The Bee++ prototype features four wings crafted from carbon fiber and mylar, along with four lightweight actuators that control each wing. Notably, this prototype is capable of stable flight in all directions, including the challenging twisting motion known as yaw. For the first time in history, the Bee++ achieves the same six degrees of free movement that flying insects typically display.
According to Pérez-Arancibia, scientists have been working on creating artificial flying insects for over 30 years. These insect robots have potential uses such as artificial pollination, search and rescue in confined spaces, biological research, and monitoring the environment, especially in harsh conditions. But just getting the tiny robots to take off and land required development of controllers that act the way an insect brain does.
“It’s a mixture of robotic design and control. Control is highly mathematical, and you design a sort of artificial brain. Some people call it the hidden technology, but without those simple brains, nothing would work.”
Previously, a robotic bee with only two wings was created by researchers, but its movement was restricted. In 2019, Pérez-Arancibia and two of his PhD students successfully constructed a four-winged robot that was light enough to take off. To perform pitching or rolling maneuvers, the researchers devised a technique where the front wings are flapped differently from the back wings for pitching, and the right wings flap differently from the left wings for rolling, producing torque that turns the robot around its two primary horizontal axes.
But being able to control the complex yaw motion is tremendously important, he said. Without it, robots spin out of control, unable to focus on a point. Then they crash.
“If you can’t control yaw, you’re super limited. If you’re a bee, here is the flower, but if you can’t control the yaw, you are spinning all the time as you try to get there.”
Having all degrees of movement is also critically important for evasive maneuvers or tracking objects.
The researchers used an insect-inspired approach to enable their robot to twist in a controlled manner. By angling the wings, they created a flapping motion that allowed for this movement. Additionally, they increased the frequency of the flapping motion from 100 to 160 times per second.
“Part of the solution was the physical design of the robot, and we also invented a new design for the controller – the brain that tells the robot what to do.”
The Bee++ weighs 95 mg and has a wingspan of 33 millimeters, making it larger than actual bees that weigh about 10 milligrams. It can only fly independently for approximately five minutes and is usually connected to a power source via a cable. The researchers are also creating other insect robots such as crawlers and water striders.
