Burrowing bot mimics Pacific mole crab

By Charles Carter, 14/10/22

Engineers from the University of California, Berkeley have built a small bot that mimics the burrowing of the Pacific mole crab.

The approach could be used in the future to build burrowing bots to explore, dig down and provide dynamic tethers for spacecraft on The Moon and other planets.

The findings from the project were published this week in the journal Frontiers in Robotics & AI.

How does it work?

The bot, called EMBUR (EMerita BUrrowing Robot), uses an innovative leg design to achieve downward motion similar to the way Pacific mole crabs bury themselves in beach sand.

Each leg has a soft fabric element which scoops away granular material during the power stroke, but folds up and retracts on the return stroke enabling the downward progress.

The team studied the physics of the mole crab’s digging technique in detail.

They found its 10 legs are split into two groups which sweep in opposite directions to each other, with a pattern of sweeping and retraction which reduces drag in one direction.

The engineers also created cuticles made of soft material to line the joints of the bot to stop sand from getting inside the different modules. This is similar to a membrane found on the mole crabs.

What are the potential benefits?

Burrowing bots like EMBUR could someday help evaluate the soil of agricultural sites, collect marine data and study soil and rock conditions at construction sites.

They could also be deployed on other planets, helping to evaluate sub surface profiles and fixing landing craft to the ground.

As well as burrowing the bot can use the same legs to walk on flat surfaces which gives it extra versatility and efficiency compared with corkscrew-shaped burrowing bots.