Engineers at University of California, Berkeley have created an insect-like robot that can scamper along quickly and turn on a dime - perhaps literally. The bot owes its fancy footwork to… well, its fancy feet, which use varying voltages to alternate stickiness and make sharp turns.
The new robot builds on a design the team described in 2019, which was made of a rectangular sheet of polyvinylidene fluoride (PVDF) coated in an elastic polymer. The idea is that when an alternating current is applied, the material bends and straightens in quick succession, translating into forward movement.
In fact, the team reported that it was surprisingly zippy – the robot could travel 20 body lengths per second across a flat surface, and even carry small payloads. The only problem was, it wasn’t particularly maneuverable, so for the new version, the engineers gave it more advanced feet.
“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,” says Liwei Lin, senior author of the study. “In this work, the major innovation was adding these footpads that allow it to make very, very fast turns.”
The robot’s fancy new feet work on the principle of electrostatic adhesion – essentially, the same force that causes a balloon to stick to your hair or clothes after you rub it. In this case, when a voltage is applied to one foot, it will stick to the floor, making the robot turn sharply in that direction.
The researchers demonstrated the bot’s agility by having it run through a maze, which it was able to complete in 5.6 seconds. In other tests, it was equipped with gas sensors and tasked with creating a map of gas concentrations within an area, which could hint at future applications in locating the source of leakages.
The team built two different versions, one that was tethered to a power source and another that ran on a battery. The tethered model was the faster one, clocking an improved top speed of 28 body lengths per second, which is almost as fast as a live cockroach. The battery model meanwhile was slower but could potentially travel farther – up to 19 minutes and 102 ft (31 m) while carrying the gas sensor.
“One of the biggest challenges today is making smaller scale robots that maintain the power and control of bigger robots,” says Lin. “With larger-scale robots, you can include a big battery and a control system, no problem. But when you try to shrink everything down to a smaller and smaller scale, the weight of those elements become difficult for the robot to carry and the robot generally moves very slowly. Our robot is very fast, quite strong, and requires very little power, allowing it to carry sensors and electronics while also carrying a battery.”
The research was published in the journal Science Robotics. The team demonstrates the robot in the video below.
Source: UC Berkeley
