How paper robots could lend a hand in delicate operations

13 February 2012 Paper robots driven by air to fold like origami and lift up to 120 times their own weight could be useful for operations that require a delicate touch, researchers say. The robots are made inexpensively by encasing…

13 February 2012

Paper robots driven by air to fold like origami and lift up to 120 times their own weight could be useful for operations that require a delicate touch, researchers say.

The robots are made inexpensively by encasing paper sheets in airtight silicone rubber. On one side of the paper, the soft translucent silicone is riddled with tiny air channels. When air is pumped into these channels, the solid layer of silicone rubber coating the other side of the sheet puffs up with that air, forcing the paper to bend.

“When the balloon part of the structure expands, it doesn’t become round, as does a child’s balloon,” said researcher Ramses Martinez, a materials scientist at Harvard University.

Rather, it “adopts more complex shapes in response to the constraints imposed by the paper sheets.”

The robots in question flex somewhat like accordion bellows or paper lanterns, capable of stretching, collapsing, bending and twisting into quite complex shapes and movements depending on how air is blown into them. The motions the researchers make the paper bots perform are inspired by starfish, worms and squid, and use pneumatics and compressed air in place of natural muscles.

“The methods we developed are astonishingly simple for the complex motions that they generate,” Martinez said. “Once we understood the materials to use, the best procedures for fabrication and the kinds of designs that worked best.”

One such device only 8.2 grams in weight could lift a block 2.2 pounds (1 kilogram) large, about 120 times its weight. If future robots use sheets of material stronger than paper, such as metallic mesh or vulcanized rubber, “robotic structures could, in principle, lift and manipulate a car,” Martinez told InnovationNewsDaily.

Adding metal wires and devices such as lights onto such robots could significantly broaden their uses, for potential applications such as navigating disasters to rescue trapped people, the researchers say. The variety of complex motions that these devices can perform and the fact that they are light and made of cheap components such as paper “allows the fabrication of dexterous and disposable soft robots,” Martinez said.

“We hope these structures can be developed into assistants for humans,” Martinez said. “Unlike the types of machines, robots used in assembly lines – which are designed to be very strong and fast [but] are also very dangerous for humans to be around when they are operating – these actuators can be more human-friendly. They might, thus, provide extra fingers or hands for surgeons, or handle easily damaged structures, such as eggs or fruit.”

Although these robots do need to be hooked up to a compressed air source to work, there are a number of commercial solutions that are portable, Martinez said. Since these devices can carry up to 120 times their weight, “we envision that autonomous multilegged robots that carry on a compressed air source and some batteries to make it work are possible.”

Martinez, along with George Whitesides and their colleagues, detailed their findings online Feb. 9 in the journal Advanced Functional Materials.