The near-field acoustic levitation of high-mass rotors

Abstract

Here we demonstrate that spherical rotors with 40 mm diameter and 0-1 kg mass can be suspended more than tens of micrometers away from an ultrasonically vibrating concave surface by near-field acoustic radiation force. Their rotating speeds exceed 3000 rpm. An acoustic model has been developed to evaluate the near-field acoustic radiation force and the resonant frequencies of levitation system. This technique has potential application in developing acoustic gyroscope.

A Non-Contact Manipulation for Robotic Applications: A Review on Acoustic Levitation

“…Unlike the standing wave method where the levitated particles hanging in the pressure nodes are very small compared to the acoustic wavelength, Near-Field acoustic levitation method has the ability to lift objects reaches to few milligrams and heavy planar objects [146], [147], [148], [149]. With a tiny air layer separating them, a sizable planar item levitates in the near-field levitation, also known as the squeeze film levitation.…”

Non-contact droplet manipulation and its dynamics based on acoustic levitation

“…Acoustic Levitation)利用声波畸变的强非线性效应实 现悬浮 [84][85][86] , 一般用于物体的传输 [87][88][89] 和轴承的减 阻 [90,91] . 本文主要关注驻波声悬浮.…”

Near-field acoustic levitation and applications to bearings: a critical review

“…A transducer which can be used to suspend high-mass rotors was designed in [114] (see figure 12). The horn on the top of the transducer has a concave surface which can be used to suspend spherical rotors with a diameter of about 40 mm.…”

“…The shape of the inner surface of the bearing could be changed from initial cylindrical to three-lobed due to the use of elastic hinges. Six piezoelectric actuators were installed in three slots evenly [114]. Reprinted from [114], with the permission of AIP Publishing.…”

“…Six piezoelectric actuators were installed in three slots evenly [114]. Reprinted from [114], with the permission of AIP Publishing. Chen et al [116].…”