We know drones have brought with them enhanced thermal superpowers that enable them to locate human life through heat detection; something which is really handy in search and rescue operations. We also know that in usual circumstances, conventional drones use visual sensors for navigation.
But Japan has just said dang that; we want a drone that can actually smell stuff. Like detecting where people are by following their scent.
Yeah. Exactly that. We guess they figure environmental conditions like dampness, low light, and dust can hinder navigation effectiveness, which could be a limiting factor in disaster recovery situations.
Researchers at Shinshu University in Nagano have developed a novel bio-hybrid drone by combining robotic elements with odour-sensing antennae from silkworm moths. Their innovation, which integrates the agility and precision of robots with biological sensory mechanisms, can enhance the applicability of drones in navigation, gas sensing, and disaster response.
Odour is not so bad now, is it?
Reports from Japan say the “insect drone” can autonomously find its way to the source of an odour or pheromone, with hope high among the researchers that – by widening the range over which it can detect odours and ultimately making it able to detect the scent of humans – they will turn the drone into a useful tool for search and rescue activities at disaster sites.
In nature, animals, birds, and insects have an inherent navigation system based on their sense of smell that helps them locate food sources, evade predators, and attract potential mates, thereby promoting their overall survival.
Insects, in particular male moths, can detect windborne sex pheromones from distances that, in some cases, extend to several kilometres through a process known as odour-source localisation.
Bio-hybrid drones that integrate these biological sensory mechanisms with advanced artificial machinery hold significant promise in overcoming the challenges associated with existing robotic technologies.
For this breakthrough, the researchers say they were inspired by male silkworm moths, which are are known to search for their female counterparts by using their antennae to detect pheromones that the females emit.
It is expected that this technology could be utilised at disaster scenes in the future, where a drone that can react to human odour could be deployed to search for and find people in need of rescue.
Shinshu University Associate Prof. Daigo Terutsuki, a researcher at the Faculty of Textile Science and Technology, began researching how to leverage the silkworm’s abilities in 2020, with the intention of testing the feasibility applying these abilities for scent tracking.
Professor Terutsuki’s research partner, Associate Professor Daigo Terutsuki came with the idea to attach an antenna cut from a silkworm moth to electrodes and mounted it as an odour-detecting sensor on a small drone that measured 10 square centimetres.
Converting the information detected by the antenna into electrical signals made the drone able to fly autonomously to a pheromone source. An antenna can continue to function for about five hours even after it is cut off of an insect, said Terutsuki.
The drone that Terutsuki first completed in 2021 could only search within a range of about two meters. But the team was then joined by an expert on insect flight mechanisms from one of Chiba University’s Graduate Schools, to develop an improved version of the drone with a range of up to 5 meters.
One factor that helped them successfully expand the range was an idea gained from the wingbeat of the silkworm moth. During the research process, they discovered that, when silkworm moths move their wings, they create air currents that bring pheromones to their antennae.
They then designed the rotation of the drone’s propellers to the flapping of the insect’s wings and designed the drone to bring odours to a sensor connected to an antenna.
They also paid attention to the insects’ behaviour of repeatedly stopping in mid-air as they tracked the source of an odour. Inspired by this, they had their drone not fly in straight lines, but make mid-air stops at regular intervals and rotate 120 degrees each time so that it could detect odour sources more accurately.
“This research couldn’t have been successful if we hadn’t gone beyond human thinking to learn from other organisms.” Terutsuki said.
Using the results of the latest research, Terutsuki and his fellow researchers are now expanding their R&D initiative to developing a sensor that uses mosquitoes’ antennae, which can also detect human scent.
The team has also sought the advice of firefighters and self-defence forces personnel who had been involved in rescue activities following the Great East Japan Earthquake and the Great Hanshin Earthquake.
“A drone can enter dangerous places that even disaster rescue dogs cannot go,” Terutsuki said.
“This is the kind of technology that is needed out in the field, and we want to make it real by all means.”