In a remarkable feat of engineering, researchers from Washington State University have successfully developed a robotic bee capable of seamless flight in all directions. Utilizing carbon fiber and mylar wings, along with lightweight actuators controlling each wing, the Bee++ prototype achieves stable flight, including the intricate yaw motion—a twisting maneuver that emulates the six degrees of freedom observed in natural flying insects.Led by Néstor O. Pérez-Arancibia, Flaherty associate professor in WSU's School of Mechanical and Materials Engineering, the team shares their groundbreaking work in the prestigious journal IEEE Transactions on Robotics. Pérez-Arancibia is set to present their findings at the upcoming IEEE International Conference on Robotics and Automation.For over three decades, researchers have been tirelessly pursuing the development of artificial flying insects. These miniature marvels hold vast potential for numerous applications, ranging from artificial pollination and search and rescue missions in confined spaces to biological research and environmental monitoring, even in hostile environments. However, achieving liftoff and landing with these diminutive robots required the creation of controllers that mimic the functionality of an insect brain.Pérez-Arancibia explains, "It's a fusion of robotic design and control. Control relies heavily on mathematical principles, and an artificial brain-like structure is designed. Some refer to it as hidden technology, but without these rudimentary brains, nothing would come to fruition."Initially, the researchers developed a two-winged robotic bee, but its maneuverability was limited. In 2019, Pérez-Arancibia and two PhD students made a breakthrough by constructing a four-winged robot that was light enough to take flight. To execute pitching or rolling movements, the team implemented a technique wherein the front and back wings, as well as the right and left wings, flapped differently, generating torque that facilitated rotation about the robot's primary horizontal axes.However, mastering the complex yaw motion proved immensely crucial. Without this capability, robots would lose control and struggle to maintain focus on specific points, ultimately leading to crashes. Pérez-Arancibia emphasizes the significance of controlling yaw, stating, "Without control over yaw, you face severe limitations. Imagine a bee attempting to reach a flower but constantly spinning due to the absence of yaw control."Attaining all degrees of movement is also paramount for evasive maneuvers and object tracking. Acknowledging the daunting challenge, Pérez-Arancibia highlights the system's high instability and the historical difficulty in controlling yaw due to limitations in actuation.Inspired by insects, the researchers devised a solution by angling the plane of wing flapping, enabling controlled twisting motion. They also increased the wing-flapping frequency from 100 to 160 times per second, ensuring more agile maneuverability. Pérez-Arancibia remarks, "The solution encompassed both the physical design of the robot and an inventive controller design—a brain dictating the robot's actions."Weighing a mere 95 milligrams and boasting a 33-millimeter wingspan, the Bee++ exceeds the size of real bees, which weigh around 10 milligrams. While it can autonomously fly for approximately five minutes, it primarily remains tethered to a power source via a cable. The researchers are actively exploring the development of other types of insect-inspired robots, including crawlers and water striders.