Contact-less Object Handling: Manipulation and Sensing Methods for Acoustic Levitation Systems

Abstract

This dissertation will discuss the design, control, and sensing capabilities of acoustic levitation systems for laboratory automation providing a flexible and programmable method for contact-less sample manipulation. Conventional tools like pipettes and well plates rely on surface contact to handle small volumes of liquids and reagents. This introduces risks of contamination, sample loss, and measurement uncertainty. Assays and laboratory experiments can require hundreds or even thousands of steps which can be labor intense if done by hand. Automated liquid handling systems can help streamline labor intense workflows, alleviate shortages in labor, and free up scientist to focus on task that benefit from individual training and expertise. These traditional tools also generate significant plastic waste and often require separate, siloed systems for manipulation and sensing, increasing operational complexity and benchtop footprint. Acoustic levitation offers an alternative by using high-intensity ultrasonic waves to trap, lift, move, mix, and measure solids, liquids, and even living organisms in mid-air without any physical contact. This eliminates contamination risk and enables continuous, real-time monitoring of samples from the moment of mixing through analysis. Advances in computing power, acoustic field modeling, and holographic beamforming have dramatically expanded the capabilities of acoustic levitation systems. This work draws from fields such as ultrasonic holography, robotics, and sensor fusion to create programmable systems capable of vessel-free containment, automated liquid handling, and embedded sensing. The system architecture discussed in this dissertation integrates control algorithms, custom hardware, and on-board sensing to enable a contact-less liquid handling instrument: one that merges manipulation and measurement in a unified platform. This dissertation will discuss contributions in acoustic levitator sensing, control and manipulation, including the ability to pick up objects from acoustically reflective surfaces, weigh droplets and particles in air using trap dynamics, translate levitated objects via frequency modulation, dispense droplets of liquid into the levitator with an acoustic launching system and control the shape of levitated liquid droplets. When applied to disciplines like chemistry, pharmaceuticals, and molecular biology, this approach could provide a contact-less robotic liquid handling solution that is programmable while minimizing contamination, eliminating consumables, reducing human error, and enabling new opportunities for automation. Acoustic levitation systems thus represent not just a new tool, but a possible shift in how laboratories can conduct precise, clean, and scalable research.