Tiny robots face two big challenges: using limited energy and overcoming obstacles much larger than themselves. Walking robots work well on flat surfaces but struggle with uneven terrain while flying robots can navigate obstacles but need lots of power to stay airborne.
MIT researchers created a hopping robot that solves both problems. It can jump over tall obstacles and uneven surfaces using much less energy than a flying robot. This tiny robot, smaller than a thumb and lighter than a paperclip, uses a springy leg for jumping and four flapping wings for lift and balance.
The hopping robot developed by MIT engineers can leap up to 20 centimeters in the air—four times its height—and move laterally at 30 centimeters per second. Impressively, it easily handles tricky terrains like ice, wet surfaces, and uneven soil and can even hop onto a hovering drone. Despite its dynamic abilities, it uses 60% less energy than its flying counterpart.
Thanks to its lightweight, durable design and energy-efficient hopping, the robot can carry payloads up to 10 times heavier than similar-sized aerial robots, unlocking a variety of new uses.
At the core of its efficiency is a clever elastic leg with a compression spring, much like the spring in a click-top pen. This spring efficiently converts the robot’s downward motion into upward propulsion, making each jump as effective as possible.
When the robot leaps into the air, its flapping wings provide lift and keep it stable, ensuring it’s positioned correctly for the next jump. These wings are powered by soft actuators—artificial muscles designed to withstand repeated impacts with the ground, ensuring the robot stays durable and functional.
Central to its impressive performance is a quick control system that calculates how the robot should be oriented for each jump. Using an external motion-tracking system to gather sensor data, an observer algorithm processes this information and determines the precise adjustments needed for optimal movement.
As the robot leaps through the air, it follows a graceful arc called a ballistic trajectory. At the peak of its jump, it calculates where it will land. Using this information, its controller determines the ideal takeoff speed and direction for the next leap. While airborne, the robot flaps its wings to adjust its orientation, ensuring it lands at the right angle and axis to keep moving effectively and at the desired speed.
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Researchers challenged the robot’s abilities on diverse terrains like grass, ice, wet glass, and uneven soil to test its abilities. Impressively, it passed every test, even hopping successfully on dynamically tilting surfaces. The angle of its landing surface doesn’t faze the robot—it simply needs to avoid slipping upon impact to maintain its trajectory and momentum.
The robot’s controller allows it to adapt smoothly to different surfaces, adjusting its movements without hesitation. For example, jumping on grass needs extra thrust because the blades of grass reduce its jump height. To compensate, the controller increases energy to its wings during flight.
Its small size and lightweight design give the robot a lower moment of inertia, making it highly agile and better at handling impacts than larger robots.
The robot’s agility stands out, as researchers showcased impressive acrobatic flips and even demonstrated its ability to hop onto a flying drone without causing any damage—a feature with potential for collaborative tasks.
While the robot has already carried twice its weight in testing, its payload capacity could be even greater. The key factor limiting its carrying capacity is the spring’s efficiency, rather than added weight.
Looking ahead, the team plans to enhance the robot’s functionality by equipping it with batteries, sensors, and circuits.
Journal Reference:
- Yi-Hsuan Hsiao, Songnan Bai et al. Hybrid locomotion at the insect scale: Combined flying and jumping for enhanced efficiency and versatility. Science Advances. DOI: 10.1126/sciadv.adu4474
Source: Tech Explorist
