Researchers make bee robots that can rotate
(Nanowerk News) A bee robot that can fly fully in all directions has been developed by Washington State University researchers.
With four wings made of carbon fiber and mylar and four lightweight actuators to control each wing, the Bee++ prototype was the first to fly steadily in all directions. That includes a complicated twisting motion known as a yaw, with Bee++ fully achieving the six degrees of free motion exhibited by ordinary flying insects.
Led by Néstor O. Pérez-Arancibia, Flaherty associate professor in WSU’s School of Mechanical and Materials Engineering, the researchers report their work in the journal, IEEE Transactions on Robotics (“Bee++ High-Performance Six-DOF Flight Control: Inclined-Stroke Field Approach”). Pérez-Arancibia will present its results at the IEEE International Conference on Robotics and Automation later this month.
Researchers have been trying to develop artificial flying insects for more than 30 years, says Pérez-Arancibia. They may one day be used for many applications, including for artificial pollination, search and rescue in confined spaces, biological research, or environmental monitoring, including in hostile environments.
But getting a small robot to take off and land required developing a controller that acts like an insect’s brain.
“It’s a mix of robotic design and control,” he said. “Controls are very mathematical, and you design a sort of artificial brain. Some people call it hidden technology, but without that simple brain, nothing works.”
Researchers initially developed a bipedal bee robot, but it had limited movement. In 2019, Pérez-Arancibia and two of his PhD students built the first four-winged robot that was light enough to take off. To perform the two maneuvers known as pitching or rolling, the researchers made the front wing flap a different way than the rear wing for pitching and the right wing flap a different way than the left wing for rolling, creating torque that spun the robot. its two main horizontal axes.
But being able to control complex yaw motions is critical, he says. Without it, the robot goes out of control, unable to focus on a point. Then they crash.
“If you can’t control the yaw, you are very limited,” he says. “If you’re a bee, this is the flower, but if you can’t control the yaw, you’re spinning all the time while you’re trying to get to it.”
Having all degrees of movement is also very important for evasive maneuvers or tracking objects.
“The system is very unstable, and the problems are very difficult,” he said. “For years, people had theoretical ideas of how to control yaw, but no one was able to achieve it due to actuation limitations.”
To allow their robot to rotate in a controlled manner, the researchers took cues from the insect and moved the wings so they flapped in an inclined plane. They also increased the number of times per second their robot could flap its wings – from 100 to 160 times per second.
“Part of the solution was the physical design of the robot, and we also came up with a new design for the controller – the brain that tells the robot what to do,” he said.
Weighing 95 mg with a wingspan of 33 millimeters, the Bee++ is still larger than the real bee which weighs around 10 milligrams. Unlike a real insect, it can only fly independently for about five minutes at a time, so it’s mostly tethered to a power source via a cable. Researchers are also working to develop other types of insect robots, including crawlers and water striders.