A team of innovative researchers at North Carolina State University has made a breakthrough in soft robotics by creating a caterpillar-like robot that can maneuver through narrow spaces with ease. Unlike traditional rigid robots, this soft robot can move forward, backward, and even dip under obstacles due to its unique bending mechanism. The secret to its movement lies in a novel pattern of silver nanowires that are used to control the way the robot bends, enabling users to steer the robot in any direction they desire. This innovation in soft robotics has the potential to revolutionize various industries, from medicine to search and rescue operations.
“A caterpillar’s movement is controlled by local curvature of its body—its body curves differently when it pulls itself forward than it does when it pushes itself backward,” says Yong Zhu, corresponding author of a paper on the work and the Andrew A. Adams Distinguished Professor of Mechanical and Aerospace Engineering at NC State. “We’ve drawn inspiration from the caterpillar’s biomechanics to mimic that local curvature, and use nanowire heaters to control similar curvature and movement in the caterpillar-bot.
“Engineering soft robots that can move in two different directions is a significant challenge in soft robotics,” Zhu says. “The embedded nanowire heaters allow us to control the movement of the robot in two ways. We can control which sections of the robot bend by controlling the pattern of heating in the soft robot. And we can control the extent to which those sections bend by controlling the amount of heat being applied.”
The caterpillar-like soft robot developed by North Carolina State University researchers comprises two layers of polymer that react differently when subjected to heat. The lower layer contracts while the upper layer expands. The top layer features a unique pattern of silver nanowires that includes several lead points to which an electric current can be applied. By varying the current, researchers can control which areas of the nanowire pattern heat up and to what extent, allowing them to manipulate the robot’s movement. This innovative technology has the potential to transform various industries, from healthcare to disaster response.
“We demonstrated that the caterpillar-bot is capable of pulling itself forward and pushing itself backward,” says Shuang Wu, first author of the paper and a postdoctoral researcher at NC State. “In general, the more current we applied, the faster it would move in either direction. However, we found that there was an optimal cycle, which gave the polymer time to cool—effectively allowing the ‘muscle’ to relax before contracting again. If we tried to cycle the caterpillar-bot too quickly, the body did not have time to ‘relax’ before contracting again, which impaired its movement.”
The researchers successfully demonstrated that they could control the caterpillar-like soft robot’s movement to such an extent that users could steer it through a very narrow gap, akin to guiding it under a door. This involved controlling both the forward and backward motion of the robot as well as adjusting the height of the robot’s upward bend at any given point in the process. This level of control over the robot’s movement has far-reaching implications for numerous fields, including search and rescue operations, healthcare, and manufacturing.
“This approach to driving motion in a soft robot is highly energy efficient, and we’re interested in exploring ways that we could make this process even more efficient,” Zhu says. “Additional next steps include integrating this approach to soft robot locomotion with sensors or other technologies for use in various applications—such as search-and-rescue devices.”
The research paper titled “Caterpillar-Inspired Soft Crawling Robot with Distributed Programmable Thermal Actuation” is scheduled to be published on March 22 in the prestigious journal Science Advances. The paper was co-written by a team of researchers at North Carolina State University, including Jie Yin, an associate professor of mechanical and aerospace engineering, Yaoye Hong, a Ph.D. student, and Yao Zhao, a postdoctoral researcher. Their work highlights a major breakthrough in soft robotics and demonstrates the potential for developing robots with greater flexibility and maneuverability in various industries.
You might also be interested in reading, UBC Engineers Develop Breakthrough Technology to Remove Forever Chemicals from Drinking Water
