Robot design gets tips from sea turtles

Article By : Arizona State University

Arizona State University's turtle-bot takes a page from nature on how to navigate different types of terrain.

Insipired by how sea turtles move across sand, a group of professors and students from Arizona State University (ASU) have developed the C-Turtle robot. The robot is based mainly on characteristics of sea turtles that have evolved naturally and have shown that they can adapt to their 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 C-Turtle robots 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 of computer science, mechanical engineering, and biology researchers at Arizona State. The C-Turtle is designed with inspiration from biology so it learns how to navigate different types of terrain. It is also 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. Amor collaborated with Daniel Aukes, an assistant professor in engineering at the Polytechnic School. Amor’s background is in artificial intelligence. Aukes’ is in designing, fabricating, and building robots. 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.

The C-Turtle took one hour to learn to walk in the sand in an earlier desert test. It is 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,” Amor added. “You can use that initial inspiration from nature to get things going.”

Drawing inspiration from nature

Janssen explained the profile of a sea-turtle flipper. “It turns out the ones shaped like that work better than just a square paddle,” he said. “We tested things that are impossible in nature. They didn’t work.” The 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. “The synergy between biologist and robotics designers goes back a ways,” he said.

Another unusual aspect of the C-Turtle is that it is fabricated out of thin cardboard. It is designed to be cheap and disposable. Each robot costs about $70. The motors cost about $5 and the chips about $10. And 3D printing does away with parts machining.

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.”

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