Soft robotics · Manipulation

A Soft Gripper Driven by Bellow Actuators and Twist Actuators for Dexterous Grasping

A soft gripper integrating bellow actuators and soft twisting actuators for dexterous grasping: the in-plane rotation of its OSPA fingers lets it grip and lift fragile or flat objects simultaneously — from cherry tomatoes to sheets of paper.

ROBIO 2021

Overview

Conventional rigid grippers struggle with soft, fragile, or flat objects. This work proposes a soft gripper that combines soft bellow actuators with origami-inspired soft twisting actuators (Actuator II OSPAs), a slider, and a supporting frame. Inflating the actuators opens the gripper; deflating them makes the two actuators shrink and rotate in opposite directions, closing the gripper while generating an in-plane rolling motion at the contact.

That rotation is the key capability: it lets the gripper clamp and lift at the same moment, which is advantageous for small fragile items and flat flexible objects that most soft grippers cannot pick up.

Key results

  • Gently grasped a cherry tomato (~30 mm diameter) using the rotation motion of the OSPAs.
  • Handled objects up to 50 mm in diameter and over 500 g in weight.
  • Picked up a piece of paper and plastic film through friction and in-plane motion, where most previous soft grippers were inadequate.
  • Demonstrated a stable lifting mode that transports a strawberry from the lower to the upper contact surface during grasping, reducing prolonged gripping stress on delicate objects.
Media

Videos

Three local supplementary videos show adaptive grasping, in-hand manipulation, and impact resistance.

~30 mm
cherry tomato grasped
500 g+
max object weight
50 mm
max object diameter
2
OSPA twist actuators

Reference

A Soft Gripper Driven by Bellow Actuators and Twist Actuators for Dexterous Grasping
Diancheng Li†, Liangmin Zhou†, Renjie Zhu, Jintao Yin, Zhengbai Liu, Han Yuan, Hongqiang Wang*
2021 IEEE International Conference on Robotics and Biomimetics (ROBIO 2021)