Lifting Small Particles with the Tweezers of Sound
Tokyo Metropolitan University researchers have fine-tuned their “Tweezers of Sound” for contactless manipulation of small objects.
Engineers from Tokyo Metropolitan University have enhanced technology to lift small particles using sound waves. Their Tweezers of Sound could already lift those particles from reflective surfaces without physical contact, but they could not do so in a stable fashion. The team has now fixed that issue using an adaptive algorithm to fine-tune how those acoustic tweezers are controlled, improving the stability of the lifted particles. They state that with the further miniaturization of the technology, the Tweezers of Sound could be deployed in a wide range of environments, including space.
Ask anyone who has been in the front row of a concert, and they will tell you sound can exert a physical force on the body. Position the speakers in a certain way and tap into the right frequency, amplitude and phase; it’s possible to use those waves to lift, push, and hold physical objects. This allows the tweezers to be completely contactless and contamination-free when manipulating those objects. Last year, the researchers could lift and move millimeter-sized particles using a hemispherical array of small ultrasound transducers; however those particles remained unstable when manipulated.
To overcome the issue, the team utilized the same setup, only with significant enhancements and two modes of functionality. Those modes dictate how the transducers can be driven, where opposing halves of their hemispherical array are driven in and out of phase. For example, an “in-phase” excitation mode is better at lifting and moving the particle close to the surface it sits on, providing accurate targeting of individual particles only a centimeter apart. The “out-of-phase” mode is suited to bringing the lifted particle into the center of an array. By adaptive switching between those modes, the engineers achieved a well-controlled, stable lift of those particles and increased stability inside the trap once it is lifted.
It will be interesting to see if this technology can be scaled to lift and move larger objects, such as heavy furniture or even people.