The team behind this groundbreaking discovery, from North Carolina State University, first introduced their fascinating rotini-like soft robots in 2022. These robots showcased their ability to navigate mazes without any computer or human guidance, relying solely on the concept of physical intelligence.
Physical intelligence refers to the idea that the materials and structural design of the robots determine their behaviors. There is no computer or human operator controlling the robot; it operates independently.
Building on their previous success, the team has now developed an enhanced version of the robot that can navigate even more complex scenarios.
“In our earlier work, we demonstrated that our soft robot could maneuver through a simple obstacle course,” said Jie Yin, associate professor of mechanical and aerospace engineering. “However, it had difficulty turning unless it encountered an obstacle. This meant that the robot sometimes got stuck, bouncing back and forth between parallel obstacles.”
“We have now created a new soft robot that can turn on its own, allowing it to navigate twisty mazes and maneuver around moving obstacles. And it accomplishes all of this through physical intelligence, without relying on computer guidance.”
The team used the same material as before, a liquid crystal elastomer. When exposed to a surface temperature of at least 55°C (131°F), the part of the material in contact with the surface contracts, causing the robot to roll. The higher the surface temperature, the faster it moves.
However, this time the design had a crucial difference. The new robot is asymmetrical, with one half being a twisted ribbon that can stretch into a straight line, and the other half being a tighter twist that also twists around itself.
This asymmetry creates a difference in the forces exerted by each end of the robot, preventing it from rolling in a straight line. You can witness this unique property in action in the video below, where the robot successfully extricates itself from tight spots.
“The concept behind our new robot is quite simple: due to its asymmetrical design, it can turn without making contact with an object,” explained first author Yao Zhao. “So, while it changes direction upon encountering an object, allowing it to navigate mazes, it cannot get stuck between parallel objects. Instead, its ability to move in arcs enables it to wiggle its way free.”
Even mazes with moving walls and gaps smaller than its body size pose no challenge for this remarkable robot, affectionately named “maze escaper” by its creators.
Aside from being an impressive example of what can be achieved with soft robotics and physical intelligence, Yin discussed the potential applications of this technology: “This work represents another step forward in developing innovative approaches to soft robot design, particularly for applications where soft robots can harness heat energy from their environment.”
The study detailing this breakthrough is published in the journal Science Advances.
