Air Jet Impingement For Levitation

Abstract

Traditional part acquisition methods such as vacuum cups and robotic grippers do not meet the handling needs of truly fragile materials, because both of these methods require surface contact. An alternative to these traditional approaches is the use of air jet impingement for levitation. This technique confines impinged air to a thin disk above the target to form radial diffuser. The Bernoulli Effect causes a pressure difference between the fast-moving impinged air above the surface and ambient air below it. The net pressure difference is sufficient to lift objects weighing more than one kilogram using standard shop air. This method of lifting is self-stabilizing and the impinged surface is contacted only by air.

The analytical, numerical, and experimental results are presented for an end effector prototype constructed to test the impingement lift effect. A first-order analytical approximation is given based on convergent-divergent supersonic flow incorporating shockwave energy losses. A numerical simulation of the end effector was obtained using the computational fluid dynamic software, ANSYS CFX. The results show transonic air flow and the formation of large stationary structures. Two experiments were conducted to provide quantitative measurements of the actual pressure profiles realized and to relate the net force of the impinging jet as a function of the distance from the surface. The data shows a linear relationship between the input pressure and the maximum net lifting force. These experiments prove that a nozzle flange fixture powered by compressed air can be implemented as a material handling solution.