A non-contact chuck using ultrasonic vibration: Analysis of the primary cause of the holding force acting on a floating object

Abstract

It is experimentally known that when a flat surface vibrates vertically at ultrasonic frequencies, both vertical and horizontal forces act on an object placed on the vibrating surface, enabling the vibrating surface to support an object vertically and horizontally without any contact. However, the cause of the horizontal force (called ‘the holding force’ in this article) has not been clarified yet. This article investigates experimentally and numerically the cause of the holding force generated by a vibrating surface. In numerical calculations, computational fluid dynamics was used to obtain the pressure distribution of air surrounding the floating object and the vibrating surface. It was consequently found that the holding force acting on the floating object is due to a negative average pressure generated at the edge of the object floating on the vibrating flat surface.