Goggle-wearing parrots flying through lasers and aerosols have shown modern flight models on animals to be inaccurate, posing concerns for drone manufacturing.
Science can often be arduous, with the minute, monotonous data creating a somewhat boring day-to-day experience. Even in robotics and drone development, there are times of relentless repetition.
However, sometimes things just click, like when Stanford researchers trained a parrotlet, the second smallest species of parrot, to fly wearing goggles.
Seeking a way to monitor bird flight to the tiniest margin, Stanford mechanical engineer David Lentink and his colleagues felt an experiment with lasers and aerosol particles would do the trick.
Training Obi the parrotlet to wear protective goggles and chin strap, and fly from point A to point B, the findings – published in Bioinformatics and Biomimetics – proved remarkable.
According to Diana Chin, co-author on the study, the goal was to establish how much lift a bird generates, “based off its wake”, and compare it to three common models of flight that scientists currently rely upon.
These models were developed to interpret airflow and understand how animals support their weight during flight – the results are commonly referenced for work on flying robots and drones.
“What we found was that all three models we tried out were very inaccurate because they make assumptions that aren’t necessarily true,” said Chin.
The equipment used was pretty ingenious. The team made tiny goggles using lenses from regular laser safety goggles, 3D printed the little frames and used veterinary tape as straps.
The goggles also had reflective markers on the side so the researchers could track the bird’s velocity, while Eric Gutierrez, lead author on the study, trained Obi to fly between two perches.
Once Obi was trained up and everything was in place, they filmed the flight through a laser sheet that illuminated non-toxic, micron-sized aerosol particles. As the bird flew through it, its wing motion disturbed the particles to generate a detailed record of the vortices created by the flight.
It essentially looked like satellite weather patterns swirling around Earth, finding that the wake behind a bird’s wings is not as distant as first believed.
“Now, whereas vortex break-up happens far away behind the aircraft – like more than 1km – in birds, it can happen very close to the bird, within two or three wing beats, and it is much more violent,” said Lentink, senior author on the paper.
“Many people look at the results in the animal flight literature for understanding how robotic wings could be designed better,” added Lentink.
“Now, we’ve shown that the equations that people have used are not as reliable as the community hoped they were. We need new studies, new methods to really inform this design process much more reliably.”