Acoustic field-based manipulation

We have discovered a new motion mechanism on the Chladni plate in addition to the two known motion modes on a vibrating plate: the first mode discovered by E. Chladni about two centuries ago, demonstrating that heavy particles move towards the nodes of vibration; and the second discovered by E. Chladni and explained by M. Faraday, showing that light particles move towards the antinodes. We discovered a new (the third) motion mode where heavy particles move towards antinodes of vibration on a submerged vibrating plate and form so-called inverse Chladni patterns. 

We have clarified the myth of motion randomness of particles on a vibrating plate before they settle on nodal lines, present since the original experiments of Ernst Chladni in the 1780s. Based on the understanding, we invented a multi-particle single actuator acoustic manipulation method. 

Contrary to many potential-trapping based acoustic manipulation methods, our technology is based on the out-of-nodal-line motion. Our method allows independent trajectory following, swarm manipulation and sorting of multiple miniature objects in a wide range of materials, including electronic components, water droplets loaded on solid carriers, plant seeds, candy balls, and metal parts. Both model-based and model-free methods have been used to control the motion. Additionally, we have developed a programmable shaping method using a nature-inspired algorithm that can iteratively assemble up to a hundred particles into complex user-specified shapes on a vibrating plate.