Meet the Robotic Octopus
Last month, I toured around CES with a board member of the CTA who shared with me the image of the show 30 years ago, folding tables and all. A qualitative read on how well a market is growing could be the number and size of trade shows in that industry. My inbox has been flooded lately with a plethora of new robot conferences from RoboUniverse to RoboBusiness to XPONENTIAL, to the newest entry – Soft Robotics Week in Livorno, Italy.
Soft Robotics has become a hot segment of the robotic industry. Earlier this year, a start-up company out of Cambridge, Massachusetts, named (originally) Soft Robotics raised $4.5 million of venture capital money to market its unique gripper to the logistics and agricultural industry. As the CEO, Carl Vause, explains, “we use no force sensors, no feedback systems and we don’t do a lot of planning…we just go and grab an object.” Last year, I personally witnessed the value proposition of Soft Robotics at the inaugural show of RoboUniverse. For those that missed it, here is a quick product demo:
However, the genesis of the discovery using air instead of metal to grip objects might date back to close to 10 years ago when Cecilia Laschi asked her father to catch a live octopus for her seaside lab in Livorno, Italy. He thought she was crazy: as a recreational fisherman, he considered the octopus so easy to catch that it must be a very stupid animal. And what did a robotics researcher who worked with metal and microprocessors want with a squishy cephalopod anyway?
Nevertheless, the elder Laschi caught an octopus off the Tuscan coast and gave it to his daughter, who works for the Sant’Anna School of Advanced Studies in Pisa, Italy. She and her students placed the creature in a saltwater tank where they could study how it grasped titbits of anchovy and crab. The team then set about building robots that could mimic those motions.
Prototype by prototype, they created an artificial tentacle with internal springs and wires that mirrored an octopus’s muscles, until the device could undulate, elongate, shrink, stiffen and curl in a lifelike manner. “It’s a completely different way of building robots,” says Laschi.
This approach has become a major research front for robotics in the past ten years. Scientists and engineers in the field have long worked on hard-bodied robots, often inspired by humans and other animals with hard skeletons. These machines have the virtue of moving in mathematically predictable ways, with rigid limbs that can bend and straighten only around fixed joints. But they also require meticulous programming and extensive feedback to avoid smacking into things; even then, their motions often become erratic or even dangerous when dealing with humans, new objects, bumpy terrain or other unpredictable situations.
Robots inspired by flexible creatures such as octopuses, caterpillars or fish offer a solution. Instead of requiring intensive (and often imperfect) computations, soft robots built of mostly pliable or elastic materials can just mould themselves to their surroundings. Although some of these machines use wires or springs to mimic muscles and tendons, as a group, soft robots have ditched the skeletons that defined previous robot generations. With nothing resembling bones or joints, these machines can stretch, twist, scrunch and squish in completely new ways. They can transform in shape or size, wrap around objects and even touch people more safely than ever before.
Inspired by the the octopus, engineers are creating robots that can twist their way around problems that rigid robots can’t handle. Researchers have already produced a wide variety of such machines, including crawling robotic caterpillars, swimming fish-bots and undulating artificial jellyfish.
“If you look in biology, and you ask what Darwinian evolution has coughed up, there are all kinds of incredible solutions to movement, sensing, gripping, feeding, hunting, swimming, walking and gliding that have not been open to hard robots,” says chemist George Whitesides, a soft-robotics researcher at Harvard University in Cambridge, Massachusetts. “The idea of building fundamentally new classes of machines is just very interesting.”
The millions of industrial robots around the world today are all derived from the same basic blueprint. The metal-bound machines use their hefty, rigid limbs to shoulder the grunt work in car-assembly lines and industrial plants with speed, force and mindless repetition that humans simply can’t match. But standard robots require specialized programming, tightly controlled conditions and continuous feedback of their own movements to know precisely when and how to move each of their many joints. They can fail spectacularly at tasks that fall outside their programming parameters, and they can malfunction entirely in unpredictable environments. Most must stay behind fences that protect their human co-workers from inadvertent harm.
“Think about how hard it is to tie shoelaces,” says Daniela Rus, director of the Computer Science and Artificial Intelligence Laboratory at the Massachusetts Institute of Technology in Cambridge. “That’s the kind of capability we’d like to have in robotics.”
Over the past decade, that desire has triggered an increased interest in lighter, cheaper machines that can handle fiddly or unpredictable situations and collaborate directly with humans. Some roboticists, including Laschi, think that soft materials and bioinspired designs can provide an answer.
That idea was a tough sell at first, Laschi says. “In the beginning, very traditional robotics conferences didn’t want to accept my papers,” she says. “But now there are entire sessions devoted to this topic.” Helping to fuel the surge in interest are recent advances in polymer science, especially the development of techniques for casting, moulding or 3D printing polymers into custom shapes. This has enabled roboticists to experiment more freely and quickly with making soft forms.
As a result, more than 30 institutions have now joined the RoboSoft collaboration, which kicked off in 2013. The following year saw the launch of a dedicated journal, Soft Robotics, and of an open-access resource called the Soft Robotics Toolkit: a website developed by researchers at Trinity College Dublin and at Harvard that allows researchers and amateurs to share tips and find downloadable designs and other information.
Perhaps the most fundamental challenge is getting the robots’ soft structures to curl, scrunch and stretch. Laschi’s robotic tentacle houses a network of thin metal cables and springs made of shape-memory alloys— easily bendable metals that return to their original shapes when heated. Laid lengthwise along the ‘arm’, some of these components simulate an octopus’s longitudinal muscles, which shorten or bend the tentacle when they contract. Others radiate out from the tentacle’s core, simulating transverse muscles that shrink the arm’s diameter. Researchers can make the tentacle wave — or even curl around a human hand — by pulling certain combinations of cables with external motors, or by heating springs with electrical currents.
A similar system helps to drive the soft-robotic caterpillars that neurobiologist Barry Trimmer has modelled on his favourite experimental organism, the tobacco hornworm (Manduca sexta). At his lab at Tufts University in Medford, Massachusetts, 20 hornworms are born each day, and Trimmer 3D prints a handful of robotic ones as well. The mechanical creatures wriggle along the lab bench much like the real ones, and they can even copy the caterpillar’s signature escape move: with a pull here and a tug there on the robot’s internal ‘muscles’, the machine snaps into a circle that wheels away5. Trimmer, who is editor-in-chief of Soft Robotics, hopes that this wide range of movements could one day turn the robot into an aide for emergency responders that can rapidly cross fields of debris and burrow through rubble to locate survivors of disasters.
Whitesides, meanwhile, is pioneering robots that are powered by air — among them a family of polymer-based devices inspired by the starfish (see previous blog posts). Each limb consists of an internal network of pockets and channels, sandwiched between two materials of differing elasticity. Whitesides reserarch led to Soft Robotics (the company that just got funded) and its grippers that are made mainly of soft, stretchy materials can envelop and conform to objects of different shapes and sizes.
The RoboSoft challenge in April could help to spur more development. There, the entries will be put through their paces: challenges include racing across a sand pit, opening a door by its handle, grabbing a number of mystery objects and avoiding fragile obstacles under water. The goal, says Laschi, is to demonstrate that soft robots can accomplish some of the same tasks that stiff robots do, as well as others that they cannot.
“I don’t think soft robotics is going to replace traditional robotics, but it will be combination of the two in the future,” says Laschi. Many researchers think that rigid robots might retain their superiority in jobs requiring great strength, speed or precision. But for a growing number of applications involving close interactions with people, or other unpredictable situations, soft robots could find a niche.
At Kings College London, for example, Laschi’s collaborators are developing a surgical endoscope based on her tentacle technology. And her team in Italy is developing a full-bodied robot octopus that swims by fluid propulsion, and could one day be used for underwater research and exploration. The prototype already pulses silently through a tank in her lab, as the real octopuses swim in the salty waters just outside.
“When I started with the octopus, people asked me what it was for,” says Laschi. “I said, ‘I don’t know, but I’m sure if it succeeds there could be many, many applications’.”
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