a novel Omega-shaped soft gripper. This gripper operates by leveraging torsional buckling to induce radial contraction of the soft membrane, enabling it to wrap the grasped object. Initially, we verify the deformation characteristics through mechanical analysis and finite element simulation. Subsequently, we experimentally evaluate the performance of this soft gripper when gripping different objects. The experimental findings demonstrate that the proposed gripper features a simple structure. It can easily handle a wide variety of food and beverage objects, regardless of their size, hardness, or weight.