Burrowing and unburrowing in submerged granular media through fluidization and shape-change

Area of Science:

• Robotics
• Underwater Exploration
• Granular Media Physics

Background:

• Subterranean exploration in submerged granular media (GM) is challenging for robots due to high drag forces.
• Existing robotic systems struggle with efficient locomotion and maneuvering within GM.

Purpose of the Study:

• To introduce a novel robotic system for subterranean exploration in submerged granular media.
• To develop a system capable of both self-burrowing and unburrowing in underwater environments.
• To investigate the effectiveness of water-jet fluidization and volume-change mechanisms for robotic locomotion in GM.

Main Methods:

• A robotic system utilizing water-jet-based fluidization for reduced drag during burrowing.
• An untethered, volume-change mechanism (inflatable bladder) for unburrowing, inspired by natural systems.
• Experimental analysis of water flow rates, depths, and comparisons between pneumatic and hydraulic untethered systems.

Main Results:

• Water-jet fluidization significantly reduces drag, enabling robots to burrow into GM with minimal force.
• The inflatable bladder mechanism proves effective for unburrowing at various depths.
• Increased water flow rates were found to accelerate the burrowing process.
• Comparisons revealed trade-offs between pneumatic and hydraulic untethered systems regarding operational time and unburrowing speed.

Conclusions:

• The developed robotic system enhances underwater robotic capabilities for subterranean exploration in granular media.
• The water-jet fluidization and inflatable bladder mechanisms offer a viable solution for efficient robotic burrowing and unburrowing.
• Potential applications include environmental monitoring and underwater archaeology, advancing robotic operations in challenging aquatic environments.