Modular Design of a Polymer-Bilayer-Based Mechanically Compliant Worm-Like Robot

Area of Science:

• Robotics
• Materials Science
• Soft Matter Physics

Background:

• Traditional robots struggle with uneven terrain and confined spaces.
• Existing soft robots often incorporate rigid components, limiting their compliance.
• Biological earthworms offer a model for compliant locomotion in complex environments.

Purpose of the Study:

• To develop a mechanically compliant, modular, worm-like robot using soft polymers.
• To enable robots to navigate challenging environments inaccessible to conventional designs.
• To demonstrate peristaltic locomotion using electrothermal actuation.

Main Methods:

• Fabrication of a modular robot body from electrothermally activated polymer bilayer actuators.
• Utilizing a semicrystalline polyurethane with a large nonlinear thermal expansion coefficient.
• Design of robot segments based on a modified Timoshenko model and validated with finite element analysis.
• Implementing basic waveform patterns for electrical activation to achieve locomotion.

Main Results:

• The soft robot successfully demonstrated repeatable peristaltic locomotion.
• The robot navigated exceptionally slippery and sticky surfaces.
• The robot could be oriented in any direction and wriggle through openings smaller than its cross-section.

Conclusions:

• A fully soft, modular worm-like robot was successfully developed.
• The robot's compliant nature and electrothermal actuation enable versatile locomotion in confined and challenging terrains.
• This design overcomes limitations of rigid components in soft robotics.