Soft Robot Mimics Caterpillar Movement Using Silver Nanowires
A team of researchers from North Carolina State University has developed a soft robot that moves like a caterpillar. This innovative robot can navigate narrow spaces by bending and crawling forward and backward. The robot’s movements are controlled by a unique pattern of silver nanowires that generate heat, allowing users to steer the robot in different directions.
Mimicking the Local Curvature of a Caterpillar
According to Yong Zhu, the Andrew A. Adams Distinguished Professor of Mechanical and Aerospace Engineering at NC State and the corresponding author of the research paper, “A caterpillar’s movement is controlled by local curvature of its body. When it pulls itself forward, its body curves differently than when it pushes itself backward. Inspired by the caterpillar’s biomechanics, we designed the caterpillar-bot to mimic this local curvature using nanowire heaters.”
Controlling Movement in Soft Robots
Creating soft robots that can move in both forward and backward directions is a significant challenge. To overcome this hurdle, the researchers embedded nanowire heaters in the caterpillar-bot. By controlling the pattern of heating and the amount of heat applied, they can determine the sections of the robot that bend and the extent to which they bend.
The caterpillar-bot is composed of two layers of polymer that respond differently to heat. The bottom layer contracts, while the top layer expands. Embedded in the expanding layer are silver nanowires arranged in a specific pattern. By applying an electric current to different lead points in the nanowire pattern, the researchers can heat specific sections of the robot.
Optimizing Motion for Efficient Locomotion
The researchers discovered that the caterpillar-bot’s motion can be optimized by allowing time for the polymer to cool and relax before contracting again. Cycling the robot too quickly hinders its movement. By finding the optimal cycle, the team achieved efficient forward and backward locomotion.
Furthermore, the researchers demonstrated the robot’s ability to navigate through very low gaps, similar to slipping under a door. They were able to control the robot’s height and motion, enabling precise maneuvering.
Promising Applications and Future Development
This energy-efficient approach to soft robot locomotion holds great potential. The researchers aim to further enhance its efficiency and explore integrating sensors and other technologies for various applications, such as search-and-rescue devices.
The research was supported by grants from the National Science Foundation (2122841, 2005374, and 2126072) and the National Institutes of Health (1R01HD108473).