A radical new robot design may change what the next generation of Mars rovers looks like.
The six-legged robot was designed to crawl over sand like a lizard, using its C-shaped legs.
The team of Daniel Goldman, a physicist of the Georgia Institute of Technology, Chen Li, a postdoctoral fellow at the University of California at Berkeley and Tingnan Zhang, a graduate student in Goldman’s lab, studied how “terradynamics” (aerodynamics and hydrodynamics for land) could help a robot traverse loose ground.
“Figuring this out is an even more difficult problem than studying movement through fluids,” the team wrote in the study. “The complexity of the interactions with such ‘flowable ground’ may rival or even exceed that during movement in fluids.”
The team tested a number of different shapes for the small robot’s legs that would allow it to traverse a number of different terrains. Developing an all-terrain rover would mean that we could send a robot to explore any part of Mars without fear of it getting stuck. That fate met the six-wheeled Mars Exploration Rover Spirit in 2009, when its wheels were caught in loose Martian soil, ending its 7.7 kilometer trek and ending its mission.
Wheels are by far the most efficient robotic locomotive configuration, but wheeled robots are prone to getting stuck in loose ground. Legged robots are much more manoeuvrable, but suck way more power, and use much more complex systems to work, requiring more joints and motors. This also means that they are much more prone to malfunction; malfunctions that are unfixable from 140 million miles away.
Goldman’s team’s latest robot is an update on the design featured in a 2009 study published in the Preceedings of the National Academy of Sciences. The 2009 robot, named “SandBot” featured a 30-centimeter-long body, weighed 2.3 kilograms and was designed to traverse granular surfaces, specifically a 2.4 meter track lined with poppy seeds. The robot also featured six “C-limbs” shaped like apostrophes.
What the researchers learned from the first SandBot, and used in the current version, was that slowing the robot’s leg movements ensured greater control on the unstable ground, and made the poppy seeds act more like a solid surface.
The C-shaped legs on the SandBot allowed it to generate larger lift on the granular surface, as well as reduce body drag. But most importantly, unlike the straighter legs also tested on the robot, they didn’t sink into the sand-like surface.
For a video of SandBot in action, check out New Scientist.
