Pollinator populations, like bees and butterflies, are collapsing all around the world. This is troubling because, in addition to playing a critical role in sustaining ecosystems, these pollinators are also important for global food production. Robots equipped with advanced sensors, artificial intelligence, and delicate mechanisms could step in to fill this gap.

Now, MIT researchers have developed small robots that can fly up to 100 times more than their predecessors, despite weighing less than a paperclip.

Mimicking insects

“Aerial insects are exceptionally agile and precise,” write the authors of the new study. “They perform impressive acrobatic maneuvers when evading predators, recovering from wind gust, or landing on moving objects. Flapping-wing propulsion is advantageous for flight agility because it can generate large changes in instantaneous forces and torques.”

However, replicating this ability in robots has proven very challenging. When insects flap their wings, their tendons and wings suffer high stress and deformation. To endure this, they must be extremely flexible and fatigue-resistant. Engineered materials don’t really exhibit these properties. Or, at least, didn’t — until now.

Previous versions of robot insects usually had four identical units, each with two wings. This made sense from an engineering perspective, but it doesn’t follow insect biology: there’s no insect with eight wings. The new design essentially slashes the structure in half, mimicking the biological structures of insects. It now has four wings with more complex transmissions linking the wings to the actuators (the robotic “muscles” that power flight).

By reducing the number of wings and optimizing their arrangement, researchers eliminated airflow interference. This allows for improved lift generation, freeing up space for potential future additions, such as batteries or sensors. This approach also enables the robots to stay in the air for more time.

“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,” says Kevin Chen, the senior author of an open-access paper on the new design for MIT News.

“Compared to the old robot, we can now generate control torque three times larger than before, which is why we can do very sophisticated and very accurate path-finding flights,” Chen adds.

Flying a pollinating robot

The motion of the robot is driven by soft actuators. An actuator is a device that converts energy (electric, hydraulic, or pneumatic) into mechanical motion to perform a specific task. The robots’ actuators are made from layers of elastic materials sandwiched between two thin carbon nanotube electrodes, rolled into a squishy cylinder. The actuators compress and elongate, producing the mechanical energy that powers the wings.

With this approach, the robotic insects can hover and maintain stability for over 1,000 seconds (17 minutes).

“When my student Nemo was performing that flight, he said it was the slowest 1,000 seconds he had spent in his entire life. The experiment was extremely nerve-racking,” Chen says.

The potential applications are broad and exciting. In agriculture, these robots could assist with pollination by navigating flowers with precision. Beyond that, incorporating onboard power and sensors could enable autonomous outdoor missions, from environmental monitoring to disaster response.

While challenges remain — such as replicating the intricate muscle control of real insects — the research lays the groundwork for autonomous microbots with real-world utility. The team’s next goals include extending flight times beyond 10,000 seconds and enabling precise interactions with the environment, such as landing on specific targets like flower centers.

The study was published in Science Robotics.