Bio-hybrid drone uses insect sensors to navigate by smell

A research team from Japan's Shinshu University has developed a biohybrid drone that can perceive and navigate its surroundings using odor-sensitive sensors from silkworm moths that are connected to robotic elements. This allows the drone to navigate in environments where there is little to no visibility.

Most drones use visual sensors to navigate their surroundings. These can be cameras, thermal imaging cameras, light detection or lidar for distance measurement. In dark, rainy or smoky environments, however, such sensors only work to a limited extent or sometimes not at all, meaning that drones may not be able to be used in extreme conditions.

The researchers at Shinshu University have taken nature as a model, as they write in the study “Advanced bio-hybrid drone for superior odor-source localization: high-precision and extended-range detection capabilities”, which was published in npj Robotics. Animals, birds and insects, for example, use a navigation system based on odors. This allows them to find food quickly, avoid predators and find potential mating partners. The scientists wanted to transfer orientation by smell to a drone by making parts of the odor sensors of living organisms readable with electronics.

For this purpose, the research team decided to use the antennae of the silkworm moth, which uses them to detect odors. The drone should be able to follow certain odors and navigate accordingly.

Following odors with insect sensors

For use in a drone, the scientists developed an electroantennography sensor (EAG) in which they made the signals of the insect sensors readable via electrodes.

In a first step, however, the sensor was only able to detect odors at a distance of less than two meters. In a further version, they introduced various improvements to increase the range. First, they discovered that insects pause when searching for odors to achieve more precise odor detection. The researchers simulated this by adding a rotation algorithm to their sensor that mimics the insects' pauses.

The researchers also increased the sensor's performance by better adapting the sensor to the structure of the insect antennae. This allowed the electrical signals to be better recorded and evaluated. The scientists placed the sensor itself in a funnel-shaped housing to minimize air turbulence during the drone's flight. They provided the interior with a conductive coating to avoid interference from electrostatic charging and thus improve the signal quality.

The modifications made led to success: odor sources could be better detected under different environmental conditions and odor concentrations. The range of the sensor was increased to five meters. The bio-hybrid drone was thus able to follow odors and locate an odor source.

The team assumes that their drone is suitable for use in search and rescue tasks. For example, the odors of missing persons could be detected and tracked. It is also possible to use the drone to detect gas leaks and dangerous substances, such as explosives and drugs, at an early stage.

(olb)