Pneumatic actuators offer interesting perspectives in applications like soft robotics and interaction design. [Aidan Leitch] makes his own pneumatic actuators from silicone rubber. His actuators contain embedded air channels that can be filled with pressurized air and completely collapse to a flat sheet when no pressure is applied. Continue reading “Building Pneumatic Actuators With 3D Printed Molds”
In his talk at 32C3 [Matthew Borgatti] talked both about his company’s work with NASA toward developing robotic spacesuits and helping people with Cerebral Palsy better control their limbs. What do these two domains have in common? “One-size fits all pneumatic exoskeletons.”
[Matthew] makes a tremendously compelling case for doing something new and difficult in robotics — making robotic systems out of squishy, compliant materials. If you think about it, most robots are hard: made of metal and actuated by motors and gears, cables, or (non-compressible) pneumatic fluid. If you want to build suits that play well with soft and squishy people, they’ll need at least a layer of softness somewhere.
But [Matthew]’s approach is to make everything soft. In the talk, he mentions a few biological systems (octopus arms and goat’s feet) that work exactly because they’re soft. Why soft? Because soft spreads force around automatically and accommodates uneven terrain. And this makes it easier on the people who wear robotic suits and on the designers of the robots who don’t need to worry about the fine detail of the ground they’re walking on.
The talk ended up being very short, but there’s a fantastic Q&A at the end. It’s a must-see. And if you can’t get enough of [Matthew] or squishy robots, we’ve covered his robots before and he even had an entry in the Hackaday Prize.
Nearly a million people in the US suffer from CP, a neurological disorder that causes spastic motion in the limbs. One of the biggest quality of life factors for CP sufferers is the ability to use their arms, and that means an expensive and clunky orthotic around their elbow. [Matthew] has a better idea: why not make a soft orthotic?
This is not [Matthew]’s first project with soft robotics. He’s the lead scientist at Super Releaser, the company responsible for the completely soft robotic Glaucus atlanticus and other soft pneumatic robots.
This soft, flexible orthotic exoskeleton is designed for sufferers of chronic movement disorders. Traditional orthotics are expensive, difficult to move, and uncomfortable, but by designing this orthotic to be just as strong but a little more forgiving, these devices minimize most of the problems.
The Neucuff is constructed out of extremely simple materials – just some neoprene, a velcro, and a CO2 cartridge. The problem with bringing this to market, as with all medical devices, is FDA requirements and certifications. That makes the Hackaday Prize an excellent opportunity for [Matthew] and the rest of Super Releaser, as well as anyone else trying to navigate regulatory requirements in order to change the world.
The 2015 Hackaday Prize is sponsored by:
This robot arm and gripper is made almost entirely out of silicone. Casting the parts by hand, [Mike] assembled this working, remote controlled robot arm gripper.
We’ll let that sink in for a minute. He turned an oversized tooth-paste tube of silicone caulking… into a pneumatic robotic arm. Holy cow. We’ve seen lots of soft robotics before, but this is some really cool stuff!
You see, [Mike] is actually planning on building an inexpensive prosthetic robot hand using this technology. This was merely a test to see how well he could make silicone based air muscles — we’d say it was pretty successful! Each silicone disk in this robotic appendage has four sealed pockets inside of it. When air flows in through them, they inflate, causing the entire appendage to stretch on one side. With four of these, and varying amounts of pressure, it’s possible to move the appendage in any direction!
Most of the robotics projects we see around here are heavy, metallic machines that move with exacting precision with steppers, servos, motors, and electronics. [Matthew] is another breed of roboticist, and created a quadruped robot with no hard moving parts.
[Matthew] calls his creation the Glaucus, after the blue sea slug Glaucus atlanticus. Inside this silicone rubber blob are a series of voids, allowing compressed air to expand the legs, gently inching Glaucus across a table under manual or automatic control.
Even though no one seems to do it, making a few molds for casting on a 3D printer is actually pretty easy. [Matthew] is taking this technique to an extreme, though: First, a mold for the interior pressure bladders are printed, then a positive of this print made in silicone rubber. These silicone molds – four of them, for the left, right, top and bottom – are then filled with wax, and the wax parts reassembled inside the final ‘body’ mold. It’s an amazing amount of work to make just one of these soft robots, but once the molds and masters are made, [Matthew] can pop out a soft robot every few hours or so.
There’s a lot more info on Glaucus over on the official site for the build, and a somewhat simpler ‘compressed air and silicone rubber’ tentacle [Matthew] built showing off the mechanics. Video below.
Soft robots are a peculiar wing of technology. They don’t use frames and motors for locomotion, but as the name implies they are made of soft materials. They move by pumping fluid — it could be air or liquid — in and out of bladders that push or pull against the body itself. [Matthew] points out that fabricating soft robots has traditionally been a time-consuming and difficult task. He’s trying to make it easier by 3D printing molds into which soft robots can be cast. This way the parts can be designed in CAD, converted to a mold design, and pushed to a 3D printer.
The object with which he’s been testing the technique functions like an octopus tentacle. The image at the bottom left illustrates the internal structure, with rings separated to allow the appendage to flex, and tubes running parallel to the appendage to provide the force needed to bend it. Above that image you can see one of the molds that was used, and the final product is on the right. The video after the break shows a demonstration of this bending left and right as air is pumped in using the bulb of a blood pressure cuff (or Sphygmomanometer for those paying attention).
If it were alive this robot would be classified as an invertebrate. It lacks a backbone and interestingly enough, all other bones are missing as well. The Harvard researchers that developed it call it a soft robot. It’s made out of silicone and uses pathways built into the substance to move. By adding pressurized air to these pathways the appendages flex relative to each other. In fact, after the break you can see a video of a starfish-shaped soft robot picking up an egg.
Now they’ve gone one step further. By adding another layer to the top, or even embedding it in the body, the robot gains the ability to change color. Above you can see a soft robot that started without any color (other than the translucent white of the silicone) and is now being changed to red. As the dye is injected it is propagating from the right side to the left. The team believes this could be useful in a swarm robotics situation. If you have a slew of these things searching for something in the dark they could pump glowing dye through their skin when they’ve found it. The demo can be seen after the jump.