Most insects and spiders climb walls and walk on ceilings through sticky footpads, allowing them to stick on surfaces. UC Berkeley engineers used the same electrostatic adhesive concept to develop an insect-sized robot with similar swerving and pivoting capabilities as a cheetah. As a result, the robot can travel through a maze while avoiding sudden obstacles.
The robot is comprised of a thin, layered material that bends and shrinks when applying voltage. This new project builds on a previous cockroach-sized bot that scurries across a flat surface at 1.5 miles per hour, the fastest for an insect-scaled machine. Now, the team outfitted two electrostatic footpads to the robot. When applying a voltage to one footpad, the electrostatic force boosts between the footpad and a surface. This causes the footpad to firmly stick in place, which makes the bot spin around the foot.
Both these footpads provide an operator with total robot trajectory control, enabling it to turn with a centripetal acceleration surpassing most insects.
“Our original robot could move very, very fast, but we could not really control whether the robot went left or right, and a lot of the time it would move randomly, because if there was a slight difference in the manufacturing process — if the robot was not symmetrical — it would veer to one side,” said Liwei Lin, a professor of mechanical engineering at UC Berkeley. “In this work, the major innovation was adding these footpads that allow it to make very, very fast turns.”
The engineers showcased the machine’s agility by recording its navigational movements through Lego mazes while equipped with a gas sensor and swerving to evade falling objects. Robust and agile, the bot can also endure stompings from a 120-pound human.
These types of robots are perfect for participating in search and rescue operations or investigating hazardous environments. For example, they could probe potential gas leaks. Even though this tiny machine was controlled through a tether to demonstrate its skills, a battery-powered version exists that runs for 19 minutes and 31 meters with an onboard gas sensor.