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Over the years, improvements have been made to robots that allow them to go places and do things that just aren’t physically possible for humans. Like, be small enough to go inside the human body.

Or land on a leaf without disturbing an ecosystem. Or travel inside a nuclear disaster zone. But robots still have their limitations.

And one area that needs considerable improvement is their flexibility. Especially when it comes to maneuvering in extreme environments. So developers are hard at work making softer, squishier robots that could one day be up to the task!

On top of that, many are being developed with no electronics involved, which gives them another leg up over traditional robots. Here are five examples of soft robot prototypes in the works, and they’re so soft and squishy that you might just be tempted to give some of them a hug. First, what better soft-bodied creature to inspire a robot than an octopus?

Octopus can flex and squish their soft bodies, bend their arms in multiple directions, squeeze through small spaces, and manipulate objects with ease. To have a robot capable of similar actions would be a huge improvement in the robotics world. One day you might find an octobot squeezing itself into small spaces like caves or beneath docks, even setting up experiments in hard-to-access spots or retrieving lost objects.

And a couple of research teams are working separately toward developing a soft robot that looks and acts like an octopus. Researchers in Italy were interested in mimicking an octopus's ability to keep the volume of its arms the same while contracting and changing the shape of its muscles. A soft robot with this ability would have much greater dexterity than current robots.

There are lots of ways to give a soft robot dexterity, but one way this particular research team has come up with is to make artificial muscles using materials called shape memory alloys. When these alloys are heated up with an electric current, they deform. Researchers can give them a predefined shape, in this case, a spring, and the alloys can remember that shape.

When the electrical current is applied, the alloys contract, just like a muscle contraction. This research team built an octopus arm out of multiple shape-memory alloy springs, giving it the ability to bend and shorten, stretch out and grab things. So far, it’s just an arm.

But this work demonstrates the huge potential of soft robotics left to be unlocked. Another group of researchers at Harvard have developed a soft-bodied octobot that uses no electricity at all. Instead, it’s powered by a chemical reaction between concentrated hydrogen peroxide solution and platinum metal inside the octobot’s brain.

The brain in this case is a little silicone disc that has a network of platinum-lined channels on top of it. These channels connect in a circuit that the hydrogen peroxide flows through. The reaction between the hydrogen peroxide and platinum generates a gas that travels through more channels extending from the brain into the arms of the octobot.

Since gas takes up more space than liquid, as it flows into the bot's eight arms, they expand to accommodate the gas. Right now, that’s all the octobot is able to do. But the researchers envision future versions being able to squeeze into tight spaces or gently touch something fragile, like a delicate sample of a soft-bodied creature.

While a fully functional robotic octopus is still a ways off, these improvements are pushing the soft robot envelope further than ever before. The deepest spot on earth is found in the Mariana Trench. Known as the Challenger Deep, it’s just over 11,000 meters deep and is unsurprisingly really difficult to explore safely.

But a newly developed soft robot, inspired by fish, has proven up to the task! You see, the pressure in that environment is immense. Anything used to explore the Challenger Deep, whether submersible or tethered robot, typically has to be made up of special, pressure-resistant materials in order to withstand the crushing pressure.

Which is about 1000 times greater than the pressure you experience on land. These special materials make the machines extremely expensive to operate. But this newly developed soft robot completely eliminates the need for pressure-resistant housings.

Instead, it’s made entirely out of silicone and its body is streamlined like a fish, complete with two fins that it uses to propel itself through the water. And its fishy shape helps it meet very little resistance as it swims through the water. The fins are attached to “muscles” on the robot’s body that are also made of soft, flexible material and when an electric current from a battery is applied to the bot’s muscles, they contract.

In order to come up with a way to protect the fishbot’s electronics from the high pressures of the deep sea and keep the robot soft and squishy. The developers drew inspiration from the hadal snailfish, whose skull bones are spaced with tiny gaps to deal with the immense pressures it experiences. So instead of packing the electronics together, the engineers spaced them out just like in the snailfish, and embedded them in silicone, to reduce the stress at the interfaces.

Not only is this soft robot able to withstand the crushing pressures of the deepest spot on earth, it’s also a cheaper, more practical approach for protecting electronics. There are still improvements to be made before you’ll find schools of fishbots exploring the deepest depths of the ocean. For instance, the current version is light enough to be easily swept away by a strong underwater current.

But this new technology could be applied to future iterations, as well as other deep-sea devices, greatly improving their cost, resilience, and reliability. Operating a robot underwater is challenging, but what about flying a robot just above the surface of the water? Researchers are interested in developing a bot that could skim right along the surface of the water, even dipping a toe in or a wing in to test the waters.

This type of bot could be used to detect conditions on the water’s surface that would alert scientists to a potential environmental disaster, like the very beginning of an oil spill. The hardest part is arguably protecting the robot’s electronics from water while keeping the entire robot lightweight enough to skim over the surface. To get around this, engineers at Duke University have developed an electronics-free, soft robot shaped like a dragonfly.

Known as DraBot, this little robot can skim across the surface of water just like a real dragonfly. The DraBot works by controlling the air pressure coming into its wings from a tank. Microchannels carry the air into the front wings, where it escapes through a series of holes pointed directly into the back wings.

This prototype is able to react to changing conditions it encounters as it skims along the water, like changing pH levels, temperature, or even the presence of oil. To detect water’s acidity, one set of DraBot’s wings is painted with a self-healing hydrogel. If the bot encounters acidic water conditions, one side’s front wing fuses with the back wing.

Instead of traveling in a straight line, the imbalance causes the robot to spin in a circle, signaling acidic conditions are present. This continues until the pH is neutralized and the fused wings separate. The researchers also put sponges under the wings with temperature-responsive materials, to make them capable of detecting contaminants and temperature changes.

When the bot skims over water with oil floating on the surface, the sponges soak it up. And when the water becomes too warm, DraBot’s wings change from red to yellow, mimicking the way actual dragonflies change color under changing temperatures. This robot’s the first step towards developing more advanced, independently operating, long-range environmental detection bots.

Future versions could be used to detect ocean acidification, warming waters, a body of water’s acidity, or even the early beginnings of an oil spill. Now the next bot is probably the least huggable of the bunch, but its development has big implications for the future of robotics in remote locations. Researchers at MIT working with the US Army are working on soft robots that can be 3D-printed right on the spot.

So they could be particularly useful in locations where resources may be low or the ability to bring in other equipment might be limited. These robots are printed from a special ink that is infused with tiny magnetic particles. The 3D printer’s nozzle has an electromagnet attached to it.

This way, the researchers can control the tiny particles as they’re being printed, arranging them in specific directions. And these robots are able to move and change shape as a magnetic field is applied. Since they are 3D printed, they can be any shape or size.

Researchers even imagine putting tiny versions of this bot inside the human body, such as one that could wrap around a blood vessel to control the pumping of blood. This type of technology responds much faster than the other soft materials that we’ve discussed so far, because magnetic particles are involved and you can manipulate them really quickly. So far, researchers say they “have printed a smooth ring that can wrinkle itself up, a long tube that can squeeze shut, a sheet that folds itself, and a grabber that can crawl, roll, or snap together to catch a passing ball.” The Army would like to use large versions of these for tasks soldiers can’t do safely, like squeezing into cracks or crawling under vehicles.

Once again, these bots aren’t yet ready for their debut outside of a laboratory, but future iterations could be really useful in extreme environments. Now, you might not want to hug this next bot on the list, but for entirely different reasons than the 3D-printed bot. That’s because this one somewhat resembles a large inflatable worm, and earthworms don’t always rank very high on the huggability list.

But that’s up to personal preferences. Current prototypes of these robots are nowhere near being ready to explore our planet, let alone outer space, but researchers envision whole fleets of them being used to work together on rough, uneven surfaces like the moon. And this soft bot is capable of movement without electronics.

Instead, it’s made entirely of silicone chambers that can be inflated using compressed air. It moves based on how much air is in each of its chambers and can change shape from completely flat to fully three-dimensional. When the bot is flat, it’s able to squeeze into tight spaces.

When inflated, it can walk, crawl, or slither along a variety of surfaces, including gravel and mud. This wormy bot was developed by researchers at Harvard, but NASA has been working with a similar design. They envision one day deploying a bunch of them for working off-planet.

So while R2D2 might come to mind when somebody mentions space robots, maybe you should be picturing a bunch of these inflatable wormbots instead. The hope is that they could be used to link together to form a large, flexible temporary structure, fill in a gap beneath an existing structure, or maneuver over rocky environments better than existing technology, like rovers. So from octopuses to earthworms, all sorts of soft-bodied creatures are inspiring engineers to develop softer, squishier and, dare I say it, more huggable robots.

And these bots' flexibility gives them a one-up on traditional, more rigid robots. They can maneuver through extreme environments like the deep sea, wreckage after a natural disaster, or even, maybe one day, other planets. And on top of that, many of these bots aren’t dependent on electronics, so they’re less expensive and have less that can go wrong with them than traditional robots.

So if you ever encounter one of these in the real world one day, don’t be afraid to give it a big ole squeeze! Thanks for watching this episode of SciShow! If you liked learning about these quirky robots,.

I bet you’ll love our podcast, SciShow Tangents! In it, some of the fun, and lovely, people who are involved in SciShow and other things here at Complexly get together for a lightly competitive knowledge showcase. Every episode, I give them points for teaching me the most mind-blowing science facts related to this week’s theme.

Like there was an episode on flying machines, which you might not be tempted to hug, BUT zipping around in a jetpack seems pretty cool to me. If you love science, laughing, and lighthearted, nerdy competitions, you should check it out! You can find SciShow Tangents anywhere you get your podcasts. [♪ OUTRO].