Quadruped Robot Shows Off More Moves
Sept. 20, 2012 --
On average, a human can run approximately 12 to 15 mph -- not bad if you're chasing down an errant Frisbee on a Sunday afternoon. But what about during an emergency? In moments like such, speed can often mean the difference between life and death. Add 60 pounds of protective gear and equipment that first responders often wear and speed and agility become a sluggish after thought. Is there anyone -- or anything -- else to turn to for a speedy rescue? "You can always send in fireman, but when it gets really bad, you’d rather lose a machine," said Jessy Grizzle, Jerry and Carol Levin Professor of Engineering at the University of Michigan. Grizzle is one of many engineers and roboticists currently working on running-robot projects for rescue efforts, humanitarian assistance and military transport. And these machines aren't your stereotypical, lumbering droids with clodhopper gaits. On the contrary, a couple of them have some real giddy-up. "These are some of the fastest legged robots that I'm aware of in today's industrial and academic laboratories," said Grizzle. We've put together a list of fleet-footed machines that, to the best of our knowledge, represents the Top 5 fastest running robots. See if you can keep up. ANALYSIS: Terror Bots Being Designed to Hunt You Down
DARPA / Boston Dynamics
Cheetah, 28.3 mph Developed and tested by Boston Dynamics for DARPA's Maximum Mobility and Manipulation (M3) program, Cheetah had already worn the crown of world's fastest robot with a land speed record of 18 mph. However, records are made to be broken and, recently, Cheetah did just that when it was clocked at 28.3 mph on a treadmill, thus trumping Bolt's top speed by .51 mph. One big difference, though: Cheetah is tethered over a treadmill. "My take on speed is that we are not trying to achieve extraordinary speeds, just trying to get legged robots into the speed range of other normal vehicles," Marc Raibert, president and founder of Boston Dynamics, wrote in an email to Discovery News. Similar to its animal inspiration, the Cheetah's back flexes back and forth like an accordion which increases its stride and running speed. "What DARPA is doing with its robotics programs," explained DARPA program manager, Dr. Gill Pratt, in a press release, "is attempting to understand and engineer into robots certain core capabilities that living organisms have refined over millennia of evolution: efficient locomotion, manipulation of objects and adaptability to environments." Later this year Boston Dynamics plans to start testing a free-running version of Cheetah capable of operating on natural terrain.
MIT Leg Lab
Planar Biped, 13.1 mph Young MC wasn't the only one busting a move back in 1989. So was a posse of engineers and roboticists from MIT's Leg Lab who were busy creating a running man of a different sort: the Planar Biped. The Planar Biped was programmed by Jeff Koechling -- now a chief scientist at Boston Dynamics -- when he was working on his PhD thesis on the limits of robot running. The machine had two telescoping legs connected to the robot's body by pivot joints at the hips. Within each leg was a hydraulic actuator that worked together with springs to change the length of the robot's leg as it ran along its circular, boom-mounted path. Algorithms used to control the Planar Biped focused on operating one leg at a time. Because the idle leg was kept short until it sprang into action, the robot ran with an alternating or hopping gait and could even do flips. The engineers used what they learned from the Planar Biped to improve legged robots that followed.
LS3, Boston Dynamics
Legged Squad Support System (LS3), 7 mph With speeds topping out at 7 mph on flat surfaces, you may think you could outrun the LS3, but I'd think twice before challenging this robot to a race. For starters, to be fair, you'd need to strap on a 400-pound back pack, because that's how much weight the LS3 has been designed to carry. Developed for DARPA by Boston Dynamics, the untethered, hydraulically powered four-legged LS3 is designed to use computer vision, sensors and GPS to follow soldiers on missions as a robotic pack mule of sorts. It's capable of relieving the squad's physical strain and fatigue by carrying over four times the weight of what an average soldier carries in gear. As the LS3 trots along over rough terrain, designers envision it will integrate with troops and interpret verbal and visual commands similar to how a trained animal interacts with its handler. Additionally, the LS3 could be an auxiliary power source, capable of recharging batteries for radios and hand-held devices. Three levels of sensors make up the LS3's head and allow the quadruped to track its leader and other objects from as far away as almost 100 feet. In the bot's robust body is the engine, cooling fans and cargo areas for gear. The LS3 may not have the physique of a sprinter, but what it lacks in speed, it makes up for in brawn. If Aesop's fable "The Tortoise and the Hare" taught us anything, it's that sometimes 'slow and steady' wins the race.
Catharine June, University of Michigan
MABEL, 6.8 mph With a peak speed of 6.8 mph, MABEL is thought to be the world's fastest bipedal robot with knees. Like a human, it has a heavier torso with light, flexible legs equipped with springs. And as a result, it has a MABEL's remarkably human-like gait. "MABEL has large springs for energy storage," said Jessy Grizzle, Jerry and Carol Levin Professor of Engineering at the University of Michigan. "They act like tendons in the human body, absorbing energy at leg impact and releasing energy when the robot is launching itself into the flight phase of running." MABEL was built in 2008 in collaboration with Jonathan Hurst, who then was a doctoral student at the Robotics Institute at Carnegie Mellon University. In the meantime, Grizzle and a variety of doctoral students from University of Michigan's Control Systems Lab have spent the last 4 years tweaking feedback algorithms to keep MABEL balanced while navigating its environment. "MABEL is a scientific test-bed for studying highly agile walking and running motions," said Grizzle. "So, speed was definitely one of our goals." Like a human runner, MABEL stays in the air for 40 percent of each stride, giving it the kind of gait suitable for speed. But not just speed for speed's sake. "We're really concerned with creating a rescue robot -- something that can go in a scenario where humans are working in a factory or living in a home, etc., and there's been a dangerous situation," Grizzle said. "There's a reason fireman don't show up on horses when they go into a home or factory because quadrupeds can't maneuver well in environments designed for upright walkers." MABEL was also funded by DARPA, along with the National Science Foundation. Grizzle and Hurst, now an assistant professor at Oregon State, are currently working on a robot that, unlike MABEL, will be untethered. "The new robot will be a free walker, able to go indoors and outdoors," Grizzle said. "The new robot, ATRIAS, won't have any such support at all. The hips can move sideways as well as forwards and backwards." Simulation's of ATRIAS calculate the robot will be able to run 11.2 mph. Testing is currently underway, so get your radar guns ready and stay tuned to see is ATRIAS sprints up the leader board.
PETMAN, 4.4 mph If MABEL left you spell bound and unable to run, get a load of PETMAN's stride. You'll be so mesmerized by it's natural human-like gait that it'll be able to outpace you just but walking. Designed and fabricated by Boston Dynamics for the US Army and DARPA, the Protection Ensemble Test Mannequin is an anthropomorphic robot used to test clothing worn by soldiers for protection against chemical warfare. Standing nearly six feet tall and weighing 180 pounds, PETMAN's top speed is 4.4 mph, which made it the fastest bipedal robot in the world before MABEL came along. But speed almost plays second fiddle to the tethered robot's other talents. Thanks to hydraulic actuation and legs equipped with shock absorbers, PETMAN can move freely, walk, crawl, do squat thrusts, perform suit-stressing calisthenics and balance itself on two feet when shoved. So if keeping pace with the machines has left you so frustrated you're thinking about pushing them off the track, take a cue from PETMAN -- the robots are just going to land back on their feet. ANALYSIS: Ginormous Armed Japanese Robot Controlled by Phone
HyQ, a quadruped robot created by the Italian Institute of Technology, already knew how to walk, trot, and kick. Last year, it learned how to quickly react to avoid falls when stepping on an obstacle. Now HyQ is back with even more tricks.
Claudio Semini, the IIT researcher who leads the project, tells us that HyQ has now a "wide repertoire of motion skills that allows it to negotiate challenging and dynamically changing terrain." He says that previous research had focused on reactive behaviors, such as overcoming obstacles or recovering from stumbles.
More recent work has centered on making the robot smarter and more autonomous. For example, Semini and his team are teaching HyQ how to use its cameras and perception sensors to plan and position its feet to traverse rough terrain.
"Like walking over stones when you want to cross a river," he says. Another trick is walking on inclined surfaces. The researchers made HyQ traverse a V-shaped platform, pressing its feet against the sides with enough force to allow it to walk without slipping and falling.
The group is also pursuing more dynamic motions such as fast trotting and reacting to disturbances, taking advantage of the robot's torque-controlled, actively compliant legs, which can adjust their stiffness and damping in real time. This capability allows the robot to absorb shocks and vibrations without damage to the body.
The researchers recently demonstrated that HyQ could perform a "flying trot," a gait in which the robot is completely off the ground during a brief period of time. And in a test that seems to be a favorite among roboticists trying to show their robot can take some hard hits, the IIT researchers slammed HyQ with a 23-kilogram [50-pound] punching bag.
Thanks to its active compliant system, the robot was able to absorb the impact and take fast lateral steps to avoid crashing on its face (if it had a face, that is.)
The IIT team created a video highlighting the old and new capabilities, some of which the researchers will describe in upcoming robotics conferences.
As you can see in the video, the IIT group seems quite happy with its results, calling HyQ "probably the most versatile quadruped robot."
We suspect that Boston Dynamics Google would disagree, claiming that title for its own agile quadrupeds, which include BigDog, LS3, and WildCat. These robots can climb slopes, walk on icy surfaces, and even sprint in circles like a crazy animal.
That said, the HyQ project is still in its infancy compared to the decades-long legged robot research at Boston Dynamics, which dates back to the 1980s when Marc Raibert founded the Leg Laboratory at Carnegie Mellon (he would later move the lab to MIT before starting Boston Dynamics in 1992). The HyQ project also has a much smaller budget compared to the funding provided by DARPA and the U.S. military to BigDog and its siblings. And in terms of design, the Boston Dynamics machines appear to be optimized for specific tasks (e.g. WildCat is designed to run fast). HyQ, on the other hand, is a single robot that can perform a broad range of motions and whose adaptability to a given task can be tweaked by software (by making the legs more stiff or more "springy," depending on the application).
Also worth pointing out is that HyQ is a much more open project, with its creators publishing ample details about the robot's design, controllers, and operation. Boston Dynamics, as you'd expect from a private company (and a military contractor), is less forthcoming in revealing how its robots work, and now that it's owned by Google, we expect that public information will be even more scarce.
So, as we've suggested before, we think that a quadruped robot olympics would be the best way of resolving this debate. And in the mean time, we think that we have a good suggestion for the IIT team to show how capable their robot is. We hear that DARPA is working really hard to recruit more international teams to join the DARPA Robotics Challenge. We would love to see HyQ get equipped with the pair of arms we had been promised and compete with Atlas and the other 'bots. A robotic Centaur is definitely what we need in the DRC!
The HyQ project is part of IIT's Dynamic Legged Systems lab and supported by the Advanced Robotics Department at IIT, in Genoa. Collaborators include the ADRL and ASL labs of ETH Zurich and the Autonomous Motion Department of the Max-Planck Institute for Intelligent systems. This week, the robot could be seen performing a live demonstration at a museum in Rovereto, Italy, as part of the European Robotics Forum 2014.
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