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#438755 Soft Legged Robot Uses Pneumatic ...
Soft robots are inherently safe, highly resilient, and potentially very cheap, making them promising for a wide array of applications. But development on them has been a bit slow relative to other areas of robotics, at least partially because soft robots can’t directly benefit from the massive increase in computing power and sensor and actuator availability that we’ve seen over the last few decades. Instead, roboticists have had to get creative to find ways of achieving the functionality of conventional robotics components using soft materials and compatible power sources.
In the current issue of Science Robotics, researchers from UC San Diego demonstrate a soft walking robot with four legs that moves with a turtle-like gait controlled by a pneumatic circuit system made from tubes and valves. This air-powered nervous system can actuate multiple degrees of freedom in sequence from a single source of pressurized air, offering a huge reduction in complexity and bringing a very basic form of decision making onto the robot itself.
Generally, when people talk about soft robots, the robots are only mostly soft. There are some components that are very difficult to make soft, including pressure sources and the necessary electronics to direct that pressure between different soft actuators in a way that can be used for propulsion. What’s really cool about this robot is that researchers have managed to take a pressure source (either a single tether or an onboard CO2 cartridge) and direct it to four different legs, each with three different air chambers, using an oscillating three valve circuit made entirely of soft materials.
Photo: UCSD
The pneumatic circuit that powers and controls the soft quadruped.
The inspiration for this can be found in biology—natural organisms, including quadrupeds, use nervous system components called central pattern generators (CPGs) to prompt repetitive motions with limbs that are used for walking, flying, and swimming. This is obviously more complicated in some organisms than in others, and is typically mediated by sensory feedback, but the underlying structure of a CPG is basically just a repeating circuit that drives muscles in sequence to produce a stable, continuous gait. In this case, we’ve got pneumatic muscles being driven in opposing pairs, resulting in a diagonal couplet gait, where diagonally opposed limbs rotate forwards and backwards at the same time.
Diagram: Science Robotics
(J) Pneumatic logic circuit for rhythmic leg motion. A constant positive pressure source (P+) applied to three inverter components causes a high-pressure state to propagate around the circuit, with a delay at each inverter. While the input to one inverter is high, the attached actuator (i.e., A1, A2, or A3) is inflated. This sequence of high-pressure states causes each pair of legs of the robot to rotate in a direction determined by the pneumatic connections. (K) By reversing the sequence of activation of the pneumatic oscillator circuit, the attached actuators inflate in a new sequence (A1, A3, and A2), causing (L) the legs of the robot to rotate in reverse. (M) Schematic bottom view of the robot with the directions of leg motions indicated for forward walking.
Diagram: Science Robotics
Each of the valves acts as an inverter by switching the normally closed half (top) to open and the normally open half (bottom) to closed.
The circuit itself is made up of three bistable pneumatic valves connected by tubing that acts as a delay by providing resistance to the gas moving through it that can be adjusted by altering the tube’s length and inner diameter. Within the circuit, the movement of the pressurized gas acts as both a source of energy and as a signal, since wherever the pressure is in the circuit is where the legs are moving. The simplest circuit uses only three valves, and can keep the robot walking in one single direction, but more valves can add more complex leg control options. For example, the researchers were able to use seven valves to tune the phase offset of the gait, and even just one additional valve (albeit of a slightly more complex design) could enable reversal of the system, causing the robot to walk backwards in response to input from a soft sensor. And with another complex valve, a manual (tethered) controller could be used for omnidirectional movement.
This work has some similarities to the rover that JPL is developing to explore Venus—that rover isn’t a soft robot, of course, but it operates under similar constraints in that it can’t rely on conventional electronic systems for autonomous navigation or control. It turns out that there are plenty of clever ways to use mechanical (or in this case, pneumatic) intelligence to make robots with relatively complex autonomous behaviors, meaning that in the future, soft (or soft-ish) robots could find valuable roles in situations where using a non-compliant system is not a good option.
For more on why we should be so excited about soft robots and just how soft a soft robot needs to be, we spoke with Michael Tolley, who runs the Bioinspired Robotics and Design Lab at UCSD, and Dylan Drotman, the paper’s first author.
IEEE Spectrum: What can soft robots do for us that more rigid robotic designs can’t?
Michael Tolley: At the very highest level, one of the fundamental assumptions of robotics is that you have rigid bodies connected at joints, and all your motion happens at these joints. That's a really nice approach because it makes the math easy, frankly, and it simplifies control. But when you look around us in nature, even though animals do have bones and joints, the way we interact with the world is much more complicated than that simple story. I’m interested in where we can take advantage of material properties in robotics. If you look at robots that have to operate in very unknown environments, I think you can build in some of the intelligence for how to deal with those environments into the body of the robot itself. And that’s the category this work really falls under—it's about navigating the world.
Dylan Drotman: Walking through confined spaces is a good example. With the rigid legged robot, you would have to completely change the way that the legs move to walk through a confined space, while if you have flexible legs, like the robot in our paper, you can use relatively simple control strategies to squeeze through an area you wouldn’t be able to get through with a rigid system.
How smart can a soft robot get?
Drotman: Right now we have a sensor on the front that's connected through a fluidic transmission to a bistable valve that causes the robot to reverse. We could add other sensors around the robot to allow it to change direction whenever it runs into an obstacle to effectively make an electronics-free version of a Roomba.
Tolley: Stepping back a little bit from that, one could make an argument that we’re using basic memory elements to generate very basic signals. There’s nothing in principle that would stop someone from making a pneumatic computer—it’s just very complicated to make something that complex. I think you could build on this and do more intelligent decision making, but using this specific design and the components we’re using, it’s likely to be things that are more direct responses to the environment.
How well would robots like these scale down?
Drotman: At the moment we’re manufacturing these components by hand, so the idea would be to make something more like a printed circuit board instead, and looking at how the channel sizes and the valve design would affect the actuation properties. We’ll also be coming up with new circuits, and different designs for the circuits themselves.
Tolley: Down to centimeter or millimeter scale, I don’t think you’d have fundamental fluid flow problems. I think you’re going to be limited more by system design constraints. You’ll have to be able to locomote while carrying around your pressure source, and possibly some other components that are also still rigid. When you start to talk about really small scales, though, it's not as clear to me that you really need an intrinsically soft robot. If you think about insects, their structural geometry can make them behave like they’re soft, but they’re not intrinsically soft.
Should we be thinking about soft robots and compliant robots in the same way, or are they fundamentally different?
Tolley: There’s certainly a connection between the two. You could have a compliant robot that behaves in a very similar way to an intrinsically soft robot, or a robot made of intrinsically soft materials. At that point, it comes down to design and manufacturing and practical limitations on what you can make. I think when you get down to small scales, the two sort of get connected.
There was some interesting work several years ago on using explosions to power soft robots. Is that still a thing?
Tolley: One of the opportunities with soft robots is that with material compliance, you have the potential to store energy. I think there’s exciting potential there for rapid motion with a soft body. Combustion is one way of doing that with power coming from a chemical source all at once, but you could also use a relatively weak muscle that over time stores up energy in a soft body and then releases it.
Is it realistic to expect complete softness from soft robots, or will they likely always have rigid components because they have to store or generate and move pressurized gas somehow?
Tolley: If you look in nature, you do have soft pumps like the heart, but although it’s soft, it’s still relatively stiff. Like, if you grab a heart, it’s not totally squishy. I haven’t done it, but I’d imagine. If you have a container that you’re pressurizing, it has to be stiff enough to not just blow up like a balloon. Certainly pneumatics or hydraulics are not the only way to go for soft actuators; there has been some really nice work on smart muscles and smart materials like hydraulic electrostatic (HASEL) actuators. They seem promising, but all of these actuators have challenges. We’ve chosen to stick with pressurized pneumatics in the near term; longer term, I think you’ll start to see more of these smart material actuators become more practical.
Personally, I don’t have any problem with soft robots having some rigid components. Most animals on land have some rigid components, but they can still take advantage of being soft, so it’s probably going to be a combination. But I do also like the vision of making an entirely soft, squishy thing. Continue reading →
Posted in Human Robots
#437929 These Were Our Favorite Tech Stories ...
This time last year we were commemorating the end of a decade and looking ahead to the next one. Enter the year that felt like a decade all by itself: 2020. News written in January, the before-times, feels hopelessly out of touch with all that came after. Stories published in the early days of the pandemic are, for the most part, similarly naive.
The year’s news cycle was swift and brutal, ping-ponging from pandemic to extreme social and political tension, whipsawing economies, and natural disasters. Hope. Despair. Loneliness. Grief. Grit. More hope. Another lockdown. It’s been a hell of a year.
Though 2020 was dominated by big, hairy societal change, science and technology took significant steps forward. Researchers singularly focused on the pandemic and collaborated on solutions to a degree never before seen. New technologies converged to deliver vaccines in record time. The dark side of tech, from biased algorithms to the threat of omnipresent surveillance and corporate control of artificial intelligence, continued to rear its head.
Meanwhile, AI showed uncanny command of language, joined Reddit threads, and made inroads into some of science’s grandest challenges. Mars rockets flew for the first time, and a private company delivered astronauts to the International Space Station. Deprived of night life, concerts, and festivals, millions traveled to virtual worlds instead. Anonymous jet packs flew over LA. Mysterious monoliths appeared and disappeared worldwide.
It was all, you know, very 2020. For this year’s (in-no-way-all-encompassing) list of fascinating stories in tech and science, we tried to select those that weren’t totally dated by the news, but rose above it in some way. So, without further ado: This year’s picks.
How Science Beat the Virus
Ed Yong | The Atlantic
“Much like famous initiatives such as the Manhattan Project and the Apollo program, epidemics focus the energies of large groups of scientists. …But ‘nothing in history was even close to the level of pivoting that’s happening right now,’ Madhukar Pai of McGill University told me. … No other disease has been scrutinized so intensely, by so much combined intellect, in so brief a time.”
‘It Will Change Everything’: DeepMind’s AI Makes Gigantic Leap in Solving Protein Structures
Ewen Callaway | Nature
“In some cases, AlphaFold’s structure predictions were indistinguishable from those determined using ‘gold standard’ experimental methods such as X-ray crystallography and, in recent years, cryo-electron microscopy (cryo-EM). AlphaFold might not obviate the need for these laborious and expensive methods—yet—say scientists, but the AI will make it possible to study living things in new ways.”
OpenAI’s Latest Breakthrough Is Astonishingly Powerful, But Still Fighting Its Flaws
James Vincent | The Verge
“What makes GPT-3 amazing, they say, is not that it can tell you that the capital of Paraguay is Asunción (it is) or that 466 times 23.5 is 10,987 (it’s not), but that it’s capable of answering both questions and many more beside simply because it was trained on more data for longer than other programs. If there’s one thing we know that the world is creating more and more of, it’s data and computing power, which means GPT-3’s descendants are only going to get more clever.”
Artificial General Intelligence: Are We Close, and Does It Even Make Sense to Try?
Will Douglas Heaven | MIT Technology Review
“A machine that could think like a person has been the guiding vision of AI research since the earliest days—and remains its most divisive idea. …So why is AGI controversial? Why does it matter? And is it a reckless, misleading dream—or the ultimate goal?”
The Dark Side of Big Tech’s Funding for AI Research
Tom Simonite | Wired
“Timnit Gebru’s exit from Google is a powerful reminder of how thoroughly companies dominate the field, with the biggest computers and the most resources. …[Meredith] Whittaker of AI Now says properly probing the societal effects of AI is fundamentally incompatible with corporate labs. ‘That kind of research that looks at the power and politics of AI is and must be inherently adversarial to the firms that are profiting from this technology.’i”
We’re Not Prepared for the End of Moore’s Law
David Rotman | MIT Technology Review
“Quantum computing, carbon nanotube transistors, even spintronics, are enticing possibilities—but none are obvious replacements for the promise that Gordon Moore first saw in a simple integrated circuit. We need the research investments now to find out, though. Because one prediction is pretty much certain to come true: we’re always going to want more computing power.”
Inside the Race to Build the Best Quantum Computer on Earth
Gideon Lichfield | MIT Technology Review
“Regardless of whether you agree with Google’s position [on ‘quantum supremacy’] or IBM’s, the next goal is clear, Oliver says: to build a quantum computer that can do something useful. …The trouble is that it’s nearly impossible to predict what the first useful task will be, or how big a computer will be needed to perform it.”
The Secretive Company That Might End Privacy as We Know It
Kashmir Hill | The New York Times
“Searching someone by face could become as easy as Googling a name. Strangers would be able to listen in on sensitive conversations, take photos of the participants and know personal secrets. Someone walking down the street would be immediately identifiable—and his or her home address would be only a few clicks away. It would herald the end of public anonymity.”
Wrongfully Accused by an Algorithm
Kashmir Hill | The New York Times
“Mr. Williams knew that he had not committed the crime in question. What he could not have known, as he sat in the interrogation room, is that his case may be the first known account of an American being wrongfully arrested based on a flawed match from a facial recognition algorithm, according to experts on technology and the law.”
Predictive Policing Algorithms Are Racist. They Need to Be Dismantled.
Will Douglas Heaven | MIT Technology Review
“A number of studies have shown that these tools perpetuate systemic racism, and yet we still know very little about how they work, who is using them, and for what purpose. All of this needs to change before a proper reckoning can take pace. Luckily, the tide may be turning.”
The Panopticon Is Already Here
Ross Andersen | The Atlantic
“Artificial intelligence has applications in nearly every human domain, from the instant translation of spoken language to early viral-outbreak detection. But Xi [Jinping] also wants to use AI’s awesome analytical powers to push China to the cutting edge of surveillance. He wants to build an all-seeing digital system of social control, patrolled by precog algorithms that identify potential dissenters in real time.”
The Case For Cities That Aren’t Dystopian Surveillance States
Cory Doctorow | The Guardian
“Imagine a human-centered smart city that knows everything it can about things. It knows how many seats are free on every bus, it knows how busy every road is, it knows where there are short-hire bikes available and where there are potholes. …What it doesn’t know is anything about individuals in the city.”
The Modern World Has Finally Become Too Complex for Any of Us to Understand
Tim Maughan | OneZero
“One of the dominant themes of the last few years is that nothing makes sense. …I am here to tell you that the reason so much of the world seems incomprehensible is that it is incomprehensible. From social media to the global economy to supply chains, our lives rest precariously on systems that have become so complex, and we have yielded so much of it to technologies and autonomous actors that no one totally comprehends it all.”
The Conscience of Silicon Valley
Zach Baron | GQ
“What I really hoped to do, I said, was to talk about the future and how to live in it. This year feels like a crossroads; I do not need to explain what I mean by this. …I want to destroy my computer, through which I now work and ‘have drinks’ and stare at blurry simulations of my parents sometimes; I want to kneel down and pray to it like a god. I want someone—I want Jaron Lanier—to tell me where we’re going, and whether it’s going to be okay when we get there. Lanier just nodded. All right, then.”
Yes to Tech Optimism. And Pessimism.
Shira Ovide | The New York Times
“Technology is not something that exists in a bubble; it is a phenomenon that changes how we live or how our world works in ways that help and hurt. That calls for more humility and bridges across the optimism-pessimism divide from people who make technology, those of us who write about it, government officials and the public. We need to think on the bright side. And we need to consider the horribles.”
How Afrofuturism Can Help the World Mend
C. Brandon Ogbunu | Wired
“…[W. E. B. DuBois’] ‘The Comet’ helped lay the foundation for a paradigm known as Afrofuturism. A century later, as a comet carrying disease and social unrest has upended the world, Afrofuturism may be more relevant than ever. Its vision can help guide us out of the rubble, and help us to consider universes of better alternatives.”
Wikipedia Is the Last Best Place on the Internet
Richard Cooke | Wired
“More than an encyclopedia, Wikipedia has become a community, a library, a constitution, an experiment, a political manifesto—the closest thing there is to an online public square. It is one of the few remaining places that retains the faintly utopian glow of the early World Wide Web.”
Can Genetic Engineering Bring Back the American Chestnut?
Gabriel Popkin | The New York Times Magazine
“The geneticists’ research forces conservationists to confront, in a new and sometimes discomfiting way, the prospect that repairing the natural world does not necessarily mean returning to an unblemished Eden. It may instead mean embracing a role that we’ve already assumed: engineers of everything, including nature.”
At the Limits of Thought
David C. Krakauer | Aeon
“A schism is emerging in the scientific enterprise. On the one side is the human mind, the source of every story, theory, and explanation that our species holds dear. On the other stand the machines, whose algorithms possess astonishing predictive power but whose inner workings remain radically opaque to human observers.”
Is the Internet Conscious? If It Were, How Would We Know?
Meghan O’Gieblyn | Wired
“Does the internet behave like a creature with an internal life? Does it manifest the fruits of consciousness? There are certainly moments when it seems to. Google can anticipate what you’re going to type before you fully articulate it to yourself. Facebook ads can intuit that a woman is pregnant before she tells her family and friends. It is easy, in such moments, to conclude that you’re in the presence of another mind—though given the human tendency to anthropomorphize, we should be wary of quick conclusions.”
The Internet Is an Amnesia Machine
Simon Pitt | OneZero
“There was a time when I didn’t know what a Baby Yoda was. Then there was a time I couldn’t go online without reading about Baby Yoda. And now, Baby Yoda is a distant, shrugging memory. Soon there will be a generation of people who missed the whole thing and for whom Baby Yoda is as meaningless as it was for me a year ago.”
Digital Pregnancy Tests Are Almost as Powerful as the Original IBM PC
Tom Warren | The Verge
“Each test, which costs less than $5, includes a processor, RAM, a button cell battery, and a tiny LCD screen to display the result. …Foone speculates that this device is ‘probably faster at number crunching and basic I/O than the CPU used in the original IBM PC.’ IBM’s original PC was based on Intel’s 8088 microprocessor, an 8-bit chip that operated at 5Mhz. The difference here is that this is a pregnancy test you pee on and then throw away.”
The Party Goes on in Massive Online Worlds
Cecilia D’Anastasio | Wired
“We’re more stand-outside types than the types to cast a flashy glamour spell and chat up the nearest cat girl. But, hey, it’s Final Fantasy XIV online, and where my body sat in New York, the epicenter of America’s Covid-19 outbreak, there certainly weren’t any parties.”
The Facebook Groups Where People Pretend the Pandemic Isn’t Happening
Kaitlyn Tiffany | The Atlantic
“Losing track of a friend in a packed bar or screaming to be heard over a live band is not something that’s happening much in the real world at the moment, but it happens all the time in the 2,100-person Facebook group ‘a group where we all pretend we’re in the same venue.’ So does losing shoes and Juul pods, and shouting matches over which bands are the saddest, and therefore the greatest.”
Did You Fly a Jetpack Over Los Angeles This Weekend? Because the FBI Is Looking for You
Tom McKay | Gizmodo
“Did you fly a jetpack over Los Angeles at approximately 3,000 feet on Sunday? Some kind of tiny helicopter? Maybe a lawn chair with balloons tied to it? If the answer to any of the above questions is ‘yes,’ you should probably lay low for a while (by which I mean cool it on the single-occupant flying machine). That’s because passing airline pilots spotted you, and now it’s this whole thing with the FBI and the Federal Aviation Administration, both of which are investigating.”
Image Credit: Thomas Kinto / Unsplash Continue reading →
Posted in Human Robots
#437776 Video Friday: This Terrifying Robot Will ...
Video Friday is your weekly selection of awesome robotics videos, collected by your Automaton bloggers. We’ll also be posting a weekly calendar of upcoming robotics events for the next few months; here's what we have so far (send us your events!):
CLAWAR 2020 – August 24-26, 2020 – [Virtual Conference]
ICUAS 2020 – September 1-4, 2020 – Athens, Greece
ICRES 2020 – September 28-29, 2020 – Taipei, Taiwan
IROS 2020 – October 25-29, 2020 – Las Vegas, Nevada
ICSR 2020 – November 14-16, 2020 – Golden, Colorado
Let us know if you have suggestions for next week, and enjoy today's videos.
The Aigency, which created the FitBot launch video below, is “the world’s first talent management resource for robotic personalities.”
Robots will be playing a bigger role in our lives in the future. By learning to speak their language and work with them now, we can make this future better for everybody. If you’re a creator that’s producing content to entertain and educate people, robots can be a part of that. And we can help you. Robotic actors can show up alongside the rest of your actors.
The folks at Aigency have put together a compilation reel of clips they’ve put on TikTok, which is nice of them, because some of us don’t know how to TikTok because we’re old and boring.
Do googly eyes violate the terms and conditions?
[ Aigency ]
Shane Wighton of the “Stuff Made Here” YouTube channel, who you might remember from that robotic basketball hoop, has a new invention: A haircut robot. This is not the the first barber bot, but previous designs typically used hair clippers. Shane wanted his robot to use scissors. Hilarious and terrifying at once.
[ Stuff Made Here ]
Starting in October of 2016, Prof. Charlie Kemp and Henry M. Clever invented a new kind of robot. They named the prototype NewRo. In March of 2017, Prof. Kemp filmed this video of Henry operating NewRo to perform a number of assistive tasks. While visiting the Bay Area for a AAAI Symposium workshop at Stanford, Prof. Kemp showed this video to a select group of people to get advice, including Dr. Aaron Edsinger. In August of 2017, Dr. Edsinger and Dr. Kemp founded Hello Robot Inc. to commercialize this patent pending assistive technology. Hello Robot Inc. licensed the intellectual property (IP) from Georgia Tech. After three years of stealthy effort, Hello Robot Inc. revealed Stretch, a new kind of robot!
[ Georgia Tech ]
NASA’s Ingenuity Mars Helicopter will make history's first attempt at powered flight on another planet next spring. It is riding with the agency's next mission to Mars (the Mars 2020 Perseverance rover) as it launches from Cape Canaveral Air Force Station later this summer. Perseverance, with Ingenuity attached to its belly, will land on Mars February 18, 2021.
[ JPL ]
For humans, it can be challenging to manipulate thin flexible objects like ropes, wires, or cables. But if these problems are hard for humans, they are nearly impossible for robots. As a cable slides between the fingers, its shape is constantly changing, and the robot’s fingers must be constantly sensing and adjusting the cable’s position and motion. A group of researchers from MIT’s Computer Science and Artificial Intelligence Laboratory (CSAIL) and from the MIT Department of Mechanical Engineering pursued the task from a different angle, in a manner that more closely mimics us humans. The team’s new system uses a pair of soft robotic grippers with high-resolution tactile sensors (and no added mechanical constraints) to successfully manipulate freely moving cables.
The team observed that it was difficult to pull the cable back when it reached the edge of the finger, because of the convex surface of the GelSight sensor. Therefore, they hope to improve the finger-sensor shape to enhance the overall performance. In the future, they plan to study more complex cable manipulation tasks such as cable routing and cable inserting through obstacles, and they want to eventually explore autonomous cable manipulation tasks in the auto industry.
[ MIT ]
Gripping robots typically have troubles grabbing transparent or shiny objects. A new technique by Carnegie Mellon University relies on color camera system and machine learning to recognize shapes based on color.
[ CMU ]
A new robotic prosthetic leg prototype offers a more natural, comfortable gait while also being quieter and more energy efficient than other designs. The key is the use of new small and powerful motors with fewer gears, borrowed from the space industry. This streamlined technology enables a free-swinging knee and regenerative braking, which charges the battery during use with energy that would typically be dissipated when the foot hits the ground. This feature enables the leg to more than double a typical prosthetic user's walking needs with one charge per day.
[ University of Michigan ]
Thanks Kate!
This year’s Wonder League teams have been put to the test not only with the challenges set forth by Wonder Workshop and Cartoon Network as they look to help the creek kids from Craig of the Creek solve the greatest mystery of all – the quest for the Lost Realm but due to forces outside their control. With a global pandemic displacing many teams from one another due to lockdowns and quarantines, these teams continued to push themselves to find new ways to work together, solve problems, communicate more effectively, and push themselves to complete a journey that they started and refused to give up on. We at Wonder Workshop are humbled and in awe of all these teams have accomplished.
[ Wonder Workshop ]
Thanks Nicole!
Meet Colin Creager, a mechanical engineer at NASA's Glenn Research Center. Colin is focusing on developing tires that can be used on other worlds. These tires use coil springs made of a special shape memory alloy that will let rovers move across sharp jagged rocks or through soft sand on the Moon or Mars.
[ NASA ]
To be presented at IROS this year, “the first on robot collision detection system using low cost microphones.”
[ Rutgers ]
Robot and mechanism designs inspired by the art of Origami have the potential to generate compact, deployable, lightweight morphing structures, as seen in nature, for potential applications in search-and-rescue, aerospace systems, and medical devices. However, it is challenging to obtain actuation that is easily patternable, reversible, and made with a scalable manufacturing process for origami-inspired self-folding machines. In this work, we describe an approach to design reversible self-folding machines using liquid crystal elastomer (LCE), that contracts when heated, as an artificial muscle.
[ UCSD ]
Just in case you need some extra home entertainment, and you’d like cleaner floors at the same time.
[ iRobot ]
Sure, toss it from a drone. Or from orbit. Whatever, it’s squishy!
[ Squishy Robotics ]
The [virtual] RSS conference this week featured an excellent lineup of speakers and panels, and the best part about it being virtual is that you can watch them all at your leisure! Here’s what’s been posted so far:
[ RSS 2020 ]
Lockheed Martin Robotics Seminar: Toward autonomous flying insect-sized robots: recent results in fabrication, design, power systems, control, and sensing with Sawyer Fuller.
[ UMD ]
In this episode of the AI Podcast, Lex interviews Sergey Levine.
[ AI Podcast ] Continue reading →
Posted in Human Robots
#437751 Startup and Academics Find Path to ...
Engineers have been chasing a form of AI that could drastically lower the energy required to do typical AI things like recognize words and images. This analog form of machine learning does one of the key mathematical operations of neural networks using the physics of a circuit instead of digital logic. But one of the main things limiting this approach is that deep learning’s training algorithm, back propagation, has to be done by GPUs or other separate digital systems.
Now University of Montreal AI expert Yoshua Bengio, his student Benjamin Scellier, and colleagues at startup Rain Neuromorphics have come up with way for analog AIs to train themselves. That method, called equilibrium propagation, could lead to continuously learning, low-power analog systems of a far greater computational ability than most in the industry now consider possible, according to Rain CTO Jack Kendall.
Analog circuits could save power in neural networks in part because they can efficiently perform a key calculation, called multiply and accumulate. That calculation multiplies values from inputs according to various weights, and then it sums all those values up. Two fundamental laws of electrical engineering can basically do that, too. Ohm’s Law multiplies voltage and conductance to give current, and Kirchoff’s Current Law sums the currents entering a point. By storing a neural network’s weights in resistive memory devices, such as memristors, multiply-and-accumulate can happen completely in analog, potentially reducing power consumption by orders of magnitude.
The reason analog AI systems can’t train themselves today has a lot to do with the variability of their components. Just like real neurons, those in analog neural networks don’t all behave exactly alike. To do back propagation with analog components, you must build two separate circuit pathways. One going forward to come up with an answer (called inferencing), the other going backward to do the learning so that the answer becomes more accurate. But because of the variability of analog components, the pathways don't match up.
“You end up accumulating error as you go backwards through the network,” says Bengio. To compensate, a network would need lots of power-hungry analog-to-digital and digital-to-analog circuits, defeating the point of going analog.
Equilibrium propagation allows learning and inferencing to happen on the same network, partly by adjusting the behavior of the network as a whole. “What [equilibrium propagation] allows us to do is to say how we should modify each of these devices so that the overall circuit performs the right thing,” he says. “We turn the physical computation that is happening in the analog devices directly to our advantage.”
Right now, equilibrium propagation is only working in simulation. But Rain plans to have a hardware proof-of-principle in late 2021, according to CEO and cofounder Gordon Wilson. “We are really trying to fundamentally reimagine the hardware computational substrate for artificial intelligence, find the right clues from the brain, and use those to inform the design of this,” he says. The result could be what they call end-to-end analog AI systems that capable of running sophisticated robots or even playing a role in data centers. Both of those are currently considered beyond the capabilities of analog AI, which is now focused only on adding inferencing abilities to sensors and other low-power “edge” devices, while leaving the learning to GPUs. Continue reading →
Posted in Human Robots
#437723 Minuscule RoBeetle Turns Liquid Methanol ...
It’s no secret that one of the most significant constraints on robots is power. Most robots need lots of it, and it has to come from somewhere, with that somewhere usually being a battery because there simply aren’t many other good options. Batteries, however, are famous for having poor energy density, and the smaller your robot is, the more of a problem this becomes. And the issue with batteries goes beyond the battery itself, but also carries over into all the other components that it takes to turn the stored energy into useful work, which again is a particular problem for small-scale robots.
In a paper published this week in Science Robotics, researchers from the University of Southern California, in Los Angeles, demonstrate RoBeetle, an 88-milligram four legged robot that runs entirely on methanol, a power-dense liquid fuel. Without any electronics at all, it uses an exceptionally clever bit of mechanical autonomy to convert methanol vapor directly into forward motion, one millimeter-long step at a time.
It’s not entirely clear from the video how the robot actually works, so let’s go through how it’s put together, and then look at the actuation cycle.
Image: Science Robotics
RoBeetle (A) uses a methanol-based actuation mechanism (B). The robot’s body (C) includes the fuel tank subassembly (D), a tank lid, transmission, and sliding shutter (E), bottom side of the sliding shutter (F), nickel-titanium-platinum composite wire and leaf spring (G), and front legs and hind legs with bioinspired backward-oriented claws (H).
The body of RoBeetle is a boxy fuel tank that you can fill with methanol by poking a syringe through a fuel inlet hole. It’s a quadruped, more or less, with fixed hind legs and two front legs attached to a single transmission that moves them both at once in a sort of rocking forward and up followed by backward and down motion. The transmission is hooked up to a leaf spring that’s tensioned to always pull the legs backward, such that when the robot isn’t being actuated, the spring and transmission keep its front legs more or less vertical and allow the robot to stand. Those horns are primarily there to hold the leaf spring in place, but they’ve got little hooks that can carry stuff, too.
The actuator itself is a nickel-titanium (NiTi) shape-memory alloy (SMA), which is just a wire that gets longer when it heats up and then shrinks back down when it cools. SMAs are fairly common and used for all kinds of things, but what makes this particular SMA a little different is that it’s been messily coated with platinum. The “messily” part is important for a reason that we’ll get to in just a second.
The way that the sliding vent is attached to the transmission is the really clever bit about this robot, because it means that the motion of the wire itself is used to modulate the flow of fuel through a purely mechanical system. Essentially, it’s an actuator and a sensor at the same time.
One end of the SMA wire is attached to the middle of the leaf spring, while the other end runs above the back of the robot where it’s stapled to an anchor block on the robot’s rear end. With the SMA wire hooked up but not actuated (i.e., cold rather than warm), it’s short enough that the leaf spring gets pulled back, rocking the legs forward and up. The last component is embedded in the robot’s back, right along the spine and directly underneath the SMA actuator. It’s a sliding vent attached to the transmission, so that the vent is open when the SMA wire is cold and the leaf spring is pulled back, and closed when the SMA wire is warm and the leaf spring is relaxed. The way that the sliding vent is attached to the transmission is the really clever bit about this robot, because it means that the motion of the wire itself is used to modulate the flow of fuel through a purely mechanical system. Essentially, it’s an actuator and a sensor at the same time.
The actuation cycle that causes the robot to walk begins with a full fuel tank and a cold SMA wire. There’s tension on the leaf spring, pulling the transmission back and rocking the legs forward and upward. The transmission also pulls the sliding vent into the open position, allowing methanol vapor to escape up out of the fuel tank and into the air, where it wafts past the SMA wire that runs directly above the vent.
The platinum facilitates a reaction of the methanol (CH3OH) with oxygen in the air (combustion, although not the dramatic flaming and explosive kind) to generate a couple of water molecules and some carbon dioxide plus a bunch of heat, and this is where the messy platinum coating is important, because messy means lots of surface area for the platinum to interact with as much methanol as possible. In just a second or two the temperature of the SMA wire skyrockets from 50 to 100 ºC and it expands, allowing the leaf spring about 0.1 mm of slack. As the leaf spring relaxes, the transmission moves the legs backwards and downwards, and the robot pulls itself forward about 1.2 mm. At the same time, the transmission is closing off the sliding vent, cutting off the supply of methanol vapor. Without the vapor reacting with the platinum and generating heat, in about a second and a half, the SMA wire cools down. As it does, it shrinks, pulling on the leaf spring and starting the cycle over again. Top speed is 0.76 mm/s (0.05 body-lengths per second).
An interesting environmental effect is that the speed of the robot can be enhanced by a gentle breeze. This is because air moving over the SMA wire cools it down a bit faster while also blowing away any residual methanol from around the vents, shutting down the reaction more completely. RoBeetle can carry more than its own body weight in fuel, and it takes approximately 155 minutes for a full tank of methanol to completely evaporate. It’s worth noting that despite the very high energy density of methanol, this is actually a stupendously inefficient way of powering a robot, with an estimated end-to-end efficiency of just 0.48 percent. Not 48 percent, mind you, but 0.48 percent, while in general, powering SMAs with electricity is much more efficient.
However, you have to look at the entire system that would be necessary to deliver that electricity, and for a robot as small as RoBeetle, the researchers say that it’s basically impossible. The lightest commercially available battery and power supply that would deliver enough juice to heat up an SMA actuator weighs about 800 mg, nearly 10 times the total weight of RoBeetle itself. From that perspective, RoBeetle’s efficiency is actually pretty good.
Image: A. Kitterman/Science Robotics; adapted from R.L.T./MIT
Comparison of various untethered microrobots and bioinspired soft robots that use different power and actuation strategies.
There are some other downsides to RoBeetle we should mention—it can only move forwards, not backwards, and it can’t steer. Its speed isn’t adjustable, and once it starts walking, it’ll walk until it either breaks or runs out of fuel. The researchers have some ideas about the speed, at least, pointing out that increasing the speed of fuel delivery by using pressurized liquid fuels like butane or propane would increase the actuator output frequency. And the frequency, amplitude, and efficiency of the SMAs themselves can be massively increased “by arranging multiple fiber-like thin artificial muscles in hierarchical configurations similar to those observed in sarcomere-based animal muscle,” making RoBeetle even more beetle-like.
As for sensing, RoBeetle’s 230-mg payload is enough to carry passive sensors, but getting those sensors to usefully interact with the robot itself to enable any kind of autonomy remains a challenge. Mechanically intelligence is certainly possible, though, and we can imagine RoBeetle adopting some of the same sorts of systems that have been proposed for the clockwork rover that JPL wants to use for Venus exploration. The researchers also mention how RoBeetle could potentially serve as a model for microbots capable of aerial locomotion, which is something we’d very much like to see.
“An 88-milligram insect-scale autonomous crawling robot driven by a catalytic artificial muscle,” by Xiufeng Yang, Longlong Chang, and Néstor O. Pérez-Arancibia from University of Southern California, in Los Angeles, was published in Science Robotics. Continue reading →
Posted in Human Robots