Contactless Positioning of Objects on Acoustically Reflective Surfaces by Means of Ultrasonic Forces

Ultrasonic forces have been used to keep small objects in a suspended state for a long time. In recent years, methods have been developed to manipulate the levitating objects and to lift objects located on acoustically transparent or reflective surfaces. This work demonstrates an ultrasonic levitation system, which is capable of transporting objects from and to acoustically reflective surfaces, while controlling the orientation of the levi-tating object. This requires two different types of piezoelectric transducers operating at two distinct frequencies (25 kHz and 40 kHz), a moveable reflector plate and a novel control method. With these properties, the levitation system presented in this work can be used as a precise contact-less robotic gripper for micro-manufacturing processes of small and fragile objects.