Micro linear motor using surface acoustic wave device

We have proposed to utilize surface acoustic wave (SAW) devices for micro actuators and demonstrated their possibility. A multi contact type slider using a silicon element whose contact surface is surface micro machined have been proposed. Diameter and density of projections fabricated on silicon sliders were examined experimentally. Then, the elastic deformation due to pre-load was estimated with the FEM analysis. The importance of elastic deformation control to obtain large output force with a surface acoustic wave motor has been discussed. By adding pre-load to the slider, stator and slider surfaces are deformed a few tens of nanometers. Appropriate deformation in normal direction against normal vibration displacement amplitude of surface acoustic wave existed. By moderate deformation, the output force of the surface acoustic wave motor was enlarged up to about 10 N and no-load speed was 0.7 m/sec. By energy circulation drive, the efficiency was improved. Nanometer order stepping motion of this motor is also investigated. Stable 2 nm motion is already accomplished. Sub nano step motion will be available.