This tough soft robot needs no umbilical
11 September 2014
Developers at Harvard have produced the first untethered soft robot — a quadruped that can stand up and walk away from its designers.
A team of researchers from Harvard’s School of Engineering and Applied Sciences and the Wyss Institute for Biologically Inspired Engineering has managed to scale up earlier soft-robot designs, enabling a single robot to carry on its back all the equipment it needs to operate — micro-compressors, control systems, and batteries.
“Earlier versions of soft robots were all tethered, which works fine in some applications, but what we wanted to do was challenge people’s concept of what a robot has to look like,” says Michael Tolley from the Wyss Institute. “We think the reason people have settled on using metal and rigid materials for robots is because they’re easier to model and control. This work is very inspired by nature, and we wanted to demonstrate that soft materials can also be the basis for robots.”
Compared with earlier soft robots, which were typically no larger than a steno pad, the system designed by Tolley and colleagues is large, measuring more than a half-metre in length and capable of carrying as much as 7½ pounds on its back.
Giving the untethered robot the strength needed to carry mechanical components meant air pressures as high as 16 pounds per square inch, more than double the seven psi used by many earlier robot designs. To deal with the increased pressure, the robot had to be made of tougher stuff.
The material Tolley and colleagues settled on was a 'composite' silicone rubber made from stiff rubber impregnated with hollow glass micro-spheres to reduce the robot’s weight. The robot’s bottom was made from Kevlar fabric to ensure it was tough and lightweight. The result is a robot that can stand up to a host of extreme conditions.
Researchers tested the robot in snow, submerged it in water, walked it through flames, and even ran it over with a car. After each experiment, it emerged unscathed.
Though additional hurdles remain — such as increasing the speed of the robots and outfitting them with sensors — the development of an untethered soft robot is a major advance, Tolley said, one that has the potential to radically transform not only what robots look like, but also how they might be used.
The design is described in the journal, Soft Robotics that appeared online September 1.
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