Robots Get Flexible

Nature inspires a new wave of soft robotics.

Ask anyone how a robot moves and they will immediately go rigid and move their arms up and down, and if you’re lucky, you may get some stiff, funky dance moves. Researchers at UC San Diego hope to put this perception to rest with a new breed of robots with smoother moves—and they’re looking to nature to make it possible.

“In nature, it’s easy to build complex systems that combine soft and hard materials,” says Michael Tolley, professor of mechanical engineering and head of the Bioinspired Robotics and Design Lab at the Jacobs School of Engineering. “Using new manufacturing techniques like 3-D printing, we’re translating this hard/soft approach to robotics.”

Bringing together soft and rigid materials will help create a new generation of agile robots that have a number of advantages: so-called “soft robots” are better suited to safely interact with humans, they are better able to adapt to their environment, and they can manipulate delicate objects without damaging them. Here’s a sample of the latest robots to grip, walk and swim out from Tolley’s lab.

 Grip Like a Gecko

The dexterity of the human hand is one of  robotics’ holy grails—extremely flexible, agile, and packed with millions of nerve endings to touch, feel and grasp objects. Robotic hands don’t yet measure up to such complex engineering, but researchers are looking to one of nature’s best climbers for inspiration.

The gecko is well known for its amazing sticking ability, owed entirely to its unique toes packed with millions of microscopic hairs, each about 20 to 30 times smaller than a human hair. Tolley and the students in his lab aim to combine the adhesive mechanics of gecko toes with air-powered soft robotics in order to build a soft, robotic gripper (pictured above). Working with colleagues from Stanford University and NASA’s Jet Propulsion Laboratory (JPL), the team coated the fingers of the soft robotic gripper with the JPL’s gecko-inspired adhesive, allowing for a firm grasp on many different objects, from rough rocks to smooth pipes, and even delicate coffee mugs. With an ability to lift up to 45 lbs., researchers see applications wherever versatility is required in grasping materials—from the factory floor to the International Space Station.

Walk Like a Dog

Most soft robots shuffle, scoot or crawl on the ground, without the ability to lift their legs. But in order to be the intrepid explorers we need on our planet and beyond, robots of the future will need the ability to effectively navigate varying terrains. Tolley’s doctoral students, led by Dylan Drotman ’13, MS ’15, developed the first soft robot that can walk on rough, uneven surfaces like rocks and pebbles, as well as softer ones. This was made possible by 3-D printing, which allowed researchers to design complex shapes for the robot’s legs, printing soft and rigid materials together within the same components.

The robot’s soft legs are positioned in the shape of an X on a rigid frame and are made up of hollow, inflatable chambers that act like bellows—inflate them in a specific order and the legs bend, creating motion. The robot’s gait is still a work in progress, with researchers developing algorithms for better control of factors such as timing and air pressure. Right now, this four-legged robot is tethered to an open-source controller board and an air pump, but researchers plan to miniaturize these components, allowing the robot to walk independently through hazardous environments for exploration or search and rescue operations.

Swim Like an Eel

One of the lab’s innovations is the least likely to hearken back to the rigid arms and legs of yesterday’s robots—because it has none.

Inspired by the sleek and smooth movements of the saltwater eel, the lab’s latest creation is intended for underwater exploration and is made up of a series of translucent pouches filled with saltwater. The robot swims by sending small electrical charges both outside and inside the pouches of water in its body, causing its “muscles” to move and propel itself through the water like an undulating eel. It is a stark contrast to most vehicles currently used to explore under the sea—typically rigid submersibles powered by electric motors with noisy propellers, just the kind of thing to spook delicate marine life. Soft robots like Tolley’s are less likely to damage underwater structures like coral reefs if they accidentally come into contact with them, or the animals themselves. And they very well might—the lab’s robot is virtually invisible underwater (that is, when it’s not glowing in the dark)—its only giveaways being thin connective wires that tether it to an electronics board that remains on the surface.

As Tolley and his team from the Bioinspired Robotics and Design Lab build more lifelike and adept robots, they will continue to look to nature for inspiration, borrowing specialized abilities that have been perfected over time in the wild. The resulting robots will no doubt make a tremendous impact on everything from manufacturing, to search and rescue operations, to space exploration.