On the EPFL, micro-drones have been developed that may be moved with out a motor or battery.No motors, no batteries, no electronics on board, simply small cavities that convert sound waves into thrust: that is the shocking propulsion expertise for drones, developed on the Laboratory for Micro-Biorobotic Programs (Microbs) on the Swiss Federal Institute of Expertise Lausanne (EPFL). It was not too long ago introduced within the journal Science Advances.
The precept is easy: the motion is generated by sounds. “By selecting the frequency, we are able to management the actions of a micro-object,” explains the director of the laboratory, Selman Sakar, to Radio and Tv of Italian-speaking Switzerland (RSI).
The functions of acoustic microrobotics are various. Sakar sees essentially the most promising within the medical area: “You would construct a tiny construction, reminiscent of a drug service to be swallowed or injected into the physique, after which management it with sound waves.”
The Drone within the Lungs
To this point, the usage of sound-controlled microrobots has been investigated primarily in liquid environments reminiscent of blood vessels. EPFL’s robots work within the air and open up attention-grabbing analysis prospects, for instance within the lungs. Though its use in sufferers remains to be a good distance off, there are already collaborations with the College Hospitals of Geneva and Lausanne.
To maneuver the drones utilizing sound, the researchers used the so-called Helmholtz resonance. Behind this identify is the phenomenon recognized to everybody, which was first investigated by the German scientist Hermann von Helmholtz: If you blow gently via the neck of an empty bottle, not solely is a sound produced, however the air trapped within the bottle is made to vibrate.
Selman Sakar’s staff has recreated this precept – utilizing so-called resonators. They appear like small ampoules. “Their form determines the tone at which the air inside begins to vibrate,” explains the knowledgeable. “When that occurs, the air is pushed out of the throat and the construction strikes in the other way, a bit like a rocket.”
Ultrasound as an Vitality Supply
To show the precept, Sakar’s staff has constructed two varieties of microaircraft. The primary combines three resonators on an ultra-light construction and weighs about 150 micrograms, or 0.15 milligrams. The downward-facing openings create the rays that elevate it. The second weighs 184 micrograms and makes use of the resonators to spin a rotor with small blades that may attain 13,000 revolutions per minute.
The vitality is equipped by an exterior system that generates an ultrasound of 40,000 hertz, past the human listening to threshold. The robotic is thus free of elements which can be troublesome to miniaturize, beginning with the battery. Nevertheless, the vitality provide stays indispensable: it’s transferred from the system that generates the acoustic area to the plane.
The researchers noticed the take-off and hovering within the air underneath laboratory circumstances. However for these objects to be managed alongside advanced routes, additional developments are wanted. The system examined up to now operates at a single frequency and nonetheless gives restricted maneuverability.
RSI, Prima Ora, 10/21/2026, 6:00 p.m.; noes
