Research on the transient behavior of near field ultrasonic levitation during lifting up

Research on the transient behavior of ultrasonic squeeze film is very important for the understanding of the movement and the controlling precision of levitating object. The present paper study the transient behavior of ultrasonic squeeze film by the use of aerodynamic theory, built up the models of free levitating disk on the squeeze gas film and the dynamic equation, and then the models solved by value methods. The pressure distribution, load capacity of squeeze film and the displacement of suspending disk are obtained. The results show that exciting amplitude and frequency have a significant effect on the transient behavior during the levitating period, the smaller amplitude, the longer the time to reach its stable position, the excitation frequency have the same effects too when the exciting frequency becomes higher. An experimental study has been carried out on the basis of theoreticM analysis, the displacement of the suspending disk is measured by a laser displacement sensor, and it shows a good agreement with the theoretical results.