Video of a Backflipping Cheetah Robot Belies a Far Loftier Goal for MIT

Meet the cute lil' 21st century version of a lab rat.

The quadruped “mini cheetah” developed at the Massachusetts Instituteof Technology has become the first four-legged robot to successfully do a backflip. The 360-degree jump from standing position is the latest in the mini cheetah’s arsenal of tricks: Kick it over, and it gets back up. Push it away, and it maintains its balance. It’s not that the engineers over at MIT aren’t vindictive; their mini cheetah has been built specifically for exactly this kind of rough-and-tumble experimentation.

If you’re going to develop robots that can handle manual labor and safely navigate construction sites, they’re going to have to be pretty tough. That presents a challenge for these robots’ would-be designers: How do you subject prototypes — ones spent years and millions of dollars developing — to rough experimentation and stress tests? That’s where bots like the mini cheetah come in, say MIT researchers.

The researchers will present the design at the International Conference on Robotics and Automation in Montreal in May. They are currently building more of the four-legged machines, aiming for a set of 10, each of which they hope to loan out to other labs.

At just 20 pounds, the mini cheetah design is entirely modular. Each of its legs is powered by three low-cost, identical motors built from off-the-shelf parts, allowing engineers to easily and quickly make adjustments. I Its preceding robot, named Cheetah 3, didn’t offer that ease of use, says lead developer Benjamin Katz.

“In Cheetah 3, everything is super integrated, so if you want to change something, you have to do a ton of redesign,” Katz said in an interview with MIT. “Whereas with the mini cheetah, if you wanted to add another arm, you could just add three or four more of these modular motors.”

Lead developer Benjamin Katz, left, and co-author Jared Di Carlo, were inspired by a class they took last year, taught by EECS Professor Russ Tedrake, and set about programming the mini cheetah to perform a backflip.
Lead developer Benjamin Katz, left, and co-author Jared Di Carlo, were inspired by a class they took last year, taught by EECS Professor Russ Tedrake, and set about programming the mini cheetah to perform a backflip.

Why Roboticists Need Lab Rats

Despite having no discernible head, the mini cheetah is still, objectively, kind of cute. But lil’ robots like the mini cheetah are not “lil’” to make you like them. They’re “lil” because they’re meant to be the 21st century version of a lab rat. Even the mini cheetah’s unofficial tagline — “We make mistakes, but Mini Cheetah is built to handle them” — hints at its larger purpose.

For centuries, medical researchers have used mice and rats as the test cases in countless studies. The rodents are small, easily transportable and low-cost. From a behavioral perspective, they’re relatively predictable; prick a rat with a needle (as horrible as that is to imagine), and the rat won’t suddenly begin stampeding through a lab. Their lifespans are naturally short, and they breed extremely quickly. And then, of course, there’s the fact that rats and humans share about 90 percent of the same DNA.

Similarly, small, low-cost robots like Boston Dynamics’ SpotMini or MIT’s mini cheetah will hopefully allow engineers to accelerate research, trying out endless limb configurations and algorithms and maneuvers before transferring them to their significantly more expensive and larger iterations. The mini cheetah, for example, has become a proxy for it’s big cat cousin, Cheetah 3.

Next on the list of “Things I can’t believe a tiny robot can do so effortlessly,” the engineering team is developing a landing controller for the mini cheetah, allowing it to, for example, be thrown out of a window and land successfully on its feet. As they say, walk before you can run; backflip before you can break through a brick wall, we guess.

MIT’s new cheetah has already struck a cord, racking up close to a million views within a week of publication. There may be more where that came from, by the time the young inventors present their designs in May, they hope to have built a cohort of at least ten mini cheetahs.

Media via MIT, http://news.mit.edu/2019/mit-mini-cheetah-first-four-legged-robot-to-backflip-0304