Insect-sized drones

A group of researchers has developed a system that approaches the mobility of insects. Drones of the same size were developed with them, with excellent dexterity and resilience. As we can all experience in good weather, insects can be extremely acrobatic and resilient in flight. This feature helps them navigate the air, amidst all its gusts of wind, obstacles, and general uncertainty. These capabilities are also very difficult to incorporate into flying robots – but Kevin Yufeng Chen, a professor assistant at the Massachusetts Institute of Technology (MIT) and a member of the Department of Electrical and Computer Science and Electronics Research Laboratory, has now developed a system that approaches the mobility of an insect. He has developed insect-sized drones with unprecedented dexterity, driven by a new kind of launcher, enabling them to withstand the physical challenges of real flight.

Chen is confident that robots can help humans in the future by pollinating plants or even inspecting machines in tight spaces. The study, published in IEEE Transactions on Robotics, involved Zhijian Ren, a PhD student at MIT, Siyi Xu, a PhD student at Harvard University, and Pakpong Chirarattananon, a robotics specialist at Hong Kong City University. As is well known, drones tend to require ample space, as they are not agile enough to navigate indoors – nor are they robust enough to withstand mass collisions. They are mostly used outdoors.

However, researchers have asked themselves: can they create insect-sized robots that can move in very complex, disordered spaces ? Building small aerial robots is a huge challenge. Due to their small size, they require a fundamentally different construction than the larger ones. Larger drones are powered by large motors, but they reduce their efficiency. Other alternatives were needed for insect-like robots. By far the most prominent of these is a small, rigid actuator built of piezoelectric ceramics. Piezoelectric ceramics allowed the first generation of tiny robots to fly, but they were quite fragile.

This is the problem when an insect-mimicking robot has to be built – wasps, for example, have to endure a collision with each other roughly once every second. So Chen and his team designed a more resilient tiny drone: using a soft actuator instead of a hard, fragile one. When carbon nanotubes are energized, they produce an electrostatic force that compresses and extends the rubber cylinder. As a result of repeated elongation and contraction, the wings of the drone begin to move rapidly. The actuators can flip nearly 500 times per second, giving the drone insect-like flexibility.

“You can hit when you fly, you won’t be in trouble,” Kevin Yufeng Chen explained. “He can even perform aggressive maneuvers, such as loops in the air.” The insect-like mini drone weighs 0.6 grams, which is about the weight of a large bumblebee. It looks a bit like a tiny wasp with wings, but Chen and his team are already working on a version that will resemble a dragonfly.