Robotics

Surgical robots of the future to be ‘squishy’ like octopuses

SCIENCE 14 JULY 14  by KATIE COLLINS

A phase-changing material created out of wax and foam could allow the robots of the future to transform from being solid to squishy and then back again.

The material has been developed jointly by MIT and Stony Brook University and promises to allow robots of the future transform between hard and soft states, which would make them ideal for using in surgery.

It’s more than a bit creepy imagining a robot being able to slither through your body, but it would allow surgeons to carry out operations less invasively and without causing any damage to the organs or blood vessels. Thanks to their sponginess and flexibility, the robots could also squeeze through rubble to hunt for survivors during in search and rescue operations.

The material was developed in conjunction with robotics company Boston Dynamics (now owned by Google) as part of Darpa’s Chemical Robotics programme. The initial idea was to try and create robots that could move in much the same way octopuses do — shifting their mass to be able to squeeze through tight gaps.

There are significant obstacles to creating this type of movement as it is very tricky to predict how soft material will move and what shapes it will shift into. In order to be able to control its movement, the robot would have to be able to exert a reasonable amount of force onto surrounding surfaces. The solution to this was to build robots that could shift between being hard and soft as and when they need to.

The researchers found that the answer lay in combining foam, which can be compressed and bounce back to its original shape, with wax, which already changes state when heated. The material turned out to be incredibly cheap to make — all that was required was polyurethane foam saturated in hot wax — meaning that it could be used even in low-cost robots. Wires were implanted inside the foam and when a current was run through it, the surrounding wax would melt, but would return to its original state when the current was switched off.

This means that any damage sustained to the robot would also be reversible. “This material is self-healing,” says Anette Hosoi, who headed up the research. “So if you push it too far and fracture the coating, you can heat it and then cool it, and the structure returns to its original configuration.”

A second version of the material has since been built using a 3D printed foam lattice that turned out to be more amenable and was easier to control. This was slightly more expensive to create, but the researchers concluded that their first attempt at creating the material would still be appropriate for low-budget projects.

Josh Sandberg

Josh Sandberg is the President and CEO of Ortho Spine Partners and sits on several company and industry related Boards. He also is the Creator and Editor of OrthoSpineNews.

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