A Novel Soft Bending Actuator Using Combined Positive and Negative Pressures

Area of Science:

• Robotics
• Materials Science
• Mechanical Engineering

Background:

• Traditional soft pneumatic actuators rely on either positive or negative pressure for bending actuation.
• Existing designs are constrained by the limitations of single-pressure systems, impacting force and deformation capabilities.

Purpose of the Study:

• To develop and characterize a novel soft bending actuator utilizing combined positive and negative pressures (PNP).
• To evaluate the actuator's force output, bending deformation, and performance in soft robotic grippers.

Main Methods:

• Design and fabrication of a single actuating structure integrating both positive and negative pressure chambers.
• Experimental testing to measure blocked force and bending angles under various PNP conditions.
• Implementation of the actuator in soft robotic grippers for object manipulation tasks.

Main Results:

• The PNP actuator achieved a maximum blocked force of 150 N at 60 kPa positive and 60 kPa negative pressure.
• PNP actuation demonstrated lower equilibrium angles than negative pressure alone but higher forces at lower angles than positive pressure alone.
• The actuator enabled a soft robotic gripper to lift 4 kg and a pinching gripper to hold a 1.85 kg notebook.

Conclusions:

• The novel PNP soft bending actuator offers a versatile solution for applications requiring both high forces and large bending deformations.
• Its ability to generate large forces at low bending angles and large bending angles independently makes it suitable for delicate yet heavy object manipulation.
• Potential applications include agriculture, where delicate handling of large, heavy items is crucial.