Researchers at Washington State University have achieved a significant milestone in the development of robotic bees. The Bee++ prototype, created by a team led by Néstor O. Pérez-Arancibia, has the ability to fly in all directions, including performing the complex twisting motion called yaw. This achievement is attributed to the use of four carbon fiber and mylar wings, along with lightweight actuators that control each wing independently. The researchers published their findings in the journal IEEE Transactions on Robotics and will present their work at the upcoming IEEE International Conference on Robotics and Automation.
For over three decades, scientists have been working on creating artificial flying insects, and this breakthrough brings them closer to realizing the potential applications of such technology. These robotic bees could be used for various purposes, including artificial pollination, search and rescue operations in confined spaces, biological research, and environmental monitoring in challenging environments.
One of the key challenges faced during the development process was enabling the tiny robots to take off and land. To address this, the researchers had to devise controllers that emulate the functioning of an insect brain.
“It’s a combination of robotic design and control,” explained Pérez-Arancibia. “Control relies heavily on mathematics, and it involves designing an artificial brain. Some refer to it as hidden technology, but without these simple brains, nothing would function.”
Initially, the researchers developed a two-winged robotic bee, but its mobility was limited. In 2019, Pérez-Arancibia and two Ph.D. students successfully created a four-winged robot that was light enough to take off. To achieve two specific maneuvers called pitching and rolling, the researchers programmed the front wings to flap differently from the back wings for pitching, and the right wings to flap differently from the left wings for rolling. This created torque, enabling the robot to rotate about its two primary horizontal axes.
However, controlling the complex yaw motion was of utmost importance. Without it, the robots would spin uncontrollably, unable to focus on a particular point, ultimately resulting in crashes.
“If you can’t control yaw, your capabilities are severely limited,” Pérez-Arancibia emphasized. “Imagine you’re a bee and you see a flower, but you can’t control your yaw—you end up spinning constantly as you try to reach the flower.”
Having full freedom of movement is also crucial for evasive maneuvers and object tracking.
“The system is highly unstable, and the problem is extremely challenging,” Pérez-Arancibia added. “For many years, researchers had theoretical ideas about how to control yaw, but they couldn’t achieve it due to limitations in actuation.”
To enable controlled twisting, the researchers took inspiration from insects and adjusted the wing flapping motion to follow an angled plane. They also increased the robot’s wing flapping frequency from 100 to 160 times per second.
“The solution involved both the physical design of the robot and the invention of a new controller design—the ‘brain’ that directs the robot’s actions,” Pérez-Arancibia explained.
Weighing 95 mg and possessing a wingspan of 33 millimeters, the Bee++ is larger than real bees, which weigh around 10 milligrams. Unlike actual insects, the robot can only fly autonomously for approximately five minutes at a time and is primarily connected to a power source via a tether cable. The researchers are also exploring the development of other types of insect robots, including crawlers and water striders.
Source: Washington State University