A standing wave-type noncontact linear ultrasonic motor

Abstract

In this study, a novel standing wave-type noncontact linear ultrasonic motor is proposed and analyzed. This linear ultrasonic motor uses a properly controlled ultrasonic standing wave to levitate and drive a slider. A prototype of the motor was constructed by using a wedgeshaped aluminum stator, which was placed horizontally and driven by a multilayer PZT vibrator. The levitation and motion of the slider were observed. Assuming that the driving force was generated by the turbulent acoustic streaming in the boundary air layer next to the bottom surface of the slider, a theoretical model was developed. The calculated characteristics of this motor were found to agree quite well with the experimental results. Based on the experimental and theoretical results, guidelines for increasing the displacement and speed of the slider were obtained. It was found that increasing the stator vibration displacement, or decreasing the gradient of the stator vibration velocity and the weight per unit area of the slider, led to an increase of the slider displacement. It was also found that increasing the amplitude and gradient of the stator vibration velocity, or decreasing the weight per unit area of the slider and the driving frequency, gave rise to an increase of the slider speed. There exists an optimum roughness of the bottom surface of the slider at which the slider speed has a maximum.

Modelling influence of Poisson's contraction on squeeze film levitation of planar objects

“…Moreover, magnetic levitation cannot always be utilised for delicate objects due to strong magnetic flux. Consequently, there is considerable interest in developing new techniques for free suspension of delicate objects 1,2,3 .…”

Noncontact Ultrasonic Motor with Two Flexural Standing Wave Vibration Disks

“…Hu et al have reported a noncontact linear ultrasonic motor utilizing a standing wave vibration, in which a wedgeshaped rectangular plate bolted to a multilayer lead zirconate titanate (PZT) vibrator is used as a stator. 17) The levitated solid object on the vibrating plate is linearly transported along the length direction only in one direction by the acoustic streaming induced between the plate and the movable object. In this paper, we propose a noncontact ultrasonic motor with two flexural standing wave vibration disks.…”

Experimental and analytical study of ultrasonic micro powder feeding

“…In the USM, the rotor is driven by friction forces between the rotor and stator. The friction force is generated by the ultrasonic wave travelling or standing in the stator of USM [8][9][10][11][12]. For liquids, there are two common mechanisms of transportation, one is ejection, and the other is ultrasonic streaming.…”