Soft Rigid Hybrid Gripper with Inflatable Silicone Pockets for Tunable Frictional Grasping

2026-03-07

AI Summary

This work proposes a hybrid rigid-soft gripper to address the limitations of conventional rigid grippers, which often damage heavy, slippery, or fragile objects due to their reliance on high normal forces. The design integrates a rigid outer shell with an inflatable silicone chamber, enabling active modulation of the contact surface’s friction coefficient through pneumatic control rather than solely increasing gripping force. This approach allows for continuous and linear adjustment of friction, achieving stable grasping even under low clamping forces. Experimental results demonstrate that the gripper can securely and non-destructively handle delicate or low-friction objects such as eggs, tofu, fruits, and paper cups, effectively balancing grasp stability with object protection. The mechanism offers a novel strategy for soft robotic manipulation, particularly in applications requiring gentle yet reliable interaction with vulnerable items.

Technology Category

• Intelligent Robots: Manipulation
• Humans and AI: Interaction Techniques and Devices
• Computer Vision: Low Level & Physics-based Vision

Application Category

• Systems and Infrastructure for Web, Mobile and WoT: Energy management for devices in mobile Web and WoT environments
• Responsible Web: Machine-in-the-loop, human agency and autonomy
• Graph Algorithms and Modeling for the Web: Efficient manipulation of static and dynamic Web-related graphs

Abstract

Grasping objects with diverse mechanical properties, such as heavy, slippery, or fragile items, remains a significant challenge in robotics. Conventional rigid grippers typically rely on increasing the normal forces to secure an object, however, this can cause damage to fragile objects due to excessive force. To address this limitation, we propose a soft rigid hybrid gripper finger that combines rigid structural shells with soft, inflatable silicone pockets, which could be integrated into a conventional gripper. The hybrid gripper can actively modulate its surface friction by varying the internal air pressure of the silicone pockets, enabling the gripper to securely grasp objects without increasing the gripping force. This is demonstrated by fundamental experimental results, in which an increase in internal pressure leads to a proportional increase in the effective coefficient of friction. The gripping experiments also show that the integrated gripper can stably lift heavy and slippery objects or fragile, deformable objects, such as eggs, tofu, fruits, and paper cups, with minimal damage by increasing friction rather than applying high force.

Problem

• grasping
• fragile objects
• slippery objects
• tunable friction
• robotic gripper

Innovation

• soft-rigid hybrid gripper
• tunable friction
• inflatable silicone pockets
• frictional grasping
• pneumatic actuation