Tag Archives: Flexible

#439941 Flexible Monocopter Drone Can Be ...

Posted on November 11, 2021 by Android

It turns out that you don't need a lot of hardware to make a flying robot. Flying robots are usually way, way, way over-engineered, with ridiculously over the top components like two whole wings or an obviously ludicrous four separate motors. Maybe that kind of stuff works for people with more funding than they know what to do with, but for anyone trying to keep to a reasonable budget, all it actually takes to make a flying robot is one single airfoil plus an attached fixed-pitch propeller. And if you make that airfoil flexible, you can even fold the entire thing up into a sort of flying robotic swiss roll.
This type of drone is called a monocopter, and the design is very generally based on samara seeds, which are those single-wing seed pods that spin down from maple trees. The ability to spin slows the seeds' descent to the ground, allowing them to spread farther from the tree. It's an inherently stable design, meaning that it'll spin all by itself and do so in a stable and predictable way, which is a nice feature for a drone to have—if everything completely dies, it'll just spin itself gently down to a landing by default.

The monocopter we're looking at here, called F-SAM, comes from the Singapore University of Technology & Design, and we've written about some of their flying robots in the past, including this transformable hovering rotorcraft. F-SAM stands for Foldable Single Actuator Monocopter, and as you might expect, it's a monocopter that can fold up and uses just one single actuator for control.

There may not be a lot going on here hardware-wise, but that's part of the charm of this design. The one actuator gives complete directional control: increasing the throttle increases the RPM of the aircraft, causing it to gain altitude, which is pretty straightforward. Directional control is trickier, but not much trickier, requiring repetitive pulsing of the motor at a point during the aircraft's spin when it's pointed in the direction you want it to go. F-SAM is operating in a motion-capture environment in the video to explore its potential for precision autonomy, but it's not restricted to that environment, and doesn't require external sensing for control.

While F-SAM's control board was custom designed and the wing requires some fabrication, the rest of the parts are cheap and off the shelf. The total weight of F-SAM is just 69g, of which nearly 40% is battery, yielding a flight time of about 16 minutes. If you look closely, you'll also see a teeny little carbon fiber leg of sorts that keeps the prop up above the ground, enabling the ground takeoff behavior without contacting the ground.
You can find the entire F-SAM paper open access here, but we also asked the authors a couple of extra questions.
IEEE Spectrum: It looks like you explored different materials and combinations of materials for the flexible wing structure. Why did you end up with this mix of balsa wood and plastic?

Shane Kyi Hla Win: The wing structure of a monocopter requires rigidity in order to be controllable in flight. Although it is possible for the monocopter to fly with more flexible materials we tested, such as flexible plastic or polymide flex, they allow the wing to twist freely mid-flight making cyclic control effort from the motor less effective. The balsa laminated with plastic provides enough rigidity for an effective control, while allowing folding in a pre-determined triangular fold.
Can F-SAM fly outdoors? What is required to fly it outside of a motion capture environment?
Yes it can fly outdoors. It is passively stable so it does not require a closed-loop control for its flight. The motion capture environment provides its absolute position for station-holding and waypoint flights when indoors. For outdoor flight, an electronic compass provides the relative heading for the basic cyclic control. We are working on a prototype with an integrated GPS for outdoor autonomous flights.
Would you be able to add a camera or other sensors to F-SAM?
A camera can be added (we have done this before), but due to its spinning nature, images captured can come out blurry. 360 cameras are becoming lighter and smaller and we may try putting one on F-SAM or other monocopters we have. Other possible sensors to include are LiDAR sensor or ToF sensor. With LiDAR, the platform has an advantage as it is already spinning at a known RPM. A conventional LiDAR system requires a dedicated actuator to create a spinning motion. As a rotating platform, F-SAM already possesses the natural spinning dynamics, hence making LiDAR integration lightweight and more efficient.
Your paper says that “in the future, we may look into possible launching of F-SAM directly from the container, without the need for human intervention.” Can you describe how this would happen?
Currently, F-SAM can be folded into a compact form and stored inside a container. However, it still requires a human to unfold it and either hand-launch it or put it on the floor to fly off. In the future, we envision that F-SAM is put inside a container which has the mechanism (such as pressured gas) to catapult the folded unit into the air, which can begin unfolding immediately due to elastic materials used. The motor can initiate the spin which allows the wing to straighten out due to centrifugal forces.
Do you think F-SAM would make a good consumer drone?
F-SAM could be a good toy but it may not be a good alternative to quadcopters if the objective is conventional aerial photography or videography. However, it can be a good contender for single-use GPS-guided reconnaissance missions. As it uses only one actuator for its flight, it can be made relatively cheaply. It is also very silent during its flight and easily camouflaged once landed. Various lightweight sensors can be integrated onto the platform for different types of missions, such as climate monitoring. F-SAM units can be deployed from the air, as they can also autorotate on their way down, while also flying at certain periods for extended meteorological data collection in the air.
What are you working on next?
We have a few exciting projects on hand, most of which focus on 'do more with less' theme. This means our projects aim to achieve multiple missions and flight modes while using as few actuators as possible. Like F-SAM which uses only one actuator to achieve controllable flight, another project we are working on is the fully autorotating version, named Samara Autorotating Wing (SAW). This platform, published earlier this year in IEEE Transactions on Robotics , is able to achieve two flight modes (autorotation and diving) with just one actuator. It is ideal for deploying single-use sensors to remote locations. For example, we can use the platform to deploy sensors for forest monitoring or wildfire alert system. The sensors can land on tree canopies, and once landed the wing provides the necessary area for capturing solar energy for persistent operation over several years. Another interesting scenario is using the autorotating platform to guide the radiosondes back to the collection point once its journey upwards is completed. Currently, many radiosondes are sent up with hydrogen balloons from weather stations all across the world (more than 20,000 annually from Australia alone) and once the balloon reaches a high altitude and bursts, the sensors drop back onto the earth and no effort is spent to retrieve these sensors. By guiding these sensors back to a collection point, millions of dollars can be saved every year—and also [it helps] save the environment by polluting less. Continue reading →

Posted in Human Robots

#439938 Tiny bubbles: Researchers develop a ...

Posted on November 10, 2021 by Android

Princeton researchers have invented bubble casting, a new way to make soft robots using “fancy balloons” that change shape in predictable ways when inflated with air. Continue reading →

Posted in Human Robots

#439263 Somehow This Robot Sticks to Ceilings by ...

Posted on June 3, 2021 by Android

Just when I think I’ve seen every possible iteration of climbing robot, someone comes up with a new way of getting robots to stick to things. The latest technique comes from the Bioinspired Robotics and Design Lab at UCSD, where they’ve managed to get a robot to stick to smooth surfaces using a vibrating motor attached to a flexible disk. How the heck does it work?

According to a paper just published in Advanced Intelligent Systems, it’s due to “the fluid mediated adhesive force between an oscillatory plate and a surface” rather than black magic. Obviously.

Weird, right? In the paper, the researchers explain that what’s going on here: As the 14cm diameter flexible disk vibrates at 200 Hz, it generates a thin layer of low pressure air in between itself and the surface that it’s vibrating against. Although the layer of low pressure air is less than 1 mm thick, the disk can resist 5 N of force pulling on it. You can sort of think of this as a suction effect, except that it doesn’t require the disk to be constantly sealed against a surface, meaning that the robot can move around without breaking adhesion.

Image: UCSD

The big advantage here is that this is about as simple and cheap as a smooth-surface climbing robot gets, especially at small(ish) scales. There are a couple of downsides too, though. The biggest one could be that 200 Hz is a frequency that’s well within human hearing, which probably explains that soundtrack in the video—the robot is, as the researchers put it, “inherently quite noisy.” And in contrast to some other controllable adhesion techniques, this system must be turned on at all times or it will immediately plunge to its doom.

The robot you’re looking at in the video (with a 14cm disk) seems to be the sweet spot when it comes to size—going smaller means that the motor starts taking up a disproportionate amount of weight, while going larger would likely not scale well either, with the overall system mass increasing faster than the amount of adhesion that you get. The researchers suggest that “it could be advantageous to combine several disk geometries to achieve the desired load capacity and resilience to disturbances,” but that’s one of a number of things that the researchers need to figure out to properly characterize this novel adhesion technique.

Gas-Lubricated Vibration-Based Adhesion for Robotics, by William P. Weston-Dawkes, Iman Adibnazari, Yi-Wen Hu, Michael Everman, Nick Gravish, and Michael T. Tolley, is available here. Continue reading →

Posted in Human Robots

#439095 DARPA Prepares for the Subterranean ...

Posted on April 9, 2021 by Android

The DARPA Subterranean Challenge Final Event is scheduled to take place at the Louisville Mega Cavern in Louisville, Kentucky, from September 21 to 23. We’ve followed SubT teams as they’ve explored their way through abandoned mines, unfinished nuclear reactors, and a variety of caves, and now everything comes together in one final course where the winner of the Systems Track will take home the $2 million first prize.

It’s a fitting reward for teams that have been solving some of the hardest problems in robotics, but winning isn’t going to be easy, and we’ll talk with SubT Program Manager Tim Chung about what we have to look forward to.

Since we haven’t talked about SubT in a little while (what with the unfortunate covid-related cancellation of the Systems Track Cave Circuit), here’s a quick refresher of where we are: the teams have made it through the Tunnel Circuit, the Urban Circuit, and a virtual version of the Cave Circuit, and some of them have been testing in caves of their own. The Final Event will include all of these environments, and the teams of robots will have 60 minutes to autonomously map the course, locating artifacts to score points. Since I’m not sure where on Earth there’s an underground location that combines tunnels and caves with urban structures, DARPA is going to have to get creative, and the location in which they’ve chosen to do that is Louisville, Kentucky.

The Louisville Mega Cavern is a former limestone mine, most of which is under the Louisville Zoo. It’s not all that deep, mostly less than 30 meters under the surface, but it’s enormous: with 370,000 square meters of rooms and passages, the cavern currently hosts (among other things) a business park, a zipline course, and mountain bike trails, because why not. While DARPA is keeping pretty quiet on the details, I’m guessing that they’ll be taking over a chunk of the cavern and filling it with features representing as many of the environmental challenges as they can.

To learn more about how the SubT Final Event is going to go, we spoke with SubT Program Manager Tim Chung. But first, we talked about Tim’s perspective on the success of the Urban Circuit, and how teams have been managing without an in-person Cave Circuit.

IEEE Spectrum: How did the SubT Urban Circuit go?

Tim Chung: On a couple fronts, Urban Circuit was really exciting. We were in this unfinished nuclear power plant—I’d be surprised if any of the competitors had prior experience in such a facility, or anything like it. I think that was illuminating both from an experiential point of view for the competitors, but also from a technology point of view, too.

One thing that I thought was really interesting was that we, DARPA, didn't need to make the venue more challenging. The real world is really that hard. There are places that were just really heinous for these robots to have to navigate through in order to look in every nook and cranny for artifacts. There were corners and doorways and small corridors and all these kind of things that really forced the teams to have to work hard, and the feedback was, why did DARPA have to make it so hard? But we didn’t, and in fact there were places that for the safety of the robots and personnel, we had to ensure the robots couldn’t go.

It sounds like some teams thought this course was on the more difficult side—do you think you tuned it to just the right amount of DARPA-hard?

Our calibration worked quite well. We were able to tease out and help refine and better understand what technologies are both useful and critical and also those technologies that might not necessarily get you the leap ahead capability. So as an example, the Urban Circuit really emphasized verticality, where you have to be able to sense, understand, and maneuver in three dimensions. Being able to capitalize on their robot technologies to address that verticality really stratified the teams, and showed how critical those capabilities are.

We saw teams that brought a lot of those capabilities do very well, and teams that brought baseline capabilities do what they could on the single floor that they were able to operate on. And so I think we got the Goldilocks solution for Urban Circuit that combined both difficulty and ambition.

Photos: Evan Ackerman/IEEE Spectrum

Two SubT Teams embedded networking equipment in balls that they could throw onto the course.

One of the things that I found interesting was that two teams independently came up with throwable network nodes. What was DARPA’s reaction to this? Is any solution a good solution, or was it more like the teams were trying to game the system?

You mean, do we want teams to game the rules in any way so as to get a competitive advantage? I don't think that's what the teams were doing. I think they were operating not only within the bounds of the rules, which permitted such a thing as throwable sensors where you could stand at the line and see how far you could chuck these things—not only was that acceptable by the rules, but anticipated. Behind the scenes, we tried to do exactly what these teams are doing and think through different approaches, so we explicitly didn't forbid such things in our rules because we thought it's important to have as wide an aperture as possible.

With these comms nodes specifically, I think they’re pretty clever. They were in some cases hacked together with a variety of different sports paraphernalia to see what would provide the best cushioning. You know, a lot of that happens in the field, and what it captured was that sometimes you just need to be up at two in the morning and thinking about things in a slightly different way, and that's when some nuggets of innovation can arise, and we see this all the time with operators in the field as well. They might only have duct tape or Styrofoam or whatever the case may be and that's when they come up with different ways to solve these problems. I think from DARPA’s perspective, and certainly from my perspective, wherever innovation can strike, we want to try to encourage and inspire those opportunities. I thought it was great, and it’s all part of the challenge.

Is there anything you can tell us about what your original plan had been for the Cave Circuit?

I can say that we’ve had the opportunity to go through a number of these caves scattered all throughout the country, and engage with caving communities—cavers clubs, speleologists that conduct research, and then of course the cave rescue community. The single biggest takeaway
is that every cave, and there are tens of thousands of them in the US alone, every cave has its own personality, and a lot of that personality is quite hidden from humans, because we can’t explore or access all of the cave. This led us to a number of different caves that were intriguing from a DARPA perspective but also inspirational for our Cave Circuit Virtual Competition.

How do you feel like the tuning was for the Virtual Cave Circuit?

The Virtual Competition, as you well know, was exciting in the sense that we could basically combine eight worlds into one competition, whereas the systems track competition really didn’t give us that opportunity. Even if we were able have held the Cave Circuit Systems Competition in person, it would have been at one site, and it would have been challenging to represent the level of diversity that we could with the Virtual Competition. So I think from that perspective, it’s clearly an advantage in terms of calibration—diversity gets you the ability to aggregate results to capture those that excel across all worlds as well as those that do well in one world or some worlds and not the others. I think the calibration was great in the sense that we were able to see the gamut of performance. Those that did well, did quite well, and those that have room to grow showed where those opportunities are for them as well.

We had to find ways to capture that diversity and that representativeness, and I think one of the fun ways we did that was with the different cave world tiles that we were able to combine in a variety of different ways. We also made use of a real world data set that we were able to take from a laser scan. Across the board, we had a really great chance to illustrate why virtual testing and simulation still plays such a dominant role in robotics technology development, and why I think it will continue to play an increasing role for developing these types of autonomy solutions.

Photo: Team CSIRO Data 61

How can systems track teams learn from their testing in whatever cave is local to them and effectively apply that to whatever cave environment is part of the final considering what the diversity of caves is?

I think that hits the nail on the head for what we as technologists are trying to discover—what are the transferable generalizable insights and how does that inform our technology development? As roboticists we want to optimize our systems to perform well at the tasks that they were designed to do, and oftentimes that means specialization because we get increased performance at the expense of being a generalist robot. I think in the case of SubT, we want to have our cake and eat it too—we want robots that perform well and reliably, but we want them to do so not just in one environment, which is how we tend to think about robot performance, but we want them to operate well in many environments, many of which have yet to be faced.

And I think that's kind of the nuance here, that we want robot systems to be generalists for the sake of being able to handle the unknown, namely the real world, but still achieve a high level of performance and perhaps they do that to their combined use of different technologies or advances in autonomy or perception approaches or novel mechanisms or mobility, but somehow they're still able, at least in aggregate, to achieve high performance.

We know these teams eagerly await any type of clue that DARPA can provide like about the SubT environments. From the environment previews for Tunnel, Urban, and even Cave, the teams were pivoting around and thinking a little bit differently. The takeaway, however, was that they didn't go to a clean sheet design—their systems were flexible enough that they could incorporate some of those specialist trends while still maintaining the notion of a generalist framework.

Looking ahead to the SubT Final, what can you tell us about the Louisville Mega Cavern?

As always, I’ll keep you in suspense until we get you there, but I can say that from the beginning of the SubT Challenge we had always envisioned teams of robots that are able to address not only the uncertainty of what's right in front of them, but also the uncertainty of what comes next. So I think the teams will be advantaged by thinking through subdomain awareness, or domain awareness if you want to generalize it, whether that means tuning multi-purpose robots, or deploying different robots, or employing your team of robots differently. Knowing which subdomain you are in is likely to be helpful, because then you can take advantage of those unique lessons learned through all those previous experiences then capitalize on that.

As far as specifics, I think the Mega Cavern offers many of the features important to what it means to be underground, while giving DARPA a pretty blank canvas to realize our vision of the SubT Challenge.

The SubT Final will be different from the earlier circuits in that there’s just one 60-minute run, rather than two. This is going to make things a lot more stressful for teams who have experienced bad robot days—why do it this way?

The preliminary round has two 30-minute runs, and those two runs are very similar to how we have done it during the circuits, of a single run per configuration per course. Teams will have the opportunity to show that their systems can face the obstacles in the final course, and it's the sum of those scores much like we did during the circuits, to help mitigate some of the concerns that you mentioned of having one robot somehow ruin their chances at a prize.

The prize round does give DARPA as well as the community a chance to focus on the top six teams from the preliminary round, and allows us to understand how they came to be at the top of the pack while emphasizing their technological contributions. The prize round will be one and done, but all of these teams we anticipate will be putting their best robot forward and will show the world why they deserve to win the SubT Challenge.

We’ve always thought that when called upon these robots need to operate in really challenging environments, and in the context of real world operations, there is no second chance. I don't think it's actually that much of a departure from our interests and insistence on bringing reliable technologies to the field, and those teams that might have something break here and there, that's all part of the challenge, of being resilient. Many teams struggled with robots that were debilitated on the course, and they still found ways to succeed and overcome that in the field, so maybe the rules emphasize that desire for showing up and working on game day which is consistent, I think, with how we've always envisioned it. This isn’t to say that these systems have to work perfectly, they just have to work in a way such that the team is resilient enough to tackle anything that they face.

It’s not too late for teams to enter for both the Virtual Track and the Systems Track to compete in the SubT Final, right?

Yes, that's absolutely right. Qualifications are still open, we are eager to welcome new teams to join in along with our existing competitors. I think any dark horse competitors coming into the Finals may be able to bring something that we haven't seen before, and that would be really exciting. I think it'll really make for an incredibly vibrant and illuminating final event.

The final event qualification deadline for the Systems Competition is April 21, and the qualification deadline for the Virtual Competition is June 29. More details here. Continue reading →

Posted in Human Robots

#439081 Classify This Robot-Woven Sneaker With ...

Posted on April 7, 2021 by Android

For athletes trying to run fast, the right shoe can be essential to achieving peak performance. For athletes trying to run fast as humanly possible, a runner’s shoe can also become a work of individually customized engineering.

This is why Adidas has married 3D printing with robotic automation in a mass-market footwear project it’s called Futurecraft.Strung, expected to be available for purchase as soon as later this year. Using a customized, 3D-printed sole, a Futurecraft.Strung manufacturing robot can place some 2,000 threads from up to 10 different sneaker yarns in one upper section of the shoe.

Skylar Tibbits, founder and co-director of the Self-Assembly Lab and associate professor in MIT's Department of Architecture, says that because of its small scale, footwear has been an area of focus for 3D printing and additive manufacturing, which involves adding material bit by bit.

“There are really interesting complex geometry problems,” he says. “It’s pretty well suited.”

Photo: Adidas

Beginning with a 3D-printed sole, Adidas robots weave together some 2000 threads from up to 10 different sneaker yarns to make one Futurecraft.Strung shoe—expected on the marketplace later this year or sometime in 2022.

Adidas began working on the Futurecraft.Strung project in 2016. Then two years later, Adidas Futurecraft, the company’s innovation incubator, began collaborating with digital design studio Kram/Weisshaar. In less than a year the team built the software and hardware for the upper part of the shoe, called Strung uppers.

“Most 3D printing in the footwear space has been focused on the midsole or outsole, like the bottom of the shoe,” Tibbits explains. But now, he says, Adidas is bringing robotics and a threaded design to the upper part of the shoe. The company bases its Futurecraft.Strung design on high-resolution scans of how runners’ feet move as they travel.

This more flexible design can benefit athletes in multiple sports, according to an Adidas blog post. It will be able to use motion capture of an athlete’s foot and feedback from the athlete to make the design specific to the athlete’s specific gait. Adidas customizes the weaving of the shoe’s “fabric” (really more like an elaborate woven string figure, a cat’s cradle to fit the foot) to achieve a close and comfortable fit, the company says.

What they call their “4D sole” consists of a design combining 3D printing with materials that can change their shape and properties over time. In fact, Tibbits coined the term 4D printing to describe this process in 2013. The company takes customized data from the Adidas Athlete Intelligent Engine to make the shoe, according to Kram/Weisshaar’s website.

Photo: Adidas

Closeup of the weaving process behind a Futurecraft.Strung shoe

“With Strung for the first time, we can program single threads in any direction, where each thread has a different property or strength,” Fionn Corcoran-Tadd, an innovation designer at Adidas’ Futurecraft lab, said in a company video. Each thread serves a purpose, the video noted. “This is like customized string art for your feet,” Tibbits says.

Although the robotics technology the company uses has been around for many years, what Adidas’s robotic weavers can achieve with thread is a matter of elaborate geometry. “It’s more just like a really elegant way to build up material combining robotics and the fibers and yarns into these intricate and complex patterns,” he says.

Robots can of course create patterns with more precision than if someone wound it by hand, as well as rapidly and reliably changing the yarn and color of the fabric pattern. Adidas says it can make a single upper in 45 minutes and a pair of sneakers in 1 hour and 30 minutes. It plans to reduce this time down to minutes in the months ahead, the company said.

An Adidas spokesperson says sneakers incorporating the Futurecraft.Strung uppers design are a prototype, but the company plans to bring a Strung shoe to market in late 2021 or 2022. However, Adidas Futurecraft sneakers are currently available with a 3D-printed midsole.
Adidas plans to continue gathering data from athletes to customize the uppers of sneakers. “We’re building up a library of knowledge and it will get more interesting as we aggregate data of testing and from different athletes and sports,” the Adidas Futurecraft team writes in a blog post. “The more we understand about how data can become design code, the more we can take that and apply it to new Strung textiles. It’s a continuous evolution.” Continue reading →

Posted in Human Robots