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One thing that turtles do very well is move across sand. That, in itself, was an inspiration for a new type of robot, the C-Turtle, developed by a team of Arizona State University professors and students.

But this robot is more than a simple machine, it is based on what has evolved naturally and has already shown that it can adapt to its environment – in this case how best to move across the ever shifting landscape of sand.

Sea turtles are “gigantic animals and they move across sand pretty easily,” said team member Andrew Janssen, an ASU doctoral candidate in evolutionary biology who helped design the robot.

Potentially, a pack of them could roam around on Earth, monitoring certain types of conditions or performing tasks like searching minefields.

The technology for the C-Turtle comes from collaboration between computer science, mechanical engineering and biology researchers at Arizona State.

C-Turtle is designed with inspiration from biology so it learns how to navigate different types of terrain. And C-Turtle is an exercise in developmental robotics, where you build robots to test hypotheses.

“From my point of view, it’s a fascinating approach,” said Heni Ben Amor, an assistant professor in ASU’s School of Computing, Informatics and Decision Systems Engineering.

Ben Amor collaborated with Daniel Aukes, an assistant professor in engineering at the Polytechnic School. Ben Amor’s background is in artificial intelligence. Aukes’ is in designing, fabricating and building robots. Ben Amor’s team worked on machine learning; Aukes’ team worked on the manufacturing aspect.

“I’m really pleased that my students were able to pair a really simple mechanism like this robot to the higher aspects of computer sciences that Heni is working on,” Aukes said.

C-Turtle took one hour to learn to walk in the sand in an earlier desert test. It’s made for sandy environments. “It finds that on its own,” Janssen said. “We don’t tell it what to do.”

“If we use tricks from nature, it learns much faster,” Ben Amor said. “You can use that initial inspiration from nature to get things going.”

Nature-inspired design succeeds

Janssen explained the profile of a sea-turtle flipper.

“It turns out the ones shaped like that work better than just a square paddle,” Janssen said. “We tested things that are impossible in nature. They didn’t work.”

C-Turtle has to dig hard to propel itself across the sand, but not so hard it digs holes.

Biology short-cuts problems in robotics, including design, Aukes added. He has worked with a biologist at Harvard, using laminate fabrication to imitate insect wings. Aukes teaches a foldable-robotics class.

“The synergy between biologist and robotics designers goes back a ways,” he said.

Another unusual aspect of C-Turtle is that it’s fabricated out of thin cardboard. They’re designed to be cheap and disposable. Each robot cost about $70. The motors cost about $5 and the chips about $10.

Three-dimensional printers are making robotics easier. Parts don’t have to be laboriously machined.

Team member Kevin Luck, a computer science doctoral candidate, envisions a stack of paper and a laser cutter being shipped to Mars someday and a fleet of bots self-assembling on the Martian surface.

“At the end of the day, you would have a working robot,” Luck said.

“How do you have a lot of these little robots collaborate and learn from each other?” Aukes asked. “I’m excited that we can use this to work on the complex dynamics between robots.”

The ASU team will present two papers about the C-Turtle this summer at MIT and Stanford. One paper will compare the design with its biological inspirations. The other will describe the robot’s algorithmic learning process in the lab and in the desert.

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