Modelling and finite element simulation of a dual friction-drive SAW motor using flat slider

The paper presents modelling and finite element simulation of a surface acoustic wave (SAW) motor based on dual friction-drive (DFD). The DFD SAW motor comprises of a flat cuboid slider tightly held between two identical piezoelectric stators typically made of lithium niobate facing each other, each stator having an interdigital transducer (IDT) fabricated on its either side. A sinusoidal excitation applied to the pair of IDTs on one side generates Rayleigh SAWs which propagate on the surfaces of the two stators and interact with the slider. With adequate preload, SAWs generate frictional forces on the two contact surfaces of the slider and impart translational motion to the slider. The direction of motion of the slider can be reversed by switching excitation to the pair of IDTs on the opposite side. The paper describes the mechanism of operation of the DFD SAW motor and studies displacement of the slider, contact pressure and forces acting on the slider through finite element simulation.