This flexible, durable robot can traverse complex terrain and swiftly swerve to avoid obstacles – traits that could make it an advantage for search and rescue operations
Berkeley – Many insects and spiders get their eerie ability to scurry up walls and walk upside down on ceilings with the help of special sticky foot pads that allow them to adhere to surfaces no one would dare to.
Engineers at the University of California, Berkeley, used the principle of some of these treads, known as electrostatic adhesion, to develop a robot of insect scales that can dodge and pivot with the agility of a cheetah, giving it the ability to traverse complex terrain and quickly avoid unexpected obstacles.
The robot is made of a thin, layered material that bends and contracts when an electrical voltage is applied. In a 2019 paper, the research team demonstrated that this simple design can be used to build a cockroach-sized robot that crosses a plane at a speed of 20 body lengths per second, or about 2.4 miles per hour Surface can scurry – almost the speed of live cockroaches themselves and the fastest relative speed of any insect-sized robot.
In a new study, the research team added two electrostatic foot pads to the robot. Applying a voltage to one of the foot pads increases the electrostatic force between the foot pad and a surface, making that foot pad more firmly attached to the surface and forcing the rest of the robot to spin around the foot.
The two treads give the operator full control over the robot’s trajectory and allow the robot to make turns with a centripetal acceleration that exceeds that of most insects.
“Our original robot could move very, very fast, but we couldn’t really control whether the robot was going left or right, and often it moved randomly because if there was a little difference in the manufacturing process – when the robot wasn’t symmetrical – it would tip over, ”said Liwei Lin, professor of mechanical engineering at UC Berkeley. “The biggest innovation in this work was the addition of these foot pads, which make it possible to take very, very fast turns.”
To demonstrate the robot’s agility, the research team filmed the robot navigating Lego mazes while carrying a small gas sensor and dodging to avoid falling debris. Because of its simple design, the robot can also survive kicking a 120-pound human.
Small, sturdy robots like these could be ideal for conducting search and rescue operations or investigating other dangerous situations, such as detecting potential gas leaks, Lin said. While the team demonstrated most of the robot’s capabilities while “tethered” or powered and controlled by a small electrical cord, they also developed an “untethered” version that could carry up to 19 minutes and 31 meters on battery power when carried a gas sensor can be operated.
“One of the biggest challenges today is making smaller robots that maintain the performance and control of larger robots,” said Lin. “With larger robots, you can easily integrate a large battery and control system. However, if you try to make everything smaller and smaller, the weight of these elements will become difficult for the robot to carry and the robot will generally move very slowly. Our robot is very fast, quite powerful and needs very little power, so it can carry sensors and electronics and at the same time carries a battery. “
Lin is the lead author of an article about the robot that appeared online in the magazine this week Science robotics.
Co-authors of the paper are Jiaming Liang, Huimin Chen, Zicong Miao, Hanxiao Liu, Ying Liu, Yixin Liu, Dongkai Wang, Wenying Qiu, Min Zhang and Xiaohao Wang from Tsinghua University in China; Yichuan Wu from the University of Electronic Science and Technology in China; Justin Yim from Carnegie Mellon University; and Zhichun Shao and Junwen Zhong of UC Berkeley.
This work is supported by the Natural Science Foundation of Guangdong Province (2020A1515010647), the Shenzhen Fundamental Research Funds (JCYJ20180508151910775), the National Natural Science Foundation of China (Grant No. 52005083), and a Start Research Grant from the University of Macau.