ROSE: Rotation-based Squeezing Robotic Gripper toward Universal Handling of Objects

TL;DR

ROSE introduces a rotation-based squeezing soft gripper that embraces objects by buckling a thin soft membrane around them, enabling universal handling in unstructured settings. The work provides a simple, scalable design, two analytical models for gripping pressure and skin deformation, and vision-based tactile sensing, validated by a 400,000-cycle durability test and demonstrations including a peeled egg in olive oil. Key results show high payload capacity (up to 328.7 N) with favorable payload-to-weight performance and robust grasping across shapes, sizes, and materials, while maintaining gentle contact. The approach holds promise for practical deployment on robot arms in factories, farms, and service contexts, with avenues for digital twin development and enhanced sensing.

Abstract

Robotics hand/grippers nowadays are not limited to manufacturing lines; instead, they are widely utilized in cluttered environments, such as restaurants, farms, and warehouses. In such scenarios, they need to deal with high uncertainty of the grasped objects' shapes, postures, surfaces, and material properties, which requires complex integration of sensing and decision-making process. On the other hand, integrating soft materials into the gripper's design may tolerate the above uncertainties and reduce complexity in control. In this paper, we introduce ROSE, a novel soft gripper that can embrace the object and squeeze it by buckling a funnel-liked thin-walled soft membrane around the object by simple rotation of the base. Thanks to this design, ROSE hand can adapt to a wide range of objects that can fit in the funnel and handle with gentle gripping force. Regardless of this, ROSE can generate a high lift force (up to 33kgf) while significantly reducing the normal pressure on the gripped objects. In our experiment, a 198g ROSE can be integrated into a robot arm with a single actuation and successfully lift various types of objects, even after 400,000 trials. The embracing mechanism helps reduce the dependence of friction between the object and the membrane, as ROSE could pick up a chicken egg submerged inside an olive oil tank. We also report a feasible design for equipping the ROSE hand with tactile sensing while appealing to the scalability of the design to fit a wide range of objects. Video: https://youtu.be/E1wAI09LaoY

Figures (9)

• Figure 1: From right to left, top to bottom: ROSE gripper on a robot arm picking a coffee can, and a peeled chicken egg submerged inside an olive oil container. The maximum lifting force that ROSE can endure is 328.7 N.
• Figure 2: ROSE's gripping process through three main steps: approaching, lifting, and holding an object at the heights of 0, $\Delta_l$, and $\Delta_g$, respectively.
• Figure 3: ROSE gripper's design and the skin's fabrication process.
• Figure 4: Applied line pressure $p$ on the top-half ($p_t$) and bottom-half ($p_b$) of a spherical object (radius $r$), illustrated by blue and red arrows, respectively. Each pressure consists of the horizontal ($p_h$) and vertical ($p_v$) components at a contact angle $\alpha$.
• Figure 5: Modelling of ROSE as an equivalent spring. The deformation of the skin is estimated by extension of the spring w.r.t. applied load $P$ of the gripped object.