Drones

Drink cup lids inspire a system that could keep drones flying safely

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Poppable domes like those in the lid of this cup could simplify the sensing of air flow across drones' wings
Depositphotos
Poppable domes like those in the lid of this cup could simplify the sensing of air flow across drones' wings
Depositphotos
The wing model utilized in the study
Purdue University/Jared Pike

You may have noticed that on some take-away drink cup lids, there are small domes that can be "popped down" to indicate what sort of beverage is in the cup. Scientists now believe that similar domes could help drones monitor the air pressure on their wings.

One problem faced by autonomous fixed-wing drones is the fact that their onboard flight computers are constantly flooded with data coming in from multiple sensors. As a result, the aircraft require a fair amount of processing power. Even then, there may still be a significant lag between the time that they receive sensory input, and then act upon that information.

In order to lighten the info-load, researchers have been exploring the use of sensors that simply don't register data that's too insignificant to matter. That's where the little domes come in.

Working with colleagues from the University of Tennessee, scientists at Indiana's Purdue University have developed a proof-of-concept model in which a grid of cup-lid-like polyurethane domes is mounted on the top surface of a section of aircraft wing. Beneath each dome is a membrane of piezoelectric polylactic acid (PLA) – along with the domes, those membranes form a linked array.

The wing model utilized in the study
Purdue University/Jared Pike

As long as the air flowing over the wing doesn't exceed a certain pressure threshold, none of the bubbles pop down. If the pressure is high enough, however, some of the bubbles will temporarily get inverted, pressing down on and deforming their underlying PLA membrane. The array registers where those deformations are occurring, and relays that information to a computer.

The computer is in turn able to map the pattern of high-pressure air flow across the wing. In practice, if that pattern indicated dangerous flight conditions, the drone's flight control system would be advised so it could react accordingly. Making things simpler is the fact that because each dome is either up or down, the data they provide is like the 1s and 0s used in binary computing.

Lead scientist Andres Arrieta believes that it should be possible to incorporate the technology into a fully functional drone wing within the next three to five years. A paper on the research was recently published in the journal Advanced Intelligent Systems.

Source: Purdue University

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4 comments
Daishi
It seems like there are other practical ways to solve the problem of too much useless sensor data besides just shifting to a mechanical/moving part that could wear out over time. When you look at examples like early shooters using inverse square root instead of floating point or how parity memory works I'd bet there are some creative ways to assess sensor states without overwhelming a central compute system with raw data. It seems like they could use dedicated data collectors that only send info north if it it meets a criteria.
Naldo the magnificent
Am I missing something here? The air pressure over the top of a wing is LESS than 'normal' air pressure (otherwise there would be no lift produced), so how are the 'domes' supposed to depress, if they require pressure to do so? They would presumably be in the raised (not depressed) condition before take-off, so the pressure over them could only get less.
clay
My question here relates to the Elon Musk adage "the best part is no part":

If the PLA Piezoelectric sensor (*VERY* cool, btw) can detect the force of the bubble collapsing/expanding then would it be more simple to just expose the pla-pz to the wing surface without the bubble? It seems these sensors would function just as well when embedded under the surface of the wing (which is also experiencing the air pressure variation)?
Treon Verdery
Interferometry can make a visual map of bending and flexing, really cheap would just be two laser diodes pointed at the drone propeller or airfoil doing interferometry and a 20¢ at alibaba phone camera imaging the interferometry lines and the way they change, this actually does the same thing as the bumps for about 28¢