Thinking about robots usually conjures up images of metal structures from Terminator or iRobot. Roger Wood’s lab at Harvard University has gone in a slightly different direction and made an X-shaped soft-bodied robot that moves around like a headless toy. The robot can be exposed to fire or get run over by a car, coming out completely unscathed.

The pneumatic soft-bodied robot was inspired by organisms that move without rigid structures. This will allow them to interact with humans more safely than traditional hard units, with possible applications for search and rescue or chemical disasters. The latest design is larger and stronger than previous models with another distinct advantage: it is not tethered to controls or a power source.

“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,” lead author Michael Tolley told the Harvard Gazette. “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.”

Image credit: Harvard University/Joe Sherman

The current design is 0.65 meters (2.1 feet) long and is capable of carrying 3.4 kg (7.4 lbs) of equipment on its back. As this is much larger than previous, tethered designs. The air pressure needed to run the machine more than doubled, going from 7 pounds per square inch (psi) up to 16 psi.

“As soon as you start thinking about putting the basic components you need to make this work — micro-compressors, controllers, and batteries — on an untethered robot, you need a design that can carry those parts,” Tolley continued. “You need to think about something that can handle much higher pressures, so there are materials challenges and there are design challenges and there are control challenges.”

Ultimately, the material that fit the bill was a composite silicone rubber: strong, flexible, and not too heavy. Glass microspheres were added to firm rubber, essentially creating tiny air pockets that made the design lighter. The bottom is coated with Kevlar, protecting the unit as it crosses potentially-damaging terrain.

The robot has been tested against extreme temperatures, submersion in water, fire, and even getting its legs run over by a car with no adverse effects. The team wants to add sensors and get the robot moving faster in the future.

This untethered design is a massive achievement for soft robotics and is extremely cool. Check it out in action here: