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#435632 DARPA Subterranean Challenge: Tunnel ...

Posted on September 13, 2019 by Android

The Tunnel Circuit of the DARPA Subterranean Challenge starts later this week at the NIOSH research mine just outside of Pittsburgh, Pennsylvania. From 15-22 August, 11 teams will send robots into a mine that they've never seen before, with the goal of making maps and locating items. All DARPA SubT events involve tunnels of one sort or another, but in this case, the “Tunnel Circuit” refers to mines as opposed to urban underground areas or natural caves. This month’s challenge is the first of three discrete events leading up to a huge final event in August of 2021.

While the Tunnel Circuit competition will be closed to the public, and media are only allowed access for a single day (which we'll be at, of course), DARPA has provided a substantial amount of information about what teams will be able to expect. We also have details from the SubT Integration Exercise, called STIX, which was a completely closed event that took place back in April. STIX was aimed at giving some teams (and DARPA) a chance to practice in a real tunnel environment.

For more general background on SubT, here are some articles to get you all caught up:

SubT: The Next DARPA Challenge for Robotics

Q&A with DARPA Program Manager Tim Chung

Meet The First Nine Teams

It makes sense to take a closer look at what happened at April's STIX exercise, because it is (probably) very similar to what teams will experience in the upcoming Tunnel Circuit. STIX took place at Edgar Experimental Mine in Colorado, and while no two mines are the same (and many are very, very different), there are enough similarities for STIX to have been a valuable experience for teams. Here's an overview video of the exercise from DARPA:

DARPA has also put together a much more detailed walkthrough of the STIX mine exercise, which gives you a sense of just how vast, complicated, and (frankly) challenging for robots the mine environment is:

So, that's the kind of thing that teams had to deal with back in April. Since the event was an exercise, rather than a competition, DARPA didn't really keep score, and wouldn't comment on the performance of individual teams. We've been trolling YouTube for STIX footage, though, to get a sense of how things went, and we found a few interesting videos.

Here's a nice overview from Team CERBERUS, which used drones plus an ANYmal quadruped:

Team CTU-CRAS also used drones, along with a tracked robot:

Team Robotika was brave enough to post video of a “fatal failure” experienced by its wheeled robot; the poor little bot gets rescued at about 7:00 in case you get worried:

So that was STIX. But what about the Tunnel Circuit competition this week? Here's a course preview video from DARPA:

It sort of looks like the NIOSH mine might be a bit less dusty than the Edgar mine was, but it could also be wetter and muddier. It’s hard to tell, because we’re just getting a few snapshots of what’s probably an enormous area with kilometers of tunnels that the robots will have to explore. But DARPA has promised “constrained passages, sharp turns, large drops/climbs, inclines, steps, ladders, and mud, sand, and/or water.” Combine that with the serious challenge to communications imposed by the mine itself, and robots will have to be both physically capable, and almost entirely autonomous. Which is, of course, exactly what DARPA is looking to test with this challenge.

Lastly, we had a chance to catch up with Tim Chung, Program Manager for the Subterranean Challenge at DARPA, and ask him a few brief questions about STIX and what we have to look forward to this week.

IEEE Spectrum: How did STIX go?

Tim Chung: It was a lot of fun! I think it gave a lot of the teams a great opportunity to really get a taste of what these types of real world environments look like, and also what DARPA has in store for them in the SubT Challenge. STIX I saw as an experiment—a learning experience for all the teams involved (as well as the DARPA team) so that we can continue our calibration.

What do you think teams took away from STIX, and what do you think DARPA took away from STIX?

I think the thing that teams took away was that, when DARPA hosts a challenge, we have very audacious visions for what the art of the possible is. And that's what we want—in my mind, the purpose of a DARPA Grand Challenge is to provide that inspiration of, ‘Holy cow, someone thinks we can do this!’ So I do think the teams walked away with a better understanding of what DARPA's vision is for the capabilities we're seeking in the SubT Challenge, and hopefully walked away with a better understanding of the technical, physical, even maybe mental challenges of doing this in the wild— which will all roll back into how they think about the problem, and how they develop their systems.

This was a collaborative exercise, so the DARPA field team was out there interacting with the other engineers, figuring out what their strengths and weaknesses and needs might be, and even understanding how to handle the robots themselves. That will help [strengthen] connections between these university teams and DARPA going forward. Across the board, I think that collaborative spirit is something we really wish to encourage, and something that the DARPA folks were able to take away.

What do we have to look forward to during the Tunnel Circuit?

The vision here is that the Tunnel Circuit is representative of one of the three subterranean subdomains, along with urban and cave. Characteristics of all of these three subdomains will be mashed together in an epic final course, so that teams will have to face hints of tunnel once again in that final event.

Without giving too much away, the NIOSH mine will be similar to the Edgar mine in that it's a human-made environment that supports mining operations and research. But of course, every site is different, and these differences, I think, will provide good opportunities for the teams to shine.

Again, we'll be visiting the NIOSH mine in Pennsylvania during the Tunnel Circuit and will post as much as we can from there. But if you’re an actual participant in the Subterranean Challenge, please tweet me @BotJunkie so that I can follow and help share live updates.

[ DARPA Subterranean Challenge ] Continue reading →

Posted in Human Robots

#435626 Video Friday: Watch Robots Make a Crepe ...

Posted on September 13, 2019 by Android

Video Friday is your weekly selection of awesome robotics videos, collected by your Automaton bloggers. Every week, we also post a calendar of upcoming robotics events; here's what we have so far (send us your events!):

Robotronica – August 18, 2019 – Brisbane, Australia
CLAWAR 2019 – August 26-28, 2019 – Kuala Lumpur, Malaysia
IEEE Africon 2019 – September 25-27, 2019 – Accra, Ghana
ISRR 2019 – October 6-10, 2019 – Hanoi, Vietnam
Ro-Man 2019 – October 14-18, 2019 – New Delhi
Humanoids 2019 – October 15-17, 2019 – Toronto
ARSO 2019 – October 31-November 2, 2019 – Beijing
ROSCon 2019 – October 31-November 1, 2019 – Macau
IROS 2019 – November 4-8, 2019 – Macau
Let us know if you have suggestions for next week, and enjoy today's videos.

Team CoSTAR (JPL, MIT, Caltech, KAIST, LTU) has one of the more diverse teams of robots that we’ve seen:

[ Team CoSTAR ]

A team from Carnegie Mellon University and Oregon State University is sending ground and aerial autonomous robots into a Pittsburgh-area mine to prepare for this month’s DARPA Subterranean Challenge.

“Look at that fire extinguisher, what a beauty!” Expect to hear a lot more of that kind of weirdness during SubT.

[ CMU ]

Unitree Robotics is starting to batch-manufacture Laikago Pro quadrupeds, and if you buy four of them, they can carry you around in a chair!

I’m also really liking these videos from companies that are like, “We have a whole bunch of robot dogs now—what weird stuff can we do with them?”

[ Unitree Robotics ]

Why take a handful of pills every day for all the stuff that's wrong with you, when you could take one custom pill instead? Because custom pills are time-consuming to make, that’s why. But robots don’t care!

Multiply Labs’ factory is designed to operate in parallel. All the filling robots and all the quality-control robots are operating at the same time. The robotic arm, in the meanwhile, shuttles dozens of trays up and down the production floor, making sure that each capsule is filled with the right drugs. The manufacturing cell shown in this article can produce 10,000 personalized capsules in an 8-hour shift. A single cell occupies just 128 square feet (12 square meters) on the production floor. This means that a regular production facility (~10,000 square feet, or 929 m2 ) can house 78 cells, for an overall output of 780,000 capsules per shift. This exceeds the output of most traditional manufacturers—while producing unique personalized capsules!

[ Multiply Labs ]

Thanks Fred!

If you’re getting tired of all those annoying drones that sound like giant bees, just have a listen to this turbine-powered one:

[ Malloy Aeronautics ]

In retrospect, it’s kind of amazing that nobody has bothered to put a functional robotic dog head on a quadruped robot before this, right?

Equipped with sensors, high-tech radar imaging, cameras and a directional microphone, this 100-pound (45-kilogram) super-robot is still a “puppy-in-training.” Just like a regular dog, he responds to commands such as “sit,” “stand,” and “lie down.” Eventually, he will be able to understand and respond to hand signals, detect different colors, comprehend many languages, coordinate his efforts with drones, distinguish human faces, and even recognize other dogs.

As an information scout, Astro’s key missions will include detecting guns, explosives and gun residue to assist police, the military, and security personnel. This robodog’s talents won’t just end there, he also can be programmed to assist as a service dog for the visually impaired or to provide medical diagnostic monitoring. The MPCR team also is training Astro to serve as a first responder for search-and-rescue missions such as hurricane reconnaissance as well as military maneuvers.

[ FAU ]

And now this amazing video, “The Coke Thief,” from ICRA 2005 (!):

[ Paper ]

CYBATHLON Series put the focus on one or two of the six disciplines and are organized in cooperation with international universities and partners. The CYBATHLON Arm and Leg Prosthesis Series took place in Karlsruhe, Germany, from 16 to 18 May and was organized in cooperation with the Karlsruhe Institute of Technology (KIT) and the trade fair REHAB Karlsruhe.

The CYBATHLON Wheelchair Series took place in Kawasaki, Japan on 5 May 2019 and was organized in cooperation with the CYBATHLON Wheelchair Series Japan Organizing Committee and supported by the Swiss Embassy.

[ Cybathlon ]

Rainbow crepe robot!

There’s also this other robot, which I assume does something besides what's in the video, because otherwise it appears to be a massively overengineered way of shaping cooked rice into a chubby triangle.

[ PC Watch ]

The Weaponized Plastic Fighting League at Fetch Robotics has had another season of shardation, deintegration, explodification, and other -tions. Here are a couple fan favorite match videos:

[ Fetch Robotics ]

This video is in German, but it’s worth watching for the three seconds of extremely satisfying footage showing a robot twisting dough into pretzels.

[ Festo ]

Putting brains into farming equipment is a no-brainer, since it’s a semi-structured environment that's generally clear of wayward humans driving other vehicles.

[ Lovol ]

Thanks Fan!

Watch some robots assemble suspiciously Lego-like (but definitely not actually Lego) minifigs.

[ DevLinks ]

The Robotics Innovation Facility (RIFBristol) helps businesses, entrepreneurs, researchers and public sector bodies to embrace the concept of ‘Industry 4.0'. From training your staff in robotics, and demonstrating how automation can improve your manufacturing processes, to prototyping and validating your new innovations—we can provide the support you need.

[ RIF ]

Ryan Gariepy from Clearpath Robotics (and a bunch of other stuff) gave a talk at ICRA with the title of “Move Fast and (Don’t) Break Things: Commercializing Robotics at the Speed of Venture Capital,” which is more interesting when you know that this year’s theme was “Notable Failures.”

[ Clearpath Robotics ]

In this week’s episode of Robots in Depth, Per interviews Michael Nielsen, a computer vision researcher at the Danish Technological Institute.

Michael worked with a fusion of sensors like stereo vision, thermography, radar, lidar and high-frame-rate cameras, merging multiple images for high dynamic range. All this, to be able to navigate the tricky situation in a farm field where you need to navigate close to or even in what is grown. Multibaseline cameras were also used to provide range detection over a wide range of distances.

We also learn about how he expanded his work into sorting recycling, a very challenging problem. We also hear about the problems faced when using time of flight and sheet of light cameras. He then shares some good results using stereo vision, especially combined with blue light random dot projectors.

[ Robots in Depth ] Continue reading →

Posted in Human Robots

#435601 New Double 3 Robot Makes Telepresence ...

Posted on September 12, 2019 by Android

Today, Double Robotics is announcing Double 3, the latest major upgrade to its line of consumer(ish) telepresence robots. We had a (mostly) fantastic time testing out Double 2 back in 2016. One of the things that we found out back then was that it takes a lot of practice to remotely drive the robot around. Double 3 solves this problem by leveraging the substantial advances in 3D sensing and computing that have taken place over the past few years, giving their new robot a level of intelligence that promises to make telepresence more accessible for everyone.

Double 2’s iPad has been replaced by “a fully integrated solution”—which is a fancy way of saying a dedicated 9.7-inch touchscreen and a whole bunch of other stuff. That other stuff includes an NVIDIA Jetson TX2 AI computing module, a beamforming six-microphone array, an 8-watt speaker, a pair of 13-megapixel cameras (wide angle and zoom) on a tilting mount, five ultrasonic rangefinders, and most excitingly, a pair of Intel RealSense D430 depth sensors.

It’s those new depth sensors that really make Double 3 special. The D430 modules each uses a pair of stereo cameras with a pattern projector to generate 1280 x 720 depth data with a range of between 0.2 and 10 meters away. The Double 3 robot uses all of this high quality depth data to locate obstacles, but at this point, it still doesn’t drive completely autonomously. Instead, it presents the remote operator with a slick, augmented reality view of drivable areas in the form of a grid of dots. You just click where you want the robot to go, and it will skillfully take itself there while avoiding obstacles (including dynamic obstacles) and related mishaps along the way.

This effectively offloads the most stressful part of telepresence—not running into stuff—from the remote user to the robot itself, which is the way it should be. That makes it that much easier to encourage people to utilize telepresence for the first time. The way the system is implemented through augmented reality is particularly impressive, I think. It looks like it’s intuitive enough for an inexperienced user without being restrictive, and is a clever way of mitigating even significant amounts of lag.

Otherwise, Double 3’s mobility system is exactly the same as the one featured on Double 2. In fact, that you can stick a Double 3 head on a Double 2 body and it instantly becomes a Double 3. Double Robotics is thoughtfully offering this to current Double 2 owners as a significantly more affordable upgrade option than buying a whole new robot.

For more details on all of Double 3's new features, we spoke with the co-founders of Double Robotics, Marc DeVidts and David Cann.

IEEE Spectrum: Why use this augmented reality system instead of just letting the user click on a regular camera image? Why make things more visually complicated, especially for new users?

Marc DeVidts and David Cann: One of the things that we realized about nine months ago when we got this whole thing working was that without the mixed reality for driving, it was really too magical of an experience for the customer. Even us—we had a hard time understanding whether the robot could really see obstacles and understand where the floor is and that kind of thing. So, we said “What would be the best way of communicating this information to the user?” And the right way to do it ended up drawing the graphics directly onto the scene. It’s really awesome—we have a full, real time 3D scene with the depth information drawn on top of it. We’re starting with some relatively simple graphics, and we’ll be adding more graphics in the future to help the user understand what the robot is seeing.

How robust is the vision system when it comes to obstacle detection and avoidance? Does it work with featureless surfaces, IR absorbent surfaces, in low light, in direct sunlight, etc?

We’ve looked at all of those cases, and one of the reasons that we’re going with the RealSense is the projector that helps us to see blank walls. We also found that having two sensors—one facing the floor and one facing forward—gives us a great coverage area. Having ultrasonic sensors in there as well helps us to detect anything that we can't see with the cameras. They're sort of a last safety measure, especially useful for detecting glass.

It seems like there’s a lot more that you could do with this sensing and mapping capability. What else are you working on?

We're starting with this semi-autonomous driving variant, and we're doing a private beta of full mapping. So, we’re going to do full SLAM of your environment that will be mapped by multiple robots at the same time while you're driving, and then you'll be able to zoom out to a map and click anywhere and it will drive there. That's where we're going with it, but we want to take baby steps to get there. It's the obvious next step, I think, and there are a lot more possibilities there.

Do you expect developers to be excited for this new mapping capability?

We're using a very powerful computer in the robot, a NVIDIA Jetson TX2 running Ubuntu. There's room to grow. It’s actually really exciting to be able to see, in real time, the 3D pose of the robot along with all of the depth data that gets transformed in real time into one view that gives you a full map. Having all of that data and just putting those pieces together and getting everything to work has been a huge feat in of itself.

We have an extensive API for developers to do custom implementations, either for telepresence or other kinds of robotics research. Our system isn't running ROS, but we're going to be adding ROS adapters for all of our hardware components.

Telepresence robots depend heavily on wireless connectivity, which is usually not something that telepresence robotics companies like Double have direct control over. Have you found that connectivity has been getting significantly better since you first introduced Double?

When we started in 2013, we had a lot of customers that didn’t have WiFi in their hallways, just in the conference rooms. We very rarely hear about customers having WiFi connectivity issues these days. The bigger issue we see is when people are calling into the robot from home, where they don't have proper traffic management on their home network. The robot doesn't need a ton of bandwidth, but it does need consistent, low latency bandwidth. And so, if someone else in the house is watching Netflix or something like that, it’s going to saturate your connection. But for the most part, it’s gotten a lot better over the last few years, and it’s no longer a big problem for us.

Do you think 5G will make a significant difference to telepresence robots?

We’ll see. We like the low latency possibilities and the better bandwidth, but it's all going to be a matter of what kind of reception you get. LTE can be great, if you have good reception; it’s all about where the tower is. I’m pretty sure that WiFi is going to be the primary thing for at least the next few years.

DeVidts also mentioned that an unfortunate side effect of the new depth sensors is that hanging a t-shirt on your Double to give it some personality will likely render it partially blind, so that's just something to keep in mind. To make up for this, you can switch around the colorful trim surrounding the screen, which is nowhere near as fun.

When the Double 3 is ready for shipping in late September, US $2,000 will get you the new head with all the sensors and stuff, which seamlessly integrates with your Double 2 base. Buying Double 3 straight up (with the included charging dock) will run you $4,ooo. This is by no means an inexpensive robot, and my impression is that it’s not really designed for individual consumers. But for commercial, corporate, healthcare, or education applications, $4k for a robot as capable as the Double 3 is really quite a good deal—especially considering the kinds of use cases for which it’s ideal.

[ Double Robotics ] Continue reading →

Posted in Human Robots

#435597 Water Jet Powered Drone Takes Off With ...

Posted on September 12, 2019 by Android

At ICRA 2015, the Aerial Robotics Lab at the Imperial College London presented a concept for a multimodal flying swimming robot called AquaMAV. The really difficult thing about a flying and swimming robot isn’t so much the transition from the first to the second, since you can manage that even if your robot is completely dead (thanks to gravity), but rather the other way: going from water to air, ideally in a stable and repetitive way. The AquaMAV concept solved this by basically just applying as much concentrated power as possible to the problem, using a jet thruster to hurl the robot out of the water with quite a bit of velocity to spare.

In a paper appearing in Science Robotics this week, the roboticists behind AquaMAV present a fully operational robot that uses a solid-fuel powered chemical reaction to generate an explosion that powers the robot into the air.

The 2015 version of AquaMAV, which was mostly just some very vintage-looking computer renderings and a little bit of hardware, used a small cylinder of CO2 to power its water jet thruster. This worked pretty well, but the mass and complexity of the storage and release mechanism for the compressed gas wasn’t all that practical for a flying robot designed for long-term autonomy. It’s a familiar challenge, especially for pneumatically powered soft robots—how do you efficiently generate gas on-demand, especially if you need a lot of pressure all at once?

An explosion propels the drone out of the water
There’s one obvious way of generating large amounts of pressurized gas all at once, and that’s explosions. We’ve seen robots use explosive thrust for mobility before, at a variety of scales, and it’s very effective as long as you can both properly harness the explosion and generate the fuel with a minimum of fuss, and this latest version of AquaMAV manages to do both:

The water jet coming out the back of this robot aircraft is being propelled by a gas explosion. The gas comes from the reaction between a little bit of calcium carbide powder stored inside the robot, and water. Water is mixed with the powder one drop at a time, producing acetylene gas, which gets piped into a combustion chamber along with air and water. When ignited, the acetylene air mixture explodes, forcing the water out of the combustion chamber and providing up to 51 N of thrust, which is enough to launch the 160-gram robot 26 meters up and over the water at 11 m/s. It takes just 50 mg of calcium carbide (mixed with 3 drops of water) to generate enough acetylene for each explosion, and both air and water are of course readily available. With 0.2 g of calcium carbide powder on board, the robot has enough fuel for multiple jumps, and the jump is powerful enough that the robot can get airborne even under fairly aggressive sea conditions.

Image: Science Robotics

The robot can transition from a floating state to an airborne jetting phase and back to floating (A). A 3D model render of the underside of the robot (B) shows the electronics capsule. The capsule contains the fuel tank (C), where calcium carbide reacts with air and water to propel the vehicle.

Next step: getting the robot to fly autonomously
Providing adequate thrust is just one problem that needs to be solved when attempting to conquer the water-air transition with a fixed-wing robot. The overall design of the robot itself is a challenge as well, because the optimal design and balance for the robot is quite different in each phase of operation, as the paper describes:

For the vehicle to fly in a stable manner during the jetting phase, the center of mass must be a significant distance in front of the center of pressure of the vehicle. However, to maintain a stable floating position on the water surface and the desired angle during jetting, the center of mass must be located behind the center of buoyancy. For the gliding phase, a fine balance between the center of mass and the center of pressure must be struck to achieve static longitudinal flight stability passively. During gliding, the center of mass should be slightly forward from the wing’s center of pressure.

The current version is mostly optimized for the jetting phase of flight, and doesn’t have any active flight control surfaces yet, but the researchers are optimistic that if they added some they’d have no problem getting the robot to fly autonomously. It’s just a glider at the moment, but a low-power propeller is the obvious step after that, and to get really fancy, a switchable gearbox could enable efficient movement on water as well as in the air. Long-term, the idea is that robots like these would be useful for tasks like autonomous water sampling over large areas, but I’d personally be satisfied with a remote controlled version that I could take to the beach.

“Consecutive aquatic jump-gliding with water-reactive fuel,” by R. Zufferey, A. Ortega Ancel, A. Farinha, R. Siddall, S. F. Armanini, M. Nasr, R. V. Brahmal, G. Kennedy, and M. Kovac from Imperial College in London, is published in the current issue of Science Robotics. Continue reading →

Posted in Human Robots

#435583 Soft Self-Healing Materials for Robots ...

Posted on September 11, 2019 by Android

If there’s one thing we know about robots, it’s that they break. They break, like, literally all the time. The software breaks. The hardware breaks. The bits that you think could never, ever, ever possibly break end up breaking just when you need them not to break the most, and then you have to try to explain what happened to your advisor who’s been standing there watching your robot fail and then stay up all night fixing the thing that seriously was not supposed to break.

While most of this is just a fundamental characteristic of robots that can’t be helped, the European Commission is funding a project called SHERO (Self HEaling soft RObotics) to try and solve at least some of those physical robot breaking problems through the use of structural materials that can autonomously heal themselves over and over again.

SHERO is a three year, €3 million collaboration between Vrije Universiteit Brussel, University of Cambridge, École Supérieure de Physique et de Chimie Industrielles de la ville de Paris (ESPCI-Paris), and Swiss Federal Laboratories for Materials Science and Technology (Empa). As the name SHERO suggests, the goal of the project is to develop soft materials that can completely recover from the kinds of damage that robots are likely to suffer in day to day operations, as well as the occasional more extreme accident.

Most materials, especially soft materials, are fixable somehow, whether it’s with super glue or duct tape. But fixing things involves a human first identifying when they’re broken, and then performing a potentially skill, labor, time, and money intensive task. SHERO’s soft materials will, eventually, make this entire process autonomous, allowing robots to self-identify damage and initiate healing on their own.

Photos: SHERO Project

The damaged robot finger [top] can operate normally after healing itself.

How the self-healing material works
What these self-healing materials can do is really pretty amazing. The researchers are actually developing two different types—the first one heals itself when there’s an application of heat, either internally or externally, which gives some control over when and how the healing process starts. For example, if the robot is handling stuff that’s dirty, you’d want to get it cleaned up before healing it so that dirt doesn’t become embedded in the material. This could mean that the robot either takes itself to a heating station, or it could activate some kind of embedded heating mechanism to be more self-sufficient.

The second kind of self-healing material is autonomous, in that it will heal itself at room temperature without any additional input, and is probably more suitable for relatively minor scrapes and cracks. Here are some numbers about how well the healing works:

Autonomous self-healing polymers do not require heat. They can heal damage at room temperature. Developing soft robotic systems from autonomous self-healing polymers excludes the need of additional heating devices… The healing however takes some time. The healing efficiency after 3 days, 7 days and 14 days is respectively 62 percent, 91 percent and 97 percent.

This material was used to develop a healable soft pneumatic hand. Relevant large cuts can be healed entirely without the need of external heat stimulus. Depending on the size of the damage and even more on the location of damage, the healing takes only seconds or up to a week. Damage on locations on the actuator that are subjected to very small stresses during actuation was healed instantaneously. Larger damages, like cutting the actuator completely in half, took 7 days to heal. But even this severe damage could be healed completely without the need of any external stimulus.

Applications of self-healing robots
Both of these materials can be mixed together, and their mechanical properties can be customized so that the structure that they’re a part of can be tuned to move in different ways. The researchers also plan on introducing flexible conductive sensors into the material, which will help sense damage as well as providing position feedback for control systems. A lot of development will happen over the next few years, and for more details, we spoke with Bram Vanderborght at Vrije Universiteit in Brussels.

IEEE Spectrum: How easy or difficult or expensive is it to produce these materials? Will they add significant cost to robotic grippers?

Bram Vanderborght: They are definitely more expensive materials, but it’s also a matter of size of production. At the moment, we’ve made a few kilograms of the material (enough to make several demonstrators), and the price already dropped significantly from when we ordered 100 grams of the material in the first phase of the project. So probably the cost of the gripper will be higher [than a regular gripper], but you won’t need to replace the gripper as often as other grippers that need to be replaced due to wear, so it can be an advantage.

Moreover due to the method of 3D printing the material, the surface is smoother and airtight (so no post-processing is required to make it airtight). Also, the smooth surface is better to avoid contamination for food handling, for example.

In commercial or industrial applications, gradual fatigue seems to be a more common issue than more abrupt trauma like cuts. How well does the self-healing work to improve durability over long periods of time?

We did not test for gradual fatigue over very long times. But both macroscopic and microscopic damage can be healed. So hopefully it can provide an answer here as well.

Image: SHERO Project

After developing a self-healing robot gripper, the researchers plan to use similar materials to build parts that can be used as the skeleton of robots, allowing them to repair themselves on a regular basis.

How much does the self-healing capability restrict the material properties? What are the limits for softness or hardness or smoothness or other characteristics of the material?

Typically the mechanical properties of networked polymers are much better than thermoplastics. Our material is a networked polymer but in which the crosslinks are reversible. We can change quite a lot of parameters in the design of the materials. So we can develop very stiff (fracture strain at 1.24 percent) and very elastic materials (fracture strain at 450 percent). The big advantage that our material has is we can mix it to have intermediate properties. Moreover, at the interface of the materials with different mechanical properties, we have the same chemical bonds, so the interface is perfect. While other materials, they may need to glue it, which gives local stresses and a weak spot.

When the material heals itself, is it less structurally sound in that spot? Can it heal damage that happens to the same spot over and over again?

In theory we can heal it an infinite amount of times. When the wound is not perfectly aligned, of course in that spot it will become weaker. Also too high temperatures lead to irreversible bonds, and impurities lead to weak spots.

Besides grippers and skins, what other potential robotics applications would this technology be useful for?

Most of self healing materials available now are used for coatings. What we are developing are structural components, therefore the mechanical properties of the material need to be good for such applications. So maybe part of the skeleton of the robot can be developed with such materials to make it lighter, since can be designed for regular repair. And for exceptional loads, it breaks and can be repaired like our human body.

[ SHERO Project ] Continue reading →

Posted in Human Robots