Dynamic characteristics of vortex levitation

Vortex levitation can achieve non-contact handling by blowing air into a vortex cup through a tangential nozzle to generate a swirling air flow. In this paper, its dynamic characteristics are analyzed and discussions are laid upon the behavior of a work piece at the moment when it is picked up by the vortex cup. From the dynamic handling experiment, it is made clear that the work piece would oscillate with little damping when it is picked up, which may lead to an unstable levitation. In order to restrain the work piece from oscillating, an auxiliary annular flat skirt is designed empirically and set on the surrounding of the vortex cup to entrap an air layer. Relative movement would cause viscous damping force due to the squeeze damping effect of this air layer so that the oscillation can be damped to zero just in several periods. Furthermore, the damping effect is confirmed experimentally by observing pressure hysteresis in a pressure dynamic response experiment.