A Comparison of Pneumatic Actuators for Soft Growing Vine Robots

Area of Science:

• Robotics
• Soft Robotics
• Actuation Systems

Background:

• Soft growing "vine" robots require flexible actuators for steering and tip eversion.
• Pneumatic actuators are crucial for enabling the growth and maneuverability of these robots.

Purpose of the Study:

• To compare the performance of three soft pneumatic actuator types: pouch motor, cylindrical pneumatic artificial muscle (cPAM), and fabric pneumatic artificial muscle (fPAM).
• To evaluate their suitability for vine robot applications based on eversion, bending, dynamic motion, and force output.

Main Methods:

• Comparative analysis of pouch motor, cPAM, and fPAM actuator performance.
• Evaluation of actuator dimensions and their impact on deformation and force.
• Development of an analytical model for pressure-to-bending behavior.
• Demonstration of a 4.8m vine robot in a 3D obstacle course.

Main Results:

• cPAMs showed superior bending and higher force output.
• fPAMs demonstrated faster actuation and lower eversion pressure.
• Pouch motors are advantageous for prototyping due to simple manufacturing.
• Larger actuators produced greater deformation and force; smaller actuators inflated faster.
• A new analytical model accurately predicts pressure-to-bending behavior.

Conclusions:

• The choice of pneumatic actuator impacts vine robot performance, with cPAMs being highly maneuverable.
• A 4.8m vine robot equipped with cPAMs successfully navigated complex 3D environments, including tight passages and lifting itself against gravity.
• The developed analytical model aids in designing and optimizing vine robot actuators.