Tag Archives: practical
Soft robots are getting more and more popular for some very good reasons. Their relative simplicity is one. Their relative low cost is another. And for their simplicity and low cost, they’re generally able to perform very impressively, leveraging the unique features inherent to their design and construction to move themselves and interact with their environment. The other significant reason why soft robots are so appealing is that they’re durable. Without the constraints of rigid parts, they can withstand the sort of abuse that would make any roboticist cringe.
In the current issue of Science Robotics, a group of researchers from Tsinghua University in China and University of California, Berkeley, present a new kind of soft robot that’s both higher performance and much more robust than just about anything we’ve seen before. The deceptively simple robot looks like a bent strip of paper, but it’s able to move at 20 body lengths per second and survive being stomped on by a human wearing tennis shoes. Take that, cockroaches.
This prototype robot measures just 3 centimeters by 1.5 cm. It takes a scanning electron microscope to actually see what the robot is made of—a thermoplastic layer is sandwiched by palladium-gold electrodes, bonded with adhesive silicone to a structural plastic at the bottom. When an AC voltage (as low as 8 volts but typically about 60 volts) is run through the electrodes, the thermoplastic extends and contracts, causing the robot’s back to flex and the little “foot” to shuffle. A complete step cycle takes just 50 milliseconds, yielding a 200 hertz gait. And technically, the robot “runs,” since it does have a brief aerial phase.
Image: Science Robotics
Photos from a high-speed camera show the robot’s gait (A to D) as it contracts and expands its body.
To put the robot’s top speed of 20 body lengths per second in perspective, have a look at this nifty chart, which shows where other animals relative running speeds of some animals and robots versus body mass:
Image: Science Robotics
This chart shows the relative running speeds of some mammals (purple area), arthropods (orange area), and soft robots (blue area) versus body mass. For both mammals and arthropods, relative speeds show a strong negative scaling law with respect to the body mass: speeds increase as body masses decrease. However, for soft robots, the relationship appears to be the opposite: speeds decrease as the body mass decrease. For the little soft robots created by the researchers from Tsinghua University and UC Berkeley (red stars), the scaling law is similar to that of living animals: Higher speed was attained as the body mass decreased.
If you were wondering, like we were, just what that number 39 is on that chart (top left corner), it’s a species of tiny mite that was discovered underneath a rock in California in 1916. The mite is just under 1 mm in size, but it can run at 0.8 kilometer per hour, which is 322 body lengths per second, making it by far (like, by a factor of two at least) the fastest land animal on Earth relative to size. If a human was to run that fast relative to our size, we’d be traveling at a little bit over 2,000 kilometers per hour. It’s not a coincidence that pretty much everything in the upper left of the chart is an insect—speed scales favorably with decreasing mass, since actuators have a proportionally larger effect.
Other notable robots on the chart with impressive speed to mass ratios are number 27, which is this magnetically driven quadruped robot from UMD, and number 86, UC Berkeley’s X2-VelociRoACH.
Anyway, back to this robot. Some other cool things about it:
You can step on it, squishing it flat with a load about 1 million times its own body weight, and it’ll keep on crawling, albeit only half as fast.
Even climbing a slope of 15 degrees, it can still manage to move at 1 body length per second.
It carries peanuts! With a payload of six times its own weight, it moves a sixth as fast, but still, it’s not like you need your peanuts delivered all that quickly anyway, do you?
Image: Science Robotics
The researchers also put together a prototype with two legs instead of one, which was able to demonstrate a potentially faster galloping gait by spending more time in the air. They suggest that robots like these could be used for “environmental exploration, structural inspection, information reconnaissance, and disaster relief,” which are the sorts of things that you suggest that your robot could be used for when you really have no idea what it could be used for. But this work is certainly impressive, with speed and robustness that are largely unmatched by other soft robots. An untethered version seems possible due to the relatively low voltages required to drive the robot, and if they can put some peanut-sized sensors on there as well, practical applications might actually be forthcoming sometime soon.
“Insect-scale Fast Moving and Ultrarobust Soft Robot,” by Yichuan Wu, Justin K. Yim, Jiaming Liang, Zhichun Shao, Mingjing Qi, Junwen Zhong, Zihao Luo, Xiaojun Yan, Min Zhang, Xiaohao Wang, Ronald S. Fearing, Robert J. Full, and Liwei Lin from Tsinghua University and UC Berkeley, is published in Science Robotics. Continue reading
Researchers at Harvard’s Wyss Institute have been testing a flexible, lightweight exosuit that can improve your metabolic efficiency by 4 to 10 percent while walking and running. This is very important because, according to a press release from Harvard, the suit can help you be faster and more efficient, whether you’re “walking at a leisurely pace,” or “running for your life.” Great!
Making humans better at running for their lives is something that we don’t put nearly enough research effort into, I think. The problem may not come up very often, but when it does, it’s super important (because, bears). So, sign me up for anything that we can do to make our desperate flights faster or more efficient—especially if it’s a lightweight, wearable exosuit that’s soft, flexible, and comfortable to wear.
This is the same sort of exosuit that was part of a DARPA program that we wrote about a few years ago, which was designed to make it easier for soldiers to carry heavy loads for long distances.
Photos: Wyss Institute at Harvard University
The system uses two waist-mounted electrical motors connected with cables to thigh straps that run down around your butt. The motors pull on the cables at the same time that your muscles actuate, helping them out and reducing the amount of work that your muscles put in without decreasing the amount of force they exert on your legs. The entire suit (batteries included) weighs 5 kilograms (11 pounds).
In order for the cables to actuate at the right time, the suit tracks your gait with two inertial measurement units (IMUs) on the thighs and one on the waist, and then adjusts its actuation profile accordingly. It works well, too, with measurable increases in performance:
We show that a portable exosuit that assists hip extension can reduce the metabolic rate of treadmill walking at 1.5 meters per second by 9.3 percent and that of running at 2.5 meters per second by 4.0 percent compared with locomotion without the exosuit. These reduction magnitudes are comparable to the effects of taking off 7.4 and 5.7 kilograms during walking and running, respectively, and are in a range that has shown meaningful athletic performance changes.
By increasing your efficiency, you can think of the suit as being able to make you walk or run faster, or farther, or carry a heavier load, all while spending the same amount of energy (or less), which could be just enough to outrun the bear that’s chasing you. Plus, it doesn’t appear to be uncomfortable to wear, and doesn’t require the user to do anything differently, which means that (unlike most robotics things) it’s maybe actually somewhat practical for real-world use—whether you’re indoors or outdoors, or walking or running, or being chased by a bear or not.
Sadly, I have no idea when you might be able to buy one of these things. But the researchers are looking for ways to make the suit even easier to use, while also reducing the weight and making the efficiency increase more pronounced. Harvard’s Conor Walsh says they’re “excited to continue to apply it to a range of applications, including assisting those with gait impairments, industry workers at risk of injury performing physically strenuous tasks, or recreational weekend warriors.” As a weekend warrior who is not entirely sure whether he can outrun a bear, I’m excited for this.
Reducing the metabolic rate of walking and running with a versatile, portable exosuit, by Jinsoo Kim, Giuk Lee, Roman Heimgartner, Dheepak Arumukhom Revi, Nikos Karavas, Danielle Nathanson, Ignacio Galiana, Asa Eckert-Erdheim, Patrick Murphy, David Perry, Nicolas Menard, Dabin Kim Choe, Philippe Malcolm, and Conor J. Walsh from the Wyss Institute for Biologically Inspired Engineering at Harvard University, appears in the current issue of Science. Continue reading
The first competitive event in the DARPA Subterranean Challenge concluded last week—hopefully you were able to follow along on the livestream, on Twitter, or with some of the articles that we’ve posted about the event. We’ll have plenty more to say about how things went for the SubT teams, but while they take a bit of a (well earned) rest, we can take a look at the winning teams as well as who won DARPA’s special superlative awards for the competition.
First Place: Team Explorer (25/40 artifacts found)
With their rugged, reliable robots featuring giant wheels and the ability to drop communications nodes, Team Explorer was in the lead from day 1, scoring in double digits on every single run.
Second Place: Team CoSTAR (11/40 artifacts found)
Team CoSTAR had one of the more diverse lineups of robots, and they switched up which robots they decided to send into the mine as they learned more about the course.
Third Place: Team CTU-CRAS (10/40 artifacts found)
While many teams came to SubT with DARPA funding, Team CTU-CRAS was self-funded, making them eligible for a special $200,000 Tunnel Circuit prize.
DARPA also awarded a bunch of “superlative awards” after SubT:
Most Accurate Artifact: Team Explorer
To score a point, teams had to submit the location of an artifact that was correct to within 5 meters of the artifact itself. However, DARPA was tracking the artifact locations with much higher precision—for example, the “zero” point on the backpack artifact was the center of the label on the front, which DARPA tracked to the millimeter. Team Explorer managed to return the location of a backpack with an error of just 0.18 meter, which is kind of amazing.
Down to the Wire: Team CSIRO Data61
With just an hour to find as many artifacts as possible, teams had to find the right balance between sending robots off to explore and bringing them back into communication range to download artifact locations. Team CSIRO Data61 cut their last point pretty close, sliding their final point in with a mere 22 seconds to spare.
Most Distinctive Robots: Team Robotika
Team Robotika had some of the quirkiest and most recognizable robots, which DARPA recognized with the “Most Distinctive” award. Robotika told us that part of the reason for that distinctiveness was practical—having a robot that was effectively in two parts meant that they could disassemble it so that it would fit in the baggage compartment of an airplane, very important for a team based in the Czech Republic.
Most Robots Per Person: Team Coordinated Robotics
Kevin Knoedler, who won NASA’s Space Robotics Challenge entirely by himself, brought his own personal swarm of drones to SubT. With a ratio of seven robots to one human, Kevin was almost certainly the hardest working single human at the challenge.
Fan Favorite: Team NCTU
Photo: Evan Ackerman/IEEE Spectrum
The Fan Favorite award went to the team that was most popular on Twitter (with the #SubTChallenge hashtag), and it may or may not be the case that I personally tweeted enough about Team NCTU’s blimp to win them this award. It’s also true that whenever we asked anyone on other teams what their favorite robot was (besides their own, of course), the blimp was overwhelmingly popular. So either way, the award is well deserved.
DARPA shared this little behind-the-scenes clip of the blimp in action (sort of), showing what happened to the poor thing when the mine ventilation system was turned on between runs and DARPA staff had to chase it down and rescue it:
The thing to keep in mind about the results of the Tunnel Circuit is that unlike past DARPA robotics challenges (like the DRC), they don’t necessarily indicate how things are going to go for the Urban or Cave circuits because of how different things are going to be. Explorer did a great job with a team of rugged wheeled vehicles, which turned out to be ideal for navigating through mines, but they’re likely going to need to change things up substantially for the rest of the challenges, where the terrain will be much more complex.
DARPA hasn’t provided any details on the location of the Urban Circuit yet; all we know is that it’ll be sometime in February 2020. This gives teams just six months to take all the lessons that they learned from the Tunnel Circuit and update their hardware, software, and strategies. What were those lessons, and what do teams plan to do differently next year? Check back next week, and we’ll tell you.
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