A robot can move on land and through water thanks to morphable limbs inspired by tortoises and sea turtles.
The Amphibious Robotic Turtle (ART), made by at Yale University and his colleagues, can adapt the shape of its limbs and its gait. On land, the legs mimic those of a tortoise to help it crawl, but in water they convert into flat flippers to swim.
Biomimetic robots that borrow design cues from nature are a common area of research, such as rubber coatings inspired by gecko feet that can stick to vertical surfaces, or suckers based on octopus tentacles so robots can grip smooth objects underwater. But Baines says this is the first time that a biomimetic robot has been created that functions like two different animals.
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ART has four morphable limbs, each controlled by a shoulder joint with three motors. Each limb consists of a pair of pneumatic actuators and layers of polymer that can be softened by embedded heaters. These allow the limbs to change shape, increasing their cross-sectional area by up to four times.
As you might expect from a robot inspired by tortoises, it doesn鈥檛 move fast, but it does better when it comes to efficiency. ART outperformed a bipedal robot developed by the Massachusetts Institute of Technology on a common robotics metric known as cost of transport, which measures the amount of energy needed to move from A to B 鈥� the turtle bot was three times better.
Baines says that the robot could be useful in ocean farming, environmental monitoring or even to assist human divers. 鈥淎 robot could transport parts or tools from land into the water to divers working on repairing a submerged structure,鈥� he says.
There is also the potential for greater flexibility. 鈥淎lthough we focused on transitions between two discrete states, flipper and leg, intermediate shapes or even radically different shapes are certainly possible,鈥� says Baines.
Nature
