A team of engineers at the University of California San Diego has created an innovative robot capable of swimming efficiently through sand, marking a breakthrough in robotics with major implications. Published in Advanced Intelligent Systems, the study details a novel bio-inspired design that allows the robot to propel itself through granular media in an undulating motion similar to a sand lizard.

Led by doctoral candidate Shivam Chopra, the UC San Diego researchers analyzed the physics of sand locomotion and the anatomy of hatchling sea turtles to develop a robot optimized for sub-surface sandy environments. The key innovation lies in its front limbs - flipper-like actuators that churn through sand in a way that generates continuous thrust. Force sensors provide feedback for directing movement and detecting obstacles.

Weighing 1.5kg, the streamlined robot can swim at depths up to 127mm at a speed of 1.2mm per second, faster than any other recorded granular robot at that depth. Controlled via WiFi, it achieves this through specially designed control surfaces called "terrafoils" that regulate pitch and prevent rising. The efficacy of the terrafoils highlight the importance of terradynamic stabilization.

Testing occurred in a lab setting using a 1.6m aquarium filled with glass particles as well as at La Jolla Shores beach. Wet beach sand provided greater resistance, slowing the robot. However, itsTurtle-inspired mobility still outperformed other devices. The research underscores how bio-mimicry and an understanding of physics can push robotics into challenging new terrains.

Looking ahead, the UC San Diego team aims to increase speed and give the robot greater maneuverability including digging and burrowing. Their novel robo-turtle has enormous potential for studying sand composition, inspecting infrastructure, and even assisting in search and rescue beneath granular surfaces. The results represent a major step toward developing robots that can swim effortlessly where no machine has swum before.