Soft Rotating Pneumatic Actuators

When we think of pneumatic actuators, we typically consider the standard varieties of pneumatic cylinder, capable of linear motion. These can be referred to as “hard” actuators, made of rigid components and capable of great accuracy and force delivery. However, “soft” actuators have their own complementary abilities – such as being able to handle more delicate tasks and being less likely to injure human operators when used in collaborative operations. The Whitesides Research Group at Harvard University has undertaken significant research in this field, and released a paper covering a novel type of soft pneumatic actuator.

The actuator consists of a series of soft, flexible sealed chambers which surround a wooden dowel in the center. By applying vacuum to these various chambers, the dowel in the center can be pulled into up to eight different positions. It’s a unique concept, and one we can imagine could have applications in various material processing scenarios.

The actuator was built by moulding elastomers around 3D printed components, so this is a build that could theoretically be tackled by the DIYer. The paper goes into great detail to quantify the performance of the actuator, and workshops several potential applications. Testing is done on a fluid delivery and stirring system, and a tethered robotic walker was built. The team uses the term cVAMS – cyclical vacuum actuated machine – to describe the actuator technology.

The world of soft robotics is a hot bed of development, and we look forward to further work in this field. It’s not just Harvard, either – we’ve seen interesting work from Yale and from the Hackaday community too!

 

Friday Hack Chat: Air Hacking

The field of soft robotics sure seems a lot less mature than your standard servo motor and metal framed robot arms. Maybe that’s because building a robot to flex is harder, and maybe it’s because the best methods of constructing soft robotics have only been around for a decade or so. Maybe, though, it’s because it’s hard to control air.

For this week’s Hack Chat, we’re going to be discussing Air Hacking with [Amitabh Shrivastava]. [Amitabh] is a grad student at ITP, NYU studying creative technology, where he makes interactive art, tools for research, and experiments with various materials. Lately he has been developing Programmable-Air, a pneumatic controller for soft robotics. We’ve seen his work at ThiMaker Faire, and it’s an awesome project in this year’s Hackaday Prize.

In this chat we will be talking about DIY soft robotics. Soft robotics is a growing field with a lot of low hanging fruits within grasp of the hobbyist maker. In addition to sharing experience and resources about building your own soft robots, we will talk about actuation! Tune in to see how you can use pneumatics in your next project.

During this week’s Hack Chat, we’ll be discussing:

  • Pneumatics
  • Programmable Air
  • Soft Robotics
  • Methods of adding pneumatics to your project

You are, of course, encouraged to add your own questions to the discussion. You can do that by leaving a comment on the Air Hacking Hack Chat and we’ll put that in the queue for the Hack Chat discussion.

join-hack-chat

Our Hack Chats are live community events on the Hackaday.io Hack Chat group messaging. This week we’ll be sitting down on Friday, October 26th, at noon, Pacific time. If time zones got you down, we have a handy time zone converter.

Click that speech bubble to the right, and you’ll be taken directly to the Hack Chat group on Hackaday.io.

You don’t have to wait until Friday; join whenever you want and you can see what the community is talking about.

Walk It Off, Healing Robots

For many of us, our first robots, or technical projects, were flimsy ordeals built with cardboard, duct tape, and high hopes. Most of us grow past that scene, and we learn to work supplies which require more than a pair of kitchen scissors. Researchers at Carnegie Mellon University and Iowa State University have made a material which goes beyond durable, it can heal itself when wounded. To a small robot, a standard hole puncher is a dire assailant, but the little guy in the video after the break keeps hopping around despite a couple of new piercings.

The researcher’s goal is to integrate this substance into bio-inspired robots which may come to harm in the field. Fish-like robots could keep swimming after a brush with a bit of coral or a curious predator. Robot snakes could keep slithering after a fall or a gravel road.

Of course, robotic simulacrums are not the only ones who can benefit from healing circuitry. Satellites are prey to punctures from errant space debris.

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Turn Your Teddy Bear Into A Robot With Yale’s “Robotic Skin”

Despite what we may have seen in the new Winnie the Pooh movie, our cherished plush toys don’t usually come to life. But if that’s the goal, we have ways of making it happen. Like these “robotic skins” from Yale University.

Each module is a collection of sensors and actuators mounted on a flexible substrate, which is then installed onto a flexible object serving as structure. In a simple implementation, the mechanical bits are sewn onto a piece of fabric and tied with zippers onto a piece of foam. The demonstration video (embedded below the break) runs through several more variations of the theme. From making a foam tube (“pool noodle”) crawl like a snake to making a horse toy’s legs move.

There’s a serious motivation behind these entertaining prototypes. NASA is always looking to reduce weight that must be launched into space, and this was born from the idea of modular robotics. Instead of actuators and sensors embedded in a single robot performing a specific function, these robotic skins can be moved around to different robot bodies to perform a variety of tasks. Such flexibility can open up more capabilities while occupying less weight on the rocket.

This idea is still early in development and the current level prototypes look like something most of us can replicate and improve upon for use in our projects. We’ve even got a controller for those pneumatics. With some more development, it may yet place among the ranks of esoteric actuators.

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Hold the Salt and Butter, This Popcorn Is For a Robot

Popcorn! Light and fluffy, it is a fantastically flexible snack. We can have them plain, create a savory snack with some salt and butter, or cover with caramel if you have a sweet tooth. Now Cornell University showed us one more way to enjoy popcorn: use their popping action as the mechanical force in a robot actuator.

It may be unorthodox at first glance, but it makes a lot of sense. We pop corn by heating its water until it turns into steam triggering a rapid expansion of volume. It is not terribly different from our engines burning an air-fuel mixture to create a rapid expansion of volume. Or using heat energy to boil water and trigger its expansion to steam. So a kernel of popcorn can be used as a small, simple, self-contained engine for turning heat energy into mechanical power.

Obviously it would be a single-use mechanism, but that’s perfectly palatable for the right niche. Single-use is a lot easier to swallow when popcorn is so cheap, and also biodegradable resulting in minimal residue. The research paper demonstrated three recipes to harness popping corn’s mechanical energy, but that is hardly an exhaustive list. There’s an open invitation to brainstorm other creations to add to the menu.

Of course, if you prefer candy over popcorn, you could build a robot actuator out of licorice instead.

Either way, the robot uprising will be delicious.

[via IEEE Spectrum]

Continue reading “Hold the Salt and Butter, This Popcorn Is For a Robot”

Programmable Air Makes Robotics A Breeze

[Amitabh] was frustrated by the lack of options for controlling air pressure in soft robotics. The most promising initiative, Pneuduino, seemed to be this close to a Shenzhen production run, but the creators have gone radio silent. Faced with only expensive alternatives, he decided to take one for Team Hacker and created Programmable Air, a modular system for inflatable and vacuum-based robotics.

The idea is to build the cheapest, most hacker-friendly system he can by evaluating and experimenting with all sorts of off-the-shelf pumps, sensors, and valves. From the looks of it, he’s pretty much got it dialed in. Programmable Air is based around $9 medical-grade booster pumps that are as good at making vacuums as they are at providing pressurization. The main board has two pumps, and it looks like one is set to vacuum and the other to spew air. There’s an Arduino Nano to drive them, and a momentary to control the air flow.

Programmable Air can support up to 12 valves through daughter boards that connect via right-angle header. In the future, [Amitabh] may swap these out for magnetic connections or something else that can withstand repeated use.

Blow past the break to watch Programmable Air do pick and place, control a soft gripper, and inflate a balloon. The balloon’s pressurization behavior has made [Amitabh] reconsider adding a flow meter, but so far he hasn’t found a reasonable cost per unit. Can you recommend a small flow meter that won’t break the bank? Let us know in the comments.

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Papercraft-Inspired Snake-bot Slithers like a Real One

Blend the Japanese folding technique of Kirigami with an elastomer actuator, and what have you got? A locomoting snake robot that can huff around its own girth with no strings attached! That’s exactly what researchers at the Wyss Institute and Harvard School of Applied Sciences did to build their Kirigami Crawler.

Expanding and contracting propel this crawler forward. As the actuator expands, the hatched pattern on the plastic skin flares out; and when it contracts, the skin retracts to a smoother form. The flared hatch pattern acts like a cluster of little hooks, snagging multiple contact points into the ground. When the skin retracts, these hooks fold back inside while giving the body a slight push forward in the process. It’s a clever tactic, and almost identical to the way real-world snakes propel themselves. In fact, after iterating on a few skin patterns, they found that a trapezoidal pattern, which most closely resembles that of snakeskin, can cover ground fastest.

We’re thrilled to see such authentic biomimicry come to us without any extreme tooling or special molds. Still not satisfied with your share of crawling robots for one day? Have a peek into the past, and indulge yourself with a sine-wave locomotion.

Thanks for the tip, [Olivia]!

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