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As we all know, insects can be remarkably agile (灵活的) in flight. This is really hard to build into flying robots, but MIT Assistant Professor Kevin Yufeng Chen has developed an insect—sized drone (无人机) that approaches insects’ agility.

Typically, drones require wide open spaces. “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 an insect-sized drone that can move around in very crowded and complex spaces?”

According to Chen, he overcame many problems when building the drone. The insect-sized drone requires a fundamentally different construction from a larger one. The large drone is usually powered by a motor, but the motor loses efficiency as you shrink it. So, Chen says, “For an insect-sized drone, you need to look for alternatives.” The principal alternative until now has been employing a small, rigid actuator (执行器) built from new materials. Chen designed a more agile tiny drone using soft actuators instead of hard ones.

Each actuator can beat nearly 500 times per second and weighs just 0.6 gram, approximately the mass of a large bee. It gives the drone insect-like agility. “You can hit it when it’s flying, and it can recover,” says Chen. “It can also turn over in the air.” The drone looks a bit like a tiny cassette tape with wings, though Chen is also working on a new one shaped like a dragonfly.

Chen says his drone can be useful in industry and agriculture. It can perform machinery inspections to ensure safety and function. Its potential applications include completing search-and-rescue missions following a disaster. “All those things can be very difficult for existing large-scale drones,” Chen explains. Sometimes, bigger isn’t better.