Researchers from North Carolina State University and the University of Pennsylvania have created soft robots capable of navigating complex environments such as mazes without the assistance of humans or computer software.
“These soft robots demonstrate a concept called ‘physical intelligence,’ which means that structural design and smart materials, rather than computational intelligence, allow the soft robot to navigate various situations,” says Jie Yin, corresponding author of a paper on the work and an associate professor of mechanical and aerospace engineering at NC State.
The soft robots are made of twisted liquid crystal elastomers in the shape of translucent rotini. When you place the ribbon on a surface that is at least 55 degrees Celsius (131 degrees Fahrenheit) hotter than the ambient air, the portion of the ribbon that touches the surface contracts while the portion of the ribbon that is exposed to the air does not. The ribbon will roll as a result of this. And the faster it rolls, the hotter the surface.
These soft robots demonstrate a concept called ‘physical intelligence,’ which means that structural design and smart materials, rather than computational intelligence, allow the soft robot to navigate various situations. The soft robot we’ve made in a twisted ribbon shape is capable of negotiating these obstacles with no human or computer intervention whatsoever.
Jie Yin
Video of the ribbon-like soft robots can be found at https://youtu.be/7q1f_JO5i60.
“This has been done before with smooth-sided rods, but that shape has a drawback — when it encounters an object, it simply spins in place,” says Yin. “The soft robot we’ve made in a twisted ribbon shape is capable of negotiating these obstacles with no human or computer intervention whatsoever.”
This is accomplished in two ways by the ribbon robot. To begin, if one end of the ribbon comes into contact with an object, the ribbon rotates slightly to avoid the obstacle. Second, if the central part of the robot comes into contact with an object, it “snaps.” The snap is a sudden release of stored deformation energy that causes the ribbon to jump and reorient itself before landing. The ribbon may need to snap multiple times before finding an orientation that allows it to navigate the obstacle, but it always finds a clear path forward.
“In this sense, it’s much like the robotic vacuums that many people use in their homes,” Yin says. “Except the soft robot we’ve created draws energy from its environment and operates without any computer programming.”
“The two actions that allow the robot to negotiate obstacles, rotating and snapping, operate on a gradient,” says Yao Zhao, first author of the paper and a postdoctoral researcher at NC State. “When an object touches the center of the ribbon, the most powerful snap occurs. The ribbon will still snap if an object touches it away from the center, but it will be less powerful. The snap becomes less pronounced as you move away from the center, until you reach the last fifth of the ribbon’s length, where there is no snap at all.”
The researchers conducted several experiments to show that the ribbon-like soft robot can navigate a variety of maze-like environments. The researchers also demonstrated that the soft robots would work well in desert environments, climbing and descending loose sand slopes.
“This is fascinating and entertaining to look at, but more importantly, it provides new insights into how we can design soft robots capable of harvesting heat energy from natural environments and autonomously navigating complex, unstructured environments such as roads and harsh deserts.” Yin states.
The researchers carried out several experiments to show that the ribbon-like soft robot can navigate a variety of maze-like environments. The researchers also demonstrated that the soft robots would perform well in desert environments, climbing and descending sand slopes. The soft robot is designed in the shape of a twisted ribbon and is capable of navigating these obstacles without the use of any human or computer assistance.
The majority of traditional robots are made of rigid materials such as steel, aluminum, and ABS plastic. They are typically powered by electric motors or pumps that force hydraulic fluids through rigid tubes. This is fascinating and entertaining to look at, but it also provides new insights into how researchers can design soft robots capable of harvesting heat energy from natural environments and autonomously navigating complex, unstructured environments such as roads and harsh deserts.
