Scientists working with soft robots have created devices made for exploring all manner of environments, from the air to the ocean. Soft robots can also operate on dry land. Thanks to researchers from the University of California, Santa Barbara, we now have a soft robot capable of burrowing under the ground. Designers of the robot were inspired by plants and animals that evolved to navigate subterranean spaces.
The team developed fast and controllable soft robots that can burrow through sand enabling new applications for fast, precise, and minimally invasive movement underground. The team believes their work lays mechanical foundations for a new type of robot. Researcher Nicholas Naclerio says the biggest challenge with moving to the ground is the forces involved. When trying to move the ground, the robot has to push the soil, sand, or other medium away.
Researchers used principles employed by diverse organisms that successfully swim and dig within granular media to develop new mechanisms robots can use to move. The team created a vine-like soft robot designed to mimic plants in the way they navigate by growing from their tips while the remainder of the body remains stationary. Tip extension keeps forces low localized only to the growing end. Researchers note that if the entire body moved as it grew, friction over the entire surface would increase as the robot entered the sand until it couldn’t move.
Burrowing animals were the inspiration for another strategy for the soft robot called granular fluidization. That process suspends particles in a fluid-like state allowing the animal to overcome high levels of resistance presented by sand or loose soil. The researchers specifically modeled the southern sand octopus, which shoots a jet of water into the ground and uses its arms to pull itself into the temporarily loosened sand.
The team created a small, exploratory soft robot with multiple applications where burrowing through dry granular media is needed. It has the potential to be used in soil sampling, underground installation of utilities, and erosion control. The researchers are currently working on a project with NASA to develop burrowing robots for moon exploration and other uses.