One of my hobbies is nature photography. I love posting some of my mountain-top photos on my Facebook page.
On a recent mountain hiking adventure trip I discovered that climbing mountains to capture such photos no longer is necessary. I was about to set off on a challenging climb where I anticipated I could take some beautiful photos. A man less than a hundred feet away beat me to it without taking a single step. He sent his drone to the site, four miles away, and it came back with photos that put mine to shame. His camera-drone system, though, cost about sixty times more than my camera and weighed nearly sixty times as much as mine, making it barely portable. Is it possible to overcome these limitations by designing and building much tinier, fully capable drones?
Tiny Drone Quest
Drones are an amazing technological wonder. However, they are either expensive and bulky or not very capable. Therefore, scientists and engineers have embarked on a quest to manufacture progressively tinier, more capable drones. Their ultimate goal is to make flying robots that are just as small and capable as small flying insects.
Drones the size of small flies would have important applications. They could be sent en masse to inspect and diagnose hazardous sites. They could fly through piles of rubble to find and determine the condition of victims trapped by the damage resulting from earthquakes, tornadoes, hurricanes, and floods. They could be released from spacecraft to assist in space exploration. They could repel and even destroy disease-carrying biting insects.
However, scientists have encountered huge technological barriers to making flying robots the size of flies. The most challenging problems are how to stabilize the flight and duplicate the hovering capabilities of insects. In drones and aircraft these barriers are overcome through the installation of gyroscopes. But there is a limit to how small one can make a gyroscope. There is also the problem of providing sufficient energy for meaningful flight. Batteries have been either too heavy or lacked the required energy. Until recently, the smallest available high-drain batteries weighed in at 350 milligrams (0.0123 ounces).
Three research breakthroughs in robotics have helped overcome the barriers. By carefully studying the flight designs in insects, a research team led by Kevin Ma developed the equivalent of flight muscles through the use of miniaturized high-power density piezoelectric devices.1 They used a lightweight wire to transfer energy from a battery on the ground to the flapping-wing flying robot. Their robot, though tethered, achieved stable unconstrained hovering and basic flight maneuvers. Ma and his colleagues were able to manufacture such a robot with a mass of only 80 milligrams (0.00282 ounces). For comparison, the average weight of a worker honeybee is about 160 milligrams (0.00564 ounces).
In a second effort in 2018, a team led by Johannes James built an untethered flying robot that weighed only 190 milligrams (0.00670 ounces).2 To get the robot down to this weight, James’s team used a hyperminiaturized gyroscope that was developed by studying the designs in the biological gyroscope possessed by bees. The gyroscope weighed only 15 milligrams (0.000529 ounces). They also designed and built an external laser device to beam power to the robot.
Third, at the end of 2022, a team led by Sawyer Fuller published their achievement of the manufacture and test flights of the first gnat-sized flying robot.3 Their robot weighed only 10 milligrams (0.000353 ounces). For comparison, gnats weigh from 1 to 10 milligrams and the average weight of an adult fruit fly is 10 milligrams.
Fuller’s team carefully examined the anatomical designs of the fruit fly. They discovered that the fruit fly lacks the equivalent of a gyroscope. Instead, tiny feathers on its antennae are designed to detect wind speed and direction. Fuller’s team discovered that their robot can do what fruit flies do by using miniaturized accelerometers. The accelerometers they installed on their robot could quickly measure the acceleration of the robot induced by wind, dust, rain, and/or snow. A micro-computer processor on the robot then calculated the adjustments needed in the robot’s flapping wings to compensate for the induced accelerations. The robot can be powered either by an external laser beam like the one developed by James’s team or by the very recently developed hyperminiaturized battery.
Physical and Philosophical Applications
Of the practical applications described earlier in this article, the one that most excites scientists about gnat- and bee-sized flying robots is their use for space exploration. Flying robots this tiny would exponentially reduce the cost of determining the characteristics of our solar system’s planets, moons, asteroids, and comets. A small, inexpensive spacecraft could be sent to orbit a solar system body. That spacecraft could then release—with very little energy expenditure—a small swarm of tiny flying robots to measure a wide range of the body’s physical and chemical characteristics.
For interstellar exploration, tiny flying robots are a must. The largest possible spacecraft that could survive—without crippling damage—a trip to the nearest stars at 10–20% light’s velocity is one no larger than about 10 centimeters across. Such a small spacecraft could encapsulate several hundred gnat-sized flying robots that could be released to determine the detailed characteristics of the nearest stars and their planets and asteroid/comet belts.
Arguably the greatest significance of the three research teams’ achievements is philosophical. Their breakthroughs critically depended upon, as best as humanly possible, copying the amazing designs in the biological machinery of bees, fruit flies, and gnats.
Genesis 1:26–27 declares that God created humans in his image. Part of the image of God we possess is the ability to invent and create. God has given us the capacity to design and manufacture an enormous variety of tools, devices, and machines. However, the tools, devices, and machines that God builds are far superior to the ones we make. As the teams headed by Ma, James, and Fuller learned, humans have much to gain by studying our Creator’s designs and implementing them into the devices and machines we desire to make for humanity’s benefit.
- Kevin Y. Ma et al., “Controlled Flight of a Biologically Inspired, Insect-Scale Robot,” Science 340, no. 6132 (May 3, 2013): 603–607, doi:10.1126/science.1231806.
- Johannes James et al., “Liftoff of a 190 mg Laser-Powered Aerial Vehicle: The Lightest Wireless Robot to Fly,” 2018 IEEE International Conference on Robotics and Automation (May 2018): 1–8, doi:10.1109/ICRA.2018.8460582.
- Sawyer Fuller, Zhitao Yu, and Yash P. Talwekar, “A Gyroscope-Free Visual-Inertial Flight Control and Wind Sensing System for 10-mg Robots,” Science Robotics 7, no. 72 (November 23, 2022): id. abq8184, doi:10.1126/scirobotics.abq8184.