학술논문

A Restorable, Variable Stiffness Pneumatic Soft Gripper Based on Jamming of Strings of Beads
Document Type
Periodical
Source
IEEE Transactions on Robotics IEEE Trans. Robot. Robotics, IEEE Transactions on. 39(5):4065-4077 Oct, 2023
Subject
Robotics and Control Systems
Computing and Processing
Components, Circuits, Devices and Systems
Actuators
Yarn
Jamming
Grippers
Soft robotics
Bending
Grasping
Grippers and other end-effectors
particle jamming
soft robot applications
soft robot materials and design
Language
ISSN
1552-3098
1941-0468
Abstract
Soft robots based on particle jamming cannot return to the initial position and initial mechanical state due to the accumulation of particles after removing the particle jamming, which means poor restorability, and the compliance of the robots during deformation will be reduced because of the jamming effect. Here, we present the design, fabrication, and tests of a novel soft actuator with good restorability and compliance. To improve the restorability of the actuator, we used cotton threads to connect the spherical acrylic beads into form strings instead of discrete beads. The beads could be pulled to the initial position by the threads, the actuator also returns to the initial state. To avoid the jamming effect during the deformation of the actuator, we used compressed air to drive the actuator and injected the beads into the actuator after the active deformation. To reduce the driving pressure and facilitate the flow of the beads, an initial noncontact, frame-type strain constraint structure was designed for the soft actuator. Experimental data show that the actuator was flexible during bending and the stiffness can increase more than 12-fold to resist the external load. By pulling the threads, the actuator could be restored to the initial state with an error of less than 3% of the actuator length after an operation cycle. The soft gripper based on the actuator can grasp repeatedly or laterally. The gripper can grasp soft objects such as a piece of tofu and a balloon of water, and the maximum weight that can be stably grasped is 2.744 kg.