Study on non-contact linear motors driven by surface acoustic waves

Experimental measurements and theoretical analyses of non-contact linear motors driven by surface acoustic waves (SAWs) through liquid layers are presented, in which the slider is suspended at the Surface of the liquid layer contained in a glass cell located at the Surface of the stator. The experimental results show that the slider velocity is essentially proportional to the exciting voltage of the SAW (as the voltage in excess of a threshold) and decreases approximately exponentially with the thickness of the liquid layer increase (as the layer in excess of some thickness). To explain the experimental phenomena, according to the acoustic mode transition from Rayleigh wave to leaky SAW wave and the generation of acoustic streaming at the solid-liquid boundary, a simplified theoretical model is introduced to simulate the slider motion. These results demonstrate that the theoretical calculations essentially explain the experimental measurements. This kind of non-contact motors are hopeful to be used as manipulators in biomedical engineering and/or micromechanical systems, etc. (C) 2009 Elsevier B.V. All rights reserved.