A team of scientists at North Carolina State University has created soft robots capable of collecting thermal energy from the environment. These robots can autonomously navigate tricky roads and other complex environments such as mazes and deserts.
Soft robots in the form of twisted tape. Image credits: Yin Lab @ NCSU / YouTube
Unlike traditional robots that are built with rigid and hard substances such as aluminum, steel or plastic, a soft robot is built with electroactive polymers, fluids, fiber, shape memory alloys (materials that change their shape on cooling) and other types of hoses. materials that have mechanical properties similar to those of living tissues. Soft robots developed at NC State University are made of liquid crystal elastomers (LCEs) that respond to external stimuli, a material that deforms in response to light or heat and produces motion.
So, for example, when placed on a hot surface, such as the roof of a car in the middle of the desert, soft LCE robots start rolling automatically due to the heat-induced shrinkage and unscrewing of their elastic bodies. Interestingly, no human or computer intervention is required to achieve self-roll motion on these twisted tape robots.
Understand the smooth movement of the robot at high temperatures
According to the researchers, LCE’s soft robots work with physical intelligence instead of a computer unit based on neurons like a brain. Physical intelligence involves the use of intelligent structural designs and materials to physically encode functions such as detection, action, control, adaptation, and decision-making in an agent’s body.
Explaining the concept of physical intelligence, Jie Yin, a corresponding author and associate professor at NC State, told ZME Science:
“These soft robots demonstrate a concept called ‘physical intelligence’, which means that structural design and intelligent materials are what allow the soft robot to navigate various situations, unlike computational intelligence. An example of physical intelligence is the Venus fly parachute, which does not need a “brain” to calculate and control its quick closing and opening. When flies touch the leaf’s sensors, they can break quickly to close. to catch flies, so it can enable autonomous sensory and action functions. “
During their experiments, the researchers placed the soft robots on a hot surface above 55 degrees Celsius (131 degrees Fahrenheit). The part of the twisted body of the robot that came in contact with the surface contracted while the segments that did not touch the surface remained the same. This gave rise to the form of bearing movement, and as the researchers increased the surface temperature, the speed of the rolling bot also increased.
Researchers had previously conducted a similar experiment with smooth-sided rod-shaped robots, but when these robots encountered obstacles in their path, they were unable to roll and began to spin in one place. Belt-shaped robots were able to continue their rolling motion even after facing obstacles, without any human or machine intervention. As an object approached the ends of the robot, the robot rotated around it. When an obstacle was placed near the center of the robot, it broke. However, the robot did not stop here, it broke several times until it managed to get into a position from where it could go beyond the obstacle.
“The two actions, turn and fit, that allow the robot to overcome obstacles work in a gradient. The most powerful complement occurs if an object touches the center of the tape. But the tape will still break if an object touches the tape away from the center, it is less powerful. And the farther you are from the center, the less pronounced the break is until it reaches the last fifth of the length of the tape, which does not produce any fit, “said Yao Zhao, the study’s lead author. .
The power, potential and limitations of soft robots
NC State scientists performed multiple experiments with their soft robots in different complex environments. Twisted robots successfully navigated maze-like paths and desert conditions.
“Applications will be open surveillance and environmental monitoring in a widely distributed area in warm and harsh environments. For example, in hot deserts, by collecting thermal energy from hot sand to drive its movement, when integrated with different sensors “Another application could be in outer space, for example, on the moon, with its daytime temperature above 120 degrees Celsius.” say Professor Jey Yin.
Twisted soft robots developed by researchers at NC State University. Image credits: Yao Zhao, North Carolina State University
In addition, soft robots could also be used to conduct search and rescue operations in complex, hot regions. However, these robots would require autonomy and intelligence before using them for large-scale object manipulation, rescue, and environmental monitoring activities. Professor Jey Yin points out that achieving autonomy and intelligence in soft robots in a controllable way is very complicated.
Currently, most power, sensory, and control units applied to robots are rigid but not suitable for soft robots. The integration of self-feeding, detection, control, computing, and decision making into smooth robots requires the development of efficient smooth technologies. Researchers hope that physical intelligence could make this possible, could emerge as a “new paradigm for simplifying designs and controls” in soft robots.
The study that highlights the navigation capabilities of the soft robots discussed is published in the journal PNAS.