
With a more efficient method for artificial pollination, farmers in the future could grow fruits and vegetables inside multilevel warehouses, boosting yields while mitigating some of agriculture’s harmful impacts on the environment.
To help make this idea a reality, MIT researchers are developing robotic insects that could someday swarm out of mechanical hives to rapidly perform precise pollination. However, even the best bug-sized robots are no match for natural pollinators like bees when it comes to endurance, speed, and maneuverability.
Now, inspired by the anatomy of these natural pollinators, the researchers have overhauled their design to produce tiny, aerial robots that are far more agile and durable than prior versions.
The new bots can hover for about 1,000 seconds, which is more than 100 times longer than previously demonstrated. The robotic insect, which weighs less than a paperclip, can fly significantly faster than similar bots while completing acrobatic maneuvers like double aerial flips.
The revamped robot is designed to boost flight precision and agility while minimizing the mechanical stress on its artificial wing flexures, which enables faster maneuvers, increased endurance, and a longer lifespan.
The new design also has enough free space that the robot could carry tiny batteries or sensors, which could enable it to fly on its own outside the lab.

“The amount of flight we demonstrated in this paper is probably longer than the entire amount of flight our field has been able to accumulate with these robotic insects. With the improved lifespan and precision of this robot, we are getting closer to some very exciting applications, like assisted pollination,” said Senior Author Kevin Chen, Associate Professor in the Department of Electrical Engineering and Computer Science (EECS), head of the Soft and Micro Robotics Laboratory within the Research Laboratory of Electronics (RLE).
Chen is joined on the paper by co-lead authors Suhan Kim and Yi-Hsuan Hsiao (Nemo), who are EECS graduate students; as well as EECS graduate student Zhijian Ren and summer visiting student Jiashu Huang. The research appears today in Science Robotics.
Here is an exclusive Tech Briefs interview, edited for length and clarity, with Kim and Nemo.
Tech Briefs: What was the biggest technical challenge you faced while developing these robotic insects?
Kim: In our new design, we did a huge redesign process for our robot. So, our existing robot had only a lifetime at, max, about 40 seconds. Then, throughout the flight test, what we figured out is that the primary failure of the original robot was the hinge material in our wing hinge structure. So, we redesigned the hinge structure so that it can be elongated along the wing areas so that we can reduce the mechanical stress on the hinge by more than 100 times. That contributed, for the most part, to the long lifetime and dispersion. And then using that, Nemo, the co-first author of our paper, was able to do a bunch of flight testing where he was able to get very precise flight as well as very aggressive maneuvers.
Nemo: I feel like the most tedious part was probably, every time we do a redesign of the hinge structure, you need to test it in real life. So, it's a lot of trial and error, trial and error, processing; it’s probably several months to get to a really good point.
Tech Briefs: In what ways does this robotic insect differ from its previous design?

Kim: So from a design perspective, the first thing is we reduced the number of wings from eight to four. As I mentioned before, the wing was one of the primary failure points. What that means is that if one wing failed in forty seconds, we had to repair it. But, after we repaired it, some of the other wings — the remaining seven — will also fail within a few 10s of seconds. So, what we did first is that we reduced the number of wings. Then, also from the dynamics perspective, what happened for the new version is that the mass was concentrated more to the center, which reduces the robot’s inertia by a lot, while body mass is maintained pretty similar. That makes the robot able to generate huge body torques. So, basically, you rotate the robot very fast and then that really comes to the control side. In his experiment, Nemo was able to do lateral motions or the adverse motions way faster than before.
Nemo: Yeah, they can pretty much reach a lot higher rotational speed. So, if you read the paper, our angular speed is like 7,000 degrees per second, which is more than twice the prior robot.
Tech Briefs: Can you explain in simple terms how it works?
Kim: Typical drones use electromagnetic motors plus propellers. But, our system is a little different in that we are primarily using an artificial muscle. We have a very tiny artificial muscle; it weighs around 0.1 gram to 0.2 grams. That creates a linear motion, it expands and contracts just like our real muscles. And then what we do is we combine the flapping wing structure on top of the muscle so that we can create flapping wing motion from the muscle movements. So, one muscle and one wing forms one module of our robot, and, just like the drones, we put four of them to make into a quadrilateral shape so that we can do balanced control.
Tech Briefs: Do you have plans for this further research. If not, what are your next steps? Where do you go from here?
Kim: There are several next steps for this specific research. I'd say, we achieved continuous thousand-second flights, but that's not actually the full lifetime. So, maybe, I would say the lifetime right now is about 2,000 seconds or a little more, but that's way longer than the existing flying robots. But, actually, if you think of using it in real life, that's totally short, right? It's like 10 or 20 minutes. So, we will keep pushing for longer and longer lifetimes; maybe roughly the order of like every 10 times. That's one of our research goals.
Then, there are three things we have to move onboard. If you take a close look at our videos, you can see very small lines coming out from the robot — they are the power tethers. So, what happens is that we have a huge system that can transpose positions and orientations of robots, but we do offboard computation for running the control loop. Then the control signal goes into the robot. So, what we will ultimately have to do is to have those three things — power system, control system, and sensing system — onboard. We are working on each part of the robot. Nemo is working on sensing plus controls, and other collaborators are working on power system and batteries. I'm mainly working on the robot’s hardware so that we can put everything together with a very small size for each piece and higher payload for the robot.
Tech Briefs: Those are all the questions I have fellas. Is there anything else you'd like to add that I didn't touch upon?
Kim: I’d like to talk about the use case for our robot. A lot of people are interested in the potential use case that my advisor is aiming for: artificial pollination. For that process, we would have to do something on top of things like flowers or leaves, which is a very delicate process. So, those are some things we look forward to achieving after our robot flies really well.