Researchers working in the field of soft robotics hope to bring about a new generation of machines that are far safer for humans to work with, and one way they hope to do that is through supple, inflatable components. Scientists at Stanford University and the University of California, Santa Barbara (UCSB) have put forward a particularly interesting solution, showing off an inflatable robot that can change shape, grab onto objects and roll in controllable directions while untethered.
“A significant limitation of most soft robots is that they have to be attached to a bulky air compressor or plugged into a wall, which prevents them from moving,” says Nathan Usevitch, a graduate student in mechanical engineering at Stanford. “So, we wondered: What if we kept the same amount of air within the robot all the time?”
The basis for the team's soft robot is a single inflatable tube. One machine pinches the two ends of the tube together, while another two machines move up and down the tube, shifting their positions to create another two corners and produce various forms of triangles. The researchers call this an "isoperimetric robot," referring to its ability to change shape dramatically, despite the amount of air inside and its overall length staying exactly the same.
“A key understanding we developed was that to create motion with a large, soft pneumatic robot, you don’t actually need to pump air in and out,” says Elliot Hawkes, assistant professor of mechanical engineering at the UCSB and co-senior author of the paper. “You can use the air you already have and just move it around with these simple motors; this method is more efficient and lets our robot move much more quickly.”
“The idea is that you can change the shape of the soft robot by using simple motors that drive along the tubes, instead of using the slow, inefficient pumps that are normally used,” adds Hawkes.
Several isoperimetric robots can be attached to each other to form more capable machines, connecting via three-degrees-of-freedom joints that create truss-like structures. A set of three of them can then be manipulated in a way that allows them to pick up a ball, or roll in a desired direction by shifting the center of gravity.
The team imagines these attributes could prove useful in disaster scenarios, where the robot could make its way through tight spaces into a collapsed building, and then reconfigure into a type of support structure. Its soft and sturdy nature could also see it find uses around the home or workplace, with significant safety benefits over traditionally harder-bodied robots. One possibility the team is particularly excited about is outer space.
“This robot could be really useful for space exploration – especially because it can be transported in a small package and then operates untethered after it inflates,” says Zachary Hammond, co-lead author of the paper. “On another planet, it could use its shape-changing ability to traverse complicated environments, squeezing through tight spaces and spreading over obstacles.”
The team is continuing to refine its isoperimetric robot, experimenting with different shapes, and will possibly even see if it can swim.
“This research highlights the power of thinking about how to design and build robots in new ways,” says Allison Okamura, co-author of the paper. “The creativity of robot design is expanding with this type of system and that’s something we’d really like to encourage in the robotics field.”
The research was published in the journal Science Robotics, and you can see the robot in action and hear from some of the team members in the video below.
Source: Stanford University, University of California, Santa Barbara
