A to-go lid from a cup holds the secret to creating a safer drone wing

The small domes on the top of to-go cups serve more than the purpose of pressing down to declare what type of soda you received. These domes on the top of plastic drink lids inspired patterns that have been incorporated into a drone’s wings.

The domes can be placed upside down, or in different directions. The purpose of these dome shaped designs is to give the drone a way to consider what dangerous conditions are like and react quickly to them.

The study was published in the journal Advanced Intelligent Systems.

Researchers at Purdue University and the University of Tennessee, Knoxville found a novel discovery in using metamaterial that uses shapes similar to the domes on the top of plastic to-go lids to adapt to its surroundings. Metamaterials are artificial materials with a structure that has properties not usually found in nature.

Speeding up the response time

Autonomous vehicles like drones (UAV— unmanned aerial vehicles) don’t have ways to filter information, in this case dangerous conditions, and therefore the response time is slowed down. “Drones cannot use their full flight capability because there is just too much data to process from their sensors, which prevents them from flying safely in certain situations,” said Andres Arrieta, a Purdue associate professor of mechanical engineering with a courtesy appointment in aeronautical and astronautical engineering.

Domes can sense the surroundings

The solution to this problem is using dome-covered surfaces that can sense their surroundings better, allowing a drone’s wings to gain only essential sensory information, and to avoid large amounts of superfluous information. A minimum amount of force is needed to invert a dome, filtering out anything else that is unnecessary.

A certain number of domes that either pop up or down at certain parts of the drone’s wings could suggest a dangerous pressure pattern by signaling the drone’s control system. Another example is using the domes to signal dangerous temperatures to the drone.

Associative memory

The invertible domes could allow the drone wings to have a type of “memory” and eventually recognize dangerous conditions. This learning strategy is called associative memory or recalling parts of a memory to construct the complete version. For example, using senses such as remembering a certain color that was seen, or a sound that was heard that and can be recalled, and then creating a full version of that memory. The researchers investigated ways that the metamaterial could be engineered to process information in a similar manner.

The research team noted that the domes can only be implemented in two ways — popped up or down. They figured the conditions could act as zeroes and ones to create spatial patterns for developing associative memory.

The outcome

The study showed that when a force inverts a dome in the drone’s wing, sensors embedded into the flat part of the material can distinguish the difference in shape. The researchers sent an electrical signal that activated a memory device called a memristor to record the force and where the force was detected.

With each dome, the metamaterial “learned” to remember the pattern of the level of force created on its exterior. The drone wing would be able to quickly recall such a pattern associated with dangerous conditions because the material would store the data as partial memories, or associative memories, from the inverted dome patterns. It would then put all this information together to create a full single memory.

Next steps

The metamaterial needed to create the domes for drone wings can be manufactured with existing techniques, Arrieta suggested. He said the next step is to see how such material responds to its surroundings based on “learned” information. The data would be coming from the domes and sent to the metamaterial.

The metamaterials combine engineering, memory and learning capabilities to create an advanced wing for drones with the ability to retain information that could change the future of UAVs.