A Gas-Ribbon-Hybrid Actuated Soft Finger with Active Variable Stiffness

Area of Science:

• Robotics
• Materials Science
• Mechanical Engineering

Background:

• Soft robotic grippers require adaptable stiffness for versatile object manipulation.
• Existing soft actuators often struggle to achieve both high flexibility and controllable stiffness.

Purpose of the Study:

• To propose and validate a novel hybrid actuated soft finger with active variable stiffness.
• To demonstrate the uncoupling of bending deformation and stiffness modulation.
• To develop a soft robotic gripper with enhanced manipulation capabilities.

Main Methods:

• Integration of gas-driven and ribbon-driven mechanisms in a soft finger design.
• Experimental validation of bending-deformation and output force using theoretical models.
• Assembly and testing of a dual-finger soft robotic gripper.

Main Results:

• The hybrid soft finger achieves a maximum bending angle of ~210° at low gas pressure (<35 kPa).
• Stiffness can be increased three to six times across all bending angles via the ribbon mechanism.
• A single finger can support a weight of 1.25 kg.
• The dual-finger gripper demonstrated stable grasping of diverse objects.

Conclusions:

• The gas-ribbon-hybrid actuation effectively enhances variable stiffness in soft fingers while maintaining compliance.
• The developed soft finger offers a promising approach for compact, cost-effective soft end effectors with active variable stiffness.
• This research provides insights for future soft robotics development.