Jumping is common in the insect world, however, it’s less common when it comes to insect-scale robotics.
Researchers from the Massachusetts Institute of Technology (MIT) have developed a tiny hopping robot which can traverse through difficult environments such as collapsed buildings while carrying weights several times its own.
The robot’s hopping design builds on the drawbacks of tiny crawling or flying robots, which are more commonly used.
The new robot is smaller than a thumb and weighs less than a paper clip. It has a springy leg that lets it hop off the ground at about 20cm, or four times its height, as well as four flapping wing modules that give it lift and control its orientation.
Insect-like crawling robots can squeeze into small and tight places that other larger robots cannot. However, they are unable to climb over objects or walk on slanted surfaces.
On the other hand, aerial robots can easily avoid such hazards but are far more energy consuming, limiting how far they can travel before needing to be recharged.
According to MIT, the new design is the best of both locomotion methods. Jumping is common in the insect world, from fleas that leap onto new hosts to hopping grasshoppers and crickets. However, it’s less commonly adopted in miniature robotics.
Research into the robot was funded, in part, by the US National Science Foundation and the MIT International Science and Technology Initiatives programme.
When the robot hops, it transforms the potential energy developed from hopping into kinetic energy as it falls.
This kinetic energy transforms back to potential energy when it hits the ground, then back to kinetic as it rises, and so on, the team explains.
To maximise the efficiency of this process, the team fixed an elastic leg made from a compression spring – which is akin to the spring on a click-top pen – onto the robot.
This allows it to leap over tall obstacles and jump across slanted or uneven surfaces, while using far less energy than an aerial robot.
In addition, it can withstand different types of terrains, including ice, wet surfaces, uneven soil or even hop onto a hovering drone.
Moreover, its light weight, durability and energy efficiency means that the tiny hopping robot could carry about 10 times more payload than a similar-sized aerial robot. While the team demonstrated a hopping robot that could carry double its weight, they expect that it can carry much more.
“If you have an ideal spring, your robot can just hop along without losing any energy. But since our spring is not quite ideal, we use the flapping modules to compensate for the small amount of energy it loses when it makes contact with the ground,” said Yi-Hsuan Hsiao, an MIT graduate student and co-lead author of a paper on the hopping robot.
As the robot bounces back up into the air, the flapping wings provide it lift, while ensuring that it remains upright and has the correct orientation for its next jump.
Moreover, its four flapping wing mechanisms, powered by artificial muscles, are durable enough to endure repeatedly falling to the ground without being damaged.
In addition, the tiny hopping robot’s controller can handle multiple terrains, meaning it can easily transition from one surface to another, the team says.
“Being able to put batteries, circuits and sensors on board has become much more feasible with a hopping robot than a flying one,” Hsiao said.
“Our hope is that one day this robot could go out of the lab and be useful in real-world scenarios.”
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