Washington State University (WSU) researchers have created a robotic bee that can fly in all directions.
With four wings made out of carbon fiber and mylar as well as four light-weight actuators to control each wing, the Bee++ prototype is the first to fly stably in all directions. Image Credit: Washington State University
The Bee++ prototype is the first to fly steadily in all directions. It has four wings made of carbon fiber and mylar, as well as four lightweight actuators to operate each wing.
The Bee++ completes the six degrees of free movement a typical flying insect demonstrates, including the challenging yaw motion.
The team behind the study, led by Néstor O. Pérez-Arancibia, Flaherty Associate Professor in the School of Mechanical and Materials Engineering at WSU, published their findings in the IEEE Transactions on Robotics journal. At the end of this month, Pérez-Arancibia will present the findings at the IEEE International Conference on Robotics and Automation.
According to Pérez-Arancibia, researchers have been working on creating artificial flying insects for more than 30 years. They could one day be utilized for a variety of tasks, such as artificial pollination, confined space search and rescue, biological research, or environmental monitoring, even in dangerous situations.
However, even enabling the small robots to take off and land required creating controllers that function like an insect brain.
It is 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.
Néstor O. Pérez-Arancibia, Flaherty Associate Professor, School of Mechanical and Materials Engineering, Washington State University
A two-winged robotic bee was first created by researchers, although it had limited mobility. In 2019, Pérez-Arancibia and two of his Ph.D. students developed a four-winged robot that could fly for the first time.
The researchers create a torque that turns the robot along its two major horizontal axes to perform two actions known as pitching or rolling by making the front wings flap differently than the back wings for pitching and the right wings flap differently than the left wings for rolling.
But he said that it is crucial to be able to regulate the intricate yaw motion. Without it, robots lose control and are unable to concentrate on a task. They will eventually fall.
He further added, “If you can’t control yaw, you are super limited. If you are 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.”
Additionally, having all degrees of movement is essential for evasive actions or tracking objects.
Pérez-Arancibia stated, “The system is highly unstable, and the problem is super hard. For many years, people had theoretical ideas about how to control yaw, but nobody could achieve it due to actuation limitations.”
The researchers took a hint from insects and adjusted the wings so that they flap in an inclined plane, enabling their robot to rotate in a controlled way. Additionally, they boosted the robot’s ability to flap its wings 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,” Pérez-Arancibia noted.
The Bee++, which has a wingspan of 33 millimeters and a weight of 95 mg, is still larger than actual bees, which weigh about 10 milligrams.
It is primarily connected to a power source by a cable since, unlike actual insects, it can only fly independently for around five minutes at a time. Other varieties of insect robots, such as crawlers and water striders, are also being developed by researchers.
Ryan M. Bena, Xiufeng Yang, and Ariel A. Calderón, former PhD students of Pérez-Arancibia at the University of Southern California, collaborated on the study. The National Science Foundation and DARPA provided funding for the project. Support has also come from the WSU Foundation and the Palouse Club via WSU’s Cougar Cage program.
Journal Reference:
Bena, R. M., et al. (2023) High-Performance Six-DOF Flight Control of the Bee++: An Inclined-Stroke-Plane Approach. IEEE Transactions on Robotics. doi:10.1109/TRO.2022.3218260.