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ASU team will present C-Turtle papers at MIT, Stanford this summer.
ASU-designed C-Turtle robot can navigate different terrains, built to be cheap.
May 25, 2017

Technology comes from collaboration between computer science, mechanical engineering and biology

It looks like the beginning of a Star Wars movie: a lone robot pushing itself across the sand with a pair of orange flippers toward lumpy red buttes in the distance.

Look closer at it. The leading edge is curved upward like a turtle’s bottom shell, so it doesn’t dig into the ground. The flippers are curved, also like a turtle’s.

The robot looks like a turtle because that was the intent of a pair of Arizona State University roboticists and a band of doctoral students.

It’s called C-Turtle. Designed with inspiration from biology — one of the team members is earning a doctorate in evolutionary biology — it learns how to navigate different types of terrain.

C-Turtle was an exercise in developmental robotics, where you build robots to test hypotheses. The team will present two papers about 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.


Video by Ken Fagan/ASU Now 

The robot was a collaboration between different backgrounds: computer science, mechanical engineering and biology.

“From my point of view, it’s a fascinating approach,” said Heni Ben Amor, an assistant professor in the 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 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 of learning to walk in the sand in an earlier desert test. It’s made for sandy environments. “It finds that on its own,” team member Andrew 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.”

Janssen, a doctoral candidate in evolutionary biology, helped design the robot. He traced 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. Nature-inspired, the design succeeds.

Sea turtles are “gigantic animals and they move across sand pretty easily,” Janssen said.

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

“This 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. Joseph Campbell, a Ph.D. student in the Interactive Robotics Laboratory, was one of the designers.

Three-dimensional printers are making robotics easier. Parts don’t have to be laboriously machined. Aukes teaches a foldable-robotics class.

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.

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

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

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

Scott Seckel

Reporter , ASU Now


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ASU’s Lunar Reconnaissance Orbiter Camera survives meteoroid hit

May 26, 2017

On Oct. 13, 2014, something very strange happened to the camera aboard NASA’s Lunar Reconnaissance Orbiter (LRO). The Lunar Reconnaissance Orbiter Camera (LROC), which normally produces beautifully clear images of the lunar surface, produced an image that was wild and jittery. From the sudden and jagged pattern apparent in the image, the LROC team determined that the camera must have been hit by a tiny meteoroid. 

LROC is a system of three cameras mounted on the LRO spacecraft. Two Narrow Angle Cameras (NACs) capture high resolution black and white images. The third Wide Angle Camera captures moderate resolution images using filters to provide information about the properties and color of the lunar surface. 

The NAC works by building an image one line at a time. The first line is captured, then the orbit of the spacecraft moves the camera relative to the surface, and then the next line is captured, and so on, as thousands of lines are compiled into a full image.

According to Mark Robinson, professor and principal investigator of LROC at ASU’s School of Earth and Space Exploration, the jittery appearance of the image captured is the result of a sudden and extreme cross-track oscillation of the camera. LROC researchers concluded that there must have been a brief violent movement of the left Narrow Angle Camera.

There were no spacecraft events like solar panel movements or antenna tracking that might have caused spacecraft jitter during this period. “Even if there had been, the resulting jitter would have affected both cameras identically,” Robinson said. “The only logical explanation is that the NAC was hit by a meteoroid.”

The NAC on a bench in the clean room at Malin Space Science Systems. The radiator (right) extends off the electronics end and keeps the camera’s sensor cool while imaging the moon. Computer modeling shows the meteoroid impacted somewhere on the radiator. Photo courtesy of Malin Space Science Systems/ASU

How big was the meteoroid?

During LROC’s development, a detailed computer model was made to ensure the NAC would not fail during the severe vibrations caused by the launch of the spacecraft. The computer model was tested before launch by attaching the NAC to a vibration table that simulates launch. The camera passed the test with flying colors, proving its stability. 

Using this detailed computer model, the LROC team ran simulations to see if they could reproduce the distortions seen on the Oct. 13 image and determine the size of the meteoroid that hit the camera. They estimate the impacting meteoroid would have been about half the size of a pinhead (0.8mm), assuming a velocity of about 4.3 miles (7 kilometers) per second and a density of an ordinary chondrite meteorite (2.7 grams/cm3). 

“The meteoroid was traveling much faster than a speeding bullet,” Robinson said. “In this case, LROC did not dodge a speeding bullet, but rather survived a speeding bullet!”

How rare is it that the effects of an event like this were captured on camera? Very rare, according to Robinson. LROC typically only captures images during daylight and then only about 10 percent of the day, so for the camera to be hit by a meteor during the time that it was also capturing images is statistically unlikely.

“LROC was struck and survived to keep exploring the moon,” Robinson said, “thanks to Malin Space Science Systems’ robust camera design.”  

“Since the impact presented no technical problems for the health and safety of the instrument, the team is only now announcing this event as a fascinating example of how engineering data can be used, in ways not previously anticipated, to understand what is happing to the spacecraft over 236,000 miles (380,000 kilometers) from the Earth," said John Keller, LRO project scientist from NASA’s Goddard Space Flight Center in Greenbelt, Maryland.

Launched on June 18, 2008, LRO has collected a treasure trove of data with its seven powerful instruments, making an invaluable contribution to our knowledge about the moon. 

“A meteoroid impact on the LROC NAC reminds us that LRO is constantly exposed to the hazards of space,” said Noah Petro, deputy project scientist from NASA Goddard. “And as we continue to explore the moon, it reminds us of how precious are the data that is being returned.”

LRO is managed by NASA's Goddard Space Flight Center in Greenbelt, Maryland, as a project under NASA's Discovery Program. The Discovery Program is managed by NASA's Marshall Spaceflight Center in Huntsville, Alabama, for the Science Mission Directorate at NASA Headquarters in Washington.

The Lunar Reconnaissance Orbiter Camera was developed at Malin Space Science Systems in San Diego, California and Arizona State University. 


The first wild back-and-forth line records the moment the left NAC radiator was struck by a meteoroid. Credit: NASA/Goddard Space Flight Center/Arizona State University

Karin Valentine

Media Relations & Marketing manager , School of Earth and Space Exploration