Newly Developed Insect-Sized Drones Resilient to Collisions

After many previous attempts in the field, researchers at the Massachusetts Institute of Technology (MIT) have succeeded in implementing insect agility into tiny-sized flying robots. As with many instances of robotic technology, the team looked to nature for inspiration. Insects are extremely acrobatic and resilient to collisions in flight, and they can efficiently navigate changing conditions like wind gusts and obstacles. 

Professor Kevin Yufeng Chen is the one who built the system. He is a member of the Department of Electrical Engineering and Computer Science and the Research Laboratory of Electronics. 

The research was published in the journal IEEE Transactions on Robotics. Co-authors included Zhiijian, MIT PhD student; Siyi Xu, Harvard University PhD student; and Pakpong Chiraattananon, City University of Hong Kong roboticist. 

Aerial Robots Powered by Soft Actuator 

The aerial robots rely on a new class of soft actuators that enable them to overcome various physical challenges in real-world flight. According to Chen, the robots could eventually be used by humans to pollinate crops or inspect machinery in small spaces.

Current drones require open spaces because of their inability to operate in confined spaces, largely due to the fact that they cannot handle collisions. 

“If we look at most drones today, they're usually quite big,” says Chen. “Most of their applications involve flying outdoors. The question is: Can you create insect-scale robots that can move around in very complex, cluttered spaces?”

According to Chen, “The challenge of building small aerial robots is immense.”

Alternatives to Scaled-Down Motors

One of the main limitations of larger-sized drones is that they require motors that lose efficiency as they are scaled down, which is why Chen says there need to be alternatives.

The main alternative up to this point has been a small and rigid actuator made out of piezoelectric ceramic materials. These materials were responsible for the first generation of tiny, flying robots. However, they are fragile, which makes it difficult for the robots to sustain collisions.

Chen relied on soft actuators to develop a more reliant tiny robot, and unlike hard ones, they consist of thin rubber cylinders coated in carbon nanotubes. Through the process of repeated elongation and contraction brought on by produced electrostatic forces, the drone’s wings can beat fast.

The new actuators can flap 500 times per second, similar to an insect. 

“You can hit it when it’s flying, and it can recover,” says Chen.  “It can also do aggressive maneuvers like somersaults in the air.”

The insect-like drone only weighs 0.6 grams, which is nearly the equivalent mass of a large bumble bee. 

“If you want to learn how insects fly, it is very instructive to build a scale robot model,” Chen says. “You can perturb a few things and see how it affects the kinematics or how the fluid forces change. That will help you understand how those things fly.”

Chen hopes that the robots can be used in various industries, such as agriculture, and potential applications include crop management and search-and-rescue missions. 

 “All those things can be very challenging for existing large-scale robots,” Chen says.