The Tiny Bee⁺⁺ Solves a Big Problem in Insect-Like Robotics: Yaw Control
This insect-inspired flying robot has finally cracked the tricky problem of yaw control, with a full six degrees of freedom.
Researchers at the University of Southern California, Applied Materials, Intuitive Surgical, and Washington State University have developed tiny "robotic bee" that can twist and turn to fly in any direction — showing the same six degrees of freedom (6DoF) as its natural inspiration.
"It's a mixture of robotic design and control," explains associate professor Néstor O. Pérez-Arancibia of his team's work, which sought to solve the tricky problem of yaw control in a tiny robotic insect. "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."
While robotic insects are nothing new, their maneuverability is lacking in comparison to nature's creations. After building something which can take off and land, years of research went into having it be able to pitch and roll — with a team led by Pérez-Arancibia using a four-winged approach to produce torque — but controlling yaw proved considerably more challenging.
"If you can't control yaw, you’re super limited," Pérez-Arancibia explains. "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. 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 team's approach, which draws even deeper from real-world insects, was to adjust the wings to flap in an angled plane while boosting their speed by 60 per cent. Coupled with a newly-designed controller, that proved enough to make the prototype — dubbed the Bee⁺⁺ and built from carbon fiber with mylar wings — able to control its yaw just like the real thing.
There's still work to be done on the project, though: the Bee⁺⁺ is nearly ten times the weight of a real bee and with a correspondingly larger wingspan, and at present can only carry enough energy to fly autonomously for around five minutes — with most tests carried out using a tether to provide power.
The team's work has been published in the journal IEEE Transactions on Robotics under closed-access terms.