Modeling and experimental validation of a linear ultrasonic motor considering rough surface contact

Abstract

Traditional lubricants are undesirable in harsh aerospace environments and certain automotive applications. Ultrasonic vibrations can be used to reduce and modulate the effective friction coefficient between two sliding surfaces. This paper investigates the relationship between friction force reduction and wear reduction in ultrasonically lubricated surfaces. A pin-on-disc tribometer is modified through the addition of a piezoelectric transducer which vibrates the pin at 22 kHz in the direction perpendicular to the rotating disc surface. Friction and wear metrics including volume loss, surface roughness, friction forces and apparent stick-slip effects are measured without and with ultrasonic vibrations at three different sliding velocities. SEM imaging and 3D profilometry are used to characterize the wear surfaces and guide model development. Over the range of speeds considered, ultrasonic vibrations reduce the effective friction force up to 62% along with a wear reduction of up to 49%. A simple cube model previously developed to quantify friction force reduction is implemented which describes wear reduction within 15% of the experimental data.

Piezoelectric bimorph-driven ultrasound scanner for high frequency ultrasound imaging

“…Transient dynamic analysis, also known as time-history analysis, is a method used to determine the dynamic response of a structure subjected to arbitrary, time-varying loads [20,21]. The ultrasound scanner designed in this work is excited by sinusoidal signals of different amplitudes, and the dynamic response of the structure can well reflect the scanning range under the corresponding load.…”

Modeling and validation of preload force effect on characteristics of a V-shaped linear ultrasonic motor

“…The contact surface of the stator/slider can be considered as a smooth rigid surface that is in contact with an equivalent rough surface (Lv et al, 2017). The average normal force (Chang et al, 1987) can be expressed as…”

“…where F el and F pl are the normal forces of the elastic deformation and the plastic deformation, respectively (Lv et al, 2017; Zhou et al, 2019), which can be written as follows…”

Dynamic preload control of traveling wave rotary ultrasonic motors for energy efficient operation

“…The effect of preload is strongly stressed in the modeling of USM since preload, unlike other parameters, can be finely adjusted postmanufacturing to yield the desired performance. [21][22][23][24] Although the effect of preload control has been well reported, it was limited to optimizing preload to have a static value that best fulfills the application requirements. In comparison to having a static preload value, dynamic preload control can enhance the controllability of USM and improve its performance.…”