In context
By late 2024, soft grippers had become a key focus in robotics for handling irregular objects in mixed-flow production lines, yet their low stiffness and poor load capacity limited industrial adoption. Researchers were actively exploring variable-stiffness mechanisms, with particle jamming offering simple, rapid control but suffering from shape uncertainty due to particle reorganization.
What was reported
A team from Shanghai University of Engineering Science designed a soft finger combining a pneumatic network actuator with a honeycomb-structured particle jamming module. The honeycomb support partitions the particles, preventing shape distortion during bending while maintaining low stiffness for conformability.
Using Ogden hyperelastic theory and constant-volume principles, they modeled the actuator's bending; a separate model captured particle contact in the jamming structure. Finite element analysis optimized structural parameters, and prototypes were cast via 3D-printed molds.
Experiments showed a maximum deflection angle of 153.2° at 30 kPa driving pressure and a stiffness of 0.1038 N/mm under −50 kPa vacuum—markedly better than existing variable-stiffness designs. A three-finger gripper demonstrated excellent shape adaptation and wrapping in grasping tests.
Why it mattered
This work addresses a core limitation of particle jamming—shape uncertainty—by integrating a honeycomb support, making soft grippers more reliable for industrial tasks requiring both compliance and load-bearing. The improved stiffness range and conformability could accelerate deployment in automated handling of delicate or irregular parts.
“The proposed design can solve the problem of shape uncertainty caused by particle reorganization.”
Source: 《机器人》期刊 (robot.sia.cn) · Published 2024-11-15 · “一种基于蜂巢结构的颗粒阻塞变刚度软体手指”