Turbulence can be unpleasant enough for passengers in full-sized aircraft, but it's even more of a challenge for unmanned micro air vehicles (MAVs) – a good gust can blow one of the little drones completely off course, or even cause it to crash. That's why a team from RMIT University in Melbourne, Australia, has looked to birds for a solution. The result is a system that detects turbulence before it buffets the MAV, allowing the aircraft to anticipate it and thus maintain a smoother flight. The technology could also be applicable to regular airplanes.
Ordinarily, MAVs attempt to minimize the effects of turbulence via inertial-based sensors such as gyroscopes and accelerometers. The problem is, these sensors only take notice once the aircraft is already in turbulence-induced motion – they're reactive, not proactive.
Birds, however, are able to detect turbulence before it disrupts their flight, allowing them to adjust their flight surfaces in order to counteract it. They're able to do so thanks to receptors known as Herbst corpuscles, which are located near the feather follicles on the leading edges of their wings (amongst other places).
These receptors sense the vibrations and pressure changes amongst the feathers in the area, caused by airflow disturbances. It's theorized that within a split-second of detecting a wind gust, the receptors cause the bird's nervous system to react by adjusting the placement of their flight-controlling wing and/or tail feathers. This in turn changes their angle of attack so that when the disturbance reaches those flight surfaces, they're ready for it.
The RMIT team, led by Prof. Simon Watkins, installed Herbst corpuscle-inspired air pressure sensors on a fixed-wing MAV. Those sensors were on probes that stuck out in front of the aircraft, so that they could detect disturbances before they reached its wings and tail. When the MAV was tested in a wind tunnel, the sensors were shown to significantly reduce the effects of turbulence – the results can be seen in the video below.
According to Watkins, the sensors would need to be arranged differently on larger, faster passenger-carrying aircraft. Once the technology is in place, however, he claims that it could be used not only to ensure more comfortable flights, but also to prolong aircraft life by reducing loads on their wings.
A paper on the research was recently published in the journal Progress in Aerospace Sciences.
Source: RMIT University