Not long ago, robots were largely confined to books and movies. Then they started showing up on YouTube, and robot fear became a viral thing. There was that terrifying video of a Boston Dynamics robot wearing fatigues and gas mask. Another Boston Dynamics video showed a cheetah robot that could outpace the swiftest human sprinter.
Back then, it was easy enough to imagine being run down by a robot—particularly because Boston Dynamics was funded by the military. But there was no good reason to fear them. Not yet. Why? They were all powered by internal combustion engines. Imagine being stalked by a car with no muffler. You’d hear it a mile off and climb a tree.
Well, all you robot fearing folk, the era of insanely noisy robots may be nearing an end—MIT’s stealthy electric robot cheetah is here to prowl your nightmares. (Sure, it looks friendly and playful, gamboling care-free on the quad—but don’t be fooled.)
A few facts about MIT’s pet mechanical cheetah. It’s been under development for awhile now. Earlier videos showed it heavily supported on a treadmill. This is the first time we’ve seen it roaming free outside the lab, not relying on an outside power source.
But simply being untethered does not make MIT’s bot special. Boston Dynamics released video of their cheetah (renamed WildCat) untethered in a parking lot last year.
The MIT cheetah can run 10 mph. Pretty good. WildCat clocked in at 16 mph. MIT’s bot may be ramped up to 30 miles per hour—on par with Boston Dynamics’ fastest bot in the lab. It would be an impressive demonstration of stability if it hits that mark outside.
What then makes the MIT cheetah unique?
To borrow a phrase, “This sucker’s electrical.” It runs on batteries alone. And may be able to do so for awhile. Previously, the team said their bot should be able to jog five MPH for over an hour. They’ve yet to note battery life in the wild.
In any case, no Boston Dynamics two- or four-legged robot can claim battery power. All of them—from AlphaDog to Petman and Atlas—use hydraulics and internal combustion.
Beyond silence, there are advantages to robots powered by electric motors. The MIT bot’s creators say the robot is nearly as efficient as a real cheetah. And they say, its electric motors enable more responsive footsteps and adaptable strides.
Jeffrey Lang’s custom, high-torque-density motors and amplifier—and a little cheetah print reminiscent of grandma’s steering wheel.
“Most robots are sluggish and heavy, and thus they cannot control force in high-speed situations,” says Sangbae Kim, MIT associate professor of mechanical engineering. “That’s what makes the MIT cheetah so special: You can actually control the force profile for a very short period of time, followed by a hefty impact with the ground, which makes it more stable, agile, and dynamic.”
According to Kim, beyond some clever algorithms, the bot’s secret sauce is in its custom electric motors, designed by MIT Vitesse Professor of Electrical Engineering, Jeffrey Lang, and its carefully engineered biomimetic legs—the combination allows force control without sensors in its feet.
The result? The bot can bound—a gait in between a trot and a gallop—and perhaps even more remarkably, it can leap over obstacles up to a foot high. Further, it may not be long before the robot refines its gait, moving from bounding to galloping.
“Bounding is like an entry-level high-speed gait, and galloping is the ultimate gait,” Kim says. “Once you get bounding, you can easily split the two legs and get galloping.”
Like the Boston Dynamics bots (before being acquired by Google), the MIT research is funded by the Defense Advanced Research Projects Agency (DARPA). But for the time being, there are no public plans to send these robots into combat.
For the most part, they’re being developed to carry heavy loads over difficult terrain and enter dangerous disaster zones in lieu of humans. That doesn’t mean they won’t eventually have more warlike applications—but for now, there’s no need to fear.
And whatever their eventual military uses, consumer robots will need to be battery powered too. Most personal robots already run on batteries—but they can’t do much. Perhaps, MIT’s electric cheetah foreshadows more capable robots for the home.
We don’t have I, Robot’s Sonny yet. But maybe he’s a little closer than we think.
Image Credit: Jose-Luis Olivares/MIT