A mechanical model for energy transfer in linear ultrasonic micromotors using Lamb and Rayleigh waves

Presents the theory, simulation results, and experimental study of the slider displacement at nanometer scale in linear ultrasonic micromotors using Lamb and Rayleigh waves, which can be used as microconveyers. To the authors´ knowledge, this is the first attempt at describing analytically the energy transfer from the acoustic wave to the slider. The model shows that the mechanism is sequential with alternative phases of levitation and contact with step-like behavior of the slider velocity. To validate the model, microconveyers using Lamb and Rayleigh waves are fabricated. These waves are generated from interdigital transducers with 10- and 20-MHz frequencies, respectively, which are the highest ones in ultrasonic micromotors. The control of motion is obtained by varying the duration of the driving signal applied across interdigital transducers. The measured displacement varies from several nanometers to several centimeters. A comparison between experimental and theoretical results shows a good agreement. This model gives a qualitative description of motion. In another way, it allows the deduction of key parameters for energy transfer, in order to improve the design of these micromotors so as to meet the requirements in nanotechnology