Insects like flies, bees, and dragonflies have incredible agility. They can fly fast in complex patterns and navigate effortlessly without crashing. The dynamic flight of such insects has long inspired engineers in the design of novel flying machines. In February of 2021, a team of researchers from the Massachusetts Institute of Technology published their findings on applying insect flight principles to drones.

Assistant Professor Kevin Yufeng Chen joined the Department of Electrical Engineering and Computer Science in 2020 after receiving his Ph.D. in engineering sciences from Harvard. In 2019, he was named as one of Forbes 30 Under 30 in the field of science in recognition for the insect-sized robotics systems he creates. In his lab at MIT, the Soft and Micro Robotics Laboratory, Chen and his colleagues develop micro drones and robotics that maneuver like insects in real world environments. The key in Chen’s micro drones comes from the use of a new type of soft actuator.

An actuator in robotics is the component that gives the machine the power to move. Up until recently, actuators were hard-set pieces that only lent limited mobility to robotics. Chen points out that rigid actuators are good at giving robotics like drones power and lift, but are not suitable for minute agility. The advancement of new materials has led to the introduction of soft actuators that open many opportunities for enhanced robotic applications. The new material that Chen uses in his lab is called dielectric elastomer actuators (DEA). Using DEA, Chen has been able to build a drone whose body mimics an insect.

For flight, an insect doesn’t simply flap its wings. It flexes its abdomen to power and control its wings movements. The DEA that Chen uses is a thin rubber cylinder coated in carbon nanotubes. When powered, the tubes begin to flex in a squeezing and elongating pattern. The contractions of the soft actuator cause the drone’s wings to move, the same way that an insect flexes and contracts its abdomen to fly. The movement of the soft actuator allows the drone to move its wings more than 500 times a second. Considering that a bumblebee’s wings have 200 beats per second, Chen’s drone is highly robust.

The rate at which the actuator moves the drone’s wings, gives it the agility to move in small cramped spaces. Also, like an insect, if the drone collides with an object, the contracting, flexing actuator allows it to recover flight with no interruption. Because the drone is about the same size as a large bumblebee, if it collides with an obstacle it will not inflict damage upon itself or the obstacle. “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?”

With Chen’s insect sized, soft actuator reliant drone, the answer is yes. Not only can the drone be flown in tight space without collision damage, but it can also navigate complex maneuvers like an insect. Imagine how a fly can zip through the air in all directions, evading capture. Chen’s 0.6 gram drone can hover, fly in any direction, recover flight if hit, and it can even perform somersaults. It is possible that Chen’s drone would be just as difficult to catch. In actuality, Chen envisions his drone being used to pollinate crops, in search and rescue missions, or to safely navigate complex machinery.

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