Category: Science & Technology
Researchers of Aalto University have made a breakthrough in controlling the motion of multiple objects on a vibrating plate with a single acoustic source. By playing carefully constructed melodies, the scientists can simultaneously and independently move multiple objects on the plate towards desired targets. This has enabled scientists, for instance, writing words consisting of separate letters with loose metal pieces on the plate by playing a melody.
Already in 1878, the first studies of sand moving on a vibrating plate were done by Ernst Chladni, known as the father of acoustics. Chladni discovered that when a plate is vibrating at a frequency, objects move towards a few positions, called the nodal lines, specific to that frequency. Since then, the prevailing view has been that the particle motion is random on the plate before they reached the nodal line. "We have shown that the motion is also predictable away from the nodal lines. Now that the object does not have to be at a nodal line, we have much more freedom in controlling its motion and have achieved independent control of up to six objects simultaneously using just one single actuator. We are very excited about the results, because this probably is a new world record of how many independent motions can be controlled by a single acoustic actuator," says Professor Quan Zhou.