Multi-Gait In-Pipe Locomotion via Programmable Friction Reorientation

Area of Science:

• Robotics
• Bio-inspired Engineering
• Materials Science

Background:

• Conventional in-pipe robots struggle with confined, curved spaces due to rigid designs.
• Existing soft crawlers often require complex multi-actuator systems for directional control.
• Biological systems offer efficient locomotion strategies using directional friction and anchor-slip mechanisms.

Purpose of the Study:

• To develop a compact, soft in-pipe robot capable of multi-directional locomotion.
• To leverage bioinspired principles of directional friction and continuum deformation for robot design.
• To enable efficient navigation in complex pipe networks using minimal actuation.

Main Methods:

• Designed a tendon-driven soft robot integrating continuum bending-twisting with modular anisotropic friction pads (AFPs).
• Optimized AFP geometry (inclination, curvature, ridge) using friction tests, modeling, and finite element analysis.
• Developed a deformation-based locomotion framework coupling tendon actuation with AFP orientation for controlled movement.

Main Results:

• Achieved three distinct locomotion modes (crawling, translation, rotation) using only two motors.
• Demonstrated repeatable anchor-slip locomotion with average speeds of 28.6 mm/s (longitudinal), 15.7 mm/s (transverse), and 11.5°/s (rotation).
• Validated stable contact and reliable gait transitions in straight, curved, and T-junction pipe sections.

Conclusions:

• The proposed friction-programmed continuum robot offers a compact and bioinspired solution for in-pipe tasks.
• The integrated design effectively mimics biological locomotion principles for enhanced maneuverability.
• This platform shows significant potential for advanced in-pipe inspection and diagnostics.