Frog-like robots to assist surgery

A tiny robot inspired by the feet of tree-frogs is being built at the University of Leeds. The device may one day allow surgeons to better visualise key-hole surgery.

The robot is designed to move across a patient’s internal abdominal wall and would enable surgeons to see what they are doing on a real-time video feed.

Lead researchers Professor Anne Neville, Royal Academy of Engineering Chair in Emerging Technologies at the University of Leeds, said: “Tree frogs have hexagonal patterned channels on their feet that in a wet surface build capillary bridges, and hence an adhesion force. It is the same kind of idea as a beer glass sticking to a beer mat, but the patterns build a large number of adhesion points that allow our robot to move around on a very slippery surface when it is upside down.”

Using basic capillary action for adhesion is ineffective as soon as there is movement, so the researchers looked at the tiny mechanisms used in nature to develop their device.

“It is only if you look at the scale of a thousandth of a millimetre, that you can get enough adhesion to give the robust attachment we need,” said Neville.

The frog-like robot has four feet which are each capable of holding a maximum of around 15 grams for each square centimetre in with a slippery surface. The researchers hope to build a device that is 20x20x20 mm, but the current prototype is double that size.

If they can halve the size of the prototype, it will be able to fit through the incisions made during keyhole surgery.

“To work effectively, this robot will have to move to all areas of the abdominal wall, turn and stop under control, and stay stable enough to take good quality images for the surgeons to work with,” added Neville.

The device is one of a number of bio-inspired robots created by University of Leeds’ researchers, including an electric ‘mole’ designed to dig through rubble in disaster zones and a giant ‘robo-worm’ that mimics the nervous system of a real nematode worm.