Effect of Surface Grooves on the Characteristics of Noncontact Transportation Using Near-Field Acoustic Levitation

Near-field acoustic levitation is a novel noncontact handling method. However, low load-carrying capacity and low transportation speed limit its application. This study proposes a novel method in which bar-type grooves are machined on the plate surface to increase load-carrying capacity and transportation speed. An experimental rig with a flexural rail vibrated by piezoelectric transducers is developed to transport the rigid plate and measure the levitation height and transportation speed. The flexural vibration mode of the rail and the dynamic position of the rigid plate are coupled with groove characteristics to determine the gas film thickness between the rail and plate. The Reynolds equation is linearized by using Green's formula and then solved by using an eight-node discrete grid finite difference method. The effects of groove direction, depth, number, width, and length on the load-carrying capacity and transportation speed are also discussed. Numerical results are consistent with the experiment results. The load-carrying capacity and transportation capability can be significantly improved with groove length direction vertical to the rail wave transportation direction. Predicted results show that optimum groove depth, number, width, and length can be used to increase load-carrying capacity and transportation capability.