The new monthly column by Texas A&M University roboticist Robin Murphy took as its first subject the beloved droids R2-D2 and BB-8, rolling robots that play a major role in "Star Wars."
Murphy asked Dan Goldman, a physicist at Georgia Tech, whether a spherical robot like BB-8 would be able to move around over rough terrain like sand — and "he just started giggling hysterically," Murphy told Space.com. ['Star Wars' Droids That Already Exist]
Goldman described buying one of Sphero's remote-control BB-8 toys as soon as the movie came out, to set up in his lab and test robot locomotion over a variety of granular materials.
"They run sand[fish] lizards through there, they run snakes, salamanders, the whole thing," Murphy said, referring to types of moving robots. "And they put BB-8 in there, and they gave it a little ramp with plywood, and it rolled in, and then — thwump! Just buried itself into the sand. And then they tried it again — it was a repeatable experiment. The only variation would be that occasionally it would stop so suddenly the head would fly off, which is kind of fun."
(And the whole idea of BB-8's head being able to reattach itself, she added, is equally dubious.)
"There's a reason you don't see a lot of animals with wheels," Murphy said. BB-8's rollable body "is fun — I love it. But it's not what you'd actually do on those desert planets that they keep winding up on."
Instead, the best-suited robots for that terrain generally use tank-like tracks, Murphy said. Legged robots work, too, but they're harder to coordinate. Scientists like Goldman and Howie Choset, a researcher at Carnegie Mellon University, experiment with more exotic, animal-inspired robots: Sandfish lizards, which dive and swim through sand like water, serve as an inspiration, as do snakes and scorpions.
For more general-purpose locomotion, Murphy said that robots with a combination of treads and tracks, with flippers to help the robot climb stairs and get over obstacles, is one promising possibility. Legged robots are also good at navigating uneven terrain — although, again, the control mechanism has to be much more complex.
In her article, Murphy cited one case where BB-8 and R2-D2's creators might be on to something: the beeps and whistles they use to communicate. Both robots look very alien, but use their beeps, whistles and body language to convey instantly recognizable thoughts and moods.
Researchers studying robots' interactions with children and adults have found that that type of communication makes people more comfortable with them; distinctive sounds and body language are how humans are used to interacting with each other nonverbally, as well as with animals.
"It's a subconscious expectation," Murphy said. "Part of our brain can deal with the fact that the robot's not doing it, but the other part's like, 'No, it's kind of alive, I want it to behave the way a dog would, the way a person would!'"
Another benefit is that nonverbal robots don't give the wrong impression of how intelligent they are. "One of the nice things about beeps and whistles is that you know that the robot isn't trying to talk, too, at a superhigh level," Murphy said. "It's not overstating its capabilities … 'I'm paying attention, but I'm really not fully your peer intelligence.'"
Although they might not navigate well in real life, "Star Wars" robots like R2-D2 particularly stood out in science fiction because they didn't look like an animal or person in a suit.
R2-D2 "looked very, very mechanical, and very engineered for a specific purpose," Murphy said. "You weren't entirely always sure, in the movie, what the purpose was, but it looked like form was following function." For C-3PO, the robot's humanoid form made sense: It was a protocol droid intended for communicating with humans. "But it was really great to see something that's there to do repairs and help out didn't have to look like a humanoid, and that was part of the charm."
Since R2-D2's debut in 1977, "Star Wars" has displayed a rich ecosystem of robot forms. Murphy could think of only one that they hadn't tried yet.
"I think one of the coolest robot styles that they've not looked at doing is the 'Big Hero' style, the soft robot, where you're using the inflatable and conformable surfaces," Murphy said. "I think that's about the only one that they've missed in the 'Star Wars' universe.
Murphy discusses robotic principles through the lens of science fiction on the blog Robotics Through Science Fiction, and she wrote a book with the same name that will be coming out soon from MIT Press. And then there's her monthly column in Science Robotics.
"Next month, in honor of 'Pacific Rim' coming out again [its sequel premieres in March], it's going to be about exoskeletons," Murphy said. "Would we really build a huge, large machine that takes two people to be telepathically connected to [control]?"
"It turns out … exoskeletons are very useful for rehabilitation, other things like that, " she added. "We're using it as a bridge to think about robotics in a fun way."