Soft Robotic Burrowing Device with Tip-Extension and Granular Fluidization

摘要

Mobile robots of all shapes and sizes move through the air, water, and over ground. However, few robots can move through the ground. Not only are the forces resisting movement much greater than in air or water, but the interaction forces are more complicated. Here we propose a soft robotic device that burrows through dry sand while requiring an order of magnitude less force than a similarly sized intruding body. The device leverages the principles of both tip-extension and granular fluidization. Like roots, the device extends from its tip; the principle of tip-extension eliminates skin drag on the sides of the body, because the body is stationary with respect to the medium. We implement this with an everting, pressure-driven thin film body. The second principle, granular fluidization, enables a granular medium to adopt a dynamic fluid-like state when pressurized fluid is passed through it, reducing the forces acting on an object moving through it. We realize granular fluidization with a flow of air through the core of the body that mixes with the medium at the tip. The proposed device could lead to applications such as search and rescue in mudslides or shallow subterranean exploration. Further, because it creates a physical conduit with its body, electrical lines, fluids, or even tools could be passed through this channel.