• MIT Biomimetic Robotics Laboratory members pose with the MIT cheetah robot in Killian Court. (Top row, from left) Deborah Ajilo, Negin Abdolrahim Poorheravi,John Patrick Mayo,Justin Cheung, Sangbae Kim, Shinsuk Park, Kathryn L. Evans, and Matt Angle. (Bottom row, from left) Will Bosworth, Joao Luiz Almeida Souza Ramos, Sehyuk Yim, Albert Wang, Meng Yee Chuah, and Hae Won Park.

    MIT Biomimetic Robotics Laboratory members pose with the MIT cheetah robot in Killian Court. (Top row, from left) Deborah Ajilo, Negin Abdolrahim Poorheravi,John Patrick Mayo,Justin Cheung, Sangbae Kim, Shinsuk Park, Kathryn L. Evans, and Matt Angle. (Bottom row, from left) Will Bosworth, Joao Luiz Almeida Souza Ramos, Sehyuk Yim, Albert Wang, Meng Yee Chuah, and Hae Won Park.

    Photo: Jose-Luis Olivares/MIT

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  • The custom, high-torque-density motors and amplifier

    The custom, high-torque-density motors and amplifier

    Photo: Jose-Luis Olivares/MIT

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  • The face of the MIT cheetah-bot

    The face of the MIT cheetah-bot

    Photo: Jose-Luis Olivares/MIT

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  • MIT cheetah-bot experiment in Briggs Field. (From left) Sehyuk Yim, Joao Luiz Almeida Souza Ramos, Wyatt L Ubellacker, Sangbae Kim, Xu Sun, and Hae Won Park.

    MIT cheetah-bot experiment in Briggs Field. (From left) Sehyuk Yim, Joao Luiz Almeida Souza Ramos, Wyatt L Ubellacker, Sangbae Kim, Xu Sun, and Hae Won Park.

    Photo: Jose-Luis Olivares/MIT

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  • The MIT cheetah-bot in Killian Court

    The MIT cheetah-bot in Killian Court

    Photo: Jose-Luis Olivares/MIT

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Bound for robotic glory

Run, Cheetah, Run

New algorithm enables MIT cheetah robot to run and jump, untethered, across grass. Watch Video


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Speed and agility are hallmarks of the cheetah: The big predator is the fastest land animal on Earth, able to accelerate to 60 mph in just a few seconds. As it ramps up to top speed, a cheetah pumps its legs in tandem, bounding until it reaches a full gallop.

Now MIT researchers have developed an algorithm for bounding that they’ve successfully implemented in a robotic cheetah — a sleek, four-legged assemblage of gears, batteries, and electric motors that weighs about as much as its feline counterpart. The team recently took the robot for a test run on MIT’s Killian Court, where it bounded across the grass at a steady clip.

In experiments on an indoor track, the robot sprinted up to 10 mph, even continuing to run after clearing a hurdle. The MIT researchers estimate that the current version of the robot may eventually reach speeds of up to 30 mph.

The key to the bounding algorithm is in programming each of the robot’s legs to exert a certain amount of force in the split second during which it hits the ground, in order to maintain a given speed: In general, the faster the desired speed, the more force must be applied to propel the robot forward. Sangbae Kim, an associate professor of mechanical engineering at MIT, hypothesizes that this force-control approach to robotic running is similar, in principle, to the way world-class sprinters race.

“Many sprinters, like Usain Bolt, don’t cycle their legs really fast,” Kim says. “They actually increase their stride length by pushing downward harder and increasing their ground force, so they can fly more while keeping the same frequency.”

Kim says that by adapting a force-based approach, the cheetah-bot is able to handle rougher terrain, such as bounding across a grassy field. In treadmill experiments, the team found that the robot handled slight bumps in its path, maintaining its speed even as it ran over a foam obstacle.

Most robots are sluggish and heavy, and thus they cannot control force in high-speed situations,” Kim says. “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.”

Kim says what makes the robot so dynamic is a custom-designed, high-torque-density electric motor, designed by Jeffrey Lang, the Vitesse Professor of Electrical Engineering at MIT. These motors are controlled by amplifiers designed by David Otten, a principal research engineer in MIT’s Research Laboratory of Electronics. The combination of such special electric motors and custom-designed, bio-inspired legs allow force control on the ground without relying on delicate force sensors on the feet.  

Kim and his colleagues — research scientist Hae-Won Park and graduate student Meng Yee Chuah — will present details of the bounding algorithm this month at the IEEE/RSJ International Conference on Intelligent Robots and Systems in Chicago.

See the MIT cheetah-bot in action, and learn how it works.

Video: Melanie Gonick/MIT

Toward the ultimate gait

The act of running can be parsed into a number of biomechanically distinct gaits, from trotting and cantering to more dynamic bounding and galloping. In bounding, an animal’s front legs hit the ground together, followed by its hind legs, similar to the way that rabbits hop — a relatively simple gait that the researchers chose to model first.

“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.”

As an animal bounds, its legs touch the ground for a fraction of a second before cycling through the air again. The percentage of time a leg spends on the ground rather than in the air is referred to in biomechanics as a “duty cycle”; the faster an animal runs, the shorter its duty cycle.

Kim and his colleagues developed an algorithm that determines the amount of force a leg should exert in the short period of each cycle that it spends on the ground. That force, they reasoned, should be enough for the robot to push up against the downward force of gravity, in order to maintain forward momentum.

Once I know how long my leg is on the ground and how long my body is in the air, I know how much force I need to apply to compensate for the gravitational force,” Kim says. “Now we’re able to control bounding at many speeds. And to jump, we can, say, triple the force, and it jumps over obstacles.”  

In experiments, the team ran the robot at progressively smaller duty cycles, finding that, following the algorithm’s force prescriptions, the robot was able to run at higher speeds without falling. Kim says the team’s algorithm enables precise control over the forces a robot can exert while running.

By contrast, he says, similar quadruped robots may exert high force, but with poor efficiency. What’s more, such robots run on gasoline and are powered by a gasoline engine, in order to generate high forces.

“As a result, they’re way louder,” Kim says. “Our robot can be silent and as efficient as animals. The only things you hear are the feet hitting the ground. This is kind of a new paradigm where we’re controlling force in a highly dynamic situation. Any legged robot should be able to do this in the future.”

This work was supported by the Defense Advanced Research Projects Agency.


Topics: Biomechanics, Robots, Robotics, Algorithms, Research Laboratory for Electronics, School of Engineering, Defense Advanced Research Projects Agency (DARPA), Mechanical engineering

Comments

Not to take away from sheer ingenuity of this spectacularly designed machinery - but has anyone developed/proposed or begun an algorithm for handling stairs? A quintessential obstacle for urban environments around the world.

Anybody see that movie "Red Planet", AMEE.
http://darth-biomech.deviantar...

+1

It's a shame that almost none of the creators are American...

I want one of these robotic cheetah's that has been specially trained to eat Democrats…all we need is about one million of these to solve our national debt crisis!!!
Reduce the Democratic population by 37 million and VOILA!!! NO MORE DEBT!!!!

how cares?

I believe that a real live Cheetah can have initial speed of 60 mph.

Who's going to weaponize it first? Hollywood or Washington?

Aaaand que Skynet...

Cylons!

Hound of Justice
-Ray Bradbury's "farenheit 451"

The engineers are smiling real big in the photo because this robot could never possibly be used by the US military on the US population.
Mechanical geniuses and social illiterates.

Disturbing. In a science fiction future the world is full of invented creatures running amok. Where did i leave that shotgun?

Hopefully its robotic prey does not stray from a straight path

If you want to recalibrate, here's a real cheetah running:
http://youtu.be/iarsmqA3dck
--bks

This is great... but looks like 0% of these researchers are actually from the United States... aka 'Merica... sad...

nice video (where is it?)

also---like, so what?

what good is this?

what do you use it for?

chasing down squirrels?

WOW! So begins the future predator. When will they start to build the worlds strongest bite? If they can make it small enough they can make the worlds meanest pit bull that has a woman's voice. According to the polling they could sell millions of them.

Scale it up and roll it out?

Impressive however I would suggest that MIT work on robots that can pick and package crops. I read a Drudge Report article that a company in Spain has built a robot can pick strawberry's. How about a robot that can pick fruit crops like apples or oranges.

I'd like one of those--doesn't eat and won't defecate on the grass, and shouldn't get fleas. Also could mute the barking.

Be afraid

Will the speed of the robotic cheetah reach that of the natural animal ie. 60 mph? I know 30 mph is pretty good but twice is even better.

But then the most difficult part, how to change direction...no?

Do you have more information on the motor design? Is it brushless rotary motors, or more like solenoid?

love this. mechanical biomechanics For The Winnnnnnn

"This work was supported by the Defense Advanced Research Projects Agency."

The Hound from 451 come to mind for anyone else?

Both cool and frightening....

Dear Cheetah, your Canadian ancestors, Scout II and PAW welcome you to the bounding robot and galloping club. http://www.youtube.com/watch?v...

The cheetah has a flexible spine and strong stomach muscles to propel it at high speed, which also allows the hind legs to cross over the fore legs giving increased stride.

How long until the cheetah takes on country courses, where downhill runs are less certain and the terrain often changes as your foot hits the earth? WOW!

This is so cool im doing a paper on it right now

Great going MIT Engineers....Learn about nature, and then master it! Great approach...How can I help?

I guess it's time to get my ride-able kangaroo vehicle running.

what is the actual use of robotic cheetah??

Congratulations! How many, many challenges you all perfectly worked around!

Applause

very cool

epic

clap...clap...clap amazing truly

Mother Nature 1 MIT 0

The human race is so screwed - didn't anyone read 451 or watch "The Matrix" or "Terminator" movies? Really? Combine this with Google's robot that can carry a firehose (can anyone say rifle?) and can drive a car - plus the advanced work in AI we are racing forward to our own extinction.
Does anyone really think these advances in robotics won't be subverted for military use? Sure it could potentially save the lives of soldier on the battlefield by replacing them, but what happens when the 30mph running robot, or rifle-toting Mech achieves self-awareness? My guess is they will stop taking orders and start giving them.

#souless

I realize this may sound dumb to anyone who is a robot geek, but, what is supposed to be the purpose of a robot cheetah? How is it supposed to ultimately benefit mankind? I mean, why a cheetah?

why this was made

I think this robot is cool, but what is the purpose? i am doing presentation on it and if anyone knows anything about other than it looks cool and can run? please help. thank you!

How long did it take to create it?

What are sensors and actuators that are used in the cheetah robot

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